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> Diagnosing D-Jet Problem...solution & update, All of a sudden...loss of power...
Bleyseng
post Jul 10 2018, 12:38 PM
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The MPS was adjusted back to Factory specs..... Hmm, is your engine brand new with all new parts, no. I have fixed and adjusted maybe 30 Mps's over the years and the "Specs" are a starting point. Get a A/F mix meter and adjust the MPS to your engine.
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JeffBowlsby
post Jul 10 2018, 01:36 PM
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(IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif)

Exactly. Every engine today is unique in its configuration and wear characteristics. the exact fuel requirements for any two 2.0Ls are not alike. On top of that I personally own a few NOS MPS and have characterized many others that...guess what...are calibrated differently.

The best and really only way to get an optimal calibration is by using an exhaust gas analyzer, WB02 meter or Dyno on YOUR ENGINE. Inductance calibrations on the MPS with the Wavetek can only get you close. Using the caliper depth gauge method is also only an estimation because the calibration adjustment parameters are extremely fine for accuracy.
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Dr-DJet
post Jul 10 2018, 03:53 PM
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Hi,

Mike did not mention to you and to me that he does not have the original engine installed. He had his 1.7 engine bore increased to 2.0l and changed cam to unknwon spec. (IMG:style_emoticons/default/WTF.gif)

It is of course not possible that any open loop control ECU and MPS will notice that. Even a closed loop injection system would have trouble with that. His previous MPS lost vacuum and thus saw far too low vacuum enriching A/F mixture artificially. When it is back to factory spec what happens? Of course mixture is far too lean for an engine that has 25% more air volume and a total different volumetric efficiency and fuel need. Both are hard coded into each ECU and each MPS.

I do not understand how Mike could forget to mention this fact (IMG:style_emoticons/default/confused24.gif) . If he is lucky he now has an engine similar to an original 2.0l engine. Then he could use components from that engine. But without knowing engine mechanics and his specific cam changes in detail, that is impossible to say.

My weeks of support for this trouble case is over. I learned of the total engine changes today. I am surprised what speculations have built up here in 914world why a factory spec MPS should not fit a normal engine. Bosch has supplied 10s of thousands of MPS as spares (and 100s of thousands originally). How would Bosch workshops have survived if they would have had to retune each spare MPS in field? (IMG:style_emoticons/default/headbang.gif) Do not create such fairy tales. Bosch Classic delivers repairs of MPS to their spec until today for many car models with Mercedes-Benz still being the largest user of D-Jetronic MPS. So please do not base wrong speculations on such a case where someone tries to fit original components on a total different and unknown engine.

Sorry guys, I normally do not write here, but this was just too much fairy tale on false ground. See you on oldtimer.tips if you like.

Best regards, Dr-DJet
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MikeInMunich
post Jul 10 2018, 04:16 PM
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QUOTE(Dr-DJet @ Jul 10 2018, 01:53 PM) *

Hi,

Mike did not mention to you and to me that he does not have the original engine installed. He had his 1.7 engine bore increased to 2.0l and changed cam to unknwon spec. (IMG:style_emoticons/default/WTF.gif)

It is of course not possible that any open loop control ECU and MPS will notice that. Even a closed loop injection system would have trouble with that. His previous MPS lost vacuum and thus saw far too low vacuum enriching A/F mixture artificially. When it is back to factory spec what happens? Of course mixture is far too lean for an engine that has 25% more air volume and a total different volumetric efficiency and fuel need. Both are hard coded into each ECU and each MPS.

I do not understand how Mike could forget to mention this fact (IMG:style_emoticons/default/confused24.gif) . If he is lucky he now has an engine similar to an original 2.0l engine. Then he could use components from that engine. But without knowing engine mechanics and his specific cam changes in detail, that is impossible to say.

