yardpro

Just finished the 24lb injector swap and inhale a very high idle... Like 3k

Ideas?

Speedtoys

Did you shark tune it?

yardpro

No.
I have porker chips coming.
I was told that the computer would adjust to them... Is this not the case.

Speedtoys

Who...said that??

dr bob

A 3k idle requires a bunch of air to go in there with the fuel. Find where the air is leaking and you'll have your answer.

Dwayne shared a Home Depot plumbing-parts fixture used to pressurize the inlet. Put the engine at any 45º mark and add a small amount of compressor air to the inlet via his fixture. You'll hear the leak(s) which may be the wrong o-rings or an oil vent or vacuum hose damaged/dislodged when the fuel rails were lifted.

Step back, take a deep breath.





Then blow into the intake. You'll find the cause.

yardpro

Thanks for the direction.....

Have of course alreadyblooked for obvious vac leaks... Will pressure test

jcorenman

Did you use the special large lower o-rings for the injectors? The lower o-rings usually supplied with new injectors are smaller, and won't seal -- letting in a bunch of air.

soontobered84

I did. And it will for 24# injectors.

But I'm betting that the lower O rings weren't replaced or that the injectors weren't seated well thus creating the vacuum leak(s).

Speedtoys

Huh...That sounds outside the +/- adjustment the ECU can do..juuust outside it.

??

yardpro

No o rings swapped.
They were tight going in.
I bought themnfrom roger. They are supposed to be plug and play.
Thevinjector kit ingot for the pintle cap had orijgs but they were smaller. So I assume these were correct

yardpro

Update.

The bottom o rings were the correct ones.

Started the car and sprayed all around injectors with carbon cleaner and no change in rpm.

Made maf boot tool as per dwaynes write up.... Piece of cake...

Will be checking for leaks later today.

yardpro

Update

Massive leak....somewhere

Pumping air in through maf and can hear leak

Sounds like it is coming from under intake plenum.

I squirted soapy water and can see bubbles around bottom maf boot. But sounds like leak is somewhere Under intake

Getting to th3 bottom maf boot will be a major pita

FredR

When was the inlet manifold last removed/updated?

Sounds suspiciously as though the ISV outlet hose may have developed a split. Trust you have checked the integrity of the connection from the servo to the inlet manifold - that could cause something along the lines you report but not the likely source if there is clear evidence of a significant leak being occurring under the inlet manifold.

Rgds

dr bob

dr bob's speculative diagnostic thought process based on reported repairs and symptoms: (no warranty expressed or implied, just the facts, ma'm, etc)

Initial likely suspects based on the work done include the oil vent hoses from the cam covers to the fitting at the rubber boot at the throttle. Besides the oil vent hoses, IIRC there's a plastic fitting that connects the hoses and inserts into a boss molded into the boot. Hoses that pass over the fuel rails and were disturbed would be early suspects, along with that fitting, then the boot itself. But that would just add false/un-maf-metered air above the throttle. The throttle is still controlling airflow in that case.

So back to stupid stuff. Is the throttle cable routed correctly, allowing the throttle to close to the stop? It would not be the first time that's happened.

If the throttle is allowed to close and you still have the high idle, we are looking for vacuum leaks below the throttle. So that isolates the 'possible-culprits under the intake' list to the idle stabilizer hoses and the valve itself. It also adds in some other major stuff like the plastic eductor for the brake vacuum system, along with the source-end of that hose. That source end hose is one likely to have been disturbed during the fuel rails removal.

dr bob

Getting to bottom MAF boot: At least on my S4, I was able to get a 1/4"-drive socket onto the hose clamp, using a long extension over the rails and under/through the intake runners, from the passenger side. I don't remember if a universal joint was used at the socket end for disassembly. On assembly I took care to make sure the socket would be a straight-on fit to the clamp for final tensioning.