PP has them NLA, so i am sure AA has them NLA too.....i did see them one time offered at over $1000 and i KNOW i dont have that kinda money...unless i sell my stash .....of computer stuff.

So, where do i get/rebuild my MPS so i can get back on the road without putting along with the damn car running rich.


I just want to thank you for helping me solve this puzzle.....this is it....i remember now WHY i replaced the hose from the MPS to the plenum in the first place.....i thought it was a vaccuum leak in the hose, which got worse, I thought it was a fuel filter when it was the MPS/Dizzy at fault.....

I *DO* have a 1.7 MPS......would that work okay or would it be way too lean..?

I read from my BOSCH fuel injection book that if you unplug TS2, the engine will run more rich....but IIRC if you unplug the CHT, it wont run at all.....so is the book referring to the intake air temp sensor, and could this possibly come close to offsetting the lean condition caused by the new 1.7 MPS ???

I'm just tossing ideas around. This condition is getting progressively worse now though.

QUOTE (bd1308 @ May 21 2005, 10:11 PM)

So, where do i get/rebuild my MPS

you can't. but maybe bleyseng can help you. they're getting rarer by the minute ...

Andy

will a 1.7 mps work better than a busted 2.0 mps......that's all i'm asking.....should i wait to put it in, or if it indeed will work better i will put it in first thing.....

It's my considered opinion that in a few years the only 914s (or any other D-Jet cars) still using an MPS will be concours cars. All the rest will either be running carbs, or an aftermarket EFI system. MPSs are essentially unrepairable, and they're getting so expensive that the cheaper EFI systems will be price competitive pretty soon.

Before someone asks, it's not practical to make a replacement MPS diagphram, as the original is made out of some unobtainable material (some say beryllium, which is expensive, hard to machine, and highly toxic), and at least one attempt at remaking them in other materials produced units that at least Cap'n Krusty said are junk. I'll take his word on that.

It's also not practical to make an electronic replacement of an MPS using a modern solid-state MAP sensor, due to the way the MPS ties in with the stock ECU. I'll direct you to Paul Anders' site on D-Jet (use Google) for all of the gory details of how the MPS works, but suffice to say that you'd need to duplicate about 80% of an aftermarket ECU to make an electronic MPS that just plugged into the stock ECU. It would be easier to just add the remaining 20% of missing stuff and have a full, tunable aftermarket ECU.

okay...so a diafragm is junk.....DAMN.....this sucks. really. i guess it's time to read on megasquirt. shit. where do i try a replacement diafragm(sp?)....?

QUOTE

Before someone asks, it's not practical to make a replacement MPS diagphram, as the original is made out of some unobtainable material

Can't the 1.7 MPS be re-calibrated to work on a 2.0.
I thought that Jeff Bowlsby does this.

OH MY GOD! WE'RE RICH! I have enough beryllium diaphrams to fix at least 10 cars!

They are in Yomamaha NS-1000s, a couple pairs... anyone feeling like cutting up my speakers? (they are for sale... 1 good 2.0 mps, and $2k/pr) Fine! Go on to your carbs! hahahaha!

I don't think they have any in them, but... if the center of an MPS tootsie roll is made out of aluminum, sputtered with beryllium, I highly suggest everyone taking at least one look at the Eye of Fly, t'least onced..

I don't see why an MPS can't be reengineered.... with the way you test them, I don't see why you can just hook a straw up instead, and hold a vac.



Yes, I am tired, sue me.


M

QUOTE

I don't see why an MPS can't be reengineered....

they have, and by a few people....it wouldn't be impossible to remanufacture them with brand new berrilium copper diaphams, the problem lies in not enough "real" interst and paying parties...figure at a minimum $300 each if you had a minimum order of 20 or so....I don't know anyone that is willing to pony up $6000 for a bunch of parts that might be sitting on a shelf for a months or worse case a few years....

was just cleaning out my storage closet today... and among the stuff i found was a stash of 5 MPS's. I know that one of them has to be from a 2.0L (since it took one off of one) the others were given me by a german/mechanic friend of mine.

