Author Topic: M42 Engine faults Cutting out at 4500 RPMs (Read 13605 times)

Broach318 · « **Reply #15 on:** February 13, 2013, 09:09:45 PM »

Well thats the odd thing, today it was doing it bad while it was cold. I feel like its something ignition related, like maybe spark plug wires, coils. Or even the cats are clogged causing it to throw the O2 sensor off and trigger the 1221 code ( bad o2).. I don't know its weird stuff. I live in SC and car stays in the garage.

Broach318 · « **Reply #16 on:** February 13, 2013, 09:39:27 PM »

What does anyone think about the possibility of a clogged fuel filter? It was replaced in june, but it fits the discrition of a clogged filter. Long cranks 10-20 turns, horrible acceleration under load...

DesktopDave · « **Reply #17 on:** February 14, 2013, 04:46:34 PM »

Toss a gauge on it and see what your pressure looks like. Dead-heading a healthy fuel pump might get you 80psi...but if you tee the supply line you should see a bit more than 2bar - 40-ish psi at idle.

A clogged cat is unlikely. Our cars have them bolted on almost as an afterthought...downstream of the O2 sensor.

DesktopDave · « **Reply #18 on:** February 14, 2013, 05:35:24 PM »

Did you check the position sensors? Crank sensor should be about 640 ohms, cam sensor about 1200-ish.

Quote from: Broach318;120077

Okay well i checked the coolant sensor got 2.250 OHMS while car was cold, as it warmed up it slowly dropped, so thats good.

Do you have the Bentley or BMW ETM? Here's a few quick tests:

Specs on the CTS - according to Bentley, you should see 5VDC between the brown/red wire and ground from the DME. Additionally:
@14degF - 7K to 12K ohms
@70degF - 2K-3K ohms
@180degF - 270-300 ohms

I know I'm kicking a dead horse here, but was it in spec? If you're saying it was 2200 ohms @ 70degF it'd be good.

The IAT range is the same on pins 4&5 of the AFM connector.

Broach318 · « **Reply #19 on:** February 15, 2013, 11:58:21 AM »

Okay thanks a lot for the help Dave, I do appreciate it! Ill check it Sunday when I get back in town, and let you know what I see. Thanks again

Broach318 · « **Reply #20 on:** February 18, 2013, 06:42:21 PM »

Okay well we did the testing, Cam sensor was 1200, and crank sensor was 510. I read A few threads, its saying that its +/- 10% which would be like 580-700 range. So I think were going to order one and see what happens. Because 70 OHMS under the minimum is a lot.

keflaman · « **Reply #21 on:** February 18, 2013, 07:46:32 PM »

I've read a few instances where people were getting bad aftermarket sensors. Might be best to bite the bullet and pay for BMW parts in this case.

Broach318 · « **Reply #22 on:** February 18, 2013, 07:56:26 PM »

Quote from: keflaman;120239

I've read a few instances where people were getting bad aftermarket sensors. Might be best to bite the bullet and pay for BMW parts in this case.

Yeah same here, its about 120$ for a Bosch so thats what we are going to do. It must be a hot item, only place i could find one was turner and bavauto. Pelican is out of stock like most other places.

Broach318 · « **Reply #23 on:** February 19, 2013, 07:52:27 PM »

http://www.m42club.com/forums/showthread.php?t=13509&highlight=crankshaft+position+sensor+specs it could also be something similar to this?

Broach318 · « **Reply #24 on:** February 19, 2013, 08:26:32 PM »

Also forgot to mention, the car has about 5 stripped out bolts on the VCG, was reading some info that it could cause PCV vacuum leak, causing it to fail, thus throwing a CEL for o2 sensor because it allows to much air in and dilutes the AFR causing it to run rich in conclusion it runs like shit and throws a 1221 code..All started couple months after the VCG bolts were stripped. Here is the link. Thanks

http://bmw.e30tuner.com/articles_vchc.php

Broach318 · « **Reply #25 on:** February 19, 2013, 08:51:38 PM »

Also forgot to mention, the car has about 5 stripped out bolts on the VCG, was reading some info that it could cause PCV vacuum leak, causing it to fail, thus throwing a CEL for o2 sensor because it allows to much air in and dilutes the AFR causing it to run rich in conclusion it runs like shit and throws a 1221 code..All started couple months after the VCG bolts were stripped. Here is the link. Thanks

http://bmw.e30tuner.com/articles_vchc.php

Broach318 · « **Reply #26 on:** February 22, 2013, 07:25:22 PM »

Anybody?

Broach318 · « **Reply #27 on:** March 06, 2013, 08:23:53 PM »

So I put a fuel pressure gauge on it.. So when i turn the car over its not pumping fuel very fast i have a clear line off the T valve thats on the fuel line, so I can actually see the fuel coming up the line takes about 15-20 cranks for fuel to reach gauge. Will start after that. idles perfect at about 32 psi now when I go to drive it this is what happens. Car at this point is at running temp ~175-180 im in second gear( does not matter does it in all gears, even neutral, psi drops faster with a load on it) cruising at 2K rpms fuel pressure is ~30 the more gas you give it the faster the psi drops until it is at 0 and has no spark you can pump the the pedal and have no response. But if you let off the gas the pressure jumps back up to ~30 psi.. So basically its when you give it gas that the PSI will fall to 0... Any thing I can check? fuel pump is about 5 months old, same with filter I replaced them at the same time.

HERE is a video, kinda crappy sound due to my Lifeproof case.

http://www.youtube.com/watch?v=MNF7GRzX4f0

As you will see when fuel pressure is at 30 im barley on the gas ( more so momentum than throttle) as you see it drop I am giving it a range from 50-100% throttle, basically the more you give it the faster it drops to 0 and has no spark. Let off throttle goes back up to 30 psi..Thanks for looking!

DesktopDave · « **Reply #28 on:** March 06, 2013, 09:27:13 PM »

I couldn't really tel what was going on with the video. Maybe check the fuel pressure regulator? I'd guess if it was broken it might be letting enough fuel past that the pump can't keep the pressure high enough? Is the FPR vac line secure to the TB?

I'd also check the fuel pump relay, sometimes the coil gets weak or the contacts wear out. I'm pretty sure it can swap with the wiper relay.

Broach318 · « **Reply #29 on:** March 07, 2013, 06:17:21 AM »

Alright I'll look at the relay, it has the same exact one for the fuel pump and the o2 heater. I tested resistance on pins 86 and 85 they were both 84.8 ohms so idk if that's good or what. But like I said I have a clear tube off the T and you can see fuel as it cranks and barely goes up the tube like its using the oil pressure to pump fuel. But in the video it has a constant 30 psi but when you give it gas it just drops out to to zero if you keep on the throttle..