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deb789
08-28-2005, 07:06 PM
Well, I was having a bit of a problem with my car cause everytime i would stop on a red light the car would stall like a choking felt like it was going to turn off. But i pressed the gas pedal 2 times and it kepted going. Yesterday the car was getting bad. This time i pressed the gas pedal and it liked choked, So i pressed the gas pedal all the way down and the car just did 15 miles. Then the check engine light appeared I smelled gas also when i turned off the car. So i decided to head back home cause the loss of power on the car then the check engine light appeared. So i turned off the car. I turned on the car back up but no power at all, like i said it just went 15 miles again the speed thats all it took. But the car starts. So im assuming torque converter or some other problems? I have a 98 Pontiac grand am se 2.4 engine .4 cylinder. Please help!!!"

deb789
09-04-2005, 12:40 PM
Okay, I took it to a man who owns his shop next to his house . This is what he fixed. He said there was a engine misfire code 0451. Multiple cylinder misfire. He replaced the coil cover, boot set, 1 spark plug #4 cylinder. Okay i tested out the car it runs better. But still doing that hesitation again. Also, I was at the grocery, I had the car at drive all of a sudden the car wanted to stop .So i put the car on the neutrol and all of a sudden the rpm started to go up about the number 6. So i decided to turn off the car. Then restarted it and it turned back on. but still giving me the hesitation . I ve noticed also when i start the car i have to give it 2 cranks then it will start after pressing the gas pedal 2 times. Does this have something to do with the problem with the hesitstion also? I went back to the mechanic and told him about the problem. He said he coudnt find anything wrong with it. He said to leave him the car for a couple of days to see if it hesitates on him. Did he cheat me out? Also, Please help me find this solution on my car ?

MantaGreen97
09-04-2005, 01:49 PM
Okay, I took it to a man who owns his shop next to his house . This is what he fixed. He said there was a engine misfire code 0451. Multiple cylinder misfire. He replaced the coil cover, boot set, 1 spark plug #4 cylinder.

...

I went back to the mechanic and told him about the problem. He said he coudnt find anything wrong with it. He said to leave him the car for a couple of days to see if it hesitates on him. Did he cheat me out? Also, Please help me find this solution on my car ?

Well the first diagnosis sounds somewhat right--he did check the codes and seems to have addressed possible causes for the problem...

However are you sure about that DTC code? I'm looking at the service manual (for a 1997 GA, but the 98 should be nearly identical if not identical) and I don't see any DTC0451 listed. Usually 0300 (Engine Misfire Detected) and 03xx (Misfire on Cylinder #xx) are the codes for misfires.

From your first description I was thinking transmission/torque converter myself as well but since you had a misfire code there it seems it is engine related instead.

Since it seems most of the ignition components have been replaced, I'm thinking fuel delivery could be the problem. Anything from the fuel pump to the filter to the pressure regulator to one or more of the injector(s) could be the problem. But that is just a guess as well, since ignition components didn't fix the problem it would seem to me fuel would be a logical suspect.

However there are several troubleshooting flowcharts for problems that sound similar ("Surges/Chuggles"; "Hesitation, Sag, Stumble"; "Cuts Out, Misses" and "Rough, Unstable, or Incorrect Idle, Stalling"). It sounds like more than one of those may describe the problem. The flowcharts are fairly lengthy and pretty exhaustive. To me it sounds like the mechanic simply replaced the ignition components and did not follow any flowcharts for troubleshooting either the DTC nor the problem symptoms.

This is not to say that he "cheated you out" per se; I don't think every mechanic (particularly a non-GM shop) would have access to vehicle-specific flowcharts and troubleshooting information that would be in the vehicles service manual, for every vehicle out there. It does sound like he replaced components which could have either caused or contributed to the problem but might not necessarily have been the solution given other factors. Even following flowchart's diagnosis instructions is never foolproof either...

Well I guess that isn't much help in solving the problem, but I will say that just looking at the chart entries for "Surges/Chuggles" I can see it covers testing things such as ignition components (pretty much already covered by the replacements done in your case), oxygen sensors, [physical] fuel delivery (pump/regulator pressure, injectors, etc.), fuel trim (PCM's fuel delivery strategy for given operating conditions), vacuum connections, PCM connections and alternator voltage.

So there are a lot of areas that could have something to do with it. It seems like you need a better diagnosis than the one you got at the original shop, but that is just my opinion...

deb789
09-04-2005, 03:00 PM
Okay, Im going to take the car elsewhere. What kind of test should they do on the car for the pressure regulator and the things you mentioned.?

MantaGreen97
09-05-2005, 11:36 AM
Okay, Im going to take the car elsewhere. What kind of test should they do on the car for the pressure regulator and the things you mentioned.?

Well the fuel pressure requires a simple pressure gauge which would thread on to the end of the fuel rail; the FPR test probably requires testing the pressure with different amounts of vacuum applied to the FPR; the injector test is called an injector balance test which requires some electronic test equipment...

If you want I could scan you a couple pages showing one of the trouble shooting flowcharts so you get an idea of how a complete diagnosis is supposed to go. While it won't say how each test is performed (because those are located in other parts of the manual) it will show the order of testing that could be followed and what tests would be done, given a certain troubleshooting scenario.

deb789
09-05-2005, 05:10 PM
Yes, Please scan a couple of pages.

MantaGreen97
09-05-2005, 08:06 PM
Okay here are the troubleshooting pages for "Hesitation, Sag, Stumble"...

Seems the files are a little large for the attachment size allowed here so I made them a little lower quality but they still look quite readable... (Make sure to maximise your explorer window when clicking on the attachments and also if your IE is set to auto-scale the image, hold your mouse over for a couple seconds and use the full-size icon and it should be clear; alternately, printing the pages should work as well.)

From the problem descriptions given at the top of the section it seems the "Hesitation, Sag, Stumble" seems to fit your problem. If you want I can send pages for other troubleshooting descriptions (like "Surges/Chuggles" or one of the others), but I'd have to email them to you...

I also re-read your post and noticed that the mechanic only replaced one spark plug, the #4 plug... Why didn't he just go ahead and replace all 4 plugs since he replaced that one plus the coil cover and boot set? Was the number 4 plug fouled? Did he take out the other plugs and inspect them and determine them to be good?