MPS- delving into it's secrets?, Update January 3, 2011 Options

[pbanders]

Yeah, I should have been more clear. I knew the had the injectors on the site, but I think these are NOS. When they're gone, they're gone. The Reman operation is actually fabricating new parts, I'd like to coax them into remanufacturing the more "consumable" parts, including injectors.

I'm hoping to hear back from them tomorrow.

[computers4kids]

Yikes...that's $218 US dollars (IMG:style_emoticons/default/blink.gif)
Great Thread and Read!

OK. How'd you get the English version?!?!?!?!?!

Jim

Google is our friend...translate any url.

[Bleyseng]

Maybe I can send them the box of 50 dead MPSs siiting in my garage so they can fix em and sell cheap....$1000 is way too much, $300 is a good target as a brand new diaphram will last another 30 years!

[jk76.914]

Too bad you can't just get a kit. Diaphram, o-rings for adjuster screws, and main seal, for maybe $100.

[McMark]

Jim, tuning is the real issue with a home rebuild kit. The best part about a factory rebuild would be that it's a 5min install and you can trust that it's right.

[jk76.914]

I know. But I also I think there's an opportunity for someone to write up a procedure, maybe do a video, on tuning D-jet to their own engine. The initial tuning done by the car manufacturers was a compromise to begin with. They had to account for production variation, variation in quality of gasoline, climates where the cars would be sold and driven, etc. And they didn't have the benefit of O2 sensors and the feedback loops they provide to help tune on-the-fly. Couple that to the fact that most of us have done SOME mods to our engines, and I think time is ripe for us to figure this thing out.

I keep thinking about that 1.99L Volvo 142E being rated at 135 HP. Or the 1985cc Saab GLE at 118 HP as exemples of where D-Jet can go with the right cam, timing, exhaust, C.R., etc. Not to mention the 2L Cosworth Vega at 122 HP-

[mtndawg]

I sent an email to Bosch via the Traditions web site telling them that I'm interested in having a 1.7L mps rebuilt. Someone named Matthias responded to me saying that they are looking at pricing for this process that would be done at Bosch in Germany and to keep an eye on the newsletter.

[Bleyseng]

Jim, tuning is the real issue with a home rebuild kit. The best part about a factory rebuild would be that it's a 5min install and you can trust that it's right.

Tuning to the known settings is pretty easy, the problem is most engines are slightly modified from stock these days. Close but tuning with a LM1 O2 setup gets you right there. New outta the box MPSs from Bosch would be set to their settings from what, 30 years ago for Brand New engines.
I have had a couple of NOS 043 that were set all over the place...and I set them to the "correct" setting I knew worked right.
I would rather have a repair kit of new parts to do the job myself so I could tune the MPS to a engine with its own quirks.

[jk76.914]

Jim, tuning is the real issue with a home rebuild kit. The best part about a factory rebuild would be that it's a 5min install and you can trust that it's right.

Tuning to the known settings is pretty easy, the problem is most engines are slightly modified from stock these days. Close but tuning with a LM1 O2 setup gets you right there. New outta the box MPSs from Bosch would be set to their settings from what, 30 years ago for Brand New engines.
I have had a couple of NOS 043 that were set all over the place...and I set them to the "correct" setting I knew worked right.
I would rather have a repair kit of new parts to do the job myself so I could tune the MPS to a engine with its own quirks.

I'm with you. The carb guys haven't weighed in. Would they take a new set of Webers and plunk them onto the car, and then never dial them in? I think not.

And either way, you really should have access to an AFR meter. I'm going to try and use a PLX Devices unit. Got it for Christmas. Haven't tried it yet... And inductance meters have come way down. I think I paid $40 for mine brand new.

[1988Hawk]

4 new 2.0 injectors from Otto, not cheap but reasonably priced.

[pbanders]

Matthias is the same guy I'm communicating with, same info I received regarding when the program will start. I'll communicate more on this stuff next week. I've had a medical issue since Wednesday that's kept me out of action, I should be back to speed by Monday.

