ECU identification Options

[tradisrad]

Hi 914 club, I am a new member to the club but a long time owner (since 1989),
Any how, I am looking to identify the make of my ECU, I know it is as simple as looking at the sticker on top of the ECU, however at some point the ECU I am currently using was spray painted and then the paint was scratched away to reveal the sticker (not by me) and when the paint was scratched away the numbers from the sticker were also removed, and I can not make out the last few critical numbers.

So my big question is how in the world can I tell what ECU I have? Is there any internal markings that may lead me to my answer?

What I do know, is that it is D-jet, it has a idle mixture knob and I am running it on a 2.0. My throttle body is a '74, but my head temp is a '73 w/o a ballast (and yes I am having some issues).

Thanks in advance,
-Rob

[bd1308]

You'll be surprised at what a new wiring harness will do for you.

Very surprised, look for Jeff Bowlsby

[914werke]

(IMG:style_emoticons/default/idea.gif) Very good question.
First how do you "know" that your TB is off a 74?
The other part that is critical in the mix is the MPS?
Matching all the parts is important but dosent guarantee
it 'll correct your issues

[bd1308]

ive had a DJET computer open and i didnt see any numbers

early boxes were FULL of resistors and junk ALL OVER.

in 73-74 there is a spot in the top-middle that is open--the factory removed fuel cut-off circuits

it returned in 75-76 in a different form and style.

b

[Bartlett 914]

The ECU, the MPS and CHT must all be the correct combination. Have you looked here? http://members.rennlist.com/pbanders/DJetParts.htm

This is the Bible fot Djet as far as i am concerned. I know this doesn't quite answer your question. There is extensive detail on the insides of your ECU. It may be necessary to open it. If it can be done otherwise, I don't know how.

I had a mismatch on my car (CHT and ECU). The main symptom was poor running until hot.

Mark

[tradisrad]

Thanks for the replies,
First how do I know that my TB is from a '74? Well I tried to run the part number (039.133.067) and did not find any matches on the web or in the D-jet Bible, I live near High Performance House and Rich "told" me that w/o the vaccume advance that it is not a '73 and is likely a '74 (the components did come from a '74 car). So while I can not be 100% certain its from a '74, but it is highly likely.....

I have printed the D-Jet bible as well as the MPS characterization and have been reviewing them. With a friend, we measured the inductance of 4 MPS's under vacuum and came up with similar slopes as the "bible" had, however our inductance values were lower across the board on all 4 units. I will check with another meter next week to see if the problem is in the meter. We decided since all 4 were very similar that they are "ok". all were p/n 280.100.043. The "bible" has the 0 in Hg listed around 1.35 henery and all of ours were 1.18 henry (or so).

The head temp sensor I had/have in the car is the 280.130.017, the '73 sensor, the reason I say had is that I am about to go out the the car and place the 280.130.012 sensor in the car.

So I do not have the '73 MPS (280.100.037), but I do have the '73 head temp( 280.130.017)(not for long), and I really want to know what my ECU (brain) is!

I've OHM'd my wiring harness out and all values seem to be in spec. from the ECU connector to the components.

I will keep searching and hopefully the answer will come.
Thanks again and any more help is appreciated, I need CSI 914 to inspect my ECU sticker.
Thanks again
-Rob

[Bleyseng]

O hg and at 1.35 for a 043? in San Mateo so you are near sealevel so close to me.

For WOT (0hg) you should be at 1.40,
for Partload (4hg) at 1.19
and 15hg (idle) .76

this is again at about sea level. My readings are off a NOS 043 unit.

[tradisrad]

Bleyseng,
I do understand that the MPS should read about 1.4 hg at WOT, weher all 4 of ours tested to about 1.18 hg at WOT. I dont know if all 4 are bad or if its a meter issue, I will test one of the units on another meter this afternoon and see if I can get that 1.4 hg. One of the units has had been adjusted and the cap/stop screw is not glued in so we played with it a bit and were unable to get the inductance to read any higher than the 1.18 at WOT. So I am assuming at this point its a meter issue, my meter is not the LCR55.

I did change the head temp sensor and the car is running a lot better, the missing is gone, however I do have a bit of hunting at idle now so I will check for a intake leak.

Any one else have any tips on determining what my ECU part is?

-Rob

[Bleyseng]

Inside there is usually a sticker that says - CUX13 or CUX14 something like that.

Could be a meter issue or all you MPS's are totally set wrong for the WOT setting. Even the 1.7's MPS has a WOT of 1.35 at 0hg.

[tradisrad]

I'll check inside the ECU for a sticker, thanks, hopefully that will answer my question.

I'll post again about my readings on the MPS from a second meter. I did try adjusting one MPS and I could not get the reading any higher than the 1.18 hg... and I followed the instructions from the "bible".

-Rob

[pbanders]

Some (not all) ECU's have a sticker inside. See the second ECU pic here for an example:

http://members.rennlist.com/pbanders/ecu.h...U%20Photographs

I did all my inductance characterizations using an LCR55. Because of variations in the inductance measurement methods of various meters, I cannot guarantee that the calibrations will be valid if you use a different LCR meter (e.g. different small-signal drive current, detection circuit, etc.).

Best way to set up your 2.0 is as a '74, as far as the FI components go. Get rid of the ballast resistor, get a 012 or a 003 CHT, a 043 MPS, and a 043 or 044 ECU. You can also get Jeff Bowlsby to recalibrate a good MPS to 043 specs. In a pinch, you can use a 037 ECU on a 2.0L '74 setup without problem.

[tradisrad]

I used the second meter to test 2 of the MPS I have avaliable, the meter was a Knight K-240C LCR Meter. I fully understand that this is not the specified meter to use, but what the heck.
At 0 hg, "A" was 1.58h, "B" was 1.57h.
At 4 hg, "A" was 1.27h , "B" was 1.25h
At 15 hg, "A" was at .74h. "B" was .82h.

Since B has no glue on the zero stop screw I adjusted that unit.
I set it to the values specified in the "bible", I adjusted for sea level. "B" is now set for 1.45h at 0 hg, 1.24h at 4hg and .75h at 15hg.

I have not yet looked into the ECU for the possible internal sticker, maybe on saturday...

While I did not drive the car after reinstalling the MPS, I did start it and it sure sounded sweet! I'll take it to work tomorow and have some fun on the way in!

I appreciate all the info avaliable on the web and from fellow owners, thanks.

-Rob