Runs in Ignition Start

[Yeahrightgreer]

My 88 Dodge has been giving me some problems.

The fuel delivery runs wonderfully however once the engine reaches alittle lower than operating temp (or about 5 minutes) the motor suddenly shuts off. Not stalls out from a lack of fuel or air, but instantly as if a coil wire or ignition wire was disconnected.

After that it won’t restart.

It will crank, spark, and run normally in the “Ignition Start” position but as soon as the key is released it turns off. I thought at first it was a “Ignition Run” fuse blown or a fusible link burnt etc but once you leave the engine for a few hours and it’s stone cold. It restarts just like normal beautifully.

I’ve checked it with a known working coil and ECU box and both do not solve the issue.

Ignition switch? Broken wire somewhere in the circuit?

 

[wagonman]

My $ is on the ign switch

 

[Sixpactogo]

Replace the Ballast resistor. Then make sure your ECU is properly grounded to the firewall.

 

[wagonman]

Oh yeah 88 Dodge what?

 

[Yeahrightgreer]

Oh yeah 88 Dodge what?

Sorry - 88 Dodge D250 pickup. 360 motor.

 

[Yeahrightgreer]

Connecting coil + to 12V source no effect

Replacing ballast resistor and grounding ECU no effect

 

[Yeahrightgreer]

Will try probing ignition switch wires

 

[BeatersRus]

it sounds like an ignition switch problem,but
did you check your starter relay?
is your alternator charging at normal levels?
it almost sounds like a thermal shutdown,esp with it starting and running in the ignition on setting.
then later on whatever overheated will now carry current again and it runs normally.
are you sure the ballast resistors are good and not cracked in any way on the backside?
oh,and silly question maybe,but does your 88 have the high beam switch on the floor or the column?

 

[Sixpactogo]

Normally, when it won't stay running when you go from start to run, it is the ballast resistor but you say after 5 minutes it shuts down, it sounds like some coil is heating up and opening. It could be the ignition coil itself or possibly the plate coil in the distributor. With it being intermittent, it don't sound like a broken wire or bad ignition switch. When they fail, they usually stay failed. Same with the Plate coil, when they fail, they stay failed but it is a coil so I guess it could overheat and open up until it cools down. I would try one of them before going too far.

 

[BeatersRus]

Connecting coil + to 12V source no effect

Replacing ballast resistor and grounding ECU no effect

okay just saw this and have to ask.
you hooked up the coil to Direct 12v power,
crossed the starter relay with a screwdriver and the car would not start up or would not stay running?
please let us know which.

 

[Yeahrightgreer]

did you check your starter relay?

Haven’t checked the relay yet. Doesn’t look corroded or visible defective.

is your alternator charging at normal levels?
it almost sounds like a thermal shutdown,esp with it starting and running in the ignition on setting.
then later on whatever overheated will now carry current again and it runs normally.
are you sure the ballast resistors are good and not cracked in any way on the backside?
oh,and silly question maybe,but does your 88 have the high beam switch on the floor or the column?

I feel like you hit it on the head. The very first time it happened, I was driving at night and I looked at my volt gauge and I was close to 18 volts. I pulled over and replaced with a spare voltage regulator and grounded it heavily and it solved the charging issue back to the normal 13ish volts but then the problems arise. I kept thinking maybe the wires suffered damage.

And Hi beams mounted on column

 

[Yeahrightgreer]

okay just saw this and have to ask.
you hooked up the coil to Direct 12v power,
crossed the starter relay with a screwdriver and the car would not start up or would not stay running?
please let us know which.

Didn’t cross the starter, turned it by key but wouldn’t stay running