: 90 Brougham - Service engine light - power loss. What could I be looking at?



Johnny Kaka
07-01-13, 06:50 PM
Hello everybody. Today on my way home, as I was accelerating up a hill, I got a service engine light and immediately lost about half of the engine power. I didn't smell anything burning, or any coolant smells. Once I got it home, I popped the hood. Saw no leaks, but it was extraordinarily hot. And the coolant reservoir was empty. An hour later, the coolant reservoir is full again. No leaks underneath.
I realize that without a reader, I will be flying somewhat blind, but do any of you know from my description what this might be?
-Thanks!

cadillac kevin
07-01-13, 07:05 PM
Hello everybody. Today on my way home, as I was accelerating up a hill, I got a service engine light and immediately lost about half of the engine power. I didn't smell anything burning, or any coolant smells. Once I got it home, I popped the hood. Saw no leaks, but it was extraordinarily hot. And the coolant reservoir was empty. An hour later, the coolant reservoir is full again. No leaks underneath.
I realize that without a reader, I will be flying somewhat blind, but do any of you know from my description what this might be?
-Thanks!

Get a paperclip and jump the ALDL....it will blink out a 2 digit code. no need for a reader

Johnny Kaka
07-01-13, 07:14 PM
How do you "jump the ALDL" with a paperclip? Is it behind the glovebox?

cadillac kevin
07-01-13, 07:36 PM
it is under the dash to the right of the center stack.
http://www.obd-codes.com/faq/read-gm-2-digit-obd-codes-free.php

Johnny Kaka
07-01-13, 08:40 PM
Holy cow. THANK YOU! 43- knock sensor circuit. I hope it is as simple as that.

csbuckn
07-01-13, 09:31 PM
I dont think its the knock sensor itself, it just picked up a noise that sounded like a knock or detonation and adjusted the timing by 5 degrees. The timing adjustment is what caused you to lose power. I had this problem for the longest and couldn't figure out what it was, I ended up adjusting the timing manually back to normal and leaving the check engine light on. If I'm not mistaking, it should run good until it warms up and then run like crap. I would try resetting it by unplugging the battery for a while and see if it happens again. The knock sensor is picking up a noise on the bottom end that shouldn't be there. If you have no noise, maybe it is the sensor but that wasnt the case for me.

Johnny Kaka
07-01-13, 11:40 PM
I have a rattling heat shield. It is making a lot of noise, but I didn't think the knock sensors were made to pick up exhaust rattles. Could that be it?

csbuckn
07-02-13, 12:04 AM
I dont think thats the problem but maybe. I think the sensor is cheap so maybe you can grab one since you have no real noise.

brougham
07-02-13, 03:22 AM
The knock sensor should only be picking up noises from the engine itself and the heat shield is probably the wrong tone to cause it. If it continues it could just be the knock sensor is over-sensitive or giving a bad reading that the computer doesn't like.

For a 1990 what engine you have will also make a difference for what's wrong. A carburetor will have more oddball problems then fuel injection will. And if you have the 5.7L you don't need the paper clip to get codes, you can get more just by holding off and warmer on the climate control. It might not give much engine information if you have a 5L car tho.

Johnny Kaka
07-02-13, 09:55 AM
it is a 5.7.
I have been running a bit rough for a while. My suspicion is that the car needs new plugs and wires, along with a distributor. When it warms up, it runs rough. Doesn't knock, but shakes a bit. This has been going on for a while.
I am also wondering about the ICM. I know that it can cause similar symptoms. Not sure it would throw a Knock sensor code, but here is some background:

A few weeks back, I came out to the car and tried to start it up. It cranked a few times then died. Then, I tried again, and lost all power on the dash. tried again a minute later, and it started up. This happened a bunch of times, then mysteriously stopped happening. I was thinking a short in a wire or something. Would a bad ICM do this? Why would the dash lose power? Could this be the reason the car loses power? OR could I have a faulty wire from the battery (Which would explain the dead dash) that is bugging out the knock sensor? I want to get this fixed by Thursday if I can.

Johnny Kaka
07-02-13, 11:57 AM
I should also add that it was raining heavily yesterday.