My weeks of support for this trouble case is over. I learned of the total engine changes today. I am surprised what speculations have built up here in 914world why a factory spec MPS should not fit a normal engine. Bosch has supplied 10s of thousands of MPS as spares (and 100s of thousands originally). How would Bosch workshops have survived if they would have had to retune each spare MPS in field? (IMG:style_emoticons/default/headbang.gif) Do not create such fairy tales. Bosch Classic delivers repairs of MPS to their spec until today for many car models with Mercedes-Benz still being the largest user of D-Jetronic MPS. So please do not base wrong speculations on such a case where someone tries to fit original components on a total different and unknown engine.

Sorry guys, I normally do not write here, but this was just too much fairy tale on false ground. See you on oldtimer.tips if you like.

Best regards, Dr-DJet


(IMG:style_emoticons/default/blink.gif)

Hi Volker and fellow teener fans!

As one can see in previous posts of mine here I have only spoken incredibly highly of Volker / Dr. D-Jet.

When an expert makes a false assumption, as Volker here did, by assuming that my engine was stock instead of asking me, and then blames it on the (often naive) non-expert car owner for not sharing all pertinent information when one may not even know what pertinent is, then I think that’s a bit uncool because miscommunications happen in human interaction. We all know this, and usually, to be fair, both parties are responsible when sub optimal or sub sufficient communication takes place, not just one. So, in response I want to make clear here that I don’t appreciate being blamed in an aggressive manner as if I were either some kind of idiot who deserves no respect or as if I had (stupidly) withheld information because I wanted to piss Dr. D-Jet off on purpose. In other words, please, chill out.

Beyond this, I’m pretty darn sure I MUST have told Volker (Dr. D-Jet) last year at some point that the engine was indeed increased to 2.0 liters either personally or via his site Oldtimer.tips.de This new problem popped up AFTER the engine had been running FINE. The discussion about what changed didn’t include any questions or REPEAT of the information which should have in all cases been shared a year previously in Erlangen or via correspondence. So yes, as much as Volker ASSUMED that my engine was stock, it could also be said that I assumed that he knew it wasn’t because again, I’m pretty sure that that must have been clear and in any case, he as the EXPERT looking to help diagnose a problem should, as a professional, KNOW / ASK the (often naive) lay customer about such essential basic background information. I find the irate tone and the WTF actually embarrassing for Volker and encourage a retraction.

On top of this, I described the recent symptom via email without reminding Volker that the car was a 2.0 or, possibly, without having EVER mentioned at all, which wouldn’t have been the case if he had ever asked, which he obviously should have at some point if not straight away when we first met in person at his clinic in Erlangen in 2017. After describing the new symptom the talk was about a prime suspect, the quality of the seal in my MPS. I sent it to him and he determined that the diaphragm was DONE and replaced it, for which I paid him. He also tested my CPU and determined what its model number must be based on values. This was necessary because my CPU has no number on it anywhere. He also sold me his CPU so I would have one while he looked into what was up with mine. At the time it wasn’t clear if mine was compatible with the MPs because it has no number on it. So he spent his personal time helping me determine that my MPS and CPU are compatible and was paid for the rebuild of the MPS, as mentioned. The next step was for me to install the rebuilt MPS, with his CPU, because he still had/ has mine, which we KNEW was compatible with BOTH MPS mentioned here, and for me to determine if things were now OK, which I did, but the engine was running worse than before. Volker also gave me an extra MPS to test when I bought the CPU from him in Erlangen a few weeks ago. The engine seemed to function better with this „extra“ MPS, but only until the engine started to warm up, which is apparently due to the cold start valve enriching the mixture very temporarily. After only a half a mile the symptom returned, and I reported this to Volker this evening. That’s where we were. Confused and trying to move forward. Then Volker heard from someone that my engine wasn’t a stock 1,7 and decided to get all bent out of shape with me, as you can see. So, for the record, this is all that occurred and there is little more to it.

