PCM write problems, cabling ?

They go by many names, P01, P59, VPW, '0411 etc. Also covering E38 and newer here.
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joukoy
Posts: 392
Joined: Tue Dec 17, 2019 3:27 am
cars: Pontiac Firebird 1978

PCM write problems, cabling ?

Post by joukoy »

Hello.

I have P59 in old vehicle (no other devices in bus). Using Obdlink LX.
First time I wrote calibration with Pcmhammer 14, I get zero errors.
Next time there was couple of "BUS BUSY" messages, but write was succesful. After that, every time more and more errors.

Then write failed every time when fuel pump started shortly during kernel upload, and write was succesful only after removing fuel pump fuse.
Now I can write calibration only if I remove green connector from PCM.

Any ideas, where I should start looking for solution?

Example of BUS BUSY messages, when writing was still working:

Code: Select all

[08.07.14.472]  OK
[08.07.14.529]  TX: STPX H:6D10F0, R:1, L:1033
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
[08.07.15.248]  Unexpected response to STPX payload: BUS BUSY
[08.07.15.249]  Unexpected response to STPX payload: BUS BUSY
[08.07.15.273]  WritePayload: Unable to send message.
[08.07.15.325]  TX: STPX H:6D10F0, R:1, L:1033
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
[08.07.16.449]  RX: 6D F0 10 76 00
[08.07.16.450]  Found response, Success
User avatar
Gampy
Posts: 2330
Joined: Sat Dec 15, 2018 7:38 am

Re: PCM write problems, cabling ?

Post by Gampy »

Please try the following,

Disconnect the tool from both the car and PC.
Disconnect the PCM from all power.

Let them set while you check the battery voltage and top it off if need be ... 12.5v or greater! (preferably greater)
Verify your wiring isn't around any power cables.

Power the PCM
Wait 15s
Hook up to car
Hook up to PC
Wait 15s
Open PcmHammer and do a Test Write.

Please post a full debug log of the one attempt.
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kur4o
Posts: 948
Joined: Sun Apr 10, 2016 9:20 pm

Re: PCM write problems, cabling ?

Post by kur4o »

To rule out any wiring in-car issues. Try a bench flash. You can also try lsdroid if the cable has bluettoth. That will rule out any pc-cable-hammer issues.

That fuel pump on is not normal behavior. When it start running, Can the voltage drop for a split second when it is turned on. Running pump indicates that the pcm is out of flash state.

Definitely something is not good there. I would stay with cal flash only till you get stable enough communication. At least that will save you from bricking.
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joukoy
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Joined: Tue Dec 17, 2019 3:27 am
cars: Pontiac Firebird 1978

Re: PCM write problems, cabling ?

Post by joukoy »

Found it:
Unplugged alternator wiring, now test-write works fine. No more fuel pump starting during kernel upload.

I will disconnect PCM from alternator and use old good alt warning light.
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Gampy
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Re: PCM write problems, cabling ?

Post by Gampy »

Thank you for letting us know!

-Enjoy
Intelligence is in the details!

It is easier not to learn bad habits, then it is to break them!

If I was here to win a popularity contest, their would be no point, so I wouldn't be here!
User avatar
joukoy
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Joined: Tue Dec 17, 2019 3:27 am
cars: Pontiac Firebird 1978

Re: PCM write problems, cabling ?

Post by joukoy »

joukoy wrote:Found it:
Unplugged alternator wiring, now test-write works fine. No more fuel pump starting during kernel upload.

I will disconnect PCM from alternator and use old good alt warning light.
No :evil:
PCM is not connected to alternator now, still looks like pcm is resetting (?) when uploading kernel.
But not if alternator is unplugged :?:

Probably it is voltage drop problem, I need to check my PCM power supply connections & wirings.
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User avatar
joukoy
Posts: 392
Joined: Tue Dec 17, 2019 3:27 am
cars: Pontiac Firebird 1978

Re: PCM write problems, cabling ?

Post by joukoy »

Didn't found any problems from +12v cables, but soldered all connectors.
Cleaned & tightened ground connections and added extra ground cables:
- Battery to body
- PCM pin 60 to body (was already to engine but long cable)

At least 3 test writes without any problems :thumbup:
User avatar
joukoy
Posts: 392
Joined: Tue Dec 17, 2019 3:27 am
cars: Pontiac Firebird 1978

Re: PCM write problems, cabling ?

Post by joukoy »

joukoy wrote:Didn't found any problems from +12v cables, but soldered all connectors.
Cleaned & tightened ground connections and added extra ground cables:
- Battery to body
- PCM pin 60 to body (was already to engine but long cable)

At least 3 test writes without any problems :thumbup:
Today tested calibration write first time after adding cables, and it failed again.
Unplugged alternator and write was succesful.

:wall:

I give up for now.
kur4o
Posts: 948
Joined: Sun Apr 10, 2016 9:20 pm

Re: PCM write problems, cabling ?

Post by kur4o »

You might have bad voltage regulator, or wrong type of alternator. It can produce too much noise to the pcm. It is known that vpp voltage can freak out the processor if on all the time.

Testing with another alternator can pinpoint the problem.
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joukoy
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cars: Pontiac Firebird 1978

Re: PCM write problems, cabling ?

Post by joukoy »

Removed wire from alternator Sense-pin to B+, after this 3 succesful calibration writes, with one BUS BUSY message.
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