[jk76.914]

Exchanged emails with Herr Matthias Klumpp at Bosch Traditions. I requested that Bosch make available a rebuild kit, composed of 3 seals plus diaphram. He replied that they were going to offer a rebuild service soon. So I replied again that the rebuild is easy, it's the tuning to the engine that is more difficult and that it really should be done for each engine anyway. So I requested again- "would Bosch consider offering the repair kit separately as described?"

Maybe with more requests they'll think about it. If they're offering the rebuild service, they obviously have these 4 parts.

Jim

[ArtechnikA]

I would be quite surprised if Bosch made a rebuild kit available. Pleasantly surprised, but surprised. It's not their style. There's not much money in it for them, and by keeping the price of the 'secret service' high it keeps demand for the parts low.

I believe they're only pursuing the 'rebuild service' because if emissions parts are really unavailable, they need to make this representation to the appropriate governing authorities (e.g. EPA, DOT, CARB) and that (manufacturer's NLA statement) removes the 'original equipment' requirement - which would kill their golden-egg-laying goose well and truly.

If you had only to meet tailpipe numbers and could do it with any induction system, would you do it with Bosch D-Jet parts?

[Larouex]

Jim, tuning is the real issue with a home rebuild kit. The best part about a factory rebuild would be that it's a 5min install and you can trust that it's right.

Tuning to the known settings is pretty easy, the problem is most engines are slightly modified from stock these days. Close but tuning with a LM1 O2 setup gets you right there. New outta the box MPSs from Bosch would be set to their settings from what, 30 years ago for Brand New engines.
I have had a couple of NOS 043 that were set all over the place...and I set them to the "correct" setting I knew worked right.
I would rather have a repair kit of new parts to do the job myself so I could tune the MPS to a engine with its own quirks.

I'm with you. The carb guys haven't weighed in. Would they take a new set of Webers and plunk them onto the car, and then never dial them in? I think not.

And either way, you really should have access to an AFR meter. I'm going to try and use a PLX Devices unit. Got it for Christmas. Haven't tried it yet... And inductance meters have come way down. I think I paid $40 for mine brand new.

Sorry to be uninformed, but what does this AFR do and how do you use it to tweak a DJet? Thanks, I am just wanting to learn how to get the most out of my setup.

Larouex

[pbanders]

I would be quite surprised if Bosch made a rebuild kit available. Pleasantly surprised, but surprised. It's not their style. There's not much money in it for them, and by keeping the price of the 'secret service' high it keeps demand for the parts low.

I believe they're only pursuing the 'rebuild service' because if emissions parts are really unavailable, they need to make this representation to the appropriate governing authorities (e.g. EPA, DOT, CARB) and that (manufacturer's NLA statement) removes the 'original equipment' requirement - which would kill their golden-egg-laying goose well and truly.

If you had only to meet tailpipe numbers and could do it with any induction system, would you do it with Bosch D-Jet parts?

I agree, I see very little incentive for Bosch to offer a kit. I'd be glad to see one, however!

For tailpipe emissions, D-Jet is a decent solution, especially compared to some of the carb arrangements I've seen. Where D-Jet beats carbs on emissions is under all of the various running conditions outside of part-load, which is why carbs fell out of favor once the Feds started the program in '70.

One manufacturer who stayed with carbs a long, long time was Honda. Anyone remember the carbs on some of their cars from the early '80's? Absolutely insane number of vacuum hoses and tacked-on systems to manage emissions. They worked fine when the cars were new, but once the hoses started to go, look out.

[Bleyseng]

Jim, tuning is the real issue with a home rebuild kit. The best part about a factory rebuild would be that it's a 5min install and you can trust that it's right.

Tuning to the known settings is pretty easy, the problem is most engines are slightly modified from stock these days. Close but tuning with a LM1 O2 setup gets you right there. New outta the box MPSs from Bosch would be set to their settings from what, 30 years ago for Brand New engines.
I have had a couple of NOS 043 that were set all over the place...and I set them to the "correct" setting I knew worked right.
I would rather have a repair kit of new parts to do the job myself so I could tune the MPS to a engine with its own quirks.

