89-W-Body-Regal Posted September 9, 2018 Report Posted September 9, 2018 (edited) Has anyone had any luck fixing this so the code won’t come back in the future? Today my Buick Regal 2.8 V-6 had a hard time starting. It drove fine all day, when coming home from the store it was running rough and noticed a delay when trying to accelerate like the car was slowing down on me when I tried to accelerate. I had to pull over in a parking lot and the engine shut off on me. It just kept cranking afterwards when trying to start it. I am experiencing all the symptoms that would qualify for a faulty map sensor, although GM map sensors aren’t common for going bad. All the vacuum lines are ok and most of them have been repaired so I know I am not loosing any vacuum. Fuel filter has also been replaced a year ago and air filter is clean. I also replaced the fuel rail test valve because that was leaking gas. Edited September 9, 2018 by 89-W-Body-Regal Quote
Dark Ride Posted September 9, 2018 Report Posted September 9, 2018 You could check the wiring by the connector, I had that happen on my Lumina. Caused it to act like a bad map. Quote
89-W-Body-Regal Posted September 9, 2018 Author Report Posted September 9, 2018 The wiring is good and so is the connector. Quote
Schurkey Posted September 9, 2018 Report Posted September 9, 2018 What is the fuel pressure? What is the cranking compression? Do you still have spark at the spark plug end of the plug wire? Quote
Dark Ride Posted September 9, 2018 Report Posted September 9, 2018 Did you replace the map sensor? Quote
digitaloutsider Posted September 10, 2018 Report Posted September 10, 2018 Sounds like what my Cutlass did years ago when the MAP failed. Quote
89-W-Body-Regal Posted September 10, 2018 Author Report Posted September 10, 2018 14 hours ago, Dark Ride said: Did you replace the map sensor? Not yet, I did order a new one. The reading on the scan tool was too high. The connector was tight on the sensor and so was the vacuum lines which were good. Quote
Dark Ride Posted September 10, 2018 Report Posted September 10, 2018 If you've confirmed the wiring and connector look good and all the vacuum lines are good I would try that next. 89-W-Body-Regal 1 Quote
Imp558 Posted September 10, 2018 Report Posted September 10, 2018 Even if the sensor turns out not to be the culprit it's probably ancient. Would be a good idea to verify 5v and low reference and check continuity on the signal wire to the ECM though. Quote
89-W-Body-Regal Posted September 10, 2018 Author Report Posted September 10, 2018 (edited) 8 hours ago, Imp558 said: Even if the sensor turns out not to be the culprit it's probably ancient. Would be a good idea to verify 5v and low reference and check continuity on the signal wire to the ECM though. I did that today. The readings were so off. I applied vacuum to the sensor and the reading didn’t change like it should do.. Plus the reading I got didn’t even match the readings from the spec chart. And it’s the original map sensor. So that makes sense it would need to be replaced. Edited September 10, 2018 by 89-W-Body-Regal Quote
Imp558 Posted September 10, 2018 Report Posted September 10, 2018 If you read across the gray and black wires and get reasonably close to 5V then the 5V reference and low reference are good. Then disconnect the battery, unplug the PCM and check continuity from the light green wire to the PCM plug and it should be about .2 ohm. Quote
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