Need help diagnosing log

92 AWD ECLIPSE · 06-26-2005, 01:05 PM

I took two logs this morning in 3rd gear at WOT. My knock count is very high and my injector duty cycle reaches 98% before I shift into 4th gear. I am only running 10psi of boost.
Relevant Mods:
Evo3B16G
RC 550
FTS afpr
Walbro 255hp
2g Maf
stage3 eprom chip
safc
30lx6wx3d FMIC
Weisico 8.8:1
Eagle Rods
Arp hardware
balanced to .5 grams

I kept the same safc setting on both logs, and the settings were set on the dyno using a wideband last week.
I really can't figure out why I am knocking so much on only 10psi of boost. Any help would be much appreciated.
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LessIsMore · 06-26-2005, 02:06 PM

You shouldn't be maxing out those injectors at such a low boost level. I would suspect a boost leak would cause this type of problem. Lots of air is being pulled through the maf pre-turbo, requiring lots of fuel. The turbo is working over time to overcome the leak and hold a certain boost level. This results in a super heated intake charge, which may lead to the knock your seeing. Maxing out your injectors may also explain the high knock counts.

Of course this is all theory and the only real way to find out is by performing an intake pressure test.

Coup D E'Tat · 06-26-2005, 05:43 PM

What were the wideband readings?

And, as "LessIsMore" said, do a boost leak test.

92 AWD ECLIPSE · 06-26-2005, 06:13 PM

I haven't done a boost leak test in a couple of weeks, so I will try one again. A couple of weeks ago when I did one, it pressurized to 20 psi and slowly decreased, but I couldn't hear any leaks. I am assuming that it was just leaking through the valves.

The wideband readings were 11.5:1 across the board, and since then I have richened the afc up +2% across the board and that also seemed to help the knock.

92 AWD ECLIPSE · 06-26-2005, 06:53 PM

Okay I just did a boost leak test, and it did the same thing, I can pressurize it to 20psi, without hearing any leaks, as it slowly depressurizes.
Do you think that my combustion temps are too hot? My egt readings are normal, and I just cleaned my FMIC.

Coup D E'Tat · 06-26-2005, 07:41 PM

What is your fuel pressure set at, and what chip do you have?

Also, when you were tuning on the dyno, did it knock at all then?

92 AWD ECLIPSE · 06-26-2005, 08:01 PM

My fuel pressure is set at 41 with the vac hose off.

And yes, we actually stopped dyno tuning because of all the knock. On his settings I was hitting 21-25 counts continuously in boost, and after I took it home and richened it up a bit, it went down. His first suggestion was water injection, then he said just to get an emanage or dsmlink.

The chip I have was programmed by a tuning shop up here called Quick Precision Racing. He did the injector and maf comp, and reset the idle to 950, put in the stutterbox, converted the boost gauge to knock gauge, shift light with cel, and no lift to shift.

The thing I don't get is why others that are running the exact same setup, Evob16g-550s-safc-eprom, aren't having the knock probs.

By the way thanks for the help

Coup D E'Tat · 06-26-2005, 08:15 PM

I'm not familiar with them, but do they do good work? Do you know of other people running their chips?

Have you tried to keep richening it up? If so, what happens?

92 AWD ECLIPSE · 06-26-2005, 08:34 PM

As far as I know my chip is pretty good, once I get the knock problem fixed I will know more. But a ton of other people use them and they say they work great.

I've tried richening it up and it just seems to have less power

. Do you think that water injection would be a better choice over another type of engine management?

Coup D E'Tat · 06-26-2005, 08:37 PM

In the future, sure, it will help, but for now, you need to figure out why you're knocking and maxing out 550's at 10 PSI.

How long does the pressure take to exit the system during the leak test? Any chance of you "borrowing" a friends knock sensor? You could try changing it and see if it helps at all.

92 AWD ECLIPSE · 06-26-2005, 10:08 PM

It probably falls 1psi per second, and I put a brand new Mitsu knock sensor in about 3 weeks ago.

92 AWD ECLIPSE · 06-26-2005, 10:12 PM

The other thing I have noticed is that the duty cycle stays around 80% or around 15ms pulse until it goes over 7 counts of knock, which is when the ecu starts to retard the timing...So do you think the high duty cycle is being caused by excessive knock and retarded timing? Or maybe it is a safe mode so that the knock doesn't hurt the engine.