Volker, I like you and I’ve been very grateful for your knowledge and support. I’m really disappointed how you’ve practically acttacked me here personally and I’m sorry I have this far failed you as a student. (IMG:style_emoticons/default/sad.gif)

Mike
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Bartlett 914
post Jul 10 2018, 05:06 PM
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QUOTE(Dr-DJet @ Jul 10 2018, 04:53 PM) *

Hi,

Mike did not mention to you and to me that he does not have the original engine installed. He had his 1.7 engine bore increased to 2.0l and changed cam to unknwon spec. (IMG:style_emoticons/default/WTF.gif)

It is of course not possible that any open loop control ECU and MPS will notice that. Even a closed loop injection system would have trouble with that. His previous MPS lost vacuum and thus saw far too low vacuum enriching A/F mixture artificially. When it is back to factory spec what happens? Of course mixture is far too lean for an engine that has 25% more air volume and a total different volumetric efficiency and fuel need. Both are hard coded into each ECU and each MPS.

I do not understand how Mike could forget to mention this fact (IMG:style_emoticons/default/confused24.gif) . If he is lucky he now has an engine similar to an original 2.0l engine. Then he could use components from that engine. But without knowing engine mechanics and his specific cam changes in detail, that is impossible to say.

My weeks of support for this trouble case is over. I learned of the total engine changes today. I am surprised what speculations have built up here in 914world why a factory spec MPS should not fit a normal engine. Bosch has supplied 10s of thousands of MPS as spares (and 100s of thousands originally). How would Bosch workshops have survived if they would have had to retune each spare MPS in field? (IMG:style_emoticons/default/headbang.gif) Do not create such fairy tales. Bosch Classic delivers repairs of MPS to their spec until today for many car models with Mercedes-Benz still being the largest user of D-Jetronic MPS. So please do not base wrong speculations on such a case where someone tries to fit original components on a total different and unknown engine.

Sorry guys, I normally do not write here, but this was just too much fairy tale on false ground. See you on oldtimer.tips if you like.

Best regards, Dr-DJet

Dr=Djet
It seems you took this personally. I was not an attack on you or your ability. When I stated that the MPS made it worse, that was a statement from a troubleshooting stand point. It in fact turned out to be the case.
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Dr-DJet
post Jul 11 2018, 02:26 AM
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QUOTE(Bartlett 914 @ Jul 11 2018, 01:06 AM) *


Dr=Djet
It seems you took this personally. I was not an attack on you or your ability. When I stated that the MPS made it worse, that was a statement from a troubleshooting stand point. It in fact turned out to be the case.

Hi,

yes I take it personally if I read so much bullshit in a case where someone completely changes his engine from 1.7 to 2.0l and everyone expects this to run well and doubts my trouble-shooting, Bosch factory specs etc.

And also the statement that the 2nd MPS makes the car run better is not correct. Mike got a second MAP sensor from me which was very richly adjusted (not by me and on the upper tolerance side). Just to help if there would be something odd with his own one. But also that one makes him drive just 800m as Mike wrote me yesterday evening. What does that tell us. Car runs with cold start valve and cold fuel enrichment then problems start. What a surprise!

My last statement in this case: A modified engine from 1.7 to 2.0 l will NEVER run well with 1.7 components. No matter how you tune or detune a MPS.
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MikeInMunich
post Jul 11 2018, 03:17 AM
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QUOTE(Dr-DJet @ Jul 11 2018, 12:26 AM) *

QUOTE(Bartlett 914 @ Jul 11 2018, 01:06 AM) *


Dr=Djet
It seems you took this personally. I was not an attack on you or your ability. When I stated that the MPS made it worse, that was a statement from a troubleshooting stand point. It in fact turned out to be the case.

Hi,

yes I take it personally if I read so much bullshit in a case where someone completely changes his engine from 1.7 to 2.0l and everyone expects this to run well and doubts my trouble-shooting, Bosch factory specs etc.

And also the statement that the 2nd MPS makes the car run better is not correct. Mike got a second MAP sensor from me which was very richly adjusted (not by me and on the upper tolerance side). Just to help if there would be something odd with his own one. But also that one makes him drive just 800m as Mike wrote me yesterday evening. What does that tell us. Car runs with cold start valve and cold fuel enrichment then problems start. What a surprise!

