1993 Buick Riviera Hot Starting Problems

Yes would try crankshaft position sensor next, if plugs are good...

Find the ignition module if it has one...................it may be on the bottom of the distributor. Hit it with some of that cold spray for electronics. If it fires up, you found the problem. Those things are notorious for going bad. I'm guessing it starts fine when it's cooled off.

If that's it, make sure to put a generous amount of heat sink compound under the new one.

sparkie,

Where have you been, since 10/03/2008 8:58 AM?

Man, I never figured to see you again.

I had an old Blazer like that. Ran like a top, till you shut it off. I finally figured out that if you tap the distributor just right with a 7 iron, it'd start right up. (True story)

I replaced the distributor, problem solved. (True story)

Good luck!

Just in case you try some of the good suggestions mentioned before and still have problems, here are some things you may think about:

This is not an all-inclusive list, and it is possible under some circumstances to add or delete items. It is a basic performance testing menu.

Basic testing sequence:

Pre (cold) start attempt:

Check for proper battery voltage

Install fuel pressure gauge

Check for pressure and volume (check spec table in repair manual)

Install engine analyzer

Check for spark at a minimum of two cylinders

Check for injector pulse at a minimum of two cylinders

Pull codes

Check ECM/ECU data stream

Attempt to start: if starts and runs:

During running, recheck:

Fuel pressure/volume

Primary/secondary ignition scope traces

Injector operation (on scope)

ECM data stream

If this car has a carburettor it is probably flooding. Solution: rebuild the carb

If it has fuel injection it is probably a bad coil. Solution check the spark and if weak replace the coil

Hello. The most useful tool when hunting for the source of a hot soak problem for me is either shop air or an old hair dryer set on cold aimed at individual parts.We used to use a refrigerant but these days the practice is frowned upon.The ignition module underneath the coil pack and mounted on top of the engine is an area most likely to be affected by left over engine heat.Actually any electrical connection or circuit board hairline fracture which can expand open with heat is suspect.Any fuel pressure or volume problems are easily diagnosed with the fuel line schrader valve installed atop the engine on the fuel rail.Hope this helps.

Have you considered a vapour lock in the fuel system around the engine?

Vapour lock is a likely candidate and easy to verify.

I had a Cherokee that exhibited the same symptoms as the OP's and found that venting the injector fuel rail until liquid fuel was expelled, via the schraeder service valve, got the engine started again.

It turned out to be a tired fuel pump. Diagnosed (after putting up with the hassle for quite a while) with a pressure gauge off the same valve.

A Toyota Camry fuel pump got everything back to normal for little cost and a little bit of bark off my knuckles.. Started quickly and reliably hot or cold thereafter.

I have an update on my progress with my hot starting problems.

I think I have narrowed it down to the fuel pump. The ECU finally threw a code (e044)that said it was running lean. the car now stalls once in a while and is running rough most of the time it seems like the lower the gas take gets the worse things get. so i plan to replace the fuel pump this weekend I hope.

some other things I have done during the week were,

switch out the ignition coils & driver, crank sensor, fuel filter, i did check at the Schroeder valve on fuel rail and there was pressurized fuel there but the local auto parts did not have a fuel gauge in stock so i do not have a gauge reading. also when the car does not start I can spray carb cleaner in the throttle body, engine does fire and run until the carb cleaner is burned up.

Thanks for all of your suggestions.

Man, I sure would check that fuel pressure and volume like folks said earlier before you throw more parts at it. I'm thinking you've got a in-tank pump, and that's a lot of work to change when it may not be absolutely sure it's the problem. You can rent a gauge pretty cheap to check that with. Lots cheaper overall to test and verify than shotgun parts at it trying to get it fixed.

Some years ago I had the following symptoms:

cool to warm weather - ran fine

Hot weather and tank over half - ran fine

Hot weather and tank lower than half - would cut out and get worse as the tank got lower ......

It turned out that I had two pumps - in tank low pressure, high volume, in line high pressure, low volume.

The in tank pump was the problem - the high pressure pump never gives problems but the low pressure, high volume in tank pump has a limited life - about 350,000km - this car is a Peugeot 505 GTI.