'93 MTX stalls, code 542

[xouroborus]

Hi guys...I need help. The car stalls after driving a short distance. It will restart after a while. The only code I pulled was 542. Once, shortly before it started to stall, it stumbled while accelerating to pass.

I don't know where to start with this one. Any thoughts?

Thanks

Greg

 

[kd7kmp]

It looks like you may need a new fuel pump. Follow this link to test the circuit to your fuel pump: http://www.shotimes.com/php-bin/mod...le=article&mode=thread&order=0&thold=0&sid=83

 

[xouroborus]

Do you mean the test where you ground out the Fuel Pump (FP) test pin to make the pump run continuously? If so, I did that and the pump ran continuously. So it seems to work fine. Maybe I didn't let the test run long enough. How long should it be tested for?

 

[Dave Kegel]

The 542 is the code that tells you it stalled, so that is no help. What did the tach do when the car stalled? If the car was in gear and rolling and the tach dropped to 0, that's a good sign that the problem is your crank position sensor.

Dave Kegel

 

[xouroborus]

I've been reading the past messages on the 542 code. Several times it was mentioned that it should just be ignored, indicating that it just recorded the stall.

It's actually my sister's car. It has almost 200K miles on it. I don't know what service has been done. Idling today in the driveway, it ran just fine. I wasn't behind the wheel the times this happened. I've asked her for some more details, specifically if the tach drops to zero. She can't remember. She did say that it really bucked the first few times. She was able to keep it running at low rpms for a short distance and get to safety, before it died and would not start. The last time it just died. The local wrench wrangler claims it is the PCM($385). When she told me that, I figured he was just guessing for $$$. He may be right, I don't know. My sister is just the type that greasers hope for when they want a new boat.

This is the first time I've cracked a SHO, so it's a steep learning curve. I should be able to solve this with a little help. This forum is great!

 

[Dave Kegel]

It is rarely the PCM. The crank sensor is a very common problem, as is the cam sensor. My money is on the crank sensor.

Dave Kegel

 

[HopefulSHO]

Crank sensor or fuel pump.

 

[kd7kmp]

Dave is most likely right. What he said sounds right.

Kevin

 

[xouroborus]

So I came across rangerj's excellent post on how to test the CPS, DIS, SPOUT, CID, etc., using a Digital Multimeter or LED Test Lamp. Since the problem is intermitent, I take it these test need to be performed after the car dies?

If it is the CPS...do I just go ahead and do the famed Lower 60K?

 

[xouroborus]

opps...that should have read Front 60K. How about it guys? It sounds like it would be a prudent thing to do.

 

[xouroborus]

update: after nealy 800 miles for perfect operation, it finally wouldn't start. She was able to get it started, but it was running rough and the CEL was on. Wiggled the wires about the firewall and it started running right and the CEL went out. When she got here, I pulled a 214 and a 542. I figure it's not a faulty CID, but a bad electrical connection, given a little wiggle seemed to fix it. I have cleaned and shined all the connections to the CID, CPS, grounds and a few others. There was a little corrosion in the CID plug. One thing she said is that the tach read zero while it was running rough.

Hopefully I got it fixed now.

 

[projectSHO89]

I'd bet on that flakey CID connector for the reason for the bucking and no tach.

Continue to keep an eye on it.

Steve