QUOTE (Mueller @ May 22 2005, 02:34 AM)

QUOTE I don't see why an MPS can't be reengineered.... they have, and by a few people....it wouldn't be impossible to remanufacture them with brand new berrilium copper diaphams, the problem lies in not enough "real" interst and paying parties...figure at a minimum $300 each if you had a minimum order of 20 or so....I don't know anyone that is willing to pony up $6000 for a bunch of parts that might be sitting on a shelf for a months or worse case a few years....

They are beryllium sputtered copper?

So it's the diaphram, and what else, included in a rebuild?


M

You'll note that I didn't say it was impossible, just impractical. The cost, as Mueller pointed out, of working up tooling and materials required to make new diagphrams that work EXACTLY like the stock units do, is too high to make it economically worthwhile. His $300 estimate may very well be LOW, and that's still only the diagphram. That doesn't include the cost of actually rebuilding and recalibrating the MPS with the new part.

If concours quality 914s ever become desirable enough, and expensive enough, then someone will eventually make these, at a very high price. People happily rebuild MFI injection pumps for $1500 a throw. 5-10 years from now, I'd guesstimate a rebuilt MPS that actually works may be sold for a similar price.

Now, the clever thing would be to make up an ECU kit that hid entirely inside the stock ECU housing, and hid a modern solid state MAP sensor inside an MPS housing (so there are no extra hoses). Now, you'd have a stock-appearing setup that would be enough for a concours judge that worked, and was repairable using readily available parts.

QUOTE (lapuwali @ May 22 2005, 03:07 AM)

Now, the clever thing would be to make up an ECU kit that hid entirely inside the stock ECU housing, and hid a modern solid state MAP sensor inside an MPS housing

That gets my vote.

Look up Jeff Bowlsby. He recalibrates them for not too much $$$.

QUOTE (lapuwali @ May 22 2005, 03:07 AM)

People happily rebuild MFI injection pumps for $1500 a throw.

we're not exactly happy about it, but it is still on the value scale considering the performance for the price.

i'm going to need one done pretty soon; i just hope i can get to it while the few guys with the tools and experience are still alive...

so far, the comparable 'modern' FI systems are still more expensive.

i'd guess there'd be money to be made building up a CARB-certified plug-n-play direct replacement EFI for D- and L-Jet cars. unless the CA law changes yet again, '76 914 and 912E guys are going to be really hurting...

they are rebuidlable and are done for 150.00 buck. No it is not the proper diaphram, but they work for the most part. Check out Brad's site. He even admits to using one that was rebuilt with no problems. Some people say that they do not respond as quick but others have not noticed any difference. Either way it is worth trying for 150.00 bucks. They only problem is that the company that does it, only does it through a retailer so you have to call GPR or AA and have them send it. Bret Instruments are the rebuilders. Check out the Q&A at the bottom of the page

http://members.rennlist.com/pbanders/manif...sure_sensor.htm

I have one sitting here, I tried to sell it on Ebay and nobody bought it. I figured there wasnt any interest in it. Whats a guy to do?

QUOTE (skline @ May 22 2005, 09:48 AM)

I have one sitting here, I tried to sell it on Ebay and nobody bought it. I figured there wasnt any interest in it. Whats a guy to do?

the problem with EBay is trust.

a perfect, functional MPS LOOKS just like an expensive paperweight.

that's where a forum like this is good - you get a feeling for who you can trust.

Scott, what do you want for it? I'm sure we need one at the shop.

I had it up on the Bay for $150 on a buy it now. Its freshly rebuilt and ready to go. It is the 043 so it is for a 2 liter. Aaron said it would go for around 2 or 300 but nobody even bid on it.

