Why is my ECU KILLING my timing?!?! 3 degress at WOT!

[spyderturbo007]

The car was equipped with an AFCII but I pulled it out(it came with the car and I wanted to remove all variables that I didn't install), heck I'm even on stock blacktop 450cc injectors.

You did remember to reconnect the MAS wire at the ECU, right?

I don't know if its worth mentioning but can a slightly loud transmission cause phantom knock?

Yes, it can. The knock sensor is basically a glorified microphone and can pick up anything, such as a rattling heat shield, and interpret it as knock.

Judging on the fact that you are on the stock maps and have tried 100 octane with no difference, I'm leaning towards phantom knock. Unless, of course, you have a huge problem that even race gas can't fix.

 

[NOMIEZVR4]

You did remember to reconnect the MAS wire at the ECU, right?




Yes, it can. The knock sensor is basically a glorified microphone and can pick up anything, such as a rattling heat shield, and interpret it as knock.

Judging on the fact that you are on the stock maps and have tried 100 octane with no difference, I'm leaning towards phantom knock. Unless, of course, you have a huge problem that even race gas can't fix.

I reconnected the mas wire. The loud transmission noise, at first sounded like a bad TOB, because each time I would press the clutch it would disappear. So....I pulled the trans off, changed the TOB and the noise was still there. Its much quieter now, especially when the car is warmed up,(I threw some syncromesh in the trans) but it seems the output shaft is the source of the noise. Its not terribly loud, but it is audible.

I believe im making some progress...read my last two posts...I'll update more tonight.

 

[pboglio]

Well, sounds like your making progress. If it started feeling good, AND your running no fuel control on that 255 Walbro and low boost, then it'll run great later on when everything is tuned better.

Yep, 100 octane is good and all but you can still knock with it. Especially if your car is running very hot.

99% of the time when somebody "thinks" they are "false" knocking, it's actually knocking. It would have to be something pounding on the block for the timing to get pulled. I have some of the worst lifter tappet noise and I never get false knock.

I'd definitely do a thorough run thru of the entire cooling system top to bottom at this point. Also get a cheap logger and get more detailed info, the stock coolant temp gauge is completely useless.

 

[NOMIEZVR4]

Well the thermostat was stuck closed. After driving 50 miles and pulling over on the highway, the lower coolant hose was dead cold. I pulled the thermostat now I'm waiting for a replacement.

 

[NOMIEZVR4]

New thermostat is in...not much of a difference from the old one. Now coolant temp registers at 212 or214. With the old one, no matter if I was on the highway or city, temperatures registered in at 217 or 219. Not more, not less. Even with the new thermostat, the lower hose is still cool..WTF is wrong with this thing...? Without the thermostat, temperatures were fluctuating from 109-167, on the highway and its pretty chilly in chicago though..

Regardless, the problem is still there. WTF Here are some more observations.

-When the car is cold it seems to run very well. I can do a 2nd gear pull and it feels great like nothing is wrong. 3rd gear seems better too...However after doing a pull or two, the car goes to crap. Especially around 5500rpms, the car just dies...so much so that I was watching timing yesterday while doing a 3rd gear pull, and it went from 12 degrees initially at 40XX rpms, to 1 degree BTDC to 1 degree ATDC. What does this indicate?

-Second observation is that even if I'm crusing in the higher gears, say 5th @ 2500rpms...then if I open up the throttle, even if under no boost, the timing will just fall to 1-5 degrees immediately.

Whats next? Im getting tired of screwing with this thing...

 

[delta448]

Those temps are not a problem but are likely higher than normal because of the retarded timing.

The first thing, you need a fuel pressure regulator that won't be overrun by the 255. The car is probably crapping out at 5500 because that's your peak VE and the injector pulse width is the longest at peak VE. IMO, the suspected overrun FPR is boosting fuel pressure like an FMU would and you're dumping significant extra fuel in at a point where the stock map is already pretty rich.

I think it's possible you're getting rich knock... -? The accel enrichment is most likely throwing you headfirst into it. Assuming your TPS is working correctly.

 

[NOMIEZVR4]

I'll try to get a fpr, but I'm sure there are hundreds of people who have run setups with a walbro 255 and no problems...such as this... it cant be that complicated...its a dsm afterall..What do you think?

Ive got a 14b, hard pipes and an exhaust with a fuel pump(which came with the car..)

 

[jrohner]

I solved it by going with DSMLink. Killed that problem dead.

A Walbro 255 on a stock fuel system is not a good combo, the corrective fuel trims have to be pegged.

DSMLink alone doesn't FIX a problem.

I've ran the 255hp with the oem regulators and everything on 3 different cars (2 2g's and a 1g) with not even so much as off fuel trims. My 1g I even rewired the pump.

 

[delta448]

If you could just find out how high your fuel pressure is climbing we'd know for sure.

Or if you could give us a log with IDC, front O2 voltage, TPS %, rpm and airflow we could figure it out.

 

[NOMIEZVR4]

If you could just find out how high your fuel pressure is climbing we'd know for sure.

Or if you could give us a log with IDC, front O2 voltage, TPS %, rpm and airflow we could figure it out.

I don't think I can post a log, but I can freeze and record frames on the scan tool...I'll get you the information you want.

 

[pboglio]

DSMLink alone doesn't FIX a problem.

I've ran the 255hp with the oem regulators and everything on 3 different cars (2 2g's and a 1g) with not even so much as off fuel trims. My 1g I even rewired the pump.

You have your experiences, I have mine. Switching to DSMLink eliminated my timing rollback issues, turned it off like a light switch.