TPS works when in neutral but not when in gear.

[Asho88]

So I’m having an issue when I rev the car in neural I can see the tps working but as soon as I put it into gear it just goes dead no signal at all any thoughts? Also at idle I’m having erratic conditions the timing jumps about (it’s at temp) and I’ve adjusted the idle timing map. Also wondering if there is a fuel map for idle or does that run off of the main map? Cheers VH 253 VN EFI setup running $12p. Cheers

[vlad01]

Not some weird issue with the neutral safety switch wired into the wrong wire or pin on what I assume you have used is the VN-VP loom? I know on the stock setup there are multiple lines running from the patch loom that connects to the auto/manual and neutral switch back to the ECU, so it could be voltage going into one of the grounds or maybe into the 5v ref line the the TPS and other sensors use some how.

Do you have the factory VN-VR wiring diagrams?

[Asho88]

It’s not wired into the car as such I’ve set it up to run standalone so basically just powered the ECU and it runs separately to the rest of the car. Interesting thought though wondering if I can configure it to run as a manual by pass neutral safety switch side of things. The actual car has the safety switch so no issue there. Cheers

[vlad01]

That is very strange indeed. Yes you can config it as manual, iirc it's one of the pins on the ECU that normally runs to the auto and neutral switch that is either grounded (back to the ECU ground I think?) or left open which tells the ECU if it's auto or manual, then the tune uses the auto and manual only tables respectively.


The 12P pinout txt file has the entire ECU pinout plus the 12P special I/Os like WB and flex outputs etc...

[Asho88]

I didn't even consider it to be honest. I thought the ECU was playing funny buggers with me lol. I will look into that and see what I can figure it out. Thanks for the good info.

[Asho88]

Ok so just looked at the pinout and nothing jumped out to me that could be for the neutral reverse switch other then the reverse lockout but that's for HSV 6 speed only lol. Also seen most just say swap out the memcal but the tps power might need another power wire added that is constant once the ignition is on. Cheers

[delcowizzid]

Don't add 12v to the tps it runs on 5v .there must be a wiring issue on your gear position switch

[vlad01]

I mean for manual/auto select. I had a look and that one is pin B10. I don't think it will be anything to do with the issue unless some real weird wiring voodoo is going on, but it will be interesting to see if changing from grounded/open has any effect on the running of the car, the auto mode has higher idle for when in drive, so if it's manual model it might stall and struggle to idle from it being "set" too low.

I think that B10 might even be switched by the neutral/park switch to tell when it's in drive once running, but I could be wrong as I haven't played with any autos for a long time.


Also, maybe check the TPS itself in case it's doing something weird like when you go into drive, the extra vac pulls the throttle blade shut a tiny bit more and the TPS happens to have a dead spot right on the boarder line. I had a 5L fault a few TPSs over a few years and it had intermittent dead spots where the throttle either went to a random value or fell back to zero, the car kept killing TPSs for some reason.

When a TPS encounters a dead spot the engine runs like shit and usually stumbles and can stall. So worth checking.

[Asho88]

@delcowizard I won't lol. It's not wired into the neutral reverse switch I've basically just powered it up and functions well other than the TPS issue cheers. PS dunno if it'd make a difference I don't have a speedo..

[Asho88]

@VLAD Yeah going auto to manaul wiring is always fiddly there isn't alot of info about.

Oh ok I'll look into it further.

Yeah have been thinking to look into the TPS though just seems strange that its fine in neutral/park but as soon as it goes to drive or reverse it dies.