BC

24s and chips went in at the same time (and basically were fine the first few times car was driven).

Both terminals on Temp II to ground are samish.

I will go do as you suggest with the other computer with the newer LH chip (I did not change EZK chip from first version to 2nd).

BC

Nope. Unplugged 02 with second computer unplugged, plugged in second computer and it will not even idle. It will rev, but still missing alot and uneven.

BC

Either its overtly and permanently rich, or something is still wrong with the ignition, which is swapped ignitors and coils and wires.

BC

Any chance an 88 will run with an ezF instead of an EZK? That's all I have to swap.

BC

It's something I haven't thought of or something I have checked but not understood or something.

I really don't want to have to change the injectors back to 19 and rip the chips out.

It just shouldn't be this hard.

Any chance a faulty crank position sensor could Do this?

FBIII

I apologize if its already been discussed. Fuel pressure regulator?

BC

Regulator. Well, I did think of that. Checked if there was fuel in the vac line. Other failure?

BC

How could the regulator add more volume or pressure if it's not going through the vac lines.

FBIII

I had a rubber elbow crack that held the vacuum line on and the engine ran real rich. Maybe take a fuel pressure reading.

jcorenman

Brian,

Basic trouble shooting theory says that if you change something, and it turns to crap, then go back to the last working configuration. I understand that's a nuisance, and I understand that it worked for a bit after swapping injectors and chips, but that's still a couple of added variables.

Another approach is to swap for known-good components. Not the "unknowns" sitting on your shelf, but something from a working car, or recently tested on a working car.

And of course there is the "scientific" approach. Sharktuner is the absolute best tool for that job, but I understand your position. In that case why not just go for the aftermarket ECU now? That will provide similar diagnostic tools and the ability to tweak things as needed.

The alternative is to go through the WSM test plan for the 87+ cars: careful measurements of each sensor that effects the LH and EZK, measured at the 35-pin connectors. Check throttle switch, temp-II, CPS, etc. Tedious to be sure, but e.g. a stuck-closed WOT switch would dump a bunch of extra fuel.

If I were a betting man, I would say MAF. But I am not, because I usually lose.
Good hunting

BC

Thanks for the suggestions. I have checked all the (replaced) elbows for the FPR and Dampeners. All held 20hg for several seconds against the Fuel pressure when running.

I have been double checking the under-intake rubber as well. It looks solid, but you never know. I don't think this is a vacuum leak, however, as the idle control valve is dancing around with the cyclic up and down of the very rich idle it can keep on the original ECU at the moment. No idle on the "other" ecu.

BC

It is. Obviously you are correct. Its getting close. I should be able to write these variables to the back of the line, but at this point, I guess I cannot.

The ECU I found essentially ran the car the same way stock as the original ECU does with the chip. I'm not sure right now how that fits in.

Rob has offered a known good LH, but I had found this 88 unit and did not wish to bother him further (he has sent a Hammer).

If I said that, I did not intend the comment to be for this car. I may have said something I usually say which is that the electrical systems on these cars are what will keep them from ever being loved by anyone but insane people like you and me. But in the midst- I hate these cars right now. No aftermarket ECU for this - this is for DD and then on the block once the interior is in for stable reduction. I don't think I know anyone with a full shark tuner.


To be clear, I did do much of this between or before even posting. TPS, TempII, Grounds, etc. I have NOT tested the CPS. I will be sure to look at the test plan on that.

How many times can you test the same items and have them come up clean before you can truly write it off as not the problem?


MAF is rebuilt. It measures the appropriate ohms between 4 and 6.

On note - I unplugged the MAF while the car was running (the plug) and it died immediately.

I have another video just because I want everyone to suffer along with me. Uploading to youtube now, posted shortly.

BC

jcorenman

The symptoms don't match CPS, my point was that once you have exhausted the "likely", then the "unlikely" needs to be considered. Which, to me, means going back to RTFM and going through it step-by-tedious-step. Because once you've exhausted the unlikely, then you need to deal with the impossible...

Unless I am mistaken (happens a lot), 4-to-6 is the CO pot which is only used for 85-86 cars, not for 87+.

The best check for MAF's is to swap for known-good, or have it tested. I understand that it is a fresh rebuild, I don't know who does Roger's rebuilds but anything can happen. Louie can test MAF's, I can also do that n/c if you pay shipping to/from (PM for address).

One of the interesting things with 87+ 928's is that the LH, with the NBO2 sensor, will compensate for a wide range of errors... until it runs out of range. The trick is knowing how much adjustment the LH is adding.

69gaugeman

If all the plugs look like your picture it definitely is running rich. There are only a couple of reasons why it will run rich. The fuel pressure is high, the injectors are leaking, the ECU is telling the injectors to be cycling too much. Start with a pressure gauge. Then put everything back to stock. That's what I would do.