87 325is cuts out around 4500

[nates 87 325is]

So i just finished my manual swap about a week ago, and under a heavy load I lose all power for a split second around the 4500 rpm area.

Here's the facts

It never happened while it was auto
It has been parked sense thanksgiving just came out a little over a week ago
It idles very smooth.
In neutral it revs fine.
In 1st gear it dosent seem to have a problem.
It happens the most in second gear.
I feel like the car has lost a little power sense this problem started.(maybe just my mind)
When driving around 75 for 20 min. I get a CEL, I haven't got it checked guessing AFM
The only thing I changed in the engine bay during swap was motor mounts.

I have never been good at trouble shooting so any help or ideas would be appreciated
Thanks
Nathan

I just drove back from work and now its cutting out just driving normal. It's about 15 degrees out, earlier when it happend it was about 30.
The car just flashes the CEL for a split second and stalls then keeps going normally.

[jlevie]

The first thing that makes me think of is the CPS.

[Sagaris]

do a "stomp test" (google it if you need help figuring out what that is) and see if the DME gives you any hints via. stored fault codes.

[ohthejosh]

So i just finished my manual swap about a week ago, and under a heavy load I lose all power for a split second around the 4500 rpm area.

You sure you dont have an eta? :)

jk we got some very knowledgeable people on this forum Im sure one of them will provide you with the magic solution.

[nates 87 325is]

The first thing that makes me think of is the CPS.

I was thinking that too, but I always thought a bad cps wouldn't let the car start. But ill give it a shot and order one.

do a "stomp test" (google it if you need help figuring out what that is) and see if the DME gives you any hints via. stored fault codes.

I don't think my car has the stomp test, or it just don't work. Could there be any codes even if the CEL isn't on?

[Sagaris]

You should be able to do a stomp test. If it doesn't work, you will need to check to see if your full-throttle switch under the throttle body is being engaged and that it works. There are 3 pins, one is for ground, the other is for the idle switch, and the other for full throttle. Check for continuity when throttle is open, you can also check the idle switch while you are at it.

http://e30world.com/fuel/BMW-E30-DME-Motronic-fault-codes

One time I had a code stored but no CEL. I ran my wideband as a narrowband into Motronic and after a few miles it gave me a CEL for "1221". After switching back to the original O2 sensor. I started the car and did not have a CEL displayed. I could tell the car was not running closed loop because of the slightly decreased performance. I did a stomp test again and still got 1221 and decided to drive for a couple days like that to see if it would work itself out. After 3 days or so it was still not running closed loop so I checked and the "1221" code was still there. I disconnected the battery for a few hours, the code was cleared and it was entering closed loop again afterwards.

[Steeler325is]

Try replacing your fuel pump with a high flow one. I had similar issues and thought it might be the throttle position sensor, bought one but returned it when the fuel pump fixed the issue. BTW I deleted the secondary pump when I installed the high pressure one in the tank. Also check tank for rust/ clogged pump sock.

[MR 325]

http://www.r3vlimited.com/board/announcement.php?f=98

[nates 87 325is]

You should be able to do a stomp test. If it doesn't work, you will need to check to see if your full-throttle switch under the throttle body is being engaged and that it works. There are 3 pins, one is for ground, the other is for the idle switch, and the other for full throttle. Check for continuity when throttle is open, you can also check the idle switch while you are at it.

http://e30world.com/fuel/BMW-E30-DME-Motronic-fault-codes

One time I had a code stored but no CEL. I ran my wideband as a narrowband into Motronic and after a few miles it gave me a CEL for "1221". After switching back to the original O2 sensor. I started the car and did not have a CEL displayed. I could tell the car was not running closed loop because of the slightly decreased performance. I did a stomp test again and still got 1221 and decided to drive for a couple days like that to see if it would work itself out. After 3 days or so it was still not running closed loop so I checked and the "1221" code was still there. I disconnected the battery for a few hours, the code was cleared and it was entering closed loop again afterwards.

I'll test this later today. It would be nice to have the stomp test. Thanks

I just looked at the link it says '88 and up I have an 87 looks like I'm screwed for the stomp test

Try replacing your fuel pump with a high flow one. I had similar issues and thought it might be the throttle position sensor, bought one but returned it when the fuel pump fixed the issue. BTW I deleted the secondary pump when I installed the high pressure one in the tank. Also check tank for rust/ clogged pump sock.

I replaced both pumps a little less then a year ago. But I suppose it wouldn't hurt to check the sock.

[PoorBoysRacing]

I was wondering why i could never get my 87 325is to thorw codes at me with a stomp test....

[jlevie]

The stomp test only works on a Motronic 1.3 DME, which is a 173 DME or later. An 87is/ic came with an 153 (Motronic 1.1).

[nates 87 325is]

The stomp test only works on a Motronic 1.3 DME, which is a 173 DME or later. An 87is/ic came with an 153 (Motronic 1.1).

Are these swapable?

And I think I found the problem!!...the clip that holds back the wires behind the water pump pully broke and the cps wire has been rubbing on the pully, and is wore through to the wire. I got it taped for now and everything seems to be good so far. Thanks for the help guys.

[jlevie]

Are these swapable?

And I think I found the problem!!...the clip that holds back the wires behind the water pump pully broke and the cps wire has been rubbing on the pully, and is wore through to the wire. I got it taped for now and everything seems to be good so far. Thanks for the help guys.

You can replace the 153 DME in your car with a 173 (or later).

Get a new plastic wire chase and the clips that hold the chase to the timing cover (the parts are cheap). And replace the CPS with a new part.