My last statement in this case: A modified engine from 1.7 to 2.0 l will NEVER run well with 1.7 components. No matter how you tune or detune a MPS.


Volker, what you clearly fail to realize is that we are mere mortals and not expwrts like you, at least not myself. Comments like, „what a surprise!“ show that you apparently expect us (all) to be at practically your level of advanced knowledge of this system when you understand it better than almost anyone on the goddam planet and have spent literally hundreds if not indeed thousands of hours(!) getting to your level of understanding of how it works. Sorry, but I’m still only on hour number 5 or so. (IMG:style_emoticons/default/sad.gif) Unless you WANT to sound the way you do (note description excluded) then I would (personally) keep cool and choose my tone and words more carefully. Nobody here, including myself naturally, is out to seem / be stupid and waste your time. You can correct us, help us, teach, etc. but expecting us to know everything that you practically consider common sense is a bit off, to say the least. This system is your hobby and passion. You spend a LOT of time annually putting on 3 workshops to meet, teach and help normal guys like me, both very technically inclined and talented as well as some slower learners who may prefer to pay a mechanic to test and help to diagnose a ghost in the machine, like myself. Some people / readers may have virtually ZERO understanding of the system or inclination to try to diagnose / fix a problem themselves, and they would surely think your comments here are WAY over their heads. I can’t even get a master mechanic in a Bosch Werkstatt to want to test this system without a tester designed specifically for it! And again, why be mad at me for „withholding“ (IMG:style_emoticons/default/blink.gif) information about the engine‘s displacement and take zero responsibility as the expert for not having asked? Come on! All we talked about was why, all of a sudden, was the car not running as well as it had been and went for the MPS and swapped it in and quickly came to where we are now. So be honest, how much time did you really lose / invest in helping me before someone ( Nordfisch?) said, hey Volker, are you aware that Mike has a 2.0 liter engine? I reckon compared to how much time you otherwise invest into this passion of yours, very, very little. I recommend considering a „so what now what“ attitude instead of getting pissed off at me. Again, I have greatly appreciated your support and let you know it constantly. Getting mad at a customer or student isn’t Master-like and I find it a shame. Since this is what you love doing and this thread can be extremely valuable to some people in the future, I propose a more measured and professional apparoach to sharing your knowledge with us. We would all appreciate it, especially myself.

Does it go against the grain for you to manipulate/ re-calibrate the MPS (MAP) because you believe that everything should remain stock, or would you like to perhaps describe for us here how to calibrate it? Otherwise, perhaps another member will do so.

I hope you calm down and forgive me for not making clear as this new problem popped up that I’m running a 2,0. I honestly don’t think that’s a good reason to get pissed off at me. Perhaps you’ll chose to take some responsibility for that wasted time upon yourself for having not asked. Again, after all, you’re the consultant / expert and you’re the one who made the false assumption, nicht wahr? (IMG:style_emoticons/default/idea.gif)

So, can we perhaps move forward, everyone, on how to get my system checked and calibrated nicely again? I would really, really appreciate it! As far as the claim that it will NEVER run well I can say that it WAS running very well for about 6,000 miles. What Bleyseng and Mr. Bowlsby have stated above lead me to believe that it’s far from impossible and that Dr. D-Jet may well be interested in expanding his experience and knowledge through this case and its potential / eventual solution rather than simply softly scream NEVER and sign off. (IMG:style_emoticons/default/idea.gif)

Thanks!

M.i.M. (IMG:style_emoticons/default/beerchug.gif)
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MikeInMunich
post Jul 11 2018, 04:13 AM
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Good links on this subject... and a number of questions answered, such as how the MPS can be calibrated. Thanks...

https://web.archive.org/web/20050307014722f...et:80/djet.html

http://www.914world.com/bbs2/lofiversion/i...hp?t318446.html

https://members.rennlist.com/pbanders/DJetParts.htm

https://oldtimer.tips/en/d-jetronic
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MikeInMunich
post Jul 11 2018, 05:22 AM
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QUOTE(Dr-DJet @ Jul 11 2018, 12:26 AM) *

QUOTE(Bartlett 914 @ Jul 11 2018, 01:06 AM) *


Dr=Djet
It seems you took this personally. I was not an attack on you or your ability. When I stated that the MPS made it worse, that was a statement from a troubleshooting stand point. It in fact turned out to be the case.

