Alternative or Compatible Pressure Sending Unit?

bengal taiga

bengal taiga

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My D-Jet crapped out on me. All diagnostics point to a bad Pressure Sending Unit "PSU". To put it bluntly, it won't hold a vacuum. An ex couper tells me it is part no. 1 3631360678 and has a list price of more than its worth. I am also informed that the ECU "brain" is part no. 1 3611355309.

This is the second bad PSU in the past 10 or so years and makes me wonder if there is an LJet or Webers in my future. I am certain I have one spare left, but at present, I cannot locate it. In the meantime, I am able to drive the car with a PSU originally found on a V-8 Mercedes that I just happened to have on the shelf. Despite the fact that I can adjust the small "inner screw" to get a fairly roadworthy engine, the idle is rough enough to make me not want to drive the car until I find my spare PSU or a suitable replacement.

I am aware that Volvo and Citroen, to name just 2 manufacturers, used the same system on their 6 cylinder models. Thinking out loud, it would seem that the ECU and the PSU from such models might be similarly "mapped" so that they might be pressed into service as a bare substitute for the E9's OEM.

This leads to the core of my post. Is anyone aware of a PSU from another vehicle that might prove a viable alternative to the part number/s listed above? If so, what have you successfully employed? Alternatively, is it feasible to consider a joint transplant (using both the ECU and the PSU) from another model?

Thank you in advance.
 
I think they are pretty much specific to a particular car. I never found another off-the-shelf replacement before I ditched the D-Jet completely. However, Bret Industries in Santa Ana, CA can rebuild and calibrate them. I got a rebuilt one from them and it worked well. May give that a try vs. the cost of new.
 
Bret Industries?

AndyM said:
I think they are pretty much specific to a particular car. I never found another off-the-shelf replacement before I ditched the D-Jet completely. However, Bret Industries in Santa Ana, CA can rebuild and calibrate them. I got a rebuilt one from them and it worked well. May give that a try vs. the cost of new.
Click to expand...

Thanks for the info. I searched for the name and came up empty. How long ago was it that you knew they existed? Do you have any more specific information on this business?

Thanks
 
D-jet, I believe, was fitted to some Peugoet 504's and Citroen DS 19's and 21's
There is a remote chance you could find one in a scrap yard....

I am also in the same position. The dear old bucket's ECU and manifold pressure sensor are stuffed. For me I think the only answer is an after market ECU.
 
Don't know if it's the same place AndyM was talking about but there is a 'Bret Instruments Co.' in Santa Ana. Their phone # is 714-954-0098.
 
more info.

Malc said:
D-jet, I believe, was fitted to some Peugoet 504's and Citroen DS 19's and 21's
There is a remote chance you could find one in a scrap yard....

I am also in the same position. The dear old bucket's ECU and manifold pressure sensor are stuffed. For me I think the only answer is an after market ECU.
Click to expand...

Ok Malc, since we are in somewhat of the same boat, here is what I have tried today. Pardon my Proustian narrative.

I borrowed the PSU from a 6cyl Volvo (Model 262 ?). The Bosch No. is 0280100035. With the original E9's ECU (Bosch No. 02800001007) the engine runs fine above 2000 rpm, but is too lean at idle and has a few progression issues. Adjusting the CO knob on the ECU helps, but not much. I removed the sealant from the PSU to access the small screw in the PSU. As I understand it, the PSU operates solely from vacuum and in lay terms, less vacuum produced a signal that says "richen." Conversely, more vacuum, translates to "leaner" signal. Thus, turning the screw clockwise produced a leaner mixture and counter-clockwise a richer mixture. Adjusting the mixture screw counter clockwise produces a fair idle and an engine that might be acceptable to drive.

