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Discussion Starter #1
about 2 weeks ago i was driving about 60mph and the car started knocking and it died. At full throttle is misses...then backfires..and finally dies after it makes a knocking noise for maybe 10-20 seconds. The car drives fine as long as i dont go over about 40mph or mash the throttle. I have already replaced the throttle positioning switch. I checked the codes and it said "P031" (MAP or Manifold Absolute pressure sensor. I replaced it and it ran fine for the past 2 weeks. Last night I was driving and it died again...SAME CODE!. I replaced the MAP sensor about 20min ago and it didnt help at all this time but still comes up with the MAP sensor code. any help on this one?
 

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01 frontier , 89 Shelby CSX vnt
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barbiedeville said:
about 2 weeks ago i was driving about 60mph and the car started knocking and it died. At full throttle is misses...then backfires..and finally dies after it makes a knocking noise for maybe 10-20 seconds. The car drives fine as long as i dont go over about 40mph or mash the throttle. I have already replaced the throttle positioning switch. I checked the codes and it said "P031" (MAP or Manifold Absolute pressure sensor. I replaced it and it ran fine for the past 2 weeks. Last night I was driving and it died again...SAME CODE!. I replaced the MAP sensor about 20min ago and it didnt help at all this time but still comes up with the MAP sensor code. any help on this one?
If i still lived in fairbanks id be right there to help ya ....

might check the wires to the map sensor , possibly all the wires in there to see if something like a connector came apart
 

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90.5 Allante, 02 Deville, 13 ATS 2.0t
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I had a similar problem. Inside the distributor a wire from the cam position sensor was rubbing on the under side of the distributor rotor plate.. In the process in was worn to bare copper. I repaired the wire with a small wire tie and some liquid electrical tape. This problem did damage to the cam position sensor, which I had to replace. On the replacement I set it in the middle of the adjustment. The net result was that the timing got retarded a little and it now runs great on 87 octane! I was getting a code for cam position sensor fault. Perhaps you just have the bare wire.
Also check your distributor cap for burning and cracks.

Blue_eldo
 

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So if you pull over to the side of the road and shut it off for a minute and then start driving how is it?
Does this happen after you drive for a while or does it start as soon as you turn the key and go?
Does this have a metal fuel tank?
Check into those things and I'll let you know what I think.
 

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BTW, many codes can set and no sensors can be failing, sometimes certain conditions can cause a diagnostic to fail because the computer sees a set of variables that aren't supposed to exist.
Many times even though a sensor code set, the sensor is still perfectly good.
 

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Discussion Starter #7
it happens all the time no matter what...but it only dies at full throttle....or of i am going up a steep hill. Yes i think the gas tank is metal.
 

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Well I can't remember the years, but it sounds like a problem we used to have with the baffles.
The old metal tanks had white plastic baffles in them and with temperature cycling (summer/winter) the tank would expand and contract and crack the baffles. Pieces will break off and settle to the bottom and as you drive the flow of fuel attracts the plastic which eventually covers up the strainer.
The strainer is a sock looking thing on the bottom of the pump that keeps out large particles. Anyway, after a period of driving so many chunks are stuck on the strainer and the suction of the pump attracts more and more.
Eventually the car will starve for fuel, this is most pronounced under acceleration or heavy load conditions like climbing a hill.
If you pull over to the side of the road and shut the key off and wait for a minute or so, the plastic will fall away from the strainer with no suction holding the pieces there. Start it back up and it should run like a monkey.
If that is the case you need to replace your fuel tank.
Based on your description it sounds like that is what's happening.
To verify it I would road test the car and "weave" lightly back and forth so the plastic would move accross the strainer. Once it lost power I would pull over and shut it off and then see how it drove, it always ran like a charm after sitting but by the time I went a few miles with a light weave, it did it again.

HTH.
 

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1991 Deville / 1989 BMW 635csi
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if your car misses and back fires, it is possible that your injectors are leaking and your gears on your distributor may be carbony. I'm not exactly sure this is your problem but check it out anyway.
 

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1995 FWB 124,*** miles
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Check out the plug wires for resistance (should be less than 15kohm) and voltage leaking to the ground.
 

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Discussion Starter #11
I will be working on it over the next few days...the gas pressue was the next thing i was going to check out. also the fuel pump and gas tank for any problems. I just want to thank you guys for your help and i should be posting again on the site within the next few days.
 
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