idle problems and late boost

[Jman]

I recently changed my fuel pump to a 255lph high pressure pump, the car ran fine for a couple days and then It started idling wierd, and I started getting full boost almost 1000rpm later. I got a fuel pressure guage and an afpr thinking that maybe the pump was killing the stock regulator, well I adjusted the fuel pressure to 40psi vacuum unhooked. it still only pulls about 12-14 vacuum at idle, and full boost still comes on late.

Any ideas what it may be?

[Jman]

ign timing 12btdc, timing belt is about 500 miles old.

[GAboySVO]

A vacuum leak can cause a rough idle. Check the vacuum lines associated with wastegate actuator.

Another thing to check is your TPS voltage and sweep continuity. If you are getting a faulty reading on the low side, then what is in reality, WOT, may be seen by the EEC as something less, thus less fuel.

[Jman]

yeah that was my next thing to check, but I can't find either one of my 2 volt meters. DOH

[Jman]

ok, I did some experimenting. I pulled the plug wires 1 by 1, When I pulled 1 the engine almost died, when I pulled number 2 there was no change in how the engine idled. so I swapped number 1 and number 2 wires, still number 2 was not having a change when pulled. So I swapped the 1 and 2 plugs. Number 2 still had no change in the idle. I know it sparking, because the there is a spark jumping the gap whenever I get the plug wire close.

The only thing I can think of is that the injector is bad and there is no fuel in the cylinder and thats why its always number 2 regardless of where I have the plug wires or spark plugs.

Any way of verifying its the injector? or how I would fix it, short of just pulling all the injectors and having them cleaned and serviced?

[Pat_in_L.A.]

I'd suggest a compression or leakdown test next unless the injector loom has had a meltdown.

Things that cause combustion: compression, spark, fuel.

[Jman]

yeah, i've got 2 more tests, i'm gonna try the leakdown test, and also i'm gonna swap injectors between 1 and 2, and see if its still 2

[Jman]

Injector it is.

I just pulled the injector, and the cap is cracked big time right through the middle.

http://members.cox.net/m.bowen/resized.jpg I guess that would cause my idle problem.

I tested the particular injector with a 9v battery, and it opens and closes just fine, so it could possibly be that the injector is plain clogged, or the wiring is bad, or possibly the ecu. or in worse case the headgasket is gone or theres a hole in the piston. I'm gonna run a leakdown test tommorrow. and hopefully clear up the gasket or hole theory

[GAboySVO]

Jman,

I don't think that crank pintel alone would cause the problem you discribed. It is possible a detonation problem caused the split and you are just not getting any or very little compression.

I think you should follow Pat's advice and at least do a compression check. You could have a burnt valve or a head gasket leak between cylinders.

You might want to smell the oil on your dip stick to see if it has a gas smell. If it does, then you gas blowing by the piston or vavles into the oil.

[Jman]

I went and smelled my dipstick, and I didn't notice any hint of gas. I guess i'll just have to wait till tommorow when I can run the leakdown test.

[GAboySVO]

Well, I don't think you have a hole in the piston. That's a good thing.

[Eyelawdoc]

Compression Check is Job One

Listen to Pat's sage advice. I believe that all will be revealed with by a compression check. By the way, using a scanner and the EECIV self diagnostics, you can run a fuel injector balance test without taking anything apart. It is part of the KOER test sequence .

[Jman]

Re: Compression Check is Job One

Originally posted by Eyelawdoc
Listen to Pat's sage advice. I believe that all will be revealed with by a compression check. By the way, using a scanner and the EECIV self diagnostics, you can run a fuel injector balance test without taking anything apart. It is part of the KOER test sequence .

is that just part of the normal KOER test? or is it something extra you have to trigger? because I ran the codes on it. And the KOER test gave me a 41 (o2 sensor reading lean) which if the injector wasn't firing would be a good reason for it to be reading lean

[Jman]

the only one that was cracked was number 2, but i'm having all 4 injectors cleaned and rebuilt anyway.

[Will]

Are injectors rebuildable? I thought they were only basically electric servo's.