One thing for certain, as adjusted with the donor PSU, I have to retard the ignition timing because of what appears to be a lean mixture causing severe pinging under load. It may be that I have a temperature sensor acting strangely since I drove the car for the better part of an hour running errands and discovered that a couple of times after shutting off the engine and restarting, that the idle settings seemed to dramatically change. Out of frustration I pulled the temp sensor connection (to the manifold) and found the engine ran smoothly. Then, after shutting the engine down and restarting, the idle settings changed again - albeit slightly.

I could not leave well enough alone. As noted in an earlier post, I suspect each PSU and ECU are mapped/calibrated for specific applications. The E9 shop manual talks of matching the ECU and PSU with specific colored "dots" or sticker. Along those lines, I decided to try the ECU from that same donor Volvo (Bosch part no. 02800001009). So far so good. The engine runs well and the idle is improved. Without an exhaust gas analyzer, co meter or the like, I can only guess as to where the engine is running stoichmetrically. I have called in a favor from an acquaintance who has parted out 1971 or 72 Mercedes 280 that he claims also used the D-Jet. I would expect the fuel curve on that ECU and PSU to be closer to the CSI's original equipment than the Volvo. Unfortunately, I may have a wait for my acquaintance to do some digging to find these parts.

I am not completely satisfied with things as they are, but at least I can drive the car. As an aside, I have also enlarged the gaps on the plugs (W8DC) to .042" to smooth out any lean transitions. I am uncertain if this is really accomplishing anything, but I can easily get to redline under a load without any discernible missing and without any black smoke from the tailpipe. The main problem right now is low speed operation "roughness" so that the old gal's engine does not exhibit the turbine-like smoothness I have come to expect.

I hope my travails will be of some assistance.

Good luck to both of us.
 
Volvo 1800 ES has the D-Jet as well. Some Mercs and the earliest application of the D-Jet was in a VW I believe.

The ECU is basically the same for all D-Jet applications. 4,6 or 8 cylinders, the external wiring just differs. BUT inside the ECU there are two circuit boards. One is the basic board that is the same on all D-Jets. The second, smaller daughterboard is where the engine specifics are situated. Thus, if your ECU is fried, an ECU from a different car, even a volvo or a Merc might get you running, but only roughly The mixture mappings will be for a different engine so you´ll be alternating between rich and lean. The adjustment screw does very little except adjust mixture at idle.

All D-Jet cars use a PSU, but frankly I don´t know wether they are even similar. Even within the M30 there were, ones with different colour codes that needed to be matched with an ECU of matching colour code for best running (blue, red, green, white and none). At the time, tolerances could not be met sufficiently for the PSU so they were colour coded and matching ECUs with adjustments were provided.

Unfortunately PSU´s can bust (usually the diaphragm gets porous and starts leaking) and cannot be repaired. They are available new, but relatively expensive.

The ECU is pretty expensive as well if bought new or refurbished, but good used ones, even the M30 Version, float on ebay regularly, Usually go for around 200bucks

Btw, forget about trying to "adjust" the PSU with the small screw that is sealed. Either your PSU is fine, then there is no point, or it is broken, then there is no point either. You´ll just get into a bigger mess.
Common wisdom: If the cap over the screw on your PSU has been tampered: Throw it away. Without the orginal testing and adjusting bench in the Bosch factory, you´d never get anywhere.
 
Thanks for your input

Tierfreund said:
Volvo 1800 ES has the D-Jet as well. Some Mercs and the earliest application of the D-Jet was in a VW I believe.

. . . .

The ECU is pretty expensive as well if bought new or refurbished, but good used ones, even the M30 Version, float on ebay regularly, Usually go for around 200bucks
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The price quoted via Realoem is substantially higher and makes precious metals look inexpensive. There is quite a bit of miscellaneous information on the net concerning D-Jet operation on 914's, and Swedish bricks. Most of the information deals with troubleshooting rather than modifications, workarounds or part substitutes. One poster took the approach that if your PSU can't hold a vacuum, try another similarly shaped PSU, it may work! It may be common practice to access the small screw in the PSU, but there are actually two adjustments. One is the small screw, the second may be the outside screw into which the smaller screw fits. The larger screw evidently has a "stop" or a limiting function. Unfortunately, it has been my experience that tuning the smaller screw usually turns the larger screw in tandem and limits the range of adjustment.