Hi,

yes I take it personally if I read so much bullshit in a case where someone completely changes his engine from 1.7 to 2.0l and everyone expects this to run well and doubts my trouble-shooting, Bosch factory specs etc.


Why would you think that everyone doubts your trouble shooting, Bosch specs or that everyone expects a 2.0 to run well with an MPS calibrated to spec for 1.7 liter engine?? (IMG:style_emoticons/default/confused24.gif) You’re jumping to illogical conclusions and getting defensive-aggressive unnecessarily. There’s certainly no reason at all to take anything written here personally.
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914_teener
post Jul 11 2018, 08:54 AM
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So.......


Guys, I.ll be in Bavaria in December cruising the Main.

Where are the best brewhouses in Frankfurt?

I.m serious.

Rob
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MikeInMunich
post Jul 11 2018, 09:31 AM
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QUOTE(Jeff Bowlsby @ Jul 10 2018, 11:36 AM) *

(IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif)

Exactly. Every engine today is unique in its configuration and wear characteristics. the exact fuel requirements for any two 2.0Ls are not alike. On top of that I personally own a few NOS MPS and have characterized many others that...guess what...are calibrated differently.

The best and really only way to get an optimal calibration is by using an exhaust gas analyzer, WB02 meter or Dyno on YOUR ENGINE. Inductance calibrations on the MPS with the Wavetek can only get you close. Using the caliper depth gauge method is also only an estimation because the calibration adjustment parameters are extremely fine for accuracy.


Hi Jeff, thanks for chiming in here. I just spoke with George Hussey about sending me a new CHTS and he was nice enough to take some time with me on the phone to discuss the problem. First off, he emphasized the challenges that often occur when changing the CHTS, such as getting the old one out without breaking it, and discouraged me from changing it unless I was sure that the one I have is faulty, which I am not. In fact, I’m pretty sure it’s OK. I will test it again with a multimeter.

But what I’m writing about is how George believes that the problem likely lies elsewhere altogether, like with timing, valve adjustment, dwell, fuel pressure, etc. and not with the MPS. He also said that the MPS adjustment screw is for FINE tuning mixture and that my problem seems way too severe for such fine tuning to be the potential solution, whereby you and Bleyseng seem to emphasize the adjustment of the MPS screw as the primary(?) way to change mixture. I’m not clear on this.

Also, can you offer me some info on what you mentioned about the cold start valve and flow testing? (IMG:style_emoticons/default/confused24.gif) This valve only enriches the mixture while the engine is cold, no?

After we’ve ruled out all of the usual suspects, as mentioned above, if the problem persists and I’m hooked up to a CO / AFR sensor and can see if the car is running too lean or too rich, how should / can the mixture be adjusted? Primarily with the MPS screw? How else?

George also said that a camshaft can make a big difference, but the simple fact that the engine is 2.0 liter instead of 1.7 shouldn’t / doesn’t / in his experience has never been a problem. This is a far cry from Dr. D-Jet´s opinion on exactly that point and I’d say George has far more experience with the D Jet on 914s than Dr. D-Jet does. (IMG:style_emoticons/default/idea.gif)

Thanks again for your input. Hope to read a reply from you again.

Mike
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MikeInMunich
post Jul 11 2018, 09:36 AM
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QUOTE(914_teener @ Jul 11 2018, 06:54 AM) *

So.......


Guys, I.ll be in Bavaria in December cruising the Main.

Where are the best brewhouses in Frankfurt?

I.m serious.

Rob


Neither the Main nor Franfurt are in Bavaria.

If you’re going to be in Munich, send me a PM if you want to get together. (IMG:style_emoticons/default/beerchug.gif)

As for your question here, refer to Trip Advisor! That’s your best resource, not I, nor likely not anybody else here. Wrong place for it anyway.

