'92 88 Overheating

[rokit.scienz]

My '92 Delta 88 (3800 V6 engine) has ~170K miles. Lately, after driving for awhile (+20 min) it's shutting off intermittently and letting me sit for 30 minutes before restarting. It doesn't have any spark during this time. Suspecting the engine was overheating and not indicating so, I replaced both the coolant temp sensor and sending unit (one for computer and one for instrument panel).

At idle the temp indicator shows the engine gets to ~260* (edge of red zone) before the cooling fans turn on. (I haven't tried running it beyond this point to confirm the overheating is shutting the engine off.) The fans only stay on for ~30 sec (long enough to cool to ~230*). What would cause the delay in turning on the fans and do you believe this is causing the engine to overheat to the point of shutting off?

Thanks!
John

[maxwedge]

Welcome to AF, I would get a scanner on it and get the true running and fan turn on temps, also when the stall occurs and no spark the same scanner will reveal whether you have cranking rpms, usually this is caused by the crank sensor wiring from the cps to the icm or the icm, least likely though.

[rokit.scienz]

Thanks for the info and a great website!! The car failed on me again yesterday during a hot day but I noted that the temp indicator was NOT in the red when it shut off. You are the second person to point me towards the crank position sensor and/or ignition control module. Is there any way to test these? (I don't have access to a scanner and don't trust the car enough to drive far.) Also, would it make sense to R&R the CPS before testing/replacing wiring to the ICM?

[maxwedge]

Without the proper equipment you cannot really test the cps, only check with an ohmeter, which is not accurate. Based on the year of the car I would just replace the cps and check for frayed or cut wiring to the icm.

[rokit.scienz]

I tried to follow your advice and replace the cps. Unfortunately, I've been unable to remove the bolt securing the crankshaft pulley. I've used an impact wrench and a breaker bar with no luck. Are there any secrets? Will the cps be accessible after removing the pulley or will I have other surprises once that's removed? (My Haynes manual doesn't describe changing the cps.)