Its a shame that in this world of ever more sophisticated electronics, someone hasn't developed an inexpensive alternative to the PSU and ECU found on our E-9's. Yes, I am aware of the megasquirt, but I am also aware that there is an L-Jet waiting to be adapted to the M30 too!

Appreciate the input.
 
Be aware when converting to L-Jet that:

1. (at least in Euro form) the D-Jet motor has a higher compression (9.5:1 instead of 9.0:1). Thus the mixture the L-Jet provides with the same outside parameters may be lean
2. The fuel pump on the D-Jet is different (it´s shared with the tii and very expensive, while the L-Jet pump is compatible with many later cars and can be had as a cheap aftermarket part. The L-Jet pump will work on a D-Jet thanks to the pressure regulator. I´m not sure about the other way round though. Pressure may be to low)
3. The D-Jet gives better throttle response and better reving thanks to the less restricted intake

I happen to like the D-Jet. It´s very robust, gives very good power, great torque and very good throttle response. Good starting, no hot starting issues, very stable idle and so on.
I believe it is actually superior to the L-Jet. If a PSU breaking every 10 years is a problem, the Air Flow meter malfunctioning on the L-Jet would be as well.
You really should be able to get a good used pair of PSU and ECU. CSIs get broken up. Bavarias as well. Usually both with engines still running strong.
 
Tierfreund said:
Be aware when converting to L-Jet that:

I happen to like the D-Jet. It´s very robust, gives very good power, great torque and very good throttle response. Good starting, no hot starting issues, very stable idle and so on.
I believe it is actually superior to the L-Jet. If a PSU breaking every 10 years is a problem, the Air Flow meter malfunctioning on the L-Jet would be as well.
You really should be able to get a good used pair of PSU and ECU. CSIs get broken up. Bavarias as well. Usually both with engines still running strong.
Click to expand...

I agree that when working, the D-Jet is quite acceptable. The problem is the lack of parts. I am in North America where the D-Jetted CSI's were never all that plentiful. I can't say I am aware of any available donors in my neck of the woods. Bavaria's, to the best of my knowledge were all equipped with 2X Zeniths. The 3.0Si used the L-Jet and not the D-Jet. These cars, not unlike 2002's are becoming less and less available. There was a time when there were so many of these cars, along with Audi 100's, Fiat Spyder's and Mirafores, Alfa Spyders were virtually given away. Now, you can't seem to find them. L-Jet would not be my first choice anymore than going to carbs (which I have in my garage.) Hence then lengths of my posts concerning the D-Jet and getting it running.

Thanks again!
 
Good tip!

Tierfreund said:
OK, it´s meant for an Opel, what an indignity, but if all that needs to match is the external shape... :lol:

http://cgi.ebay.de/OPEL-Admiral-Dip...ryZ42486QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Click to expand...

I do not personally subscribe to the theory that if the PSU's look externally the same, they are interchangeable. Nevertheless, that does not mean its not worth trying! At this rate, I am interested in what may be a similar offering from the Mercedes 280, assuming that the parts are available and they -work. In the meantime, I will add Opel to the list.
 
About carbs: If you´re thinking about the Zeniths: Unless they are brand spanking new or expertly rebuilt: You´ll get about the same poor running as with a volvo D-Jet ECU and a broken PSU :wink:

About converting to Webers: I´ve run the D-Jet and I´m now on 3x40DCOE (brand new)(different car, the D-Jet was fine, the body was rotting), and while the Webers sound and run great when on song (3000-5000rpm), below that and when starting, I really long back to the D-Jet...

Oh well...

Good luck in sourcing spares for the D-Jet or when converting to whatever. As long as anyother beautifull coupe stays on the road!
 
