Throttle sensitive

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T.Hanson
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Joined: Wed Jul 26, 2006 7:39 am

Throttle sensitive

Post by T.Hanson »

What are possible causes of throttle being jerky sensitive ?

Unplugged the low end switch. It slows down nicer. I swear it is set to click off at the last possible instant.

Lags, stumbles just a bit before accelerating. If reving to say, 2000 just sitting still, it backfires some into the exhaust system.

Idles at 850, I swear it's timed right, plugs are new, wires good, etc.

What else ? Bad O2 sensor ? Old AFM or set wrong ?

Aggravating because my '79 runs smooth, strong, so I know something is goofy.
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Lenny D.
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Post by Lenny D. »

If you have identical everything, try swapping components (one at a time). I would start with the AFM, I bet you will be surprised.
HTH

'80 528i
T.Hanson
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Post by T.Hanson »

Thank you. I was beginning to think I'd been ex communicated.
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Peter Florance
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Post by Peter Florance »

I think the fuel cut-off rpm values are different from the 79 to the 81.
Peter Florance
First Fives.Org - The E12 Registry
1981 E-Street Prepared Euro BMW 528i w/3.5L & Megasquirt Fuel Injection
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T.Hanson
Posts: 1696
Joined: Wed Jul 26, 2006 7:39 am

Post by T.Hanson »

So ? Then what.

The '79 (spare) AFM had the same serial # as the '81. I swapped it in, no big difference.

All I'm reporting is, after everything from replacing the pedal bushings to engine swap for 56,000 block, total clean up, fuel regulator, two pumps, blah blah,...

If I diddle the gas pedal the engine will surge, jerk, bounce off the guibo right now. Boing, boing boing. The '79 is normal, to mean smoother, not a noticeable deal at all.

O2 sensor next.

Just for fun, the in tank pump I replaced for buzzing, there's still buzzing. I know the old pump was making noise, now to find out it was a duet from a speaker or seat or what.
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