I do rebuild them by installing a good 1.7 diaphram in a 2.0 core. The calibration is done with a wavetek meter which I have the specs to do 037 and 043 MPS's. Resealing them is a pain as is taking them apart without destroying 'em.

Yes, the Brett ins ones work but it ain't the same as they set them up for only 1.7 MPS's. Mild differences in calibrations and if they install new steel cells the thing runs like shit with very poor drivability. Throttle response just plain sucks!

You can send me you two MPS's and I'll work on them.
here is a pic of the inside of one

Brett Instruments no longer exists...It was sold to Fuel Injection Corporation. Their price, supposedly across the net, is $275 for a rebuilt one.

I am having some rebuilt (maybe, a long story) that could be sold for $200. It is a waiting game on this one.

The one that Scott Kline has was rebuilt by the old Brett Instruments (I can tell by the tag).

If all the diaphrams are the same, I have a shit pile of MPSs (various numbers)....Maybe I should take them apart and retrieve the diaphrams

Yes, that is the only thing in them that is worth $$$. I have MB guys emailing me to rebuild theirs.

Do a test sometime running a nos unit and then plug in a Brett rebuilt and then a AA one. You will be suprised at the difference in throttle response!

I have a few extra MPS' that I am holding onto 'cause I have 2 cars with d-jet.

How about the compatibility of an MPS from my type III and my 1.7 type IV. They look the same to me, although I haven't looked at the number.

Not knowing all the intracies, I would assume the diaphrams were essentially the same from a lot of cars that had DJet. The numbers would refer to calibration and electrical outputs.

the type 4 have the altitude adjustments built in which is way better than the type 3 style.

turns out i had a un-molested T-3 MPS in there....from a 1600 engine. So my T-4 MPS should be closer to spec.....its a 1.7 MPS......still has the miss....i think i should check continunity between my crimp connections i did with the Fi trigger point connections. How hard is it to take out my FI harness wiring to look at it? Oh and are the 1.7 and 2.0 harnesses interchangeable..? I have 2 1.7s that i could fix while the 2.0 is doing it's thing.......i believe my problem IS electrical (due to the intermittent random problem)and i believe that a harness may help with my issues....

QUOTE (bd1308 @ May 22 2005, 10:01 PM)

How hard is it to take out my FI harness wiring to look at it?

Easy. Take pliers, and pull the ends off, then cut any wires that get in the way, when you pull hard.. and do pull *very* hard.


M

dude......

QUOTE (bd1308 @ May 22 2005, 06:15 PM)

and you wonder why you're car sucks......

actually i have seen his car it is a dapo from hell. things like jb welding in cut mirror in to the side mirrors. a repaint over waxed un sealed previous paint job.

i wont go on any further

QUOTE (redshift @ May 22 2005, 07:09 PM)

QUOTE (bd1308 @ May 22 2005, 10:01 PM) How hard is it to take out my FI harness wiring to look at it? Easy. Take pliers, and pull the ends off, then cut any wires that get in the way, when you pull hard.. and do pull *very* hard. M

Miles, you are cruel.....

Now back to George, for the weather!



M

I dont like bugging miles, so i changed for ya man.....


what's the non-miles approach to taking off the FI harness for DIY soldier and shrink tube repair??

QUOTE (bd1308 @ May 22 2005, 07:32 PM)

what's the non-miles approach to taking off the FI harness for DIY soldier and shrink tube repair??

Don't start a thread about it....

well then answer the question.......

Sent ya a PM on a source for a known good MPS... I have one that I'm not sure of. I'll send it to you for free if you would like... As far as the pulling of the FI harness, contact Bowlsby, he's got the shizzle fer ya....

If you take each harness connection off, after you have properly tagged it, and just keep marking, and removing til it comes out.. I am pretty sure taking pictures of it as you go will help alot.


M

i have a spare laying on the shelf, looks like itll stay there! How do i test to see if the mps is good, just if it hold a vaccum or what? how many lbs.

