do you have correct knock sensor? i believe on 7427 knock module is with the memcal, you can try reseating the memcal.
do you have correct knock sensor? i believe on 7427 knock module is with the memcal, you can try reseating the memcal.
duplicate post
Last edited by Daveo91; 08-05-2021 at 10:18 PM.
Pretty sure I have the correct KS: Delphi AS10016. As recommended by @daveW and it's what shows up for a '94 350 truck. I'll try and reseat the memcal - thanks great suggestion. I really think it's something along these lines since it flags as soon as engine starts or even after 30 seconds with key on. Also, KS appears to have been working for my first few runs after the conversion.Originally Posted by tayto
pretty sure 7060 and 7427 share the same knock sensor, but it's an easy check to do with DMM.
Yep, you're correct, they are. I tested resistance on both, old one was around 100K ohms which AFAIK is right within spec, but the new one was only testing around 2K. So I swapped them and am running the old now. But I'm still having the same problem with the flag setting within 30 seconds, engine running or not. I'm wondering if the low resistance could have killed the memcal or something in the PCM?
I might have solved this issue with the KS, but not exactly sure how.
First, I'm fortunate to live in the same city as Dave W (Vancouver, WA) He let me try a different 7427 and memcal. Exact same issue, no change at all so we were both mystified. In the course of this, Dave informed me that the KS with the much lower resistance - that I had taken out - was indeed the correct one. So tonight I reinstalled the correct (Delphi AS10016) KS, and, lo and behold, no code. I have not driven it yet, but left the key on for twice as long as it was taking to set the flag before, and then started engine and let it run for a bit. No code. Before it would have flagged within 20-30 seconds of either just key on or engine running. Won't know for sure till I drive it which won't be for a week or so now.
With the correct KS installed I back-pinned a paper clip in to the B15 terminal so I could check voltage on the KS circuit to engine ground: 2.43 (key on) and I think 2.48 or so engine running. Do those voltages seem correct?
Not sure if this covers your year PCM...
That's a great fault tree, thanks for posting. Is that for the 7427 auto pcm or for the '95 manual ecm with a 2732a and not a memcal?
-Carl
Awesome - thank you for the fault tree. So sounds like the consensus is that this is for a '7427 auto truck?Not sure if this covers your year PCM...
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