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It started as my car randomly shuting off. It would happed while driving, I would wait a little while, then it would come back to life. Then I removed my Field's harness and returned the electronics to stock. After doing that, the car entered some sort of limp mode where it would stall past a certain throttle position (or maybe airflow, not sure what its based on). It also shook noticably, moreso at lower RPMs than higher.

The only difference between the field's and stock harness is that the field's had the Turbo Pressure Sensor disconnected. I know the TPS is used when the ECU enters limp mode, so I assumed the car would not run before because it was not getting a TPS signal. That is, I'm assuming this is the same problem as before, but the pressure sensor lets the car limp home.

Today I was driving home when suddenly it entered limp mode again. Same as before, it would stall past a certain throttle position, and the car shook noticably.

My OBD2 scanner doesn't seem to be working very well (latest patch screwed it up) when it comes to reading codes. I was able to get P0303 and P0300, random missfire and cylinder 3 misfire, but their could be more. I know my plugs are shot (the car missfires under WOT at only 13 psi, or could that be
another symptom?), the IK22s should be here soon. But I don't see how a missfire would cause all my symptoms (I know it could shake the car if it was only one cylinder), and I really don't understand why the car would enter limp mode because of it.

Also, the ! and MIL lights started blinking during my drive home. The blinked for a few seconds and then stopped. As far as I could tell they only did this twice. Anyone know what would cause the light to blink? I know if the cam and crank angle sensors disagree (timing belt slips) it will blink. But the timing belt has obviously not slipped, as it runs fine most of the time. I have had the timing belt slip, and the ECU would not cut power like it is doing now.

Because I couldn't read all the codes, I looked at every variable available to my logger to see if the ECU was getting the correct signals. RPM, timing, load, MAF, throttle position, O2, even water and air temp all checked out fine. Timing might have been a little high, 23 degrees @ 900 rpm idle (I raised it by joining the 2 PS vacuum lines together). Even at throttle position past where the car stalls, all signals looked normal. My FJO of course read full lean while the car was stalling.

Thanks for any help,
Grant
'97 T66 6-speed

PS: This all started after a run at an autocross, about a week or two after getting my single running.
 
Z

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sorry to hear that....off topic, is it the Direct Engineering cast manifold you got with T66? got pictures?
 

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Discussion Starter #3
Zerosoul said:
sorry to hear that....off topic, is it the Direct Engineering cast manifold you got with T66? got pictures?
Yes, I don't have any pics yet, no digi camera and my car isn't even running...

Update:
I've checked the crank position sensor, ignitor box, EFI resistor and ECU. Swapped out from another car with no change in symptoms. I'm done continuity tests between the ECU and ignitor.

I also found out why the MIL was blinking, the ECU does that during excessive missfire to tell the driver to stop, because there is a danger in overheating the cat.

Also, my battery has drained twice now, both times overnight. Most of the time it is fine, but sometimes it will just have no voltage left in it... Anyone know what else is powered directly by the battery except for the ECU and clock?

Thanks for any help,
 

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Possibly bad coil on #3 or the connector isn't making good contact? I'd take a look at the connector, they tend to crack with age and can cause poor contact. After that I'd swap the #3 coil to another cylinder and using the scan tool see if the misfire moves to the cylinder where you swap the coil to. That will tell you if the coil is no good. You've ruled out most of the inputs and the car is behaving normally. Several malfunctions can initiate limp mode and that's what it's doing.

As for the battery, I would use the amp draw function if it has one. Disconnect the positive terminal and hook the multimeter up between the battery terminal and positive terminal and read the milliamps being drawn. Car should be off and doors closed. My car is around 25 ma. If you don't have excessive draw, charge the battery and disconnect it from the car. Let it sit over night and check the voltage. If it drops by itself, then your battery has an internal short. I just replaced an interstate with that problem. The guys at a shop charged it and imediately did a load test and said it was fine. I checked current draw with the car off and that was fine. It finally hit me that maybe the battery was discharging itself and that was it.
 
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