Kinda stumped here with this new situation.

First gear knock, at low RPM and low/no boost?

In addition, EBC says IDC's can hit 100% @ 100% WOT.

Running just below 1 bar right now, thought maybe backing it down might help.

Datalogger seems to disagree, O2 sensor says rich, but not overly, like all is well. Everything else looks okay and tests okay from the DL.

If I cannot diagnose and fix quickly, I'll need to sell my time at RA.

Any ideas most welcome.

SJ

P.S. I should mention the car now has a new fuel pump and fuel pump regulator, and a fuel pump hotwire kit via 3SX. I will be pulling the front three plugs just for a looksy, but these were changed, with MSD wires in May, and the plugs looked perfect at NG.

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Well, these look like the plugs BEFORE we changed them back in May...



<sigh>

SJ

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Plugs look good. #5 look like it has a little extra carbon on the ground electrode. If you haven't put them back in yet give that one a spray with some electric cleaner.

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'94 vr4- Now with extra slowness

what are your fuel trims looking like? Also note what FT02 is doing.

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1991 Stealth RT/TT

I don't run iridiums because I like coppers, so I'm going to ask a dumb question.

shouldn't they have more brown on them?

But, yeah, the plugs look good. I'd put them in my car.

Just because I'm goofy, though, I'd prolly go pick up a set of coppers for 10 bucks, gap 'em down, screw them in, and see if it changed anything... but I'm goofy like that.

Secondly, checked the motor mounts, or anything else banging/popping that could give false knock readings?

Thirdly, what injectors? Aren't you running stock 360s? because you SHOULD be able to max them out at 14.7 psi (1bar). That's normal. unless your running bigger injectors... but I forget if you upgraded and got a piggyback. (Didn't think, you did.)

Fourthly, What did you say says injector duty cycle? your electronic boost controller? The Apexi that you had at elkhart? who hooked it up? How does it read injector duty cycle.

I'd trust my logger over an apexi boost controller reading IDC. and regaurdless of the other crap, you should not have knock at low throttle conditions unless something else is up. false knock, or something the knock sensor is picking up.

is it a constant 6-8 value, no matter what? I believe the knock sensors give a consistently low value all the time when they go bad.

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Yes, we are fairly sure that is contributing (like all 4 are shot), but you can also feel when the car acts up during acceleration, like something begins to restrict it and slow the acceleration.



Stock. Really? Not what I was told. No, not yet.



Yes, IDC only read off this. Wire to ECM. We resoldered all the wiring a while ago.



Probably motor mounts, and possibly other things.



Believe it was spikes, but Vef Fer will have to chime in here.

Thanks,

SJ

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I questioned the IDC reading of the Apexi as well, but I could only get his logger to show pulse width. The knock came in at part throttle and increase with RPM.
The injector are close to being maxed out, but I think the real problem is the fuel pump just can't keep up and the pressure is falling off.

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'94 vr4- Now with extra slowness

O rly.

Change the fuel filter any time recently? If that is clogged it could be restricting flow.

Also, if all four motor mounts are "iffy" to "shot" you will pick up more knock as you go up in speed. and if the computer picks up more than 7 counts of knock it will retard timing. and if it retards timing, you will feel less power.

Also, did you pressure test for boost leaks?

Also, when you changed the pump did you seat the little bastard o-ring in the asembly right? if that is pinched or off, you spray fuel out back into the tank, and the pump cannot keep up with demand. (I told you to just gong that crap and go with aluminum fittings. )

um... that's all I got for now. I'll think on it more later, when the head ache gets smaller.

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About a year ago.



This is beginning to sound plausible.



Will do it again hopefully Wed., after CC meet, @ Uncle Benny's.




That's what we had to do.





Good luck with that.

Thanks,

SJ

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Well, if you're sure you didn't botch the fuel pump install, I'm gonna say you have an intake leak SJ.

...but I'm still gonna put $$ on a leaky fuel pump o-ring.

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06 Blue EVO 9

I'd listen to this man.

what I would do (and this is where most people would stop reading) is pull the pump assembly again, take out the pump, and pull out that little o-ring. then I would lube the little bastard up with a copious amount of brake fluid, and very very carefully re-insert it. then put the car back together.

Then, before even starting it, I'd pressure test it. C'mon SJ, I've got a pressure tester for our cars, and I can't even use it. With as much fiddling and driving as you do, it would be a great investment.

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I'll see what Ver Fer thinks about this idea.

Even if I had a pressure tester, I too couldn't use it.

I'm seriously thinking it is the engine mounts, based on the areas we noticed the engine is hitting, th fact the engine can be seen moving at idele and the fact it's not acting up all the time.

I guess we'll see what the pressure test gets me tomorrow night and take it from there.

Thanks men,

SJ

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Should the fuel pressure drop to zero when you turn the car off with the stock FPR? SJ's didn't I thought it was his FPR was bad and swapped it with my old one. It could be possible that it is leaking at the pump and bleeding the pressure off.

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'94 vr4- Now with extra slowness

Ver Fer meant to say my car DOES DROP TO ZERO when you turn it off.

Ver Fer -- why don't you call me...

SJ

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No. the pressure should not drop to zero while you are standing there. over the course of many hours it will, as the assembly is not perfectly sealed, but it should not go to zero quickly.

that's a bad thing. re-do the o-ring. brake fluid. it's your friend. it's the slipperiest sh*t on earth.

Or just do it the right way with aeroquip/earls fittings.

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