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j1mmer5
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Apr 9, 2008, 7:30 AM
Post #1 of 5
(4628 views)
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1993 Buick Regal Limited
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1993 Buick Regal Limited 3.1 130,000 miles
This vehicle ran fine till last week. It's my sisters car and shes down on her luck, no job, now car broke down. My brother and I are trying to repair it on a limited budget.
Last week she drove it about 3 miles to the grocery store it ran fine, shut it off come out of store 10-15 minutes later car started but it was running a little rough. Went to pull out of parking lot and car died, tried restarting it, no go, drained the battery down, freindly gentleman came over and gave her a jump. Car started but when she put it in gear it stalled, started it, and again when put in gear it stalled. She was able to get it going and kept feathering the throttle when she put it in gear and moved the car back in parking lot.
My brother went and checked it out and thought maybe the gas filter either froze up or dirty. He put a bottle of isopropyl in got car going put it in gear and it stalled. He also was able to feather the throttle put it in gear and drove it around parking lot but when excelrating it had a big miss at 1500-2000 rpms. I went and checked it out a few days later tried starting it and it would fire but not start. When it was firing there was a little bit of backfiring thru the air box. When I say a little I mean it was like a slight rumble like maybe it was flooded. So I thought it was either flooded or the timing.
My brother and I went and towed the car to his place and for the heck of it we put a new fuel filter in it, still no luck, so we looked at the plugs and wires they looked original so we replaced them and the air filter.
It seems to start and idle better and we can rev it in park sometimes it revs fine other times you got to feather the throttle to rev it up. Tried putting it in gear and it will stall. next we pulled the EGR off and cleaned it still no luck. We talked to a local mechanic and right away he thought EGR.
Then we talked to our sister and she has another regal with a bad tranny. So we pulled the EGR off it still no luck. We talked to another mechanic and he says maybe the TPS so back to the donor car tried that one, the car started idled fine took it for a ride around the block and about three quarters of the way it started missing again.
I checked for codes with check engine light but theres none in it. The second mechanic we talked to was from the local GM garage and was supposed to bring scan tool over last night but didn't show up.
So I figured I would come here to get some info.
Any thoughts would be appreciated. Thanks Jim
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brbettge
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Apr 9, 2008, 8:02 AM
Post #2 of 5
(4625 views)
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Re: 1993 Buick Regal Limited
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one thing you might look at is the fuel pressure regulator. it is located (assuming this is a car with fuel injectors) on the fuel rail on top of the engine. it will look kind of like the egr on top but will have a vacuum line to it. pull the vacuum line off and examine the inside of it(the end that you pulled off the regulator) if it is the least bit damp or wet it means the regulator is leaking and raw fuel is being pulled into the engine causing a flooding situation. they are fairly easy to change but would not use a used one as the diagphragms tend to get brittle and break when sitting for long periods. besides they are pretty cheap new. one other thing might be the mass air flow meter assuming there is one here. it is the kind of box looking thing in the tube between the air filter and throttle plates(engine). to test; start engine and let idle. as engine is idleing use a screwdriver handle or similar object to moderately tap on the mass air flow meter's housing. if the engine stumbles, shakes, shimmies or otherwise acts up when you tap then the mass air flow meter is bad. a used one is ok here. best of luck, and i'll keep thinking about it....might remember something else.
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j1mmer5
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Apr 10, 2008, 5:33 PM
Post #3 of 5
(4610 views)
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Re: 1993 Buick Regal Limited
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Little more info-
The mechanic with the GM scan tool was over last night.
The only thing he came up with is o2 sensor.
We got a new one replaced it with no luck. So we decided to try the MAP sensor off of the donor car but didn't help. Also replaced IAC with one from donor car- no luck.
To me it seems like its loading up on fuel.
I am pretty sure I found the fuel pressure regulator took the vaacum line off and it was dry.
It does seem to start and idle better but when you rev it to about 2500-3000 rpms then it cuts out and if you hold it there it will stall. You can feather it and go thru there.
Bout ready to try a little TNT!!!!
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brbettge
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Apr 11, 2008, 5:03 AM
Post #4 of 5
(4601 views)
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Re: 1993 Buick Regal Limited
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Ok, sounds like it's time to go back to basics. if it is "cutting out" at any speed or rpm you might have an electrical problem that is disguising itself as a fuel problem. my next step would be to get the coil pack and module assembly off the donor car and put it on. Understand, of course, that none of your donor car's parts are "known good". over the years i have learned that even new is not spelled the same as good. it may be that the tps from the donor car is breaking up at a different place than your car. think of the tps just like a volume control on a radio. it is simply a variable resister that is controlable by you. if the "windings" inside have a break then your volume will get scratchy at that point...same thing happens to it's signal to your car's computer. you also have a crank sensor on this engine that could be faulty at a certain rpm. it is located next to the front crank pulley and is fairly easy to change out. it may help if i explain the function of each of the sensors in plain english. the map is almost exclusively an idle control device. it changes variances in manifold pressures into electrical signals that help the computer control idle quality only. the O2 sensor function is to tell the computer how much fuel to feed the engine at most any speed but is usually only noticeable at idle when refering to quality of engine running (or so that you notice a difference in the way the engine sounds) the O2 sensor sends a varying voltage signal to the computer from .1volt to .9 volt; with .1 being lean fuel mix and .9 or above being rich. I explained the tps except that it sends a varying voltage signal ranging from about 1 to about 5 volts with one volt being idle and 5 volts being wot or wide open throttle. The tps normally takes over for the O2 and MAP in above idle situations. your crank sensor simply tells the coil packs when to fire-it takes the place of the distributor. it uses a magnet to detect exactly where #1 cylinder is at in it's stroke and sends a signal to the coil pack module when #1 reaches (basically) top dead center and the module fires the right coil at the right time depending on load and speed requirements of the engine. The IAC is simply that: idle air control- it controls idle speed only; nothing else.
Worst case and weirdest case scenerio would be the ECM breaking down at around the speed or RPM you are talking about and shutting off the fuel; probably injector pulse section.
you indicate the problem is only at higher rpm"s and idle seems to be fine. So, the thing to do is re-read this and concentrate on only those items which come into play at higher rpm's. tps,ignition module, coil packs, crank sensor, fuel pressure regulator(which could possibly be malfunctioning even without leaking-possibly due to a small hole in the vacuum hose which opens up under high vacuum situations only). This is a rather simple computer control system that has specific control functions; so once you understand which sensors do what and when (which i have basically explained here) then you can pretty much pinpoint any problem. all voltages can be measured useing a DVOM and backprobing connectors to read voltages. the only real thing you must be careful of is the high voltages in the spark plug wires/coils...they pack quite a wallop!
after re-reading this and both of your posts i am inclined to believe that you should change out the coil pack assembly - which is the thing your spark plug wires attach to on the side of the engine. that is the one thing that keeps jumping out at me. also you might locate the crank sensor and make sure it is not loose and moving even slightly on it's mount bolts...let me know, rick
(This post was edited by brbettge on Apr 11, 2008, 5:12 AM)
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j1mmer5
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Apr 30, 2008, 3:26 PM
Post #5 of 5
(4558 views)
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Re: 1993 Buick Regal Limited
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Hey Guys
Got the car fixed- it was the fuel pump.
Thanx for all the help!!!!
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