E34: Shuddering While Accelerating

[C Lyon]

Hello, I have an E34 1990 535i/5. It has ~346k miles on it now but the engine was completely overhauled about 70k ago. After I bought it, I promptly had the dual mass flywheel replaced by a used single mass along with a new M5 clutch (yes with springs) to go with it. I am not too sure if the shudder would be flywheel or clutch related, but it is most prominent while under load such as going up a hill, heavy acceleration, or while accelerating in a turn. Once rpm is closer to 4.5k and up it seems to go away, but the shuddering starts near 1.5k. I've noticed that while driving like a granny it almost goes away completely but it can still be felt. It is a strange feeling, like the car has an awful misfire but yet you can feel it underneath the car and vibrations through to your feet on the pedals. Also, on rare occasion, that being around once every 50 miles or so, the car will stutter as if all cylinders went dead for half a second and then it will go on as normal for the rest of the drive. Other possible related problems are when the gas pedal is quickly tapped about 1/4 to 1/2 an inch the rpm will drop as if the car wants die but it will shake and then go back up to around 900rpm. Some mornings when the car is cold, about 30 seconds after it is started (always starts 1st attempt when cold) the rpm will climb and drop from around 650 to 1300 over and over until it warms up a bit. Last summer I had the same symptom which then led to a crank-but-no-start situation that was fixed by a new Crankshaft position sensor. So far my guesses are Throttle position sensor (makes no difference when unplugged..so I need a new one, but is that the pedal problem only or the stuttering problem?), warped flywheel or worn clutch , or flex disc, but that was replaced about a year ago. Any help would be greatly appreciated.

TL;DR - Vehicle Shuddering under load/acceleration. What could be the issue?

[Mike W.]

My money is on the driveshaft. Specifically the non replaceable (in a reasonable manner) U joint(s). Starts with a shudder on take off. Gets worse from there.

[C Lyon]

I'll check it out. Thanks for the insight.

[demetk]

Does it have a limited slip diff? In a LSD, sometimes shuddering is due to incorrect diff oil.

[C Lyon]

Does it have a limited slip diff? In a LSD, sometimes shuddering is due to incorrect diff oil.

I didn't find any play in the driveshaft. And yes, it has a 3.46 LSD. I haven't touched anything to do with it since I bought the car, so I can take a look at it. It was fine when I bought the car, and some days it would be totally smooth even after the problem started. This is why I thought it may be a vacuum leak but nothing came up on the smoke test.

[demetk]

So maybe it's fuel pump related then like fuel starvation under high loads caused by low fuel pressure from the main pump or a dead intank pump. If the O2 sensor is working then you can check the O2 sensor signal with a meter. If the meter shows the engine going lean under those conditions then definitely check the pumps.

[tn535i]

Does it have a limited slip diff? In a LSD, sometimes shuddering is due to incorrect diff oil.

I didn't find any play in the driveshaft. And yes, it has a 3.46 LSD. I haven't touched anything to do with it since I bought the car, so I can take a look at it. It was fine when I bought the car, and some days it would be totally smooth even after the problem started. This is why I thought it may be a vacuum leak but nothing came up on the smoke test.

Play in the driveshaft doesn't mean much unfortunately. If you are feeling this in the seat of your pants on take off it could still be the D/S as failing u-joints usually get sticky and then cause the D/S to wobble (thus the shuddering). I think once this starts it weakens the center bearing support and starts getting worse quickly.

[stoney]

Put it on a hoist and check over everything. Easiest way to diagnose, rather than us guessing on the line.

Check everything from suspension mounts and bushes, engine/trans mounts, to driveshaft bolts, guibo, centre bearing, uni joints, CV shafts, rotor condition and caliper security and even pad wear, front control arm bushes, rear dogbones, tyres for uneven wear/bubbling/delamination.

Always eliminate the basic stuff that can be inspected visually and free, then resort to things like a basic service, if it might be a failing fuel pump, or a faulty alternator not charging properly, or a blocked fuel filter, or a set of fouled/worn plugs, VAFM playing up, valves not adjusted properly, ignition system worn.

It's all about a process of elimination

[C Lyon]

Put it on a hoist and check over everything. Easiest way to diagnose, rather than us guessing on the line.

Check everything from suspension mounts and bushes, engine/trans mounts, to driveshaft bolts, guibo, centre bearing, uni joints, CV shafts, rotor condition and caliper security and even pad wear, front control arm bushes, rear dogbones, tyres for uneven wear/bubbling/delamination.

Always eliminate the basic stuff that can be inspected visually and free, then resort to things like a basic service, if it might be a failing fuel pump, or a faulty alternator not charging properly, or a blocked fuel filter, or a set of fouled/worn plugs, VAFM playing up, valves not adjusted properly, ignition system worn.

It's all about a process of elimination

So far, everything driveline-wise has been checked out and looks good. This weekend I'll be working on plug wires and fuel pump/filter. I'll stay posted.

