I have a 1992 Buick Riviera that runs fine when the sun is out but after a hard rain, the next day the car just turns over and tries to fire but doesn’t catch. Sometimes it catches but then makes a belching sound. I have had the plugs and wires replaced and the ‘mass air sensor’ cleaned. It seems like water is coming in somewhere but I can’t get the problem to repeat for the mechanic because it’s always sunny when I can get it started!
My suspicion would be a devective set of ignition coils. I drive a 1990 Riviera. Same body and engine. I had a major problem with the ignition coil packs. Either the gasket or the coil packs themselves could be at fault.
In order to be sure of this, you’ll have to check for fuel first. On the top of this engine, there’s a plactic cover (branded with the number 3800.) There should be a small hole in the cover through which a little plastic cap pokes out. Unscrew this cap. When the engine has this problem, turn the ignition on, poke the little valve that is under that cap (keep your eyes covered, sheilded, or turned away.) Fuel should spray out. If it does, you’re probably okay on fuel.
Check the air filter, the air cleaner box, the duct and the throttle body to ensure they’re free of restrictions. The filter should be clean.
You’ll have to check for good, bright spark also. But if the car passes the other two tests, I’d assume that it is in fact the ignition coils or the gasket, only because I’ve had simmilar problems. As the coil packs begin to wear out, they start to have trouble firing when cold, or wet. At first, this problem will only affect you after rain, but eventually, you’ll begin to have starting problems any time the car’s off for more than 8 hours. If you have an ohmeter/multimeter, you can check the resistances of the coils to see if they’re good or bad.
Also, be sure to check the diagnostic codes. The check engine light would probably be on if there was a problem, but just to be sure, pull the codes. To do so, turn the ignition to on, and press and hold the TEMP UP and OFF buttons on the Climate Control panel, until all the lights flash on. After the lights burn for a few seconds, the computer trouble codes will begin to flash on the instrument panel where the odometer displays. If any come up, post them here. But sure to get the letter (E, B or R) before the code, the number, and the letter after the code (C or H).
I believe that an ignition problem is most likely. You can try spraying the ignition wires with some WD-40 (WD means water displacement) and see if that helps. Of course if the plug wires are old (10 year old wires would be ancient) you should just replace them along with any other original ignition parts like plugs and coils.
[quote]I should have told you what has already been done. The ignition wires were replaced and also the plugs. A lab scope test was done and computer codes were checked. Mass air flow sensor was cleaned. Thanks for the ideas, too.
Also, check the distributor cap. If moisture creeps in under the cap, it will cause all kinds of shorts in the spark circuit. I’d just go ahead and replace it and the rotor, since you replaced the wires and plugs.
Hey, thanks for such a detailed reply. I erred in not telling you what had already been tried. The first time I brought it in (I’m quoting from the invoice),
"physical inspection of fuel ignition, vacuum, and electrical components and connections. Test fuel pressure, engine vacuum and compression test. Scan computer data stream for trouble codes. Lab scope test. Examine ignition for primary and secondary patterns. Locate vehicle test connector, connect our scan tool to vehicle computer. Operate engine and examine engine management data. All data looks good with no trouble codes stored. Installed new ignition wire set. Install new spark plugs. Clean mass air flow–remove old sensor, clean sensor wires. Reassemble and retest. Car checks out.
Of course, it was a sunny day when I brought it in and a sunny day when it was worked on. Would the problem you describe have been picked up by anything they might have already looked at? I’m not a mechanic but your explanation really sounds plausible; especially since your car is so similar. They told me the last time that if I still had problems I should replace the mass air sensor. I really don’t want to get into that process of “parts roulette” where things just keep getting swapped out until someone makes a lucky guess. I will give them your suggestions, if they haven’t already tried them! Thanks.
I just went outside. Still won’t start, but almost. Here are the codes that came up during the test
no r Code
I hope these give you a clue or tell you something? Thanks.
E34 is Mass Air Flow sensor frequency low
E44 is O2 sensor signal (lean)
B552 is MBCM memory reset
The O2 sensor signal issue can be tied back to the MAF sensor being a problem. Try replacing the sensor, then clear the trouble codes. To do this, go back into diagnostic mode like you did before. Wait for the codes to finish flashing. When they’re done, a message “ec?” will display. Press the UP button for the fan (fan speed up), you should see “Data EC?” displayed (sometimes the button presses don’t register, you may have to press more than once, just be sure you see the right message, and be patient). When you see “Data EC?”, press the DOWN button for the fan (fan speed down) repeatedly (slowly) until you see the message “Clear E code?”. When you see this message, press the UP button on the fan. The message “E Code Clear” should display after a few moments, followed by the message “Snap BC?” Hit the Bi-Lev button to exit diagnostics. As long as the engine remains off, the codes won’t set again. So replace the sensor before restarting the engine. Once the sensor is replaced, operate the vehicle for at least half an hour (drive it somewhere, not just idling) and then return home, and pull the trouble codes again. Repost with the codes that remain.
Oh and, you’re welcome. I know the post was detailed. The fact is that I am intimately familliare with this car by now (maybe too much so.) So this is almost like I’m working on my own car.
Did the error codes I listed tell you anything?
Okay, thanks. I’ll give it a try and keep you posted. Maybe two things are going on, the mass air flow sensor and the ignition coil problem. Seems like the latter would be more related to the wet weather issue.
This car uses DIS, distributorless lgnition. It’s a waste spark system using three distinct, seperate coil packs mounted directly to the ignition control module, which is mounted to a bracket on the front of the passenger side of the engine.