Question: 86 intermittent engine shut off

[JimmyK]

Hello, everyone. My name is Jim and I've been a member of this forum for some time, but have never posted a question, I am the third owner of an 86, automatic, completely stock. Has about 57K on it. I have complete records and receipts for any maintenance and repairs over the years. I'm sure the issue I'm having has been discussed in the past. The problem I'm having is intermittent shutdown , regardless if the engine is up to temp or not. This usually happens when my wife drives the car, but has happened to me twice in the past two weeks. It starts right up when cold, but sometimes has an extended crank time, but will fire up. Recent tune up was done including ignition coil and module. runs smooth and has correct 700rpm idle when warmed up. No stumble on acceleration and runs strong. Battery is about two years old, and passes load test. Alternator was replaced earlier this summer, charges at 13.8 to 14.2 consistently. TPS, IAC, and some faulty injectors were replace last year. There is no check engine light on. Does anyone have any ideas what else to check over? Wife is afraid to drive it,(it killed on her this past Sunday on the way to a car show) and the problem is driving me nuts. Thank you for any advice.

 

[GWinter]

have you had a fuel pressure gauge on it? they need a stronge 50 lbs to run right, under 50 may fail t start, Has fuel filter been changed, under pass feet where frame turns out. Kind of a pain to change.

 

[JimmyK]

Haven't had a gauge to it since new injectors were installed last year. Fuel filter was replaced when fuel pump failed a couple of years ago. I'll put a gauge to it and check that out. Pressure regulator was rebuilt a few years back,also. Thanks for the help.

 

[DEUTERON]

Hello, everyone. My name is Jim and I've been a member of this forum for some time, but have never posted a question, I am the third owner of an 86, automatic, completely stock. Has about 57K on it. I have complete records and receipts for any maintenance and repairs over the years. I'm sure the issue I'm having has been discussed in the past. The problem I'm having is intermittent shutdown , regardless if the engine is up to temp or not. This usually happens when my wife drives the car, but has happened to me twice in the past two weeks. It starts right up when cold, but sometimes has an extended crank time, but will fire up. Recent tune up was done including ignition coil and module. runs smooth and has correct 700rpm idle when warmed up. No stumble on acceleration and runs strong. Battery is about two years old, and passes load test. Alternator was replaced earlier this summer, charges at 13.8 to 14.2 consistently. TPS, IAC, and some faulty injectors were replace last year. There is no check engine light on. Does anyone have any ideas what else to check over? Wife is afraid to drive it,(it killed on her this past Sunday on the way to a car show) and the problem is driving me nuts. Thank you for any advice.

With that few miles on it. It sat alot which electronics don't like. I have a 96 collector with 58k on it and that started cutting out and was hard to restart. Had the control module checked out and that was the problem. Replaced it and upgraded the fuel pump assembly to a Delphi unit just cause.
Runs great.
Gordon

 

[JimmyK]

Thank you for the reply. The ignition module was replaced earlier this year when I replaced the cap and rotor when I did a tuneup. I had a new one in the garage from a previous vehicle, so I put it in while I had it apart. Also checked the ohm reading and checked the wires on the magnetic pickup coil,too. Which were fine. The fuel pump and filter was replaced a few years back with a Bosch unit, which if I remember correctly was OE on the 1986. I agree that sitting doesn't agree with the electronics. I know these cars are loaded with grounds all over the place, so I'm going to start checking those,too. Electronic bugaboos are the worst.

 

[DEUTERON]

The Ecm module adjusts the timing and fuel delivery at about 200 times per second. The majority of the operations are routed through the ECM.
The 86 has a more advanced prom. The ecm is located under the dash.
Some c4s also have a black box which can control more than you might think.
GS

 

[JimmyK]

Thank you. The ECM was replaced last year with the latest version.