EEC Adaptive learning and bucking

Tony8470

Registered User
I've had some peristant bucking issues with the car the past few years and haven't been able to locate the issue. Replaced cam and crank sensor, and really every sensor when I had the engine built. The DIS was run with a known working one and still had the issue. As it stood until today I thought and Dalke thought it was heat related. Or possibly mechanical (fuel pump).

This problem has only happened after long drives 100+ miles and the days thereafter. I would let the car sit for a week and it would go away. Only to return after another long highway drive.

Today it happened again just after starting the car. But after I came to a full stop at a red light it went away.

I remember reading and article on TCCoA about coming to full stops after disconnecting the battery for extended periods to "teach" the EEC. I've had to reference this in the past because of a high rpm idle after reconnecting the battery.

Is there a way to turn off adaptive learning, or is it even a good idea? This is an 89 5-speed model computer.
 
Its not adaptive learning that is at fault, it is something else, more than likely mechanical. A lot of people have the false impression that it takes days for adaptive to learn, but it doesn't.

As soon as the car goes into closed loop adaptive is learning.... all the time, not just for awhile then stops. Within minutes its "adapted" to whats going on and is correcting, and very accurately at that. Thats why we can use adaptive to tune the car.

As for idle adaptive, that to is working right away and is always correcting within seconds.

Turning off adaptive thinking that is going to correct the issue is actually proving there is an issue with the car and adaptive can't compensate for it. This is the reason I spend time "properly" setting up the tune for idle state which includes adjusting the bypass on the throttle body, and not just mess with the stop screw to get idle to "work" right. Ford put the bypass on the stock throttle bodies in the later years for a reason ;).

Something on your car is getting heat soaked and not liking it. How about the coil pack? How about the EEC itself, as it could be getting heat soaked and starting to go wonky.

Fraser
 
I've had some peristant bucking issues with the car the past few years and haven't been able to locate the issue.

Try and describe the bucking with some more detail. When is it happening, specifically. What are you doing with the throttle, at what speed or RPM is this happening, are there any other behaviors that occur at the same time as the bucking, electrical gremlins?
 
It will happen at any time. Or any temperature (from startup to full operating temp). No electrical problems known, or any indications thereof. It can happen while cruising on the highway or accelerating after a stop. I can't tell if it happens at idle or not. Dalke said he saw it cutting fuel or ignition on the datalogger. Sometimes not even physically noticeable.

If I go light on the throttle it won't go away. If I step into it, it won't go away. One thing I have nailed down is if I make 2 consecutive stops it tends to appear after the first stop and disappears after the second.

One thing I know for sure. If I don't follow the protocol listed for teaching the adaptive, the idle will be in the 1500-2000 range indefinitely. Or untill I repeat and teach it properly.

I don't know much about the open and closed loop stuff. But the car sat for 3 hours today, and when I starting to pull away it was about 120 degrees operating temp. It started bucking. Came to 2 consecutive stops and problem went away. Next stop about 30 min later, at full operating temp it's started bucking as I pulled away. Second stop, it dissapeared.

All the stops I describe are stop lights or signs. The car is running the whole time.

I'm pretty convinced this is EEC related now.
 
Have you tried pulling any stored codes? Does the tach always show properly, never gets stuck anywhere during the bucking?
 
It will happen at any time. Or any temperature (from startup to full operating temp). No electrical problems known, or any indications thereof. It can happen while cruising on the highway or accelerating after a stop. I can't tell if it happens at idle or not. Dalke said he saw it cutting fuel or ignition on the datalogger. Sometimes not even physically noticeable.

If I go light on the throttle it won't go away. If I step into it, it won't go away. One thing I have nailed down is if I make 2 consecutive stops it tends to appear after the first stop and disappears after the second.

One thing I know for sure. If I don't follow the protocol listed for teaching the adaptive, the idle will be in the 1500-2000 range indefinitely. Or untill I repeat and teach it properly.

I don't know much about the open and closed loop stuff. But the car sat for 3 hours today, and when I starting to pull away it was about 120 degrees operating temp. It started bucking. Came to 2 consecutive stops and problem went away. Next stop about 30 min later, at full operating temp it's started bucking as I pulled away. Second stop, it dissapeared.

All the stops I describe are stop lights or signs. The car is running the whole time.

I'm pretty convinced this is EEC related now.
The high idle concerns me. I know that wasn't an issue when the car was here. A high idle is usually a mechanical problem (like a vacuum leak).

I know the bucking was an odd thing when I experienced it. I could not determine any cause for it but it seemed to happen only when the QH was connected to the car. After I put a chip in it never did it again while I had the car. Obviously I just didn't drive it enough to encounter the problem. I don't often blame the EEC for stuff but it certainly wouldn't hurt to swap the processor if you have another one available.
 
wont start

My 1990 super coupe quit running the other day. I replaced the key switch, ignition switch, ignition module, coil, fuel pump. Will only start when primed and run until prime is burnt. It has 40 lbs fuel pressure. It has good spark. I am stumped because this is hi tec ~~~~. I am new to sccoa and any help forthwith is cool
 
for tony it sounds like fuel pump mine acted up for a year or more mostly when warm after you drive an hour or two mostly when you would lift or stop it would shut off . then restart . it was fuel pump fixed it .
for the other guy that replaced everything im not sure sounds puzzling maybe the ground wire on the back of the heads needed to fire the injectors . if it only runs when primed i would be looking at the fuel pressure regulator or the inertia switch in the trunk but he says 40 pounds of fuel pressure

ralph
 
Run it with the cam sensor disconnected. Still sounds like it to me (random time, temp, etc.) Starting is tricky. It might take multiple tries, key off between attempts. It can take up to 5-6 tries for it to guess right on the coil sequences.
 
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