Vapor lock or what?


#1

My grandfather has a 1988 oldsmobile 98. It has a service engine soon light on. I have checked all the fluids & etc. The car runs like a champ for about 30 to 45 mins then shut off like you turned off the ignition. Directly after, the engine will turn over but will not start. after about setting 30 min the car will start up and run like a champ agian, just as hard as you want to go, for about 30 to 45 mins then it happen all over again. The engine is a V6 3800 fuel injection. If you need any more info you will have to tell me were to look for it. When it dies it does not cough or sputter it dies as if you turned off the key.

Thank for your time.

Sincerly,

Waiting for Papaw to get back from the store.


#2

There is a temperature sensitive-component inside the distributors of many cars, I think this one. GM calls it an ignition control module. Other makers may call it signal generator or pickup coil, or maybe something else.

It is the component that determines when a cylinder’s spark plug fires. When it fails there is no spark.

It can be removed and tested - but the test may be unreliable because the problem occurs only when the component is hot.

I had this part fail on a 1984 Chev and a 1979 Toyota. It would be one of the first things I would investigate.


#3

This engine utilizes a full digital ignition system. Called a “waste spark” system, ignition timing is fully regulated by the ECM. The ECM signals the timing adjustments to the ICM (Ignition Control Module). Directly mounted to the ICM are three coil packs, each powers a pair of cyliders that are opposite each other in the firing order. Spark is triggered in direct response to the ICM’s control signal. No distributor, no points, no timing adjustment.

Next time she dies on ya, pull one of the plugs and test for spark. Wear gloves because they’ll be hot AND you wouldn’t wanna get shocked. Be sure to disable the fuel system and give the engine a few seconds of cranking before starting the test. If you have spark, then that rules out the ignition system. If no spark is present, then it could be a bad ignition module. This part is under the hood and it IS a computer, so it’s succeptable to heat. It’s been running in that 215?F environment for almost twenty years, it’s getting tired.

If you have spark, then the NEXT time it dies, get a gauge on the fuel rail test port and check the fuel pressure. This engine is specced for around around 42psi not running, and should experience a drop of 4psi once the engine is running.

Just wondering, does it take this engine a long time to reach operating temperature? It should take no longer than five minutes of driving.

-Matt


#4

This one does not have a distributor but it sounds like either the ignition module or the coil is going south when it heats up. The ignition moldule is bolted under the coils. I guess what I would do is just go to a junk yard and get a replacement module and coil for about $25 and bolt it in.

Bing


#5

It has a service engine soon light on.

You’re ignoring what is probably your best clue by not finding out what codes are being flagged by the ECM. This is where you should start.


#6

You need the code the check engine light will flash when you put a jumper wire into the test plug. The test plug is on the bottom edge of the dash, near the steering column. It may have a cover on it. Put the cover off. The test plug has 12 holes. To get the trouble code to flash, jumper, with a piece of wire, the two plug holes in the plug’s upper right hand corner. Turn the ignition key on. Read the number of times the check engine light flashes. An example: it will flash four times, pause and flash two time. This would be trouble code 42. Then, one goes to the DTC (Digital Trouble Code) chart, or here, and finds out the component/circuit that 42 indicates there is a problem in. +++ You need to know if there is spark when the engine doesn’t start. I like the Lisle Spark Indicator ($7.95). Your local auto parts store may have one. www.jcwhitney.com, for sure. It’s pencil shape. With the engine cranking, or running, you touch the spark plug wire with the Lisle Spark Indicator. Its light (small and dim) flashes each time the spark plug fires. + Better, is the NEW 4PC INLINE IGNITION SPARK PLUG HT TESTER TOOL


#7

The NEW 4PC INLINE IGNITION SPARK PLUG HT TESTER TOOL (www.ebay.com item # 230148950752) fits between the spark plug and the spark plug wire. Put them in (four are enough) and crank the engine. If spark is being sent to the spark plugs, the spark indicators will flash. AND, the spark STILL goes to the cylinders. If the engine runs, it will run fine with the spark indicators installed. +++ If you had a timing light, you could attach it to a spark plug wire, also, to check for spark. If you get the check engine light code, send it to us, here.