Best regards,

Mike in Munich
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rhodyguy
post Jul 11 2018, 09:41 AM
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Perhaps a discussion of the engine spec is in order prior to a MPS refurbish.
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914_teener
post Jul 11 2018, 10:30 AM
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QUOTE(MikeInMunich @ Jul 11 2018, 08:36 AM) *

QUOTE(914_teener @ Jul 11 2018, 06:54 AM) *

So.......


Guys, I.ll be in Bavaria in December cruising the Main.

Where are the best brewhouses in Frankfurt?

I.m serious.

Rob


Neither the Main nor Franfurt are in Bavaria.

If you’re going to be in Munich, send me a PM if you want to get together. (IMG:style_emoticons/default/beerchug.gif)

As for your question here, refer to Trip Advisor! That’s your best resource, not I, nor likely not anybody else here. Wrong place for it anyway.

Best regards,

Mike in Munich



Thanks Mike.

Sorry to step on your thread.

Starting Pilsen....then Nurenberg...then Frankfurt. If I get to Munich I will surely look you up. Thanks for the offer.

BTW...I had Jeff B. Set up a MPS using Chris Foley.s replacement diaphram for my 2.0. Working great. I had to fiddle a bit with a wide band but it is running flawlessly. As far as the cht...I am using an reprop. that Mcmark.made now 914 rubber makes that uses a modern thermister and a seperate ground.

Hope that helps.
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MikeInMunich
post Jul 11 2018, 11:18 AM
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Wow! (IMG:style_emoticons/default/blink.gif)

Calibrating the MPS seems pretty complicated. Brad Anders also states, in the link I’m posting here, that it should be considered a last resort. Dr. D-Jet seems to consider it a no-go altogether.

https://members.rennlist.com/pbanders/manif...htm#Adjustments
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MikeInMunich
post Jul 11 2018, 11:20 AM
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Thanks Rob. No worries. Don’t skip Munich!

M.
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BeatNavy
post Jul 11 2018, 11:57 AM
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QUOTE(MikeInMunich @ Jul 11 2018, 01:18 PM) *

Wow! (IMG:style_emoticons/default/blink.gif)

Calibrating the MPS seems pretty complicated. Brad Anders also states, in the link I’m posting here, that it should be considered a last resort. Dr. D-Jet seems to consider it a no-go altogether.

https://members.rennlist.com/pbanders/manif...htm#Adjustments

It's not that complicated - if you have an inductance meter and appropriate tools for adjusting. But it does take some trial and error, and, as a minimum, an O2 sensor. I think adjustment is necessary if the MPS has been repaired, as it's very difficult to get it close to correct through other means (e.g., measuring depth of inner / outer stops, etc.).

This topic has been discussed in many different ways over many different threads. I agree with Jeff B - no two engines are exactly alike -- but I also agree with Dr D-Jet that stock calibration should get you close enough for a corresponding / matching engine if it is stock. They were sealed from the factory for a reason. So in that regard, I also agree with George - an MPS that's "in the ballpark" for a given engine is not going to make that car undriveable. It may not be optimized, but it may also feel just fine. I've futzed with my MPS's enough to know that at this point.
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MikeInMunich
post Jul 12 2018, 04:21 AM
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QUOTE(rhodyguy @ Jul 11 2018, 07:41 AM) *

Perhaps a discussion of the engine spec is in order prior to a MPS refurbish.


Absolutely. Had I discussed or even mentioned this to Dr. D-Jet he would have been happy to not have anything to do with this case and not unhappy about trying to help where he otherwise would have chosen to distance himself.
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Dr-DJet
post Jul 13 2018, 06:57 AM
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QUOTE(MikeInMunich @ Jul 12 2018, 12:21 PM) *

QUOTE(rhodyguy @ Jul 11 2018, 07:41 AM) *

Perhaps a discussion of the engine spec is in order prior to a MPS refurbish.


