My Bonnie running funny

bigboyisme · #1 08-10-2004, 07:51 PM

I am having problems with my car starting, especially when it is parked uphill. It also doesn't accelerate as it should, it kinda shudders and when I floor it, it putters till it makes up it's mind it wants to go. When I start it, sometimes it missfires, but once started it idles pretty good. In any case I sure could use some help with it. I was thinking it may be the crankshaft sensor...whatever that is, I read it on the board. Are they hard to replace and what do they cost and where can I get instructions to replace it? I am very much mechanically inclined so I'm not intimidated by such things. Again any help would be appreciated

It's a 95 SE and I love it, I'm hooked on it and don't want to get rid of it.

pntcbonnesse · #2 08-16-2004, 11:38 PM

I could be wrong but another reason your car could be dong that is because of the Ignition Control Module... I might be wrong though hope this atleast helps

pntcbonnesse · #3 11-10-2004, 06:05 PM

well now that I relook at it it could be the ICM, crankshaft but I would start with the fuel filter

bigboyisme · #4 11-10-2004, 07:05 PM

I have narrowed part of the problem, but I still need help.

I went through a drive thru today and as usual, they got my order wrong so my wife went in to get it corrected. I turned the car off while she was in there. When she came back out the car wouldn't start so I decided to spray some starting fluid in the throttle, well needless to say the car started running till it ran out of starting fluid. Eventually, I was able to get it started again on it's own. I should note, that every time the car is warm, where the temp needle is at the half way point (slightly high) it does this and the temp needle fluctuates quite a bit from driving to stopping at a light, about a 4th of the total range. So in short, it seems as if when the engine gets very warm, the fuel flow to the engine gets restricted in some way.

Does the coolant temperature sensor control this? If the sensor causes the guage to fluctuate in the manner I described, should I replace it?Possibly the fuel pressure regulator? Bad O2 Sensor maybe? Clogged cat. converter?
Is there something else that might be causing it? Something causing it to run lean, does an engine run hot when it is running lean?
Could it possibly be getting a rich indication creating a lean response?

I think I have a throttle position sensor problem also. I believe this is the case because there is a dead spot in the gas peddle when I accelerate and it doesn't want to start when I press on the gas while turning the engine over. It starts pretty well when cold (foot off the peddle,... foot on the peddle it won't start).

Jrs3800 · #5 11-11-2004, 10:42 AM

Have you ever had the fuel pressure check with the engine warm to see what the pressure is? I have even seen the fuel pressure regulators go bad as well... You should have between 48 - 55 psi fuel pressure...

bigboyisme · #6 11-13-2004, 12:41 PM

Well, I did find part of the problem. I had problems with the car starting and accelerating, there seemed to be dead spots when I pressed the peddle and much trouble getting the car to start when the car was warm. I replaced the TPS with a good used one ($10.00) from a parts yard and now those problems seemed to have vanished. Now I just need to get rid of the other acceleration problems where the car shudders under load.

Is it possible that the stumbling is caused by a clogged converter and bad O2 sensor? The car has close to 200K miles on it. It's a 3.8L non supercharged car. I was thinking that it might be clogged enough to overheat the O2 sensor causing a lean reading to the computer and excessive backpressure to the exhaust valves resulting in low oxygen getting to the cylinders. Could these things be possible, causing it to shudder under load?

MRDANGERUS · #7 11-15-2004, 02:08 AM

Pull out the thermostat out and run without it for a while. Observe the symptoms. If problem goes away, buy a 180 degree thermostat, drill 2 holes in non moving ring, 2 mm each. Reinstall.

scooter72908 · #8 11-15-2004, 09:10 AM

I would check the Fuel pump screen in the tank. I had an acceleration problem on my '93. The problem was that the screen was collapsed and plugged but the dealer also replaced the fuel pump as well.

bigboyisme · #9 11-15-2004, 03:01 PM

Quote:

Originally Posted by MRDANGERUS

Pull out the thermostat out and run without it for a while. Observe the symptoms. If problem goes away, buy a 180 degree thermostat, drill 2 holes in non moving ring, 2 mm each. Reinstall.

Could you tell me why you are suggesting this Dangerus? If I do replace it with another thermostat, why do I drill two holes in it? Are you possibly suggesting that the car itself is overheating or that the temp sensor is messed up?

I definitely will remove the thermostat and check it out, but I am curious about the other things and the reason behind them.

bigboyisme · #10 11-15-2004, 03:03 PM

Quote:

Originally Posted by scooter72908

I would check the Fuel pump screen in the tank. I had an acceleration problem on my '93. The problem was that the screen was collapsed and plugged but the dealer also replaced the fuel pump as well.

I was thinking that I would check this out but I need to check out the fuel pressure first, trouble is the guage to check it costs $35.00, and I only need to use it once. I think that's a high price to pay for a one time check. If I could only find a place to rent one for a day.

cscottyr · #11 11-16-2004, 10:10 PM

If you own a GM product you will likely use that fuel pressure guage more than once. As I read through your posts it sounded a lot like a fuel pump problem. I'm on my second Bonny and my 5th pump between the two vehicles including the originals - They only seem to last about 80 or 90k - then fail. I'd get the gauge and keep it handy.
cscottyr

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