Engine dies during KOER EEC self test (and other issues)

April 28, 2014, 10:42:32 AM

Ever since I went to the dyno earlier this month I have been trying to track down why my car isn't performing quite like it should. It runs great in the lower RPM range but once you get to 3800+ it just stops pulling and takes FOREVER to rev up.

Here is a run down of the car. The car is an 86 Cougar with the engine and wiring harness from an 86 XR7 and a T5 from an 87 TC. The engine itself is all stock with the exception of an A237 cam. The engine only has 52k on it. The turbo is the stock T3 with an SVO compressor housing and a .63 AR turbine housing. Gillis at 15 psi of boost. Stock TC intercooler. The exhaust is all 3" with a Dynomax race bullet ler. It has an LA2, big VAM, and 35lb injectors. The fuel pump is a 320 lph (rating might be embelished a bit...) from highflowfuel.com. Plugs are fresh Autolite 764s gapped at .030. Timing is stock 10 degrees BTDC, spout out. Cam timing was just set and checked when I did the cam swap last month.

Dyno video:
https://www.youtube.com/watch?v=YtEuOJi54LQ

Dyno graph:
http://img.photobucket.com/albums/v648/Loaded87IROC/dynoscan_zps70720ac0.jpg

After the dyno, I lowered the boost as much as possible with the Gillis. It is at around 10 psi now. I made a few highway pulls and it feels the same as when it was at 15 psi. Afr is now around 12ish during the pull (used to be right at 11-11.5) which seems pretty high considering I have the base FP at 44 and it's pretty much a stock engine. I confirmed fuel pressure is rising at a 1:1 ratio to about 54 during the test runs and is steady with no fluctuation. I didn't hear any pinging during these runs.

The next thing I noticed is that I no longer have cold start enrichment. It used to be as soon as I would start the car after sitting overnight it would run in the 10.5-11 AFR range for about a minute then it would lean out to the 14-15 range. The last few times I have started the car it has instantly been around 16-17 and idling slightly rough.

The last thing I found was that it won't do a KOER test. KOEO ran fine but when I tried the KOER it flashed the two flashes for the engine ID then revved up to about 2200 for about 10 seconds before dropping down, stumbling, and dieing. I repeated it several times with the same result. No codes were reported.

I pulled the plugs to see I any of them looked different (injector clogged or not firing maybe) but they all looked the same. While I was at it I did a compression test and got 150-160 on all cylinders. The car still runs fine and has nice power at low to moderate throttle.

The general consensus on Turboford for the low power/slow revving is worn valve springs. I'm OK with that and will hopefully be swapping them out soon but what about the weird fuel related issues? Could it be that the EEC is damaged and not controlling fuel properly?

Any suggestions are appreciated!

Engine dies during KOER EEC self test (and other issues)

Reply #1 – April 28, 2014, 12:24:47 PM

They often die when doing KOER if base idle is too slow... Disconnect TPS, set idle to 600 hot and then reset TPS...

If you haven't verified fuel pressure under boost do so...

Engine dies during KOER EEC self test (and other issues)

Reply #2 – April 28, 2014, 12:41:05 PM

This is a longshot, but what are you using for your AFR meter? I had a sunpro (I think) in my old 83, and it screwed with the O2 signal something fierce. If I disconnected it, the car ran much better. I don't know if it was a problem with the gauge, or if I had some other electrical issue, but if I left the gauge connected, it ran like and got terrible mileage.

Have you checked for a plugged catalytic? I had a van that acted like that. Ran ok, would go down the road ok, but very slow to accelerate. Turns out the catalytic converter was broken inside and severely restricting flow.

Just a couple ideas for ya.

Engine dies during KOER EEC self test (and other issues)

Reply #3 – April 28, 2014, 01:13:30 PM

Quote from: TurboCoupe50;433053

They often die when doing KOER if base idle is too slow... Disconnect TPS, set idle to 600 hot and then reset TPS...

If you haven't verified fuel pressure under boost do so...

Shouldn't he also disconnect the IAC when setting the base idle? You have to do that with every other EEC-IV controlled engine.

Engine dies during KOER EEC self test (and other issues)

Reply #4 – April 28, 2014, 01:13:42 PM

The car wanted to make a liar out of me today so when I started it up, it started out rich like it should and then leaned out to 14.5-15.5 AFR. I bumped the FP up another 5psi (now 49 with no vacuum reference) and took it for a drive and AFR at WOT was good again, in the 11-11.5 range. FP was rising properly, was at 59 at 10 psi.

The car wasn't done making me look bad though, I ran another KOER test and the engine didn't die this time.

KOER codes came back as:
24 - IAT (I don't have one)
34 - EGR (Deleted)
74 - Brake Circuit (I didn't press the brake)
77 - Operator Error Dynamic Response Test (I didn't floor it during test)

KOEO codes remain the same. 54, 82, 83, 84, all normal for an LA swapped car.

I am using an AEM wideband for AFR readings. The exhaust is straight though, no cat.

The car has always idled right at 1000, is that too low?