I'm with you. The carb guys haven't weighed in. Would they take a new set of Webers and plunk them onto the car, and then never dial them in? I think not.

And either way, you really should have access to an AFR meter. I'm going to try and use a PLX Devices unit. Got it for Christmas. Haven't tried it yet... And inductance meters have come way down. I think I paid $40 for mine brand new.

Sorry to be uninformed, but what does this AFR do and how do you use it to tweak a DJet? Thanks, I am just wanting to learn how to get the most out of my setup.

Larouex

First you weld a "bung" onto the exhaust so you can mount the O2 sensor.
Then you drive around at partload (2000-2500rpms) and record it onto a laptop.
Then a WOT run
Check your results and see what your AFR is varying conditions to see what your average AFR it. It should be between 13.7 and 14 to one at Part load.
WOT should be 12 to one to start and end at 13 to one at 5000 rpms.
Idle is set with the knob.

[pbanders]

First you weld a "bung" onto the exhaust so you can mount the O2 sensor.
Then you drive around at partload (2000-2500rpms) and record it onto a laptop.
Then a WOT run
Check your results and see what your AFR is varying conditions to see what your average AFR it. It should be between 13.7 and 14 to one at Part load.
WOT should be 12 to one to start and end at 13 to one at 5000 rpms.
Idle is set with the knob.

(IMG:style_emoticons/default/agree.gif)

Those are the same ratios I recommend, too. If everything in your FI checks out (especially check on the fuel pressure) and you're running rich at part-load, you'll need to adjust the MPS to get the mixture right.

From what I can tell, these engines will run just fine with extremely rich mixtures, part-load at 13:1 or less. These high levels may work OK, but contribute to higher pollution, poor fuel economy, cylinder wall wear, and oil contamination.

[kconway]

So if Bosch does a rebuild kit over a complete rebuild I've got buy a AFR and a laptop, cut holes in my exhaust, and learn to weld? Or, I guess I could buy a rebuild kit and then try to find a mechanic that knows Djet and is willing to do the tuning at a reasonable price.

Ugg, doesn't make sense for 95% of the 914 owners out there.

[pbanders]

So if Bosch does a rebuild kit over a complete rebuild I've got buy a AFR and a laptop, cut holes in my exhaust, and learn to weld? Or, I guess I could buy a rebuild kit and then try to find a mechanic that knows Djet and is willing to do the tuning at a reasonable price.

Ugg, doesn't make sense for 95% of the 914 owners out there.

I agree (again). While it may cost a wad of cash to get an NOS or Bosch rebuilt MPS, the investment in the stuff required to DIY, plus the time, is likely to cost more.

Regardless of whether the MPS is NOS or rebuilt, I still suggest a dyno evaluation for all D-Jet owners, with gas analysis. That way you'll know for sure what your part-load and full-load mixtures are. Shouldn't cost more than $100, and you'll get that cool HP graph, too.

[jk76.914]

So if Bosch does a rebuild kit over a complete rebuild I've got buy a AFR and a laptop, cut holes in my exhaust, and learn to weld? Or, I guess I could buy a rebuild kit and then try to find a mechanic that knows Djet and is willing to do the tuning at a reasonable price.

Ugg, doesn't make sense for 95% of the 914 owners out there.

I agree (again). While it may cost a wad of cash to get an NOS or Bosch rebuilt MPS, the investment in the stuff required to DIY, plus the time, is likely to cost more.

Well, I suppose. But I'm not doing anything here based on cash flow analysis. I'm having fun, and I'm learning lots of new things. That's pretty much what I've been doing with this car for the past 28 years that I've owned it.

And I still don't see why this isn't like dialing in new carbs..... which lots of people have learned or taught themselves to do...

I have a theory on that plastic ring.....