[C Lyon]

Replaced plugs/plug wires/fuel filter and the car starts and idles much better. Runs smoother and most of the vibration is gone. Now I've noticed it is only under harder acceleration. Possible compression issue? Not sure, it was near perfect back in February when I bought it and I've only put about 4500m on it.

[Kyle in NO]

Can you not tell the difference between an engine vibration and a driveline vibration?

[C Lyon]

Can you not tell the difference between an engine vibration and a driveline vibration?

It is enough to shudder the whole car when accelerating, so it's difficult to pinpoint. My best bet would be engine since I feel the vibration through the pedal more than I do through the seat. My guesses now are throttle position sensor and/or compression. Compression as of 4 months ago was good though. It runs much better now than it did before the tune up.

[davintosh]

Can you not tell the difference between an engine vibration and a driveline vibration?

It is enough to shudder the whole car when accelerating, so it's difficult to pinpoint. My best bet would be engine since I feel the vibration through the pedal more than I do through the seat. My guesses now are throttle position sensor and/or compression. Compression as of 4 months ago was good though. It runs much better now than it did before the tune up.

I'd say you're barking up the wrong tree here. Go back up to the first response in this thread; Mike is likely right on the money.

My money is on the driveshaft. Specifically the non replaceable (in a reasonable manner) U joint(s). Starts with a shudder on take off. Gets worse from there.

What you described in the first half of your opening post is EXACTLY what my e32 was doing. Most likely culprit, like Mike said, is the center u-joint. If your center support bearing (CSB) is still intact, the shudder is what you get. If you wait long enough before doing something, the rubber on the CSB will fall apart and that shudder will turn into a banging on acceleration.

Also, on rare occasion, that being around once every 50 miles or so, the car will stutter as if all cylinders went dead for half a second and then it will go on as normal for the rest of the drive. Other possible related problems are when the gas pedal is quickly tapped about 1/4 to 1/2 an inch the rpm will drop as if the car wants die but it will shake and then go back up to around 900rpm. Some mornings when the car is cold, about 30 seconds after it is started (always starts 1st attempt when cold) the rpm will climb and drop from around 650 to 1300 over and over until it warms up a bit. Last summer I had the same symptom which then led to a crank-but-no-start situation that was fixed by a new Crankshaft position sensor.

I'd bet this part is something different than the shuddering. I'd start by checking/replacing the coolant temp sensor. Then check the ignition system (plugs, wires, cap, rotor), then the fuel pump and fuel pressure regulator.

[C Lyon]

OK cool thanks for the insight. I'll jack it up and check tomorrow to find out. I went on a long drive today to see if I could feel out the symptom a bit better, and what I've gathered is that it is mostly just when starting out in first gear, then at speed in first gear and onward the shuddering goes away. I'll update as soon as I can.

[davintosh]

I inspected the driveshaft from my e32 when I had it off for some rear-end work; when it was on the car there was no discernable play in the joint, but I could feel a little notchiness when I twisted the joint around a little when it was off the car. That the only sign that something was wrong with the joint. The CSB was shot at the time, and had got to the point where it was making a loud knocking on acceleration. I had hoped that would be cleared up by replacing the CSB; after being replaced, the knocking was gone, but the driveline shudder was there, which was probably the same problem as the knocking, but the fresh CSB dampened the knocking down to a shudder. The car had about 200,000 miles on it, and the shaft & u-joint were presumably original. The good news is that it didn't get any worse after continuing to drive it for a couple of years after that.

[tn535i]

OK cool thanks for the insight. I'll jack it up and check tomorrow to find out. I went on a long drive today to see if I could feel out the symptom a bit better, and what I've gathered is that it is mostly just when starting out in first gear, then at speed in first gear and onward the shuddering goes away. I'll update as soon as I can.

This sounds like you are describing D/S wobble. A new CB might make it 'better' but that is a lot of work not to fix it.

And I'll second that you can't tell much of anything about u-joint condition with the DS in the car. It must come out to inspect and at that point you ought to be prepared to replace.

[C Lyon]

Alright, I'll let you all know how a bearing and u-joint replacement go then right after I fix the massive hit and run dent in my door courtesy of college parking

[C Lyon]

Finally got the chance to check the car. No play in the shaft at all, center support+guibos are good. Play in the diff. (3.46 LSD). Could 350k mi finally have taken its toll? or is it a dodgy u-joint? Definitely not looking forward to taking the shaft out to get a remanufactured one for 500+... if it is the diff I think maybe a 3.91 would be a fun option. I'd like to hear your guys' thoughts on what else to check so that I cover all my bases down here. Thanks everyone

[Mike W.]

BMW u joints get stiff and notchy, they don't get loose, so no play doesn't mean anything.

[C Lyon]

BMW u joints get stiff and notchy, they don't get loose, so no play doesn't mean anything.

You're absolutely right, I jacked the car up and let it run it 1st gear and there's the wobble on the shaft. Thanks for the help and the advice!