Sanchez

Here it is...
'91 Pickup, 4x4, 3.0 V-6

Thanks for all the helpful advice and tips in the past... A truely awesome resource. Though with this problem I can't seem to find an answer...
Here is what my problem is...

Recently replaced the knock sensor, pigtail and eventually the wiring to the ECU. Still a code 52 - even after pulling the battery cable and efi fuses and relay repeatedly. It makes no difference in results whether the new KS is plugged in or not. Within a minute or by the time I hit second gear the CEL comes on. I am hoping that I can find an ECU to test on my system soon. Starting to affect my quality of life. Not to mention that winter is coming quickly...
Has anyone had similar experiences?

Thanks

Tim

shaeff

Doublecheck the wiring to make sure the signal wire isn't grounding out. If it is, you get code 52. There are only three possible problem areas.
1) Knock sensor
2) Wiring
3) ECU.

It's usually NOT the ECU. Most commonly, the wiring has failed. Did you torque the knock sensor to the proper spec?

to4menon4u

i had the same problem and it turned out to be the ecu. i got a used one off ebay and it works perfect!

Sanchez

Thanks guys... signal wire isn't grounded - sensor is torqued... I have a sneaking suspicion that this ecu might be done. I will know tomorrow... Fingers crossed...

Team420

I had the same problem and it turned out to be a vacuum leak... I think.

If the cel comes on as soon as the truck is started, it would mean no signal to ecu from the ks, but if it dont come on till say a min or 2 down the road, it could be unmeterd air getting in, and causing a knock, or ping, the ks picks that up, and the ecu retards timing to compensate, if it runs out of room for compensation, it throws the cel, and runs in retard mode.

shaeff

You are wrong. The knock sensors are invisible, meaning that you have no idea that they're working if everything is functioning properly. When you get code 52, it has absolutely NOTHING to do with spark knock/detonation/pre-ignition, or vacuum leaks.

Code 52 is an ELECTRICAL problem. The possible trouble areas are:
1) Knock sensor(s)
2) Wiring
3) ECU.

That's it.

James64

Hey Sanchez, I'm having the same exact problem. Was it your ECU?

calipatient

iTrader: (1)

i just popped the code 52 last night. been reading and working on it all day. wires were fried! i rewired the driver side. but on the v6 3.0 are there 2 knock sensors? 1 on each side? any pics of their location would help! this is driving me crazy.

Innervision

only one KS it is between the heads down in the block. You have to take off the plenum and intake manifold to get down to it. See here:

http://personal.utulsa.edu/~nathan-b...ne/69cylin.pdf

calipatient

iTrader: (1)

innervision:

thats what i thought... just need conformation. that site is very helpful. makes a complete rebuild look like a 1st grader could handle it!

calipatient

iTrader: (1)

theres 2 wires to it... ones brown and ones black. any idea which goes to which? someone said in a previous that black was to the ecu... is this correct?

91diesel

I have the ecu from a 91 V6 truck left over from my swap if someone needs it. I'll let it go cheap!

calipatient

iTrader: (1)

diesel: ill let ya know if it comes to that!

dntsdad

I also have a ECM from a 92 3.0 4x4 excab manual if someone needs it that wont be used as I swap a 3.4 into mine.

Calipatient....I have friends who work in Visalia so i could get it there for ya. PM and maybe I'll just let you use it and see if thats he problem. That way at least you know for sure without buying one and wasting your money.

Jason

ahhhh....just saw you have a RUnner. That probably means auto so not sure if this ecm would work for you. probably not but maybe someone will chime in and confirm.

calipatient

iTrader: (1)

dont think it will... the offer is much appreciated though!