Code 52 info

morganson

morganson

New Member
Jan 19, 2012
274
0
0
Columbia, SC
Hey guys, i know there are alot of code 52 threads on here. But none of them ever close with a solution. I have an 88 turbo car with the perpetual code 52. Its fine until it goes into boost and just doesnt go anywhere. My biggest question is can this code be triggered by a problem with the maf. Im going to do the ks rewire just for giggles and i have a maft i am putting on. But its all moot if the knock problem persists. My afrs sit around 14.7 to 13 no major spikes, and im running a stock maf on stock injectors. Biggest mod is a 57 trim turbo and a holley fuel pump.
 
CyFi6

CyFi6

Aliens.
Oct 11, 2007
2,972
0
36
Phoenix
www.google.com
Code 52 will only be caused by one of 3 things...either a dead knock sensor, bad wiring, or a faulty ECU. Faulty ECU is not very likely, so chances are you either have a dead knock sensor or the wiring to either knock sensor is faulty. Those are the only things that can cause that code, no amount of engine knock will set a code 52.
 
morganson

morganson

New Member
Jan 19, 2012
274
0
0
Columbia, SC
Well i bridged the two then alternated disconecting either and the same thing happened every time. The code came on after a few revs. Reset and repeat. No change. So im leaning toward wiring or both knocks are bum. But....doesnt the knock code come on under detontion as well or was there another code for that? (hence the maf question)
 
CyFi6

CyFi6

Aliens.
Oct 11, 2007
2,972
0
36
Phoenix
www.google.com
I'm not aware of a code for engine knock. The ECU will adjust timing according to knock but it wont set a code. 52 is strictly a sensor or wiring or ECU problem. When certain RPM and load values are met, the engine looks for certain normal engine noise signals from the knock sensors, and when it doesn't see them, it sets a code 52. That is why when you start the engine the code is not present, but when you rev the engine the code is then set. And like JJ said, no, that code cannot be triggered by the AFM.
 
CyFi6

CyFi6

Aliens.
Oct 11, 2007
2,972
0
36
Phoenix
www.google.com
No problem good luck! There are some write ups on how to do the knock sensor re-wire, you should check those out if you plan on rewiring them. You need to use coax and ground the shielding properly.

Also, when I had this problem, I also had a dead knock sensor. What I did was depin the knock sensor wires under the glove box at the ecu (they are the wires with clear insulation on them) and hook my multimeter positive lead to one knock sensor and the other lead to ground, then went for a drive. I set my meter to AC voltage, and saw different voltage outputs when I would accelerate. The good knock sensor showed low but changing voltage according to how hard I would accelerate, and the dead sensor stayed at a constant low voltage regardless of acceleration. I had already checked the wiring itself so I knew it was the sensor. This is a quick and dirty way to check them if you don't have an oscilloscope which is what you need to properly test the sensors.
 
You must log in or register to reply here.
Top Bottom