02 4v Swap issues.

[32vNomad]

My only issue I am having is the IAC valve. The setup I have is a built Mark Motor with a 98 Mark intake.



Now at startup I had noticed a very large air leak. The engine would start but die. I fixed the accel to barely stay open so the engine would run. I traced the leak to the IAC. Not from the gasket but from the metal cap on top. So I changed it out with my 2v one, running a hose from the iac to the intake tube. With a turn or the key the engine fires and idles smooth as silk.



I went out and got another IAC for a Mark and still the same leak but it did idle at about 450rpm. I'm at a loss at this, I'm wondering if a restictor would work. Is there anyone that has did this swap have any info. Photos would be nice.

[32vNomad]

*bump

[AgentOrange]

Not trolling, but why not just stick with the 2v iac? BTW I love that you did the Mark swap.

[NeedSomeMods]

Originally Posted by AgentOrange

Not trolling, but why not just stick with the 2v iac? BTW I love that you did the Mark swap.

That's exactly what I was thinking.

[95v686gt]

You could try a restrictor plate. If it works on the 6ers then it should on the mark. Don't see a reason why t wouldn't. Your running off the gt ecu or the mark?

[32vNomad]

Originally Posted by AgentOrange

Not trolling, but why not just stick with the 2v iac? BTW I love that you did the Mark swap.

Well the pipe that pops up of the 2v IAC is past the hood line. Not sure what the issue is with the stock style iac valve. But I've tried a new one and still a leak but did hold at 400-450 rpm basically just keeping it from dying. I'm going to look in to a restrictor plate to see if that works. As for the stock ecm yes it is the stock GT but that should have no effect on the fact the iac housing sucks air. I was gonna use a 03 mach but its $70-90 and usually unavalible.

[32vNomad]

I believe I have solved the issue. Im using a Mach 1 TB. It is different than the Mark. Though looking almost identical the Mark TB has provisions for the IAC motor build in the TB. Unlike the Cobra and Mach 1 has a output for a hose to be run to the intake tube.

[32vNomad]

Update: I was correct if you use a Mark Intake then you have to use its TB.

[Azure]

Originally Posted by 32vNomad

Update: I was correct if you use a Mark Intake then you have to use its TB.

That kinda sucks! Can you get an adequate aftermarket TB made for the Mark engines? Is the Mark TB a dual setup like the Mach1?

[32vNomad]

Yeah the mark tb is almost identical to the Mach. The Marks TB has a provision for the IAC so you don't need a hose fromt the intake to the air inlet pipe.

[95v686gt]

Originally Posted by 32vNomad

Yeah the mark tb is almost identical to the Mach. The Marks TB has a provision for the IAC so you don't need a hose fromt the intake to the air inlet pipe.

Why not block it off and use the Mach 1 tb with the iac mounted to it instead?

[32vNomad]

Originally Posted by 95v686gt

Why not block it off and use the Mach 1 tb with the iac mounted to it instead?

The Mach TB does not have the IAC on the throttle body.
(Mach 1)

(Mark VIII)


Notice how the Mark has the holes in the bore. That is for the IAC. She's all fixed now and looks stock.