Apparently the computer in my 1974 2.0 is not working properly and making the car run rich. Does anybody know where I can find another one or who to go to have mine rebuilt? It's for a 1974 2.0 with D-jet fuel injection.

Also my 3rd cylinder is misfiring. Would this have anything to do with the computer? If not, any idea what may be causing it to misfire? I have a new working AAR valve installed, my MPS works, no bad wiring in the wire harness or spark plug wires, the timing and dwell are on point and the valves are adjusted.

there should be someone with one in the classifieds
I'm surprised, but anything is possible.

did you ever put an ohm meter on the cht to 100% rule out that the new one you installed wasn't faulty?

Pelican Parts

http://www.pelicanparts.com/cgi-bin/smart/...C%2520Each%2520

Have you had your injectors cleaned?

Yes, CHTS ohm reading checks out fine and the injectors are clean. Car was not misfiring before. Idle issue before was the AAR valve. Which was also causing the car to not start once it got hot. My mechanic took it for a drive after and those issues (seemed) to be resolved (will really know about the car not starting once hot after I drive it for a while). But during the test drive, he said the 3rd cylinder started misfiring. New issue I guess. :/

I believe the computer is only for adjusting and measuring fuel

I don't believe it has anything to do with spark

pull the offending plug and check plug condition
too much fuel could of fouled it?
but that heavy amount of fuel would still likely point back to the CHT or MPS.

put a spare plug into the wire and check for spark
or better yet, put a timing light onto the wire and check for spark.

brant

Thanks for the tip, Brant. He checked the plugs. They are dry and look good and sparking. CHTS is new and working and MPS is working (was tested by Jeff Bowlsby). The only thing he has found in his research is faulty wiring or bad computer. The wiring is fine so he is assuming it is the computer by process of elimination. Everything else is working as it should. Is there any way to test the computer?

What's the part number on the computer? I may have one

post the ecu #.

Could be a bad injector on #3...was that checked for consistency and spray pattern? Also, the ignition wires can mess with the fuel injection wiring (EMI) if they are in close proximity...especially the #3. Is the wiring separated?

On the FI harness, if you would want to send it to me I would be happy to check it out to see if it needs anything at no cost other than shipping both ways.

Check/clean the trigger points?

I highly doubt it. They *rarely* ever go bad.

And it's not really a "computer" either, there really aren't any sophisticated electronics inside at all.

My money would be on either one or more faulty sensors or broken wiring.

Jeff, don't you have an ECU test board/box?

You should listen to the advice here, it's most likely not the ECU, which is hardware a/f maps the work or do not.
There is no way an ECU could affect tuning.

Inputs are
Cylinder head temp sensor
Throttle position switch
Manifold pressure sensor
Ambient air temp sensor

If this have all be properly checked, and the FI wiring harness has been checked, along with your ground connections and the fuel pressure, it will be an ignition issue.

Two things mentioned
Injectors sometimes get dirty after 40 years and can stick open
Cold start injectors can stick open all the time and spray in raw fuel

Both of these things can also make it run rich.

Not sure of your location, but there may be better mechanics to bring your car to that are more familiar with D-jet fuel injection.
It's not complicated, and everything can be tested in an hour or so to rule out part replacement methodology

Just saw you are in Jacksonville Florida.
How close are you to series9 shop?
Joe Sharp just moved there to work at the shop and those two know djet tuning in their sleep.

I have a complete 2.0L FI system with ECU, 5 Green injectors, and all sensors + harness.

I would be willing to part with the entire system, but I do not even know an approximate value.

i would talk to one of the 2 joes at SERIES9. buy new injector seals. they're cheap. and talk to stu.

Make sure ALL the ground wires under the intake plenum are secure on the tabs AND that the wiring integrity at the crimped on connectors is good. Harnesses age, just like everything else, and a compromised ground will certainly cause the symptoms you describe.

The Cap'n

I do, just have not had an opportunity to test it yet. It inteposes the ECU into a complete car set-up...I have a 1974 2.0. :thinking:

I have one for I think a 73 2.0

part # 0 280 000 037

has not been tested.

Ferg

I have two bosch Djet test machines if you think that would work.

rich

Hey guys! Haven't been able to check back the last couple days due to Christmas errands. There's no points. I'll have to swing by the shop to get the ECU number. Hopefully tomorrow. Working a 17 hour day today. thanks so much for the responses! I will check them on my lunch break today (at work already).

