rithsleeper

87 L98 - Well it made it 200 miles but on the return trip not so great. I just started loosing power then finally stalled. Sat on roadside for like 25 min then it started right up again and I took off. but then it died again about another 60 miles down the road. same thing, waited then it started and died. Finally would not start and got towed last 30 miles. Then once it got off the truck, started up again.

My first guess is fuel pump. but why would it be fine after it sits? I thought fuel pumps would gradually fail. This happened in one day. The car had been sitting for about 2 years so maybe filter is clogged and pump is bad too?

rick lambert

First thing I'd do is check the fuel pressure. Next, if the FP is OK I'd pull the ignition control module and take it to Autozone and have them check it.....they usually show their ugly heads as temps increase.

RandyJ75

And if its bad, replace the coil too.

jfb

When it won't restart, that is the time to do some diagnosis. Engines require fuel, air, spark to start and run. Use a timing light to see if you have spark during cranking. Measure fuel pressure and see how long pressure holds up with the ign sw off. Use a noid light (available at parts stores), or a low power 12v lamp like a 194 side marker lamp across an injection plug to see if it pulses during cranking.

87Beast

If you still have precats, it won't hurt to check to see if they have dissolved and clogged the main cat. That will cause a mysterious stalling.

87 rag

Sounds like the ignition module to me.
I had the same problem. Only acted up when warm.
Stealership waned to replace everything else.
Finally after spending all kinds of money I listened to the people on this forum and I told them to replace the ingnition module and the car was fixed.

The problem with testing it is when it's cold it will work fine.

Can86Z51

Sounds just like my late-86 coupe started to do a few years back. Turned out to be a bum F-pump Relay! Was intermittent! They are not expensive, and if your relay is the original, it's past due! Could very well be the cure. Ciao!

87 rag

I guess the next time it happens check for spark to the plugs. If no spark it's the ignition module. If there are sparks it could be the fuel pump relay.
Fuel pump relay sounds cheap, as Can86Z51 said, if it's original it's past due. You might want to just change that and see if it solves your problem.

rick lambert

I'd bet against the FP relay, if it fails the oil pressure switch acts as a backup and provides 12 volts to the fuel pump. When you have the ignition module tested make sure they cycle it at least 10 times, need to do that to see if it's being affected by heat....which is usually the case.

Chatman

If you don't have a couple useful tools, invest in them.

Attach a timing light to any spark plug wire and run the light inside your car. If the problem occurs again, just press the switch and you will know whether there is spark.
Likewise, attach a fuel pressure gauge and tape it to your windshield so that you can see it while driving. The next time the problem occurs, you should quickly see the cause.

Can86Z51

I agree that the FSM says that is the way a faulty FP Relay 'should'-work' and maybe sometimes it will, or does! All I know for sure is that on my late 86, and by report on some other similar era C4's, the intermittent fault was, absolutely, a bad/old Relay was the problem - despite the FSM Indicated back-up!? A new Relay, in my case, immediately and permanently(at least to this point) solved those problems. That was my experience. IMO-its worth a try. Cheers.

j-wireman

Sounds like a problem I had last year. It turned out to be the alternator. I had it rebuilt, charged the battery, and haven't had a problem since.

Good luck.

carls1957

My late 86 had a problem where the fuel pump slid down on it's mounting inside the tank. The pump could maintain pressure at the fuel rail but could not keep up with the volume, so it would start, but the engine would starve under throttle. Hit a bump on the freeway, the pump moved off the connection completely and had to be trailered home.

cv67

L98 fuel pump did the exact same thing as the OPs. $80 for an Airtex FP at Autozone solved that problem.