Hmmm... I have a spare sitting on the shelf as well. Martin Baker tells me it is good based on his doing some quick test that I did not see. But considering it is Martin Baker I am going to trust that he knows what he is talking about. What are these things worth??? Mine is from a 2.0 with 70K miles...

Rob

Pull a 15hg vacuum on it for 5 minutes as it should leak down hardly at all. If it drops quickly its toast.

a good 2.0L MPS is worth $150 to 250 if its been checked for vacuum and calibration. Lots of buggered MPS's out there that run like shit, thats why they are on the shelf.

This thread makes me appreciate my Porsche mechanic more than I already did. Mine went bad, they had the car for a couple of days before they finally verified that the diaphram was cracked. He raided his bone pile and rebuilt mine. Its worked great ever since.

my PO bought a complete used injection system because the computer was bad in my car. He replaced the computer and put the rest in a box, which i now have on a shelf. comes in handy when in need.

QUOTE (dgw @ May 22 2005, 09:26 PM)

This thread makes me appreciate my Porsche mechanic more than I already did. Mine went bad, they had the car for a couple of days before they finally verified that the diaphram was cracked. He raided his bone pile and rebuilt mine. Its worked great ever since.

I would hazzard a guess that the A/F ratio is off on that MPS unless he used a Wideband on it to calibrate the MPS. You can't get closer than "it runs" using the "ear" method to calibrate. Its also nearly impossible to set the WOT without somesort of wideband or electronic meter like a Wavetek inductance meter.

QUOTE (bd1308 @ May 22 2005, 07:32 PM)

I dont like bugging miles, so i changed for ya man..... what's the non-miles approach to taking off the FI harness for DIY soldier and shrink tube repair??

It isn't that hard to change a complete harness in the car....have done it several times....Jeeezzz Britt, it's only spade connectors except for the throttle body, MPS, cold start valve, injectors, trigger points and Temp Sensor II. Label the shit if you have a short memory. After 30 years of heat, the harness kinda conforms to where it was connected...you can dam near throw it at the car and it will lay like it is supposed to.

The worst part is just running the harness and wires under the runners & such where reuquired.

According to Jeff Bowlsby, the 1.7/2.0 are very similar electrically, but some of the connections would be located in a different place...I would think mainly the cold start valve and throttle body connector.

Better yet, just buy a rebuilt/new harness from Jeff...................

i think thats ultimately what I would need to do.......anybody have a link?

QUOTE (bd1308 @ May 23 2005, 08:27 AM)

i think thats ultimately what I would need to do.......anybody have a link?

I thought you were a computer nerd the way you talk....regardless, a search would have found what you were asking about AND if you had looked in 914 Parts and Resources, you would have found it also.

http://www.914world.com/bbs2/index.php?act=...T&f=4&t=2949&s=

Here is a more direct link Britt:

Harness Link


M

QUOTE (redshift @ May 23 2005, 09:20 AM)

Here is a more direct link Britt: Harness Link M

LOL

QUOTE (wilchek @ May 22 2005, 05:36 AM)

they are rebuidlable and are done for 150.00 buck. No it is not the proper diaphram, but they work for the most part. Check out Brad's site. He even admits to using one that was rebuilt with no problems. Some people say that they do not respond as quick but others have not noticed any difference. Either way it is worth trying for 150.00 bucks. They only problem is that the company that does it, only does it through a retailer so you have to call GPR or AA and have them send it. Bret Instruments are the rebuilders. Check out the Q&A at the bottom of the page http://members.rennlist.com/pbanders/manif...sure_sensor.htm

Bret's stuff was crude and unreliable in the 70s and 80s, why should it be any better now? I've had a Bret rebuilt ECU apart, and it was festooned with jumper wires like streamers at a backyard birthday party for a 5 year old. The MPSes they sold then had SS diaphragms .............. RAMs stuff was better, but I dunno if they're still around. Maybe Python does them? The Cap'n

Britt: what have you done to determine that your MPS is bad?