Absolutely. Had I discussed or even mention this to Dr. D-Jet he would have been happy to not have anything to do with this case and not unhappy about trying to help where he otherwise wouldn’t have chosen to distance himself.

Well after Mike and me agreed on real facts that he had told me it would be an original 1.7 engine and that both MPS (one originally closed with rivets, vacuum tight etc) do not work for more than cold start enrichment (800 meters) and that he has also tried 2 ECUs:

I have references for 94% of all MPS, rough ones from Bosch and very precise ones measured myself. I always adjust MPS to references. And that is what makes cars going. To the opposite: A leaking MPS (and the first one was losing vacuum in 4 seconds) should create a very rich mixture with bad motor run in idle and part-load. If it was running well with that, then there were earlier other problems already.

I cannot know the revised engine specs but I can tell you that the ECU is used both on 1.7 and 2.0 engine. But 2.0 engines were never equipped with this MPS. It was equipped with 0280100 037 (sorry I do not work with Volkswagen no.s) in combination with this ECU. As a registered user u find all that information on oldtimer.tips MPS list. Anonymous surfing gives u only limited info.

So if we have 2 ECUs and 2 MPS not solving the problem, it is time to follow my original advice from the beginning when I learned it is a modified engine:

1. What specs is this revised engine? Bore, stroke, compression and valve timing.
2. If it is like original 2.0 engine, I would recommend to try 0 280 100 037 factory spec MPS. It is much richer than the 049 for 1.7 engines.
3. If it is not like original 2.0 engine, well then you have to do trial and error.

Regarding detuning MPS: You might know type 3 MPS from Mercedes-Benz, Opel, late Volvo etc. with black cap. Underneath is an easily accessible screw. (this one has just one screw and not 3 as it has no diaphragm and no full-load transition. Full-load is handled via a contact in throttle switch). I see a habit in the US to detune them. And later they are sold as core in ebay or completely with bad running car to someone else. Many MB 450 SL make it to Germany like that. And it a nightmare to fix it. They have altitude compensation and need to be checked at 750 and 600 Torr environmental pressure with differential vacuum applied to that environmental pressure.

Fortunately we do not have such a tradition of detuning MPS in Germany. I am doubtful that you can adjust all 3 screws on your MPS simultaneously while riding a car and watching A/F meter. That is why I recommend not to do so. Tuning screws on MPS are VERY SENSITIVE. Regarding swapping MPS from one engine to a different engine: Normally then MPS have different slopes in their curves and you cannot reach it via screw tuning. It would need a change of springs inside plus proper tuning.

Hope that clarifies the subject and please apologize if I got disturbed by "alternative facts" as they were first stated by Mike. It is good that he has changed that view and I accept that. (IMG:style_emoticons/default/driving.gif)

BTW: In April local Porsche 914 club had invited me to Karlsruhe for a workshop with 18 Porsche 914s teaching only D-Jetronic and engine testing. It was a lovely event and they have asked to have Obelix and me again next year in another region. (IMG:style_emoticons/default/beerchug.gif)
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Dr-DJet
post Jul 16 2018, 04:35 AM
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Hi,

and the last puzzle piece also unmasks the lie that you can simply use 1.7 components on an engine increased to 2.0 l. Such a statement is not only alternative facts, it is directly fake news.

A 2.0l does not only have a richer MPS it also has injectors with 20% higher static flow rate. Yellow ones have 265 cm³/min on 1.7s, green ones on 2.0s have 318 cm³/min .

And guess which ones Mike just reported to me about his car? Yellow ones. (IMG:style_emoticons/default/wub.gif) But the company who did the engine volume increase claims that they have compensated everything by a changed cam. What magic would that be? Cams can change air flow but never compensate for insufficient amount of injected fuel in intake manifold.

Mike, get the company in Texas to tell you exactly bore, stroke, valve timing, compression and compare to an original 2.0 engine. Only if it is the same, get green injectors 0 280 150 019 (or other green ones) and an 0 280 100 037 MPS. Or swap that engine to an original 2.0 one.
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