CA18DET Code 34 Problem.

[zbeffreyCA18]

Hey guys, here is my setup:
T28BB Turbo
Deatschwerks 550cc injectors
Bosch Z32 MAF
Tomei Poncams
Full Exhaust
Front Mount Interooler
SPEC Stage 2+ Clutch

I fitted the injectors and MAF and wired everything in recently when I had the engine out of the car to do the clutch. Everything went together smooth until I went to connect the knock sensor and the connector broke off the harness. So I peeled back some of the shielded wire and fixed the break in the wire (WITH Heat shrink), put the shielding back over the wire and electrical taped everything to make it look nice again. Before initial startup, I did the Change MAF and Resize injector functions and set fuel pressure to 53psi static (i think I need to lower it to 43psi though.)

I started the engine and it idles a little lean at times and has an hunting idle and always, no matter what, throws a code 34 for the knock sensor at me. I don't have a screen shot, but it looks to be running off the knock fuel map, and sometimes highlights the knock timing map, but most of the time neither of the timing maps are highlighted at all. Here is what I have tried to fix the issue:

Continuity at the Knock sensor connector - YES
Continuity between ECU connector and knock sensor connector - YES
Good engine ground - YES
Good knock sensor - YES

I'm running out of ideas. The only thing that would make sense is what one of my buddies told me, and that's that the metal wires in the shielded wire may be touching the signal wire for the knock sensor and grounding it out causing it to throw a fault code. I didn't change anything other than the MAF and Injectors, except for adding a Volvo cruise control pump to control the butterfly valves, but the problem persist even when this is disconnected. I ran NIStune all last year without any issues or codes at all and while the engine was out, the ECU sat on my passenger seat in my garage for 6 months. Any ideas? Oh, and I have not adjusted any tables or did anything in NIStune except for the injector resize and change maf functions.

Thanks in Advance!
Zak

[UNISA JECS]

I wroite this a long time ago I think you'll find it useful

Well I fixed my knock sensor error code problem.

After spending many hours actually days on this shit I finally fixed the problem and the ECU now gives me a code 55 ......

Heres are the diagnosis steps I performed:

1. Disconnect ECM harness connector from ECM.
2. Disconnect KS subharness connector from KS.
3. Check harness continuity between terminal (B) and ECM terminal (27).

Im my case continuity did exist (so good to go right? NOPE) im still getting a code 34 and my knock sesnor is good to go.

Next I pluged everything back together like it should be then:

Step:
1) With a DMM, one probe to ground other back probing pin 27 (Knock Sensor) with KOER and KOEO.

Results = 0.013v (no good) FSM states you should see aprox. 2.5v at idle and or KOEO.

2) I disconnect ECM harness connector from ECM and de-pin, pin 27 from harness connector alltogether.
3) I re-attach the ECM harness connector to the ECM with pin 27 detached from connector.
4) With my DMM I ground one probe and the other to pin 27 and I get 5v, so the ECU is good to go.

So next step:
1) Taking a jumper wire to pin 27 and reconnecting the original (white) KS wire to the jumper wire I instantly lose the 5v (so im thinking why what is causing this to happen (a short to ground etc etc)
2) I take the same jumper wire and disconnect the original (white) KS wire from it and get about 3ft of regular 16 gauge wire and run it directly to the knock sensor subharness terminal (B).
3) I take measurements back at the ECM with my DMM one probe to ground other to pin 27 and I get 2.5v (good to go finally
4) So now I clear the codes and start the car run it for a few seconds and shut it off.
5) Check codes for any errors and all is good (code 55 finally)

If some of you are wondering why I didn't get 5volts when I rewired, its becasue the KS itself is a 0.560M-Ohm resistor and it reduces the voltage down to approx. ~2.5v.

My code 34 was instantanious means I could clear the codes and get code 55, start the car for 1 second then turn it off and check teh codes and I have a code 34, thats becasue it basically had no voltage present of pin 27.

Some other things that still stump me is I still got continuity between pin 27 and the KS sub harness but why or where was the voltage going to im by no means an electrical expert but I wanna know where it was going, is that what a short to ground would do???

[zbeffreyCA18]

FIXED!!

When I originally repaired the knock sensor connector, I must have forgotten or to heat shrink one of the solders and just wrapped the wire in electrical tape. Turns out the wires in the shielding were touching the knock sensor signal wire and grounding out causing the dreaded Code 34. I re-repaired the wire and Code 34 no longer appears on my ECU Message screen in Nistune. All fixed!