Engine dies like key was turned off

[6PKRTSE]

Bulkhead issue on one of my cars before would just kill the car driving down the road. While it is running, wiggle the engine harness bulkhead connector at the firewall. Also, try wiggling the ignition harness plug under the steering column. My current New Yorker had the ignition harness plug issue. A couple of zip ties run between the wires and pulled the two halves of the plugs together and it has been fine for years now. That little retaining center tab allows the plug to swing Slightly from side to side even while plugged in.

 

[Detective D]

No, engine temp has nothing to do with it. The first time it died the engine had been running about 5 minutes. The second time the engine was at temp. Also no condenser, electronic ignition.

Electronic ignition requires a pick up signal from the distributer or elsewhere. That is what is failing. Most common with MSD is people install a new distributer with the pick up installed, but sometimes people source one from a more modern engine for less money if there is that option available. A few local stories have made me personally very leery of the MSD "billet distributers" as two different guys(one Ferd, one chebby) had to send their brand new one back under warranty, 2 years apart.
1990's era electronic ignition this was a very common thing, when distributer got older the pick up failed and this is EXACTLY what would happen. I had a 94 Mustang back in the day I put up with it for about 3 weeks while I waited for my new distributer to arrive.

It could also be the MSD box. Did you mount it somewhere away from heavy vibration and heat? It would only take one event to cook something.

Modern, brand new electronic anything is a crap shoot if you got a good one or a china time bomb. If you were careful and precise with the wires, it is likely a sub-component that you can't really do anything but replace, like the pick up or the whole MSD box.

 

[Jeff Erwin]

Electronic ignition requires a pick up signal from the distributer or elsewhere. That is what is failing. Most common with MSD is people install a new distributer with the pick up installed, but sometimes people source one from a more modern engine for less money if there is that option available. A few local stories have made me personally very leery of the MSD "billet distributers" as two different guys(one Ferd, one chebby) had to send their brand new one back under warranty, 2 years apart.
1990's era electronic ignition this was a very common thing, when distributer got older the pick up failed and this is EXACTLY what would happen. I had a 94 Mustang back in the day I put up with it for about 3 weeks while I waited for my new distributer to arrive.

It could also be the MSD box. Did you mount it somewhere away from heavy vibration and heat? It would only take one event to cook something.

Modern, brand new electronic anything is a crap shoot if you got a good one or a china time bomb. If you were careful and precise with the wires, it is likely a sub-component that you can't really do anything but replace, like the pick up or the whole MSD box.

Thanks, I'll look into this.

 

[Geoff 2]

An operational vac adv unit twists the pick up wires during operation. A high mileage dist will eventually break the wire causing no spark.
Which is why I suggested the SIMPLE test in post #11, which is going to eliminate some variables.

 

[Ray70Chrg]

Hey Jeff, any progress on this problem?

 

[Sixpactogo]

IMO, you have two different issues. One has to do with the NSS (Neutral safety switch). Could be a bad connection in that circuit somewhere. The abrupt shutdown has many times been caused by a poor case ground at the ECU. The only way I know of to verify it is to check between Neg post on battery to the ECU case. You need less than .05 ohm on a digital ohm meter. More than that, causes the transistor in the unit to heat up and open the circuit. Once it cools a little, it will close back up until it overheats again. All caused by a bad ground. I have heard the newer ECU's are shoddily made and are more prone to failure.

 

[Jeff Erwin]

I went after this like I had two issues, the car engine dying suddenly and occasionally not starting when the selector was in P. While replacing the ignition switch I did find a loose wire in the connector to the main wiring harness, and it just happened to be the RUN wire, so odds are that was causing the engine dying issue. Not confirmed yet, I have to figure out how to put the whole upper steering column back together. Confidence is high.

I ordered a new neutral switch for the transmission and will get it installed once I get things running again and can move the car to my lift.

I asked my friend the mechanic how I would know if I fixed the problem. He said I will just have to go drive it around. Swell.....

So it seems like you guys nailed it!. Now if I can just get someone to follow me around for the next few weeks...

 

[Sixpactogo]

I went after this like I had two issues, the car engine dying suddenly and occasionally not starting when the selector was in P. While replacing the ignition switch I did find a loose wire in the connector to the main wiring harness, and it just happened to be the RUN wire, so odds are that was causing the engine dying issue. Not confirmed yet, I have to figure out how to put the whole upper steering column back together. Confidence is high.

I ordered a new neutral switch for the transmission and will get it installed once I get things running again and can move the car to my lift.

I asked my friend the mechanic how I would know if I fixed the problem. He said I will just have to go drive it around. Swell.....

So it seems like you guys nailed it!. Now if I can just get someone to follow me around for the next few weeks...

Well...You are making progress and may very well have fixed your shut down issue with the run wire connector. I think your mechanic is probably correct but you could verify your ECU ground in short order. Electrical gremlins can be elusive.

 

[Gary Spaid]

Glad you seem to have fixed your problems. I was having that intermittant won't start issue. I found the NSS connection on the starter relay was kind of loose and very close to the engine so I suspect vibration caused the problem. I ended up slightly rotating the starter relay so the connector was not too close to the block. No issues since.

 

[59pwrwgn]

With the car in Park. Use a screwdriver to jump the relay between the main power wire and the wire the goes down to the start. This would reduce it to battery, stater and the cables to the starter as well as the ground wire from battery to engine