In any case: I´d rather match a "foreign" PSU with the original M30 ECU than an M30 with a foreign pair of PSU and ECU. I would think that the right mapping for the engine in the ECU is more important than the right mapping of the PSU to ECU.
I´ll bet your M30 ECU is still fine. They hardly ever break.

I´ve run differently colour coded combinations of ECU and PSU (albeit all M30) and didn´t notice much of a difference.

Or try all combinations you can get a hand on. At least they´re really easy to swap.
 
Tierfreund said:
In any case: I´d rather match a "foreign" PSU with the original M30 ECU than an M30 with a foreign pair of PSU and ECU. I would think that the right mapping for the engine in the ECU is more important than the right mapping of the PSU to ECU.
I´ll bet your M30 ECU is still fine. They hardly ever break.

I´ve run differently colour coded combinations of ECU and PSU (albeit all M30) and didn´t notice much of a difference.

Or try all combinations you can get a hand on. At least they´re really easy to swap.
Click to expand...

I do not think my ECU is bad. The PSU is not holding a vacuum. When I try the Volvo PSU with the original ECU, the rev transition is "relatively" smooth. However, the idle ist schrecklich. Switching to the ECU and PSU, both from the Volvo provides a decent idle but it has low speed transition issues. Either way it is a trade off.

Tangentially, I had a 02 tii that had the Kuglefischer freeze up. I later used the same block with an aftermarket ported manifold and a Weber 38/38 that I rejetted. I know it is counter intuitive, but I found the combination every bit as smooth and stingy on fuel as the injection system. I did not have back to back dyno comparisons, but the simplicity of the Weber made up for recurring fuel injection issues.
 
It is Bret Instruments I was thinking of. It's been a few years now since I ditched the D-Jet. :?

I believe the MPS is one of the only pieces of the D-Jet system that cannot be swapped across lines. It's my understanding that the MPS is specifically calibrated to each particular motor. I had to face all of these issues when I swapped out my stock motor for my 3.5. I didn't want L-Jet or Motronic since they have the bulky AFM and lack the throttle response of the D-Jet. I finally built my own injection system using a GM ECU with the D-Jet manifold. It took a fair amount of tuning, but was well worth the effort. Looks nearly stock, too, unless you really, really know what to look for. I have about 30k miles on it now. Throttle response is instant, it still puts out over 200 hp at the rear wheels and consistently gets over 25 mpg.
 
AndyM said:
It is Bret Instruments I was thinking of. It's been a few years now since I ditched the D-Jet. :?

I believe the MPS is one of the only pieces of the D-Jet system that cannot be swapped across lines. It's my understanding that the MPS is specifically calibrated to each particular motor. I had to face all of these issues when I swapped out my stock motor for my 3.5. I didn't want L-Jet or Motronic since they have the bulky AFM and lack the throttle response of the D-Jet. I finally built my own injection system using a GM ECU with the D-Jet manifold. It took a fair amount of tuning, but was well worth the effort. Looks nearly stock, too, unless you really, really know what to look for. I have about 30k miles on it now. Throttle response is instant, it still puts out over 200 hp at the rear wheels and consistently gets over 25 mpg.
Click to expand...

If it is not proprietary, what GM ECU did you use? I have gone through this before and ultimately bit the bullet to acquire the correct Pressure Sensing Unit. That is why I am hoping to locate my "spare". I am convinced I can get by with using the make shift PSU, but as noted, it remains to be seen, for how long. On the other hand, if the fuel economy improved, I might be able to accept a few annoyances.

I was informed a long time ago that GM used the D-Jet on a Cadillac model in the late 70's. I am unable to confirm this but would like to for prospective PSU donors. As you will note below, a couple of sites make the claim.

I recall throttle body injection with the "Olds" gold painted 350 V-8 that Cadillac transfused into its Seville model in the late 70's. For what its worth, here is some information from a "Wouter's page" for more alleged uses of the D-Jet ( http://www.164club.org/d-jet.html ) Please note the list can hardly be complete given certain obvious omissions (E9 and Citroen).

