Rb20 Only Idles

[Guest HnM]

I have just bought a VL wagon with an RB20 redtop motor installed with the intention to fit it into my sedan, I bought it from a bloke who could only get it to idle but for some reason blamed the AFM while at the same time ripping the fuel pump out etc leaving me a bit of work till I can get to the problem

Oldmate reckons you could slowly feed up the revs but as soon as he stabbed the throttle quickly it would die out.

I have searched, all I could find was problems with coil-packs and rough idling etc.

I tend to agree with him on the AFM but there is a little prep work currently needed before I can start to look at the problem and I would like to have the motor running in the wagon before swapping it into my sedan but at the same time wanna get the wagon out of my shed quickly

I don't have any mates who have RB20 powered vehicles either so I can't exactly swap parts to suss it out

Is this a common problem associated with the RB20's with an easy answer

Thankyou in advance, I am ofcourse a new member and I have half an idea but in this instance I am not wanting to waste cash given the circumstances

Cheers, Cregga

[The Dan]

As with any problem on a car, it could be many things. From the description, though, I would say the AFM is you most likely cause. That's not to say it couldn't be something else though.

Try testing the sensors with your multimeter.

[blind_elk]

The red-top is the early RB20. They have variable length runners, using a butterfly setup to switch between 2 sets of runners. That butterfly setup was prone to failure, so the engine would idle but not rev, or rev really well but idle crappy.

Other things to consider - dirty fuel filter, dirty injectors, faulty CAS.

[Guest HnM]

Thankyou for the kind replies, I appreciate your knowledge.

I don't exactly understand the variable length runners etc though and I am sure I will find out soon when I get some fuel up to the motor, it's on the back burner for a week or two because of a cam job I am doing on my brothers car

I will get back to you when I have it back together and the turbo all booty-fabbed, I have a feeling he was also trying to run it without the intercooler or a cross-over pipe which imo would make sense with him saying he could slowly feed the revs to it but not stab the throttle.

Mystery bags suck

[R31Nismoid]

is it a ECCS or NICS red top?

Im with AFM too, sounds too similar to many a AFM drama.

Failing that, its a red-top mate... they have SOOO many electrical problems with sensors etc your better off replacing it with a silvertop, works out cheaper in the long run. Once you problem solve and replace 2-3 sensors (various ones love to die) you could have had a updated motor with better electrics etc

[Guest HnM]

ECCS DET

[Guest HnM]

[blind_elk]

I don't exactly understand the variable length runners etc

The inlet manifold. You should notice that the inlet manifold appears to have 2 inlets per cylinder where it bolts to the cylinder head.

[Guest HnM]

I had it firing yesty and idling relatively smoothly considering it was running on aerostart only, the fuel pump is dead(has power and only clicks) I am still at the AFM though, once the pump is in ofcourse