Author Topic: Solved! - Antilock & Check Engine at the same time? (Read 4043 times)

jmsra · « **on:** December 15, 2011, 09:20:05 PM »

So I tried a rather hard launch on my 91 318iC and both the Check Engine & Anti-lock lights came on at the same time the ignition cut out. The engine came back as i let off the pedal and the lights were only on momentarily as the ignition was cutting out. Any ideas? Could i be yanking on some wiring when the clutch is let out? it only does it from a stand still when its trying to pull hard. Doesn't matter if its cold or hot.

DesktopDave · « **Reply #1 on:** December 15, 2011, 09:51:16 PM »

That's an odd one. If I had to guess I'd say maybe a flaky wheel sensor is confusing the ABS? I'd think the rev limiter is cutting out & running the O2 sensor too rich.

I'll bet it's two different problems. Try a stomp test and see if you get a 1221.

jmsra · « **Reply #2 on:** December 15, 2011, 10:22:46 PM »

Thanks for the quick response Dave. Yes it did give a 1221, but like you said, i think its two different issues. I don't think its the rev limiter because the rpm doesn't go above 4k before it cuts out. if i gradually take off there are no issues all the way to redline, its only on the hard take offs where i see the cut out and both lights coming on. I was thinking maybe bad motor mounts causing the engine to move more than it should?

DesktopDave · « **Reply #3 on:** December 16, 2011, 07:13:55 AM »

Might be mounts. I'd check the throttle position sensor, but that's unlikely since the stomp test works. Maybe a flow problem? Sticky AFM? Plugged fuel filter, weak pump?

I notice that my car does a similar thing if it's near-stalling. All the dash lights will flicker, not just the ABS & CEL. Try to stall it in first gear without throttle & see if it has the same symptoms.

jmsra · « **Reply #4 on:** December 16, 2011, 01:06:28 PM »

Thanks for the help Dave, i will try stalling it first. I'll see if i have enough time tonight to check fuel pressure, filter, and AFM. post findings after. BTW, i have ordered a COP kit from HQ Autosport since they are the original coils, currently at $160 year end sale!

jmsra · « **Reply #5 on:** December 17, 2011, 01:35:44 PM »

so i think i figured out what seemed to be the ignition cutting out. A couple of the hoses seemed like they were tight, but came off rather easy so i used some clamps and tried the hard launch. no bucking, but still get the goofy ABS light. still plan on replacing the the coils with a COP kit as they are originals. Will look at the ABS sensors and wiring next and update after.

jmsra · « **Reply #6 on:** January 09, 2012, 09:35:48 PM »

So i finally got around to driving the car again and trying to stall it. it stalled alright! and wouldn't start on the side of the road! Came back after work and just tried swapping the o2 sensor and fuel pump relays. started! drove it to my brothers house as it was closer. on the way there tried everything to stall it and it drove fine. as I take the last turn before his house it bucks again with the same ABS light at the same time. parked it and wouldn't start. Switched the relays again and it started right up? to dark to check anything tonight so i came back home to find COBRA JETS thread. very informative by the way. Going to check the ICV and ohm both crank and cam sensors. While reading the thread i did find a curious "link" between the fuel pump circuit and the ABS circuit. They both go through the engine harness splice #S122. Going have to check that as well. any idea where that may be?

DesktopDave · « **Reply #7 on:** January 10, 2012, 05:07:42 PM »

They share a splice? I've been looking but the only thing I saw was the ABS pump relay. I didn't find S122 either...

I'd test the crank sensor too. 640 or so on pins 1 & 2, much higher (100Kohms IIRC) on 1 & 3 and 2 & 3.

jmsra · « **Reply #8 on:** January 10, 2012, 09:02:23 PM »

Well Well. S122 it is. I looked at the car today after work and it started right up. before i shut it off i figured i would do the wiggle test around the fuel pump relay. I followed the power wire through the harness back to the battery. At the battery there is about 3 wires bolted together on the positive terminal. Wouldn't you know the bolt holding them together had come loose!!!!!!!!!!! I nudged the wire and the car sputtered and died. I started it again and had someone watch the gauges as i moved the connection, sure enough the ABS light came on and the car shut off. I'm guessing the battery moved just enough on hard starts where it would pull the cable loose and power to the fuel pump, DME, and O2 Sensor were cut off and shut the car off. So glad i read COBRA JET's No Start Thread. I only saw the that those relays shared a power splice by going through that thread, otherwise i would have never thought to look there. I think this weekend will be dedicated to cleaning and tightening grounds and checking splices! Thanks for the help Dave!

keflaman · « **Reply #9 on:** January 11, 2012, 08:30:03 AM »

Thanks for posting everything you did and the final analysis/fix! It's threads like this and the ones you referenced that make this forum a great troubleshooting resource.