Author Topic: Hesitation/surging problem  (Read 3691 times)

91 318i

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Hesitation/surging problem
« on: April 17, 2013, 11:18:20 PM »
Recently got my car running again. Ran great for about 5 days. Not a single issue.

It happens at any rpm and any gear. Mostly in first and second. Lacks power and feels like a bad miss on one or two cylinders.

Today I swapped the throttle position sensor, cam sensor, crank sensor, and replaced both intake manifold gaskets. I bought a fuel filter that I plan on putting in tomorrow. It looks really old and probably wouldn't hurt to change anyways. I've cleaned the iac and afm as well. Cleaned the throttle body too. No change at all.

I tried unplugging the o2 sensor and still no change. When I unplug the afm however it runs for a few minutes with no problem then reverts to the hesitation issue again. Does this mean its the afm?

Please help
Thanks
1991 BMW 318i Sedan
1995 Ford F150 4x4

91 318i

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Hesitation/surging problem
« Reply #1 on: April 18, 2013, 12:31:10 AM »
Update!

I was at a friends house and on the way home it decided to misfire at any rpm and now in the driveway it has a really bad lopey idle. It drops down to a near stall then up to about 1000.

All 4 cylinders have spark. Fuel pressure regulator? Injector?
« Last Edit: April 18, 2013, 12:44:20 AM by 91 318i »
1991 BMW 318i Sedan
1995 Ford F150 4x4

colin86325

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Re: Hesitation/surging problem
« Reply #2 on: April 18, 2013, 10:59:42 AM »
Does your AFM harness have an extension lead on it? Basically just looks like another harness that attaches  onto the wire that comes from under the intake.  I was having some problems and I removed my extension and found it was full of water and corrosion.

91 318i

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Hesitation/surging problem
« Reply #3 on: April 18, 2013, 12:13:14 PM »
I do have that extension on there. I took it off because I thought it was pointless. That's when the problem started. I have since put it back on
1991 BMW 318i Sedan
1995 Ford F150 4x4

91 318i

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Hesitation/surging problem
« Reply #4 on: April 18, 2013, 07:28:47 PM »
Today I swapped injectors between the current one and one of the set I had laying around. Changed the fuel filter. No improvement in how she runs. Verified spark on all 4 cylinders. Compression is 120+. Swapped in a different fuel pressure regulator. Messed with the afm some more but got it to a good spot as far as adjustments go. Runs just as bad or worse. Now it barely wants to idle. Has almost zero power. All 4 coils appear to be firing. Has code 1234 according to stomp test.

What does this mean??
« Last Edit: April 18, 2013, 11:05:24 PM by 91 318i »
1991 BMW 318i Sedan
1995 Ford F150 4x4

colin86325

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Re: Hesitation/surging problem
« Reply #5 on: April 19, 2013, 09:33:23 AM »
I'd suspect some kind of problem with the wiring to the AFM or with the AFM itself.

91 318i

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Hesitation/surging problem
« Reply #6 on: April 19, 2013, 10:54:38 AM »
I've tried everything except swapping the afm because I don't have another one laying around

« Last Edit: April 19, 2013, 07:21:50 PM by 91 318i »
1991 BMW 318i Sedan
1995 Ford F150 4x4

91 318i

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Hesitation/surging problem
« Reply #7 on: April 19, 2013, 07:23:22 PM »
Update.....

I feel so dumb right now. Ended up being a hole in the number 3 spark plug wire.. Anyways. Got her fixed. Runnin like she should.
1991 BMW 318i Sedan
1995 Ford F150 4x4