another code 52

[87targa]

hey guys,

I got code 52 once again. I don't know what it is. I got new knock sensors a few months ago when i was doin a rebuild. so the sensors are not bad. i got good wires from the sensors to the ecu plug. got the wires around the beginning of spring. i checked for continuity from plug to ecu and it is fine. there is some resistance about 100 ohm resistance for both wires. i took the plugs apart so the pins would "sit" tighter. I also have my knock wire shielding grounded to the bar behind the dash.

I would imagine that if there is continuity then the solder should be fine. I will try to re-solder the wires on saturday to see if that helps any. and then try to change the ground wire to somewhere else.

I drove around my neighborhood with the plugs un-plugged to see if the CEL comes on at the same time interval as with the plugs plugged in. and it does. i unscrewed the knock sensors and routed my wires into the cabin. plugged the knock sensors in and drove around with the sensors in the passenger seat and still the CEL comes on. same amount of time as when the plugs were unplugged and about the same RPM in 2nd gear (~2800). It's as if there were no plugs plugged into them.

also, this happened when i changed battery. i.e. before the battery change everything was fine. after the battery change comes code 52. I noticed that my old battery was touching my radiator and arced pretty badly. Would that have caused anything? other than electrolysis.:3d_frown:

thanks for the help

 

[87targa]

I re-soldered the knock sensors. there is nothing else soldered to the wires other than the ecu and the knock sensors. i moved the ground to another bolt and still the code comes back on. i adjusted the pin so the plugs would sit tighter on the sensors and the ecu.

What can be wrong? I put some anti-seize on the knock sensor threads. I don't think that should cause a problem...but would it? I don't know what else could be wrong other than the ECU. the rewire kit i got from shaeff in march and the knock sensors are new. is it my ecu? i don't know anyone around the salt lake valley that has an '87 turbo whom i can swap an ecu with. if someone would be willing to do that that would be awesome.

 

[jetjock]

i unscrewed the knock sensors and routed my wires into the cabin. plugged the knock sensors in and drove around with the sensors in the passenger seat and still the CEL comes on

That's pretty funny.

The fact you got new sensors a few months back is meaningless. The 100 ohms is not. Your grounding method leaves a lot to be desired too.

 

[87targa]

i did that with the knock sensors because wanted to make sure the plugs were not shaking loose. but i also have heard that the code can go off when the knock sensors aren't screwed on tight enough so that move might have been useless.

so what does the 100 ohms tell you? too much resistance? not enough resistance? i'll try to move the ground around and see what happens.

there are 6 bolts on the passenger side that mounts the bar behind the dash. that is where i have been grounding the wires to. there is one ground wire. i guess it is the wire for the shield.

so you think it's a grounding issue with the wires or a grounding issue somewhere else that has to do with the ecu?

thanks for the help.

 

[87targa]

ok i seem to have fixed the code. I'll drive around for another day to make sure it is really fixed.

I disconnected the ground and no code so far.

It's really weird.