"D-Jetronic Fuel Injection
This page could be found on the Internet for several years but suddenly disappeared. Since we think it contains some useful information we have put a copy of it here on our website. Volvo 164 Club of Sweden, January 15, 2001.

The Bosch D-Jetronic fuel injection system was used by VW in the Type III in 1968. This was the first electronic fuel injection system to be fitted to a production car. The Bosch Fuel Injection Systems 1970-1979 Shop Manual published by CARBOOKS, INC. gives the following list of cars using the D-Jet system:

------Make------ ------Year------ ------Model------
Cadillac 1976-79 Full Size

Mercedes-Benz
1971
1972
1973-75
280SE, SEL
300SEL
3.5 Litre
280SE, SEL
300SEL
4.5 Litre
450SE, SEL, SLC

Porsche
1970-73
1973-75
914/4 1.7L
914/4 2L

Renault
1972-74
17TS
1.6L

Saab
1970-74 99E

VW
1968-73
1971-74
Type III
Type IV (411/412)

Volvo
1970-73
1971-73
1972-75
1800
142/144
164E

The following text is Bill Lewis' explanation of how the D-jet system works.

Keep in mind that the D-Jetronic is Bosch's first generation system and is very crude by todays standards. In the USA, parts are somewhat hard to find and are expensive. D-Jetronic (from now one I'll call it just D) works on the principle of measuring the intake manifold vacuum. If you accept that the manifold vacuum is the same (give or take) as the vacuum in the cylinders themselves during the intake stroke, and that vacuum is really the inverse of pressure, then knowing the manifold vacuum gives you the cylinder pressure in absolute terms. Like 30 inches of vacuum = 0 psia. 0 inches of vacuum = 15 psia. If you know the pressure in the cylinder, and the volume of the cylinder, then you know the mass of air you have"
 
bengal taiga said:
If it is not proprietary, what GM ECU did you use? I have gone through this before and ultimately bit the bullet to acquire the correct Pressure Sensing Unit. That is why I am hoping to locate my "spare". I am convinced I can get by with using the make shift PSU, but as noted, it remains to be seen, for how long. On the other hand, if the fuel economy improved, I might be able to accept a few annoyances.
Click to expand...

I never found anything that would work as a direct swap with the D-Jet parts. After a ton of research, I used a 1227730 from a 90-92 F-Body (Camaro/Firebird) with Tuned Port Injection. This is a speed-density ECU that doesn't need an air mass sensor - only a MAP sensor. Unfortunately, you can't use any of the D-Jet sensors so it requires swapping over to later GM based sensors and buying or making a new harness. It also needs to be programmed from the ground up to work on the six cylinder. Its a lot of work up front -- pretty much the same as a Megaquirt conversion -- but the results were worth it. Plus, all the GM diagnostics still work and I can walk into any Pep Boys or Kragen and buy any sensor I need. I can provide pictures and most part numbers if you ever decide you want to pursue something like this.
 
Alternate parts?

I was curious as to whether any other vehicles used the exact same ECU or PSU as originally found in the E9. To my surprise, I discovered that someone is advertising ECU no 0280001007 on several Ebay sites. What makes things interesting is the fact that the seller is advertising the ECU as fitting Mercedes W107 and W116 models. http://cgi.ebay.at/Mercedes-STEUERG...8556606QQihZ001QQcategoryZ61534QQcmdZViewItem
Other sites list the box as fitting the E9, although accuracy is questionable when the sellers also state it fits 3.0CS as well as the "i" model. I did the best I could thumbing through the Bosch research site and found one Benz model (280SL W107)) used 02800001008 ECU (PSU 280 000 160 007) and another used 02800002004, so perhaps the Ebay seller is mistaken.

Should anyone have better information or can confirm that other models used the exact same ECU and PSU as the E9, - contrary to popular opinion, please share.

Thanks
 
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