surging at high speeds

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surging at high speeds

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surging at high speeds - 4/25/2005 4:08:09 AM

audibaby

Posts: 9
Joined: 4/25/2005
Status: offline

As well as the automatic transmission and heater troubles, posted below, the car (1988 80 4cyl) has a tendency to surge when travelling at high speeds (anything over 55mph). Could anyone shed some light on what might be wrong? I've been told that it could involve the injection system (k-jetronic), if it is then what components should I/how do I check? Could other systems be involved? I know this is probably a big question to respond to but I love my audi very much and want to get it back up to scratch - while learning about cars at the same time :)

Post #: 1

RE: surging at high speeds - 4/25/2005 11:07:58 AM

0fframp

Posts: 758
Joined: 3/9/2004
From: Swamplands of NJ
Status: offline

From the three posts I can see that you got yourself a real prizewinner! I’m not sure what you mean by "surge" more description is needed but it could be due to transmission problem especially when it becomes a problem at certain speed. The CIS system is quite reliable and I wouldn't mess with it. You can check the obvious, injector seals, vacuum leaks, sticking sensor plate, fuel filter, etc.

(in reply to audibaby)

Post #: 2

RE: surging at high speeds - 4/26/2005 12:05:30 AM

audibaby

Posts: 9
Joined: 4/25/2005
Status: offline

Hmm... When the car surges it feels like it's beeing buffeted by a head wind, I guess it losses power momentarily and then it comes back on again but this alternates quickly. Thanks for the heads up about the CIS.

(in reply to 0fframp)

Post #: 3

RE: surging at high speeds - 4/26/2005 2:07:14 PM

0fframp

Posts: 758
Joined: 3/9/2004
From: Swamplands of NJ
Status: offline

What happens to the tachometer during the moments of surging?

(in reply to audibaby)

Post #: 4

RE: surging at high speeds - 4/26/2005 10:40:17 PM

audibaby

Posts: 9
Joined: 4/25/2005
Status: offline

Nothing unusual, it doesn't jump. What does that mean? Thanks a lot for the effort you're putting into replying to me. I appretiate it a lot.

(in reply to 0fframp)

Post #: 5

RE: surging at high speeds - 4/27/2005 8:45:22 AM

0fframp

Posts: 758
Joined: 3/9/2004
From: Swamplands of NJ
Status: offline

Is the climate control set to "auto" or "def"? It might be the AC compressor cycling on-off. On my old 4000S and my current 100Q it is quite noticeable when the compressor is cycling.

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Post #: 6

RE: surging at high speeds - 5/5/2005 11:34:55 PM

gmatov

Posts: 204
Joined: 2/19/2005
Status: offline

Audibaby may not be expressing his problem properly.

My own 90, 100, with auto, has a similar problem, but on hills. It will pull well, drop in RPMs, maybe 50 revs, pickup again for a 1/4 mile or so, drop 50 again. Almost as though it is starving for fuel, which it quite well may be.

Alternately, going downhill, no gas pedal, will surge, again, nearly 100 RPM, in this mode. Gives you like a hmmmmm, hmmmmm, hmmmmm, a few seconds apart.

Mine is not set to auto, nor defrost.

Cheers,

George

< Message edited by gmatov -- 5/5/2005 11:35:53 PM >

(in reply to 0fframp)

Post #: 7