bluAM2

hey all, could use a little help on this one. I just put in a remanned 3.0L back in my 93 pickup. when i did i replaced the knock sensor and wire just because it's so hard to get to. the old wire was pretty brittle and corroded. anyway, i've put about 500 miles on the engine now to break it in and it hasn't run completely right yet. i'm getting a code 52 still after a brand new knock sensor and wire combo. could it be my whole wiring harness? or something else? i've changed just about everything on it aside from the injectors (next step). i bought the truck with 243k on it and replaced the engine at 244k. the engine just doesn't have the pickup and go that it should. i replaced the MAF sensor 2 days ago and that helped a little. i was thinking maybe the O2 sensor next. exhaust smells a little rich and fuel mileage sucks. any info helps! thanks a lot!

bluAM2

i forgot to add that i have a small exhaust leak coming from my EGR valve hard line that i've been meaning to fix or remove. i don't know how much that will affect things.

flecker

Nobody knows..... There is NO fix.

shaeff

The code 52 would be your power loss. It will retard timing and as a result of that, fuel mixture will be enriched, both those are very good at killing power. Test continuity to ground on the signal wire. If you get continuity, rewire straight from the KS to the ECU and you'll be golden. Make sure you use coax cable, and ground it on ONE side (preferably the ECU side). Do not let the signal wire touch the ground.

bluAM2

update: STILL have the code 52 CEL. I haven't had much time and haven't thrown any parts at it in a while. Just changed the oil at my 2500 mile mark on this brand new engine and haven't gotten the full power yet. I've been running premium to help make it run better because of how badly it sucks. right now timing is set at 17* BTDC and without the check engine light on. come to think of it i haven't checked timing with the CEL on. maybe i'll do that tomorrow too.

recently made a 500 mile round trip from whidbey island, wa to portland, or to return my cores from the engine change and got 20 MPG! performance sucked though as expected but it threw me for a loop because i was thinking i was running rich so i should be getting crappy mileage. but 20 mpg with a long block and short block in the bed? that sounds a lot more like LEAN to me which scares me though i can smell fuel in the exhaust so i'm confused. the new engine i have in is a "high torque" (ha ha i know) motor. basically different cams and reworked heads i'm thinking. would something like that require the ECU to be reflashed? can you even reflash a 93' v6 ecu?

anyway, for a refresher ... this is how i'm set up right now:
- 2.5k on 3vze
- new with engine change:
- knock sensor & pigtail
- MAF sensor & K&N intake
- clutch & resurfaced flywheel
- lce headers and crossover pipe (header tape on passenger side only to protect
starter)
- temporary 'custom' catless exhaust (muffler from '82 jag lol)
- EGR removed
- power steering idle up vacuum lines removed

i also might have an air valve going bad? if i read the book right you're supposed to be able to adjust the flathead screw on the throttle body all the way closed and with the engine warm it shouldn't idle down at all ... mine coughs almost to a stall and occasionally idles at around 200-250 rpm.

i guess that's quite the book for now. those that have the patience to read it ... help! those that don't ... help! i think i'll chase wires in the morning. i'll be damned if i'll let tiny little v6 whoop me! (even though it's doing a pretty good job at it)

shaeff

Rewire straight from the KS pigtail to the ECU. Don't trust the old wiring. Code 52 is limited ONLY to the knock sensor circuit, which involves the following:

1) Knock sensor(s)
2) Wiring
3) ECU

I can nearly guarantee it's not the ECU. So do a few simple tests and figure it out!

badboycustom

I also have the code 52 problem. yesterday I unplugged my KS and advanced my timing to 18 BTDC and filled it with premium. The CEL still comes on like clockwork but now i have no power loss when it lights up and don't seem to have any pinging going on. I am not willing to tear down the top end to fix this persisting problem.

bluAM2

figures, i've gotten my two most promising answers in forever and i'm 2100 miles away from my truck for 2 weeks ... thanks for the info! i'll let you know how it works

shaeff

Or you could just fix it properly. I went further in depth about how the knock sensor works in this thread, if you'd like to read how to properly fix the problem:
https://www.yotatech.com/forums/f116...al-fix-211252/


You should take a look at the thread I linked above as well for a better understanding of the KS circuit. Definitely post up and let us know how you make out!

bluAM2

https://www.yotatech.com/forums/f116...l#post51827313