efi question

[Garth]

what could cause a normal injected car, with a disy, i.e. the vl setup to loap, or have a up and down idle? it's not a rough idle, it's a surging up and down idle.

[Darren_L]

could be a lot of things.
I'd be checking for vacuum leaks first though. Make sure all the intake manifold bolts are tight for a start

[Calaber]

I'm not familiar with the old F.I. setup on the Nissan 6, but I experienced this problem on a Telstar I had some years back.

It had a "stepper motor", designed to regulate idle speed as the engine temperature increased. Suppose it was something like an auto choke.

It carked it and caused the engine to accelerate, then drop back, accelerate, drop, just the same as if you were sitting in the car and operating the accelerator on and off. It became bloody dangerous when driving in traffic - bastard of a thing kept wanting to kiss the car in front.

If the early F.I. system has something similar, it could be that.

[Blown V6 Hatch]

All EFI engines have a stepper motor of some description, or more commonly known as an IACV (idle air control valve).

[Calaber]

All EFI engines have a stepper motor of some description, or more commonly known as an IACV (idle air control valve).

Well, thank you very much for that piece of information. Now, does it help the op, or were you just trying to enlighten me?

[Cheap6]

Maybe a dead/dying TPS?

I think that VL have a solenoid (valve), as distinct from a motor, to control idle speed. It's possible that is sticking.

Airflow meter or a leak between that and the engine?

Any fault codes?

The vacuum leak would do it.

[Garth]

nah, it's a old ford corsair motor and box we have put into a off road buggy, been thinking it was the old iac valve, today we played around a little bit more, took it out and gave it a clean, put it back in, and it's running heaps better, just not 100% might have to do a wrecker run one day and find a iac valve

[Ado]

Love to see some pics of the buggy.Is it the 2.0 or the 2.4 motor?

[Garth]

Love to see some pics of the buggy.Is it the 2.0 or the 2.4 motor?

2.0 and a tempermental one

has issues with idleing right. ill get it sorted out one day

[delcowizzid]

what sort of air flow meter does it have it isnt a vane style one with the door that swings open inside it they can get a bit sticky and way out of adjustment