1990 Buick Regal Ltd. 3.1 has rough idle, hesitates and dies when accelerating. Replaced TPS, IAC, PCV, Oil pressure sensor, EGR, O2 sensor, coolant temp sensor, fuel pump, fuel filter, injectors, plugs and wires, fuel pressure regulator, crankshaft position sensor, air temp sensor, MAP sensor. Codes change, once it says too lean, then too rich, then tps, then map sensor. Checked for vac leaks, couldn't find any. Cleaned throttle body and ICM. New gaskets everywhere still to no avail. Car still runs like s***. Can't even go 2 miles to town without stalling. Now I'm really stuck. Any ideas? Thanks Dirk
A lot of new parts! Have a compression test done to gauge the engine's internal condition, and go from there. If compression is good on all 6 cylinders, scan for trouble codes. The compression test may find your problem, something like an exhaust valve burned or not seating properly.
Check all of your blow by hoses and valves for smog
I have worked on a 3.8 w/ similar problems and agree w/
"Honeymokey" about the crank sensor which can crack from long term wear/ heat....also that is a spot that's prone to oil build up.
After changing the sensor the car ran great but refused to climb hills and sputtered, sometimes chugged on flat highway speeds for no reason,....I did the paper clip trick and found the code.....wohla,...the cam sensor was out.
After changing that it ran beautifully.
The funny part is this car was an 90 Buick Lesabre, (still the same engine, 3.8) and the owners bought it NEW and haven't ever serviced it until I met them in 2011....Quite impressive, yet almost everything under the sun kept going wrong.
They got a kick outta keeping me busy and I kept them on the road.
SOURCE: buick lesabre nightmare
Need to get a scan tool and look at the data stream while it is running for alot more info.Also any trouble codes.Sounds like initially,the engine isn't getting any fuel.I would have a pressure gauge connected to the fuel rail on the engine,so i could monitor the fuel pressure while all this is going on.Items to look at on the data stream would be timing,what timing is the PCM commanding for the engine.Also,have you checked for continuos power feed to the coils during this no start condition,and fire at the plugs while cranking.You could possibly still have spark,but maybe it is extremely weak?I have seen bad ignition switches cause weird problems before too.Many things power up through the ignition switch,just a thought.Have also seen bad PCM's cause strange problems..38 volts is a little on the low side for GM.Usually see those at,at least .50 and up,and rise steadily while pressing the throttle,up to just under 5.0 volts.Potentiometer with 5 volt supply.Vacuum leak can be checked with engine running at a steady idle speed,spray brake cleaner all around the intake manifold and listen for engine speed change.
SOURCE: I have a 1990 Buick Regal that stalls...
You might try a crank sensor, most of the time if you pull it out you may see a crack in it. It's between the top of the oil pan an the transmission, good luck.
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