VN 304 wont Idle. Weird

[lb9]

Hi All,
First time posting here because I am at a loss. I have a 304 out of a VN that I have put in my Nissan patrol. everything seems to work except it wont idle properly.
on cold startup, I have to keep the revs up otherwise it will just konk out. once it gets some heat built up it idles super low and inconsistently. if I take it for a spin around the block, come back it idles fine, but at 1100 - 1400 rpm. if I adjust the idle screw down on the throttle body it will idle normally at 650 - 700 rpm but the next time I go to cold start her it's the same issue. I have replaced throttle body, IAC, tps and nothing has worked. and yes when i did the timing i jumped the ALDL.

Any suggestions?

 

[Immortality]

Does it have a working speed sensor?

These also need to have the idle manually reset IIRC. Once the engine is warm hold the engine at 3000rpm for 10 seconds and then let it return to idle and the ECU should reset the IAC to achieve the correct idle.

 

[lb9]

I have already tried to reset the idle exactly how you described but it is still doing it. i'll give it another go tonight.
there is no speed sensor because it is mated to a re4 gearbox (manualised), which is wired up to the bcm of the patrol. i am using a conversion loom so there is no gearbox loom. connected to the motor loom.

 

[Immortality]

No speed sensor is an issue. The ECU uses the speed sensor to determine when to go into idle mode.

 

[lb9]

that doesn't make much sense from a logical point of view. if you're rolling and put the car in neutral, it should idle. Maybe i'm wrong.
There is no speed sensor as a part of my loom, and there are no speed sensor pinouts on my ecu.. it is a manual ecu.
the car still idles when its supposed to, but only when its warm.

 

[Immortality]

On the factory loom there is definitely an input for the speed sensor. Manual and auto used the same ECU

See the attached wiring diagram.

 

[lb9]

yep.. the loom has no brown/yellow in the ecu plugs. it has a modified memcal so I assume that has been made to ignore it. when warm, the car runs perfectly, it idles, accelerates and decelerates fine. its only on cold starts where it doesn't want to idle.

 

[Immortality]

Then I suggest you contact whom ever supplied the tune as it's not set up as per normal.

 

[Lex]

it has a modified memcal

Who supplied the memcal?

 

[lb9]

I have no idea. I bought the conversion loom and ecu off some guy a few years back.
its HSV stamped and has "unlocked" written on it. I do recall him saying that it has been modified for the conversion.