4g61t.org

ECMTuning found issues with the 5v circuit, fixing/recap/testing underway.

so it was the ecu?

i love it when im right. (about once a year LMAO)..

glad its getting fixed so u can get back on the road soon.



Steve

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Steve 89 colt 2.3 stroker stock top end. evo3@20 psi 13.489@99.30mph 3/10 2012
On drag radials.auto trans.launching @ 5 psi and no traction thru 2nd.

Got my ECM back this morning. Plugged it in, started it up, set hard idle, SAS, adjusted timing, adjusted TPS, and tickled the kinks out.

ISC no longer clicks back and forth when the engine stalls (had to kill it on purpose)

Throttle drop has returned to almost normal, half the time, and the now intermittent delay is down to about 1 second from over 2.

Colt start idle speed hits 2k, down to 1100, back to 1600, down to 900, then idle. Takes about 30 secs.

It's running rich as hell.

It hasn't died, but its only been idling for an hour.

Why is it running so rich ??

What do the wires attached to the ECT sensor look like? What ohms does the ECT measure at various temps?
With increased resistance, as these are reverse type sensors to normal thought (hotter means less resistance, colder means higher resistance) the ECU thinks it is super cold and follows suit by richening the mixture to likely unbearable levels. If you unplug the sensor, this is what happens or as the sensor dies or gets corrosion at the connector/wiring.
Check that out per the manuals and see what you find. www.lilevo.com/mirage/
http://www.lilevo.com/mirage/89-92%20Co ... charts.pdf

Secondly, failing 02 sensors could cause the car to run badly, but it is usually a skewed ECT that throws things this badly.

It sounds good that your car starts and hits 2000 RPM, then comes down but it should not bog to 1100, jump to 1600 and back down to 900 or lower once warm. Something is out of wack and the ECU is likely compensation, assuming no other issues with vacuum hoses, gaskets, etc. Figure out the cause of running so rich, and see what happens.

Was the idle stop switch confirm to be adjusted properly and therefore working? It should be contacted as the throttle blade is just closing, and enough to seat it, as the blade closes fully. You can unplug the switch and use a test light for this. Clip on the bat+ terminal and use the needle to contact the switch connector terminal, and when the throttle touches and then closes, it should light up the test light. The ECU needs to see this function, and it can lead to stalling as you come to a stop, and weird idle in general. The 4G15 is very picky about idle, but once everything is setup correctly, it will be rock steady.

Ct sensor resistance is at 3.4k cold, 180 ohm hot, and the engine stalls when it's unplugged. Wires are visually fine, arms not being long enough to test resistance in the wires.

Idle stop switch engages fine.

MAF isn't within range, but I should be able to compensate with the TPS at least to get me home. After a day of driving around its cleaned up considerably and (by smell) is only 2 or 3 points rich now.

Anyone played with plug gap? I'm at .44 atm and I'm wondering if maybe its picky enough that squeezing down to .39 will smooth it out until I can order in a new coil.

Well, it made it. 996 miles at 30 mpg average. I did jump a tooth the day before the trip, had me mad as all hell until I figured out what it was and cranked on the dist.

A big thank you to everyone for all their help. Now I can get back to working on updates for the build thread!