Negative timing WTF!!!
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From: Bastrop , TEXAS
Negative timing WTF!!! Ok guy's, I'm stumped. I have been having some drivablity issues that I can't figure out and I need some suggestions.
I was having a very high idle at start-up and the automatic cruise control. I've done a few things to fix this but it is still an off and on thing.
Last night when I started the car, it initially started idle at 2000 far a few seconds then dropped down to 800. My iac steps were still hanging a little, but timing and everything seemed fine (22-24 degrees at idle). I drive approx 20 miles, park and turn off the car. When i re-started it, instead of going to 2000 rpm's and hanging there, it would barely run and die if I didnt peddle the gas.
I looked at the HP scanner and it was showing (-20) degrees timing!!!!! At this time my injector pulses were showing 22xx m/s (instead of 2.3 normally).
I then ran an history and it was showing (-16 to -21) degrees only on the .08 line. No matter how much throttle ( which showed 0-50% accuralty) it did not get off the .08 line or off of negative timing.
After a couple of miles it went back to normal but was running a lot more iac steps to idle.
I am also having o2 issues with the drivers reading lower than the passanger even with a new o2. Maybe it's related. Maybe a bad coil, plug, injector ect, i don't know.
I have no idea what could be malfuctioning and causing it to act so eratically. Any help would be great!
fyi, my mods are 9.1 compression, 221-.558 114 cam, pp heads. Changing FI set-ups
Thanks,
Dave
I was having a very high idle at start-up and the automatic cruise control. I've done a few things to fix this but it is still an off and on thing.
Last night when I started the car, it initially started idle at 2000 far a few seconds then dropped down to 800. My iac steps were still hanging a little, but timing and everything seemed fine (22-24 degrees at idle). I drive approx 20 miles, park and turn off the car. When i re-started it, instead of going to 2000 rpm's and hanging there, it would barely run and die if I didnt peddle the gas.
I looked at the HP scanner and it was showing (-20) degrees timing!!!!! At this time my injector pulses were showing 22xx m/s (instead of 2.3 normally).
I then ran an history and it was showing (-16 to -21) degrees only on the .08 line. No matter how much throttle ( which showed 0-50% accuralty) it did not get off the .08 line or off of negative timing.
After a couple of miles it went back to normal but was running a lot more iac steps to idle.
I am also having o2 issues with the drivers reading lower than the passanger even with a new o2. Maybe it's related. Maybe a bad coil, plug, injector ect, i don't know.
I have no idea what could be malfuctioning and causing it to act so eratically. Any help would be great!
fyi, my mods are 9.1 compression, 221-.558 114 cam, pp heads. Changing FI set-ups
Thanks,
Dave
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From: Bastrop , TEXAS
Originally Posted by SmokingWS6
Sounds like you might have a vaccum leak. When you were hitting 2k rpm at idle what were your iac counts?
The iac counts were 121 to 118 and would drop after a few seconds.
I have removed all the egr and air crap, is there anyway that could be causing a problem? I've also removed the motor a couple of times and thought that but I didn't find any. I removed and re-installed the intake and
I can only think of a couple of vaccum lines that could be lose: small one and brake booster line on the back of the intake, and pvc. Any more that you can think of (besides a/c stuff)?
Thanks,
Dave
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Joined: Nov 2001
Posts: 7,036
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From: Lake Zurich, IL
was anything done recently? (mods?) the idle sounds like a vacuum leak, but the high Injector pulse width is strange... if it's doing it on startup then there's an open loop problem I believe... for some reason the car's being commanded to run really rich
Add the Air Fuel Ratio Commanded (lo res) PID to your scan, and see what it's commanding on startup
It should be commanding the car slightly rich, but 22ms pulse widths are almost 100% duty cycle so it's dumping a crap load of fuel in (which is why it wouldn't run... questio is why is it dumping so much fuel)
Are you running Speed Density or off the MAF?
Stock MAF? Descreened? any SES lights?
Add the Air Fuel Ratio Commanded (lo res) PID to your scan, and see what it's commanding on startup
It should be commanding the car slightly rich, but 22ms pulse widths are almost 100% duty cycle so it's dumping a crap load of fuel in (which is why it wouldn't run... questio is why is it dumping so much fuel)
Are you running Speed Density or off the MAF?
Stock MAF? Descreened? any SES lights?
Negitive timing is a result of knock retard timing reduction. -20 degrees is a mega-f*ck-wack of timing reduction. Sounds like a serious problem is happening. Is the timing chain installed correctly? That is is the only thing I can think of right off hand that would cause that much problem.
Keith
Keith
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From: Bastrop , TEXAS
Originally Posted by horist
was anything done recently? (mods?) the idle sounds like a vacuum leak, but the high Injector pulse width is strange... if it's doing it on startup then there's an open loop problem I believe... for some reason the car's being commanded to run really rich
Add the Air Fuel Ratio Commanded (lo res) PID to your scan, and see what it's commanding on startup
It should be commanding the car slightly rich, but 22ms pulse widths are almost 100% duty cycle so it's dumping a crap load of fuel in (which is why it wouldn't run... questio is why is it dumping so much fuel)
Are you running Speed Density or off the MAF?
Stock MAF? Descreened? any SES lights?
Add the Air Fuel Ratio Commanded (lo res) PID to your scan, and see what it's commanding on startup
It should be commanding the car slightly rich, but 22ms pulse widths are almost 100% duty cycle so it's dumping a crap load of fuel in (which is why it wouldn't run... questio is why is it dumping so much fuel)
Are you running Speed Density or off the MAF?
Stock MAF? Descreened? any SES lights?
I've checked for vacuum leaks and I can't find any. I've even disconnected stuff to create vacuum leaks the motor doesn't seem to run any wrose. The only other thing I can think of is maybe a cracked intake (however unlikely)
I'll add the afr and see what it says. I've also searched a little more and think I may have to change the back up VE table to match the changes to the primary table.
I'm running with the stock ported and de-screened maf. (came with the car and has run fine for 3 years).
I think you're right about an open loop issue, not I just need to be able to get it right.
Thanks for the help Horist!
Dave
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From: Bastrop , TEXAS
Originally Posted by ls1290
Negitive timing is a result of knock retard timing reduction. -20 degrees is a mega-f*ck-wack of timing reduction. Sounds like a serious problem is happening. Is the timing chain installed correctly? That is is the only thing I can think of right off hand that would cause that much problem.
Keith
Keith
I'm always real careful about knock (have to be with FI) and haven't had any in a while (running N/a 9:1 compression, stock timing on 93 oct fuel). The negative timing went away after a couple of miles so I don't think it could be a mechanical issue. The idle it just very erratic, cold start idles up to 2000 and runs like it’s got cruise control for a while then stops doing that. Next time, it barely runs and has (-) timing for a while and wants to die at every stop light. Next time it idles perfect sitting in the drive way and idles up while I’m driving.
My wife is even ******* me now! Yesterday It started with a real high idle. Killed it a a friends house. Five hours later, I started it and had to give it gas and brake at the same time to keep it running any time I pushed in the clutch, and then the POS died as I pulled into the driveway. Then she busts out with "What's wrong with your car? It's running like ****! LOL "
Last edited by SUPER DAVES Z; Aug 29, 2005 at 02:48 PM.
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Verdad Gallardo Unmetered air flow will not cause knock retard unless it is super lean causing the valves or spark plugs to over heat and produce detention. If that is happening, it would be totally obvious.
Keith
Keith
