Signs of dying injectors?

[boostjunkie]

I either have a problem with my fcd or my injectors are going screwy. I just noticed yesterday that when I get on the throttle and go past 14.7 psi that the engine totally cuts out. Fuel goes from 90% IDC to 50% and a/f goes WAY down.

I lowered the boost down to 12psi and did some hard accelerations this afternoon and again I noticed 80% IDC and a/f in stoich. Could this be signs of an injector(s) failing?

I'm going to double check my fcd tonight but any other suggestions you guys could give would be appreciated.

[vrg3]

I don't know about the injectors, but a faulty FCD should not be able to cause stoichiometric ratios at 12psi. When the throttle is wide open the ECU intentionally fuels a rich mixture based on the MAF.

You say the A/F ratio goes way down when you go past 14.7psi -- do you mean it goes way up, i.e. gets leaner? If it's really going way down it could be similar to what I had once -- I had a similar problem to what you describe in the first paragraph... Whenever I'd get above about 8psi the engine would cut out until boost fell back down (which was quick) and then it'd happen again. It felt almost like a fuel cut or something. It turned out to be bad plug wires; the coolant tank had leaked a little onto the cylinder head and some coolant seeped past the spark plug and started all kinds of crazy arcing. When the wire was pulled, the terminal at the end stayed on the plug rather than staying on the wire! You might want to quickly check your ignition system.

If you're really not getting enough fuel, I guess the injectors or FPR (you have a Walbro pump, right, so that should be trustworthy) might be responsible. Have the fuel filters been changed recently?

[boostjunkie]

Actually, that's EXACTLY what is happening to my car!! I guess I should mention that it has been raining for almost a month now. Perhaps, that might be attibuted to the arching as well?

I'll check the plugs and wires tonight. I was running a .44 gap on the plugs and it's been fine until now. Perhaps I should try a smaller gapping? I'll see if they're fouled, too, while I'm in there.

As for the ignition system, I know the coil's new since I got the car (15,000 miles) along with the wires, and the plugs are even newer (10,000 miles).

Oh, and I did mean that a/f ratios went up. WHOOPS!!

[vrg3]

Yeah, the whole mid-Atlantic region's been deluged, and your open hood scoop is probably letting quite a bit of water into your engine compartment when you're moving. (I'm assuming Adam opened up the scoop when he installed the intercooler.)

Even if the wires are new, water seeping in around the boots will ruin them quickly. You could probably repair them if you're up to it and use more dielectric grease to seal the boots, or you could just get new wires, and try very hard to seal them with plenty of grease.

You're running fairly high boost, so you probably should reduce the plug gap a little. .044" is a little above the stock range (which is between .039" and .043") to begin with, and under boost it's harder to bridge the gap. Try bringing it down to .040" or .039".

And, dude, be careful. Stoichiometric ratios at 12psi, even with an intercooler, are dangerous!

[boostjunkie]

And, dude, be careful. Stoichiometric ratios at 12psi, even with an intercooler, are dangerous!

I know, once the gauge started reading into those ranges, I shut down.

Yup, Adam opened up the hoodscoop when he installed the intercooler, which completely exposes the coilpack to the elements. I'm starting to wonder whether it's a good idea to have that coilpack on top of the manifold (is it any wonder why all of the stock turbocharged/intercooled subarus don't have these????). I'll try to check for cracked/leaking boots tonight and let you know what I come up with.

[vrg3]

I'm starting to wonder whether it's a good idea to have that coilpack on top of the manifold (is it any wonder why all of the stock turbocharged/intercooled subarus don't have these????).

That's a really good point! I never thought about that... I always just thought coil-on-plug made for better performance. Although that's true, it does also move the coils to a safer location!

Hmm... I wonder if I can still find my old coil cover that I removed in the first week of owning this car...

[boostjunkie]

I wish I had that cover. Looks like I'll have to hit the junkyard sometime.

[vrg3]

The covers are different between turbos and N/As... You're probably better off fabricating a little cover yourself. If you still have the bracket that it mounted to you can attach it with zipties or something.

[rsstiboy]

14.7 psi is boost cut on Aus spec models, could this be the problem? 80% at 12psi?!?!? what size injectors do you guys have? i run 17psi all day everyday with standard top mounted water/air cooler and no problems yet.