Bucking between 2000-2500 rpm while accelerating
10-19-2012, 11:51 PM
#1
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Bucking between 2000-2500 rpm while accelerating
I have an 84 928S and it is my daily driver. If I lope around, it bucks extremely badly when I gently give it throttle in the 2000 to 2500 range. If I stomp on it, it picks right up with no issues. Also, if I hold the shifts until above 3000, no bucking present. Smooth up through 5000 rpms, so i dont think it is an ignition breakup issue It appears to be associated only with lower RPMs.
I have a vacuum gauge in the cockpit and it is plumbed directly into the spider leading to the injector vacuum lines. At idle, or between shifts, I get at least 15 inches. I've also run throrugh several bottles of injector cleaner and I run premium gas Any ideas/suggestions would be greatly appreciated.
I have a vacuum gauge in the cockpit and it is plumbed directly into the spider leading to the injector vacuum lines. At idle, or between shifts, I get at least 15 inches. I've also run throrugh several bottles of injector cleaner and I run premium gas Any ideas/suggestions would be greatly appreciated.
10-23-2012, 06:49 AM
#3
Such symptoms could occur when running with low octane fuel.
Check on the LH socket whether a green wire is sliced and routed through a small black box connected in turn to a lambda sensor on the exhaust. Positively, you could reconnect the sliced green wire and see the change.
Otherwise, the MAF: when was it rehauled last?
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Ralph
Euro 1984 S maual
Check on the LH socket whether a green wire is sliced and routed through a small black box connected in turn to a lambda sensor on the exhaust. Positively, you could reconnect the sliced green wire and see the change.
Otherwise, the MAF: when was it rehauled last?
-------------------
Ralph
Euro 1984 S maual
10-23-2012, 09:16 AM
#4
Rennlist Member
False air. Look for air leaks after the MAF.
10-23-2012, 09:38 AM
#5
Three Wheelin'
Is your car US or a Euro dual dizzy car? I had a similar problem on my '84 Euro that had a fresh rebuild with all new items. THrough here I learned that it is very tempermental to the AFR. Once I set the correct AFR at that range, the bucking went away.
10-23-2012, 09:42 AM
#6
Rennlist Member
Such symptoms could occur when running with low octane fuel.
Check on the LH socket whether a green wire is sliced and routed through a small black box connected in turn to a lambda sensor on the exhaust. Positively, you could reconnect the sliced green wire and see the change.
Check on the LH socket whether a green wire is sliced and routed through a small black box connected in turn to a lambda sensor on the exhaust. Positively, you could reconnect the sliced green wire and see the change.
Wouldn't suspect that with above information indicating good vacuum.
I would start by replacing plugs, coil, cap, etc. Sounds like a simple miss. Check your wires also. Wait until it's dark outside and run the engine with the hood open. You will easily see any arcing.
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09-06-2013, 12:02 PM
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I figured it out and I'm feeling pretty stupid. After replacing all of the vacuum and ignition components, it turned out to be the o2 sensor. I have no Cats and an X-Pipe and I assumed that the sensor was deleted. No so. $100 clams and 1 hr later and I got my car running like I remembered it should.
