GSL-SE Rough Hot Start
 

Lately, my stock '85 GSL-SE (225k miles) has intermittently been running really rough on a hot start.
It starts fine cold, then runs fine, for anywhere from 10 to 60 minutes. Then I turn it off for another
10 minutes to an hour, and try to re-start. Sometimes, it starts just fine. Other times, it runs super
rough, won't hold an idle, and low power. I was able to limp my way home, and the idle never improved.
The next day, it will start up and run, just fine.

No smoke.

The first time it did this was right after a fill-up at a gas station I'd never been to, before. I don't know
if it could be a fuel filter issue, but I'll be changing that out, on Monday.

Any other ideas?

Thanks,
Frank

Check the fuel filter, Pump, Evap canister. Air Flow Meter not sticking. I doubt it's a vac leak or the Air Control Valve or it would probably happen all the time.

I like the Evap canister idea, especially since it made me remember that I've heard a whistling coming from under the behind the driver's seat, which I traced to some valve related to the evaporative system. I'll have to look that up, when I get home.

I run a pump without a check valve on mine and sometimes a hot start takes a minute for the idle to stabilize. Its not really unstable, it holds solid idle at 800 RPM, but it just has a little more brap to it.Basically whats going on is fuel pressure drops and all the fuel in the lines returns to the tank when you shut the car off and takes a minute to re-pressurize. Same thing happens if you have all your tank nipples and gas cap open to atmosphere.

To me your issue sounds like a failing trailing ignitor. Fuel injection triggers off the trailing ignitor. When the ignitor gets hot it starts acting up and sends a poor injector pulse signal to your N304 ECU.

I hate to say it - but it's the elephant in the room; 225k mi is a lot of mileage for even our 13b's in the -SE and mine started exhibiting low compression at the 220k mark, finally dying at 222k original miles after becoming incredible difficult to cold-start to the point that it wouldn't.

Up until the end, I was able to cold-start it 100% of the time, because the seals and engine housings were tight enough to get compression to start it, but once shut down - any heat in the engine at all would prevent compression from building.

I swapped to a newer engine a few months back and have yet to fire it up. I hope that's not your issue, but wanted to mention it in case the problem gets worse over time. Summer makes it more of a problem as air temps keep the engine from cooling down rapidly as in winter. Good luck,

i'm with LongDuck. test the compression.