Help!!! Shutting off issue

[texas tough]

There’s the two wire connector, so which wire do I jump to check for juice? Or do I unplug it all together and just put the screwdriver to the coil?

the big wire that look just like the spark plug wires

 

[Matt Conner]

if your not getting spark from the coil, you have a problem in the distributor or the coil is failing,

It has a new coil on it. Could the coil possibly be getting hot and degrading causing the engine to just shut down?

 

[texas tough]

theres one big wire going from the coil, to the center of the distributor cap.. unplug the side going to the coil.

 

[Matt Conner]

theres one big wire going from the coil, to the center of the distributor cap.. unplug the side going to the coil.

Then crank it to see if it arcs to the screwdriver, if it doesn’t, then there’s a coil or distributor issue, correct?

 

[texas tough]

yes these are by pass ignition systems,, the computer doesnt really come into play to do the ignition untill the motor starts, and gets to 400 rpms.. then the computer helps regulate ignition timing,..

 

[Matt Conner]

yes

Okay, I will try this the next chance I get to work on the truck, and I’ll keep the thread updated

 

[texas tough]

divide and conquer,, determine if it is a fuel problem or ignition problem.

 

[Schurkey]

I just had an exhaust put in the truck and they didn’t reinstall the o2 sensor. The headers I have on the truck have a bung for an o2 sensor and I plan to install it. But the truck has no cats on it.

You understand that not having a catalyst in the exhaust makes NO difference in the need for an O2 sensor?

With no O2 sensor, the computer cannot achieve closed-loop operation. Fuel economy, power, and driveability all go in the toilet.

Obviously, the engine shouldn't stall even in open-loop operation. However, since that is still a mystery at this point, while the lack of O2 sensor is entirely known and critical to the proper operation of the engine, FIX THE O2 SENSOR, and see what happens.

AGAIN, you need to connect a scan tool to this vehicle so you can look at the data stream. You're stabbing in the dark without the data stream. The results you're getting are typical, given the lack of information presented to you via the scan tool.

If you don't have spark, and you don't have fuel, a common problem is lack of cranking signal to the ECM from the pickup coil and ignition module--which could just as easily be a failed wire anywhere from pickup coil to the ECM. Doesn't have to be the pickup coil, the module, or a fault within the ECM--although any of those are possible.

 

[Macg]

A shot in the dark but could be the temp sensor on top of motor. My '94 5.7L would not start with this sensor unplugged. ECM gets a reading from it. Don't know if it would shut down a running engine if unplugged with engine running as I didn't do that.

 

[Markgyver]

You understand that not having a catalyst in the exhaust makes NO difference in the need for an O2 sensor?

With no O2 sensor, the computer cannot achieve closed-loop operation. Fuel economy, power, and driveability all go in the toilet.

Obviously, the engine shouldn't stall even in open-loop operation. However, since that is still a mystery at this point, while the lack of O2 sensor is entirely known and critical to the proper operation of the engine, FIX THE O2 SENSOR, and see what happens.

AGAIN, you need to connect a scan tool to this vehicle so you can look at the data stream. You're stabbing in the dark without the data stream. The results you're getting are typical, given the lack of information presented to you via the scan tool.

If you don't have spark, and you don't have fuel, a common problem is lack of cranking signal to the ECM from the pickup coil and ignition module--which could just as easily be a failed wire anywhere from pickup coil to the ECM. Doesn't have to be the pickup coil, the module, or a fault within the ECM--although any of those are possible.

I agree with Schurkey most likely when the engine gets warm and goes into closed loop operation not having the O2 the engine ECU will most likely lean out or richen up until it stalls.