Wow that's sweet! It seems I have ongoing issues with my fuel injection. Or it's the same issue and just hasn't been found yet. All I know is that I've taken my car back for the same thing three times now. It's been in the shop for three months and six months total in nine months. I replaced the AAR valve, the MPS is good and has a new CHTS sensor. I don't want to keep replacing parts that may not need to be replaced just to take it back again for the same thing.

Series 9 is about 2 hours from me. But my car isn't running still to drive it.

Thank you guys for all the input suggestions. I will forward them to my mechanic.

What state is your engine harness in?

I had a whole slew of FI problems on my 1.7L D-Jet and one weekend decided to go through my engine harness, which initially looked to be OK.
As soon as i started cutting back the hard plastic protection i found several wires had become brittle from years of heat and had broken inside the insulation!
It took 3(!) used D-Jet harnesses and a full weekend to make one good harness.

That made all the difference in the world and i finally was able to get the engine to run smooth.

I'd take Andy's advice above, have your FI harness checked out. Jeff Bowlsby stated that he'd look at it
and test it for you; send him your harness. Even if it's not the root cause, it'll be good for peace of mind later knowing that your wiring is good and not causing an issue with any components. Jon

Knowing the issues I had getting the FI to run right. I would not be surprised if the wiring is the core issue. Gone through & replaced damn near everything else but that. I would seriously take it down to Series 9 & Joe. I guarantee it will be worth the trip.

Very similar to an issue I was having with my car about 5 years ago. At the advise that the computer rarely goes bad I chased the head temp sensor and a list of other things before I changed the computer. Mine would flood out when hot. Could take 15 to 30 of drive time and was a little inconsistent but always flooded out even when full open at 45 mph. I would pull the fuel pump fuse and it would start(after cranking) and run out the gas in the cylinder. After letting it cool it would run fine again for a bit. Change the computer it is easy to do in five minutes and there a a fair amount out them out there. It is a lot easier than trying to track down a wiring issue. As these cars get older things that never where an issue are starting to come up. The computer takes a lot of heat and thaw cycles over the course of 40 years.

Please let us know what it ends up being so we can figure out if the computers are starting to be an issue.

Ps. If it is always flooding out remember to change the oil once you figure it out as the oil tends to collect some of the excess fuel and the excess fuel washes the cylinders down.

Hi Andy! I'm in FL. My mechanic went over the harness and said it was all good. I think it was replaced/repaired prior to my ownership.

Sounds like you really had your work cut out for you!

Ah. I thought that had been done already. My mechanic said he checked everything and the wires looked good. I will relay this to him just to be absolutely sure. What kind of problems did you have with it, Jamie? Were they ever resolved? I replaced the AAR valve and the CHTS as well.

FYI Since he has my car, I forwarded this thread to my mechanic Frank so he can follow it and see any suggestions as to what the possible problems may be.

Chased proble, smultiple times with the FI. Thought I had them all sorted. Mark from Original Customs had me all squared away. Like any older car. There are not to many new parts out there for it. So many fixes involve another used part. So while it gets you going. You never know how long the new used parts will last. I believe I have a computer. Ill checkwheni get home

Thanks Jamie. Let me know.

PM sent

That's a good idea about changing the oil afterward, thanks!
Yeah, I still don't know what the issue is. The car is still in the shop and the shop has been closed since just before Christmas for the holidays. I think it opens at the end of the week.

From what I'm hearing, it's likely not the computer. But the CHTS sensor was just replaced, the MPS works fine, the wiring (I was told) is good, the plugs are good and the distributor is clean. The idea of the computer being bad was decided upon by process of elimination. I was told it came down to either bad wiring or bad computer, and teh wiring checked out. I guess I'd just rather know for sure what the problem is instead of guessing. A few parts have been replaced and fingers pointed at others already that didn't need to be replaced. I'm hoping he finds out what needs to be done to get it running in optimal performance order soon.

send your fi harness to jeff bowlsby. if it's bad buy one of his. by the time the shop gets done charging you to 'plug and play' you could have a new harness on your car and have a 'definitely not the problem'.

I considered that at first so I specifically inquired about the harness but my Porsche mechanic said all the wires are fine, that the first thing he did was check them thoroughly.

It's been said before, and I know you're confident your mechanic is 914-savvy, but you need to get that car down to Joe at Series9. It sounds like your mechanic is 'stale' on the car and grasping at straws. Bite the bullet and get a fresh set of eyes on the problem. I'm betting the solution will be a real forehead slapper and probably something that's already been cleared of suspicion.