Can't accelerate past 3500 rpm!

[pitythafool]

What's up guys I have a 1995 325i and I've been having this issue when accelerating I can't go past 3500 rpm, if I attempt to go past that and not change gear the car jerks, loses power and does so again until I change gear and repeats the same thing until I shift again. This go's on every gear so while I can still drive the car I'm peaking out at about 75 -80 mph. I've had the diff bushing changed because we thought that could've been the issueguy. But before I changed the diff bushing this would only happen every other day and on the days when it wouldn't act up I was still able to accelerate with no issues. But now that I have a new bushing it does it everyday. So at this point I'm not really sure what it could be. If anyone has had a similar problem or knows if this is a common issue please let me know. Thanks for reading the post

- Completely stock other than a muffler delete and coilovers

- 2.5L M50

[Eric93se]

Could be the speed sensor in the diff.

Searched about "limp mode"

- - - Updated - - -

Can also be bad fuel pump, be sure to do the filter if you replace it.

[pitythafool]

Thanks I'll definitely check that out . The speed sensor makes more sense now as the place I took it to for the bushing replacement didn't reconnect it and there's nothing plugged in right now. I wasn't sure if the sensor could have been the problem but now that you mention it I'll try that out

[ed323i]

Here's some info on a special engine limp mode when there is no speed signal.. I never heard of it, but at least some people think it exists.. It limits rpm to 5300 rpm though.
Check it out here: https://www.bimmerforums.com/forum/s...Speedo-related

What I'd also check is the crank position sensor.. Perhaps it isn't in great shape, or it isn't aligned well, and above 3500 rpm it loses sync..

Also, if you downshift into a higher rpm range (4000 or 5000 rpm for example), then it also doesn't run well until you drop below 3500 rpm?

Best to connect a laptop with INPA software and see what errors you can find..
I've never before heard of an rpm-limiter at 3500 rpm with the speed sensor disconnected.

[jc43089]

It's not the speed sensor, you can drive around with no problems except a non working speedometer with it unplugged.

It sounds like a crankshaft position sensor signal is failing at higher engine speeds. Any codes?

[ArcticM]

I’ve heard of this happening due to clogged cat. Car wouldn’t shift right and rev up

[jc43089]

I’ve heard of this happening due to clogged cat. Car wouldn’t shift right and rev up

Easy test anyway, unhook the down pipe section and take it for a quick spin. It will be terribly loud but the exhaust can't fall down because the crossbar underneath is right under the down pipes.

I have seen that happen on a gm 3800, it was just dead feeling, after an actual trip to Mexico. Must have found some poor fuel. I hooked up a vacuum gauge to the intake first and saw really weak vacuum so I unhooked the down pipe and then the vacuum was back and it ran well.

[Richkid79]

When was the last time you changed your spark plugs? Also, have you tried disconnecting your MAF or checking for vacuum leaks? You still have the stock 20+year old coil packs? My RX-8 does this when the coil packs go bad (around every 15k miles-I love/hate the rotary engine)

[Richkid79]

And I would check for the clogged cat problem-Ive been through that before as well and changed sooo many things before i disconnected the exhaust

[MParallel]

MAF connector fully fitted/locked in place?

[Audi200tq]

There's a multi-page official thread regarding bogging and hesitation. Search for it.

My own problem, which sounds similar, turned out to be bad coils. Took me almost a year to trace it though.

[terrencekeenan]

Did you ever figure this out? Having a similar problem.