1988 928S4 Has Intermittent "Bucking" Problem
01-19-2005, 10:33 AM
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1988 928S4 Has Intermittent "Bucking" Problem
The 88 S4 project car is coming along nicely. Got the LH Brain rebuilt which solved most of it's issues. However, the last couple of days it has been acting strangely. The car seems to hessitate BADLY at times causing a mildly concerning not quite violent bucking of the car for a few seconds. This problem seems to rear it's head most when under load while accelerating, but is not isolated to that scenario. It also happens when just crusing at speed. At idle the car mostly runs smooth as silk, but I have noticed some intermittent fluctuations.
Is it possible that some kind of sensor (hall sensor, etc.) is about to give up the ghost? Is the ignition module about to go? Anyone else ever experienced this problem?
Regards,
JE
Is it possible that some kind of sensor (hall sensor, etc.) is about to give up the ghost? Is the ignition module about to go? Anyone else ever experienced this problem?
Regards,
JE
01-19-2005, 11:01 AM
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That sounds like the problem that I had for a while with my '85's timing and reference sensor. In my case, the connector was bad, not the sensor itself. Under acceleration, it would completely cut the ignition at random for half a second or so.....nearly launching me through the windshield.
B safe!
N!
B safe!
N!
01-19-2005, 11:07 AM
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Bummer, that's what I feared. I have little experience with these new fangled LH-Jet systems. Looks like I'm going to learn the hard way. 
Originally Posted by Normy
That sounds like the problem that I had for a while with my '85's timing and reference sensor. In my case, the connector was bad, not the sensor itself. Under acceleration, it would completely cut the ignition at random for half a second or so.....nearly launching me through the windshield.
B safe!
N!
B safe!
N!
01-19-2005, 11:45 AM
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Hi John,
HAPPY NEW YEAR!
Take a CLOSE look at your Ignition Coil wires, especially the one on the drivers side. Over time the drivers side coil wire and the large power feed cable for the ABS pump can become a little too "friendly" with each other. I had an 89 that did just as you described and it took me forever to find the culprit. I happened to be looking under the Power Steering reservoir for another reason and saw this nice little arc going between those 2 wires. Replaced the coil wire and routed it away from the ABS power feed and it ran smooth as silk.
HAPPY NEW YEAR!
Take a CLOSE look at your Ignition Coil wires, especially the one on the drivers side. Over time the drivers side coil wire and the large power feed cable for the ABS pump can become a little too "friendly" with each other. I had an 89 that did just as you described and it took me forever to find the culprit. I happened to be looking under the Power Steering reservoir for another reason and saw this nice little arc going between those 2 wires. Replaced the coil wire and routed it away from the ABS power feed and it ran smooth as silk.
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01-19-2005, 12:01 PM
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Hey DR,
Happy New Year to you also!
Phewwwww!!! This may be the best news that I have gotten this year. I sure hope it's something as simple as that. I'll give it a look.
Best regards to you anf Jeannie,
John
Happy New Year to you also!
Phewwwww!!! This may be the best news that I have gotten this year. I sure hope it's something as simple as that. I'll give it a look.
Best regards to you anf Jeannie,
John
Originally Posted by DR
Hi John,
HAPPY NEW YEAR!
Take a CLOSE look at your Ignition Coil wires, especially the one on the drivers side. Over time the drivers side coil wire and the large power feed cable for the ABS pump can become a little too "friendly" with each other. I had an 89 that did just as you described and it took me forever to find the culprit. I happened to be looking under the Power Steering reservoir for another reason and saw this nice little arc going between those 2 wires. Replaced the coil wire and routed it away from the ABS power feed and it ran smooth as silk.
HAPPY NEW YEAR!
Take a CLOSE look at your Ignition Coil wires, especially the one on the drivers side. Over time the drivers side coil wire and the large power feed cable for the ABS pump can become a little too "friendly" with each other. I had an 89 that did just as you described and it took me forever to find the culprit. I happened to be looking under the Power Steering reservoir for another reason and saw this nice little arc going between those 2 wires. Replaced the coil wire and routed it away from the ABS power feed and it ran smooth as silk.
