85 318i rev limiter problem

[Dominick]

ive always thought it was just my tach was messed up b/c it sound like im redlining my m10 at 3.5k rpm. so i was just thinking my SI batteries were on their way out.

then i realized that it will rev normally when out of gear. so i thought maybe my cat/exhaust was clogged.

but then i read this article:

http://www.bmwe30.net/cgi-bin/datacgi/database.cgi?file=articles&report=view&ID=00167&Section=02

"Some of these cars have a rev limiter built into the rotor. This limiter wears out over time causing the revs to be limited, more an more, causing a severe loss in performance on the car."

Anyone know how true this is? I cant imagine my 318i being faster than it is being only 103-105hp

[KenC]

Mine will rev all the way to the redline on the tach.

[hamann318is]

It "sounds" like it's redlining? Does it hit the limiter?

[AdamF 88iS]

If your limiter was worn out it would do it at all times, not just when you're moving.

[Dominick]

about the limiter i changed the rotor out a long time ago (7-8 months ago) and i didnt see anything like that picture, it looked like a normal rotor. i just got one at autozone, maybe the oem ones are different.

and yes ive hit the limiter, but not in a long time. when i first got the car (about a year ago) i would take off at a red light and hit the limiter b/c i didnt know i was gonna hit it.

i do about 15 miles on the highway at 85-90mph everyday and the tach stays at 2k rpm, thats with stock wheels/tires and aftermarket and stock differential

if i were to downshift into 4th it will rev up to about 3.5k rpm and speed up and im sure im very close to redline

i can take a quick video if anyone can host it

[arnoldgtr]

at 85-90mph everyday and the tach stays at 2k rpm

Obviously, your tach is only reading half speed. No clue why, unless it's a problem in the tach itself.
I wouldn't consider Pee-pee Boys, Auto Zone, etc. as a source for parts. I will only buy Bosch ignition parts.

[///M Powered]

Mine will rev all the way to the redline on the tach.

When the tach is working, same.

[AdamF 88iS]

This is the 3rd time I've heard of an early 318 with the tach reading half. One of them is a customer of mine, but until he actually complains about it then I can't fix it and thus don't have the answer for you.

[kylebes1]

I used to have the key for the back of the tach. maybe someone replaced yuor tach (say when teh original Odo took a dump) with one of a 325is.

I will look.

does it ever read over 3.5k?

If you can, pull the cluster, and on the back side of the tach there should be a flat black thing that is about 5mm x 20mm and has a hole in the center. that should pull out and is about 5 cm long.

find one of these that does not have the same numbers on it, or one that you know is correct for a 4 cylinder car.

I did this when I got my car. then had to reverse it when I did the m50 swap.

-Luck

[AdironRider]

Sounds like your tach itself is busted. Source out a new cluster and throw it in. They're cheap

[kylebes1]

if that is the case I have one. As well as a new face, not just eh plastic numbered part, but the entire front peice.

I'll sell them to you for $60.00

[e30jones]

My tach on my 84 318i does this intermitantly as well. I figured this out when I hit the rev limiter at around 4 grand. However, it only does it sometimes. You can watch it happen sometimes when you are travelling down the highway at 3k and then it will all of a sudden drop to 2k at the same speed. I'm still trying to figure out what's wrong with it.

[kowalski]

check the ground nuts on the back of your tach if it just sudenly drops they tend to rust. or your tach is just crapping out... also could be the SI board/batteries...

[Dominick]

ill get video, i let my friend drive and didnt tell him and he almost shit his pants when he hit the revlimter halfway, he thought the engine was f*cking up.

so whats the deal with this rotor thing, i didnt see one on mine when i replaced it. i'd check in the distributor but my car is not with me as my fuel pumps died on me.