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Old 09-26-2009, 02:34 AM   #1
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Default Rough running and bucking :(

Big problem with my car.

A week ago it suddenly began to drive very rough and lost some power. It also sounded very drone-y. These were the exact same symptoms I had a year ago (two separate times) when I had fuel injectors die. So, I figured I have yet another bad injector. Paul sold me one of his extras (I use 460cc). I never installed an injector before, but I observed the procedure several times (Paul), so I had a decent idea of what to do.

But first, I thought maybe the problem was my coil wiring, because of my previous unsuccessful COPS attempt (a few months ago I ran out of time and went back to stock coils and wiring.) So rather than diving into the injector installation, and rather than trying to diagnosis possibly fault stock coil wiring, I figured it made more sense to go back and finish the COPS. Did that, COPS now works fine, but the current problem remained. Guess it wasn't the coil wiring; at least I got the COPS done though.

So .... next I changed one injector. I listened to all four with a long screwdriver, and decided #1 sounded quieter than other three. Reassembled everything. The car started, but immediately jumped to 2500 rpm. Called up Paul; he said I must have a vacuum leak. I disassembled everything, reseated all four injectors, rebuilt it again, and this time the idle was back to normal. (Miraculously, despite this being my first hands-on injector change, I didn't lose any spacers!)

However the current problem STILL remains. Maybe it wasn't #1, but a different injector .... maybe it's some other problem entirely ....

At that point I had to go home (was at my parent's house to use their garage all day.) Went for the 20-minute trip up the highway and found a NEW problem that I never experienced before: the car now has severe bucking from approx. 2,700 rpm and up. Great ......

Bottom line is, I fixed nothing this weekend despite two days of working on my car, and now there's a much worse problem.

This is very, very bad, as I nee my car running because I don't have another one, have to drive my mom to chemo next week, etc.

What could it be, at least re: the bucking ????

Many MSM owners had problems with their stock fuel pumps, but the car seems to start strong, so I don't think the fuel pump is bad.
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Old 09-26-2009, 02:44 AM   #2
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hmmm. Before you go buying a new fuel pump slap a fuel pressure gauge on that sombitch. And from there i would verify you are getting good spark, and from there i would make sure you are getting exhaust flow out of the tailpipe. What do your plugs say and what kind of AF'rs are you seeing at idle and when the problem happens. This should put you back on the track to being driveable GL to ya.
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Old 09-26-2009, 03:05 AM   #3
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Sounds like good advice, but as for the details:

Quote:
Originally Posted by magnamx-5 View Post
Before you go buying a new fuel pump slap a fuel pressure gauge on that sombitch.
Don't have one, nor would I know how to use it.

Quote:
Originally Posted by magnamx-5 View Post
And from there i would verify you are getting good spark
How?

Quote:
Originally Posted by magnamx-5 View Post
and from there i would make sure you are getting exhaust flow out of the tailpipe.
Seriously?

Quote:
Originally Posted by magnamx-5 View Post
What do your plugs say
They're newish .....

Quote:
Originally Posted by magnamx-5 View Post
what kind of AF'rs are you seeing at idle
Normal-ish. (Somewhat rich, but that was a whole other issue long before my car started running rough last week.)

Quote:
Originally Posted by magnamx-5 View Post
and when the problem happens
When the problem happened, I was too busy trying to make my car go forward and not get rear-ended on the highway.

I'm in WAY over my head .... and appealing to Paul for help. Alas he is very busy with his work and a million other things.
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Old 09-26-2009, 03:17 AM   #4
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mine did that when FP went bad idk my
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Old 09-26-2009, 03:23 AM   #5
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Quote:
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mine did that when FP went bad idk my
Please elaborate.
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Old 09-27-2009, 10:33 PM   #6
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Problem was COPS. Switched back (again!) to stock coils. Works fine. Funny part is, when I switched back, I forgot to change the dwell in Megatune. So there were lots of backfires and scared the crap out of teenagers walking next to where I test-drove it. BOOM!!!! Finally it dawned on me to put the stock dwell back.
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Old 09-27-2009, 11:38 PM   #7
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whats wrong with flames out the tail pipe? :-P

so it was injector 1 then?
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Old 09-27-2009, 11:42 PM   #8
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Yes, seems to have been injector 1. Was raining tonight so I didn't get on the throttle too much, but it seems okay now.

I've had a bunch of injectors die in the past couple of years. Always seems to be 1 or 4, never 2 or 3. Coincidence? Or some logical reason I'm not thinking of?
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