Quick V1 scan tool question

[Leonard Sparks]

Does the V1 scan only toll only for DVT's such as CASE learn procedure? I didn't really see any specifics on the product page.
Thanks in advance for your reply.

[joecar]

V1 scan only does perform bidirectional/DVT functions (such as CASE relearn) for Class 2 OBD-II serial bus connected GM PCM's.

For what vehicle...?

[Leonard Sparks]

This is a freshly built iron block LS6 in my 1978 Camaro.
This is what I have done so far:
1) Timing gears at correct position
2) Reluctor is at correct phasing, < .015" run out, air gap around .030"
3) Injectors check out at around 12.5 ohms +/- .5 ohms
4) Noid light pulses on all injector connectors
5) No shorts to ground, or voltage. Solid 13.8 V at injectors with engine running. 14.5 output at the alternator.
6) All ignition coils are firing, even though the engine is only firing on the companion cylinders ( 1,6 and 4,7)
7) Fule pressure at 55 psi
During further observation this what I found.
With the engine first started (stone cold) all the injectors are firing. I connected a noid light to the suspected injector pair (2,3 ) that does not fire with the engine hot. What I found is that all injectors fire on initial start up BUT when you rev the motor above idle the noid light will quit blinking and you can hear and feel the roughness in the engine.
Another thing I notice, is about a minute or so with the engine running, the injector pairs (2,3) and (5,8) do drop off where the engine is only now firing 4 injectors.

My question is, even with no codes set, do I still need to do a crank learn procedure? They way it acts when the engine is first started and revved up, does the pcm loose it reference position, and with the engine going to close loop and it cannot readily indentify the timing coorelation and go to a "safe" mode".

Any answer to this would be much appreciated and thanks in advance for your help.

[joecar]

Hi LS,

The PCM uses the crank relearn to prime the misfire detection algorithm, it will not fix the mis-sequencing problem, but try it anyway.

(after changing the rotating assembly (from pulley to flexplate) from what the PCM previously knew, you should do a crank relearn anyway)

Questions:
- which wiring harness are you using (what vehicle is out of...?)...?
- which PCM/ECM are you using (and what vehicle is out of...?)...?
- which crank reluctor are you using (24x or 58x/60x)...?
- which cam reluctor are you using (1x or 4x)...?
- are all engine grounds connected (list them)...?
- are all PCM ground connected (list them)...?

With the V1 Scan Only, you can still use the V7.5 tunetool to read the PCM calibration and save to .tun file... read it out and post it here.

[Leonard Sparks]

Questions:
- which wiring harness are you using This is a custom built harness ( I sell these through ebay and never has had a customer complaint dealing with this type of problem.-
which PCM/ECM are you using 0411 originally programmed for a LS6 by spare ecm, I went through and deleted all emission codes, APPS, and secondary fuel pump codes-
which crank reluctor are you using 24X-
which cam reluctor are you using 1X-
are all engine grounds connected grounded from the r. rear cylinder head to the cowl, alos block is grounded to the frame and to the negative bat. terminal-
are all PCM ground connected [COLOR="blue"]:confused:

[joecar]

Are all the PCM pins labelled as Gnd connected to ground...?

Does problem persist on same cylinders when you move coils, or does it follow the coils...?

[Leonard Sparks]

Are all the PCM pins labelled as Gnd connected to ground...? Yes, they are and I have been over the entire harness, no shorts to ground, no high resistance, no shorts to voltage.Does problem persist on same cylinders when you move coils, or does it follow the coils...?
*************** I have not moved the coils, I have checked spark at the plugs and they are all firing, I don't beleive that by moving the coils if that would take care of the problem, but may be worth a try?

[Leonard Sparks]

I am in the process of finishing up a harness for a customer and I was going to try it out on the engine to see if there may be something going on with my harness such a excessive current draw, EMI etc.