car does not like timing!
10-25-2005, 09:58 PM
#1
Launching!
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car does not like timing! My car for some reason does not like timing at WOT. Car was tuned with HP tuners and we could only get 19* of timing out of it. Car made 358/349 hp/tq. Which for the mods it has is way low. Numbers were on a dyno jet as well. Something is not right with that! I know that I was getting a little false knock so we turned the knock sensors off to give it the added timing without it wanting to pull any. This was all done with 115 oct gas just to make sure.
Heads are bone stock except springs for now and in the next month or so I am planning on putting some TEA's on. Just want to fix the timing issue for now.
Car does drive and start perfect with the exception of some driveline bucking at low rpms when coasting. No oil consumption and about 80 on the clock.
I was told that the computer should be reflashed by a dealer and then manually add my tabels back in.
HAS ANYONE HEARD OF ANYTHING LIKE THIS? This car should LOVE 28* and about 20 hp more!!
Sorry for the long windedness.... TIA!
Mods are in sig!
Heads are bone stock except springs for now and in the next month or so I am planning on putting some TEA's on. Just want to fix the timing issue for now.
Car does drive and start perfect with the exception of some driveline bucking at low rpms when coasting. No oil consumption and about 80 on the clock.
I was told that the computer should be reflashed by a dealer and then manually add my tabels back in.
HAS ANYONE HEARD OF ANYTHING LIKE THIS? This car should LOVE 28* and about 20 hp more!!
Sorry for the long windedness.... TIA!
Mods are in sig!
10-25-2005, 11:35 PM
#2
FormerVendor
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First thing you need to do is get the race gas out of the tank. I see no indication from your mods that that motor should need anything but premium pump gas. Too much octane, when not needed, is a power robber. High octane fuel burns slow to resist detonation.
Where is it starting to show KR (knock retard) and how much is it showing.
That setup should be fine on a stock timing table!
Where is it starting to show KR (knock retard) and how much is it showing.
That setup should be fine on a stock timing table!
10-25-2005, 11:55 PM
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I run mixed maybe 98-100 octane with ~12:1 static compression and a very high dynamic compression, 20-21* timing. Get that stuff out of your tank. What was the AFR on your dyno runs? If you think you're getting false knock, fix whatever is causing it. There is almost no reason to turn off the knock sensors, especially if you're having knock problems.
If the car is having that many problems I wouldn't throw more mod money at it until I fixed it.
Another option might be to have a different person look at it with tuning software.
If the car is having that many problems I wouldn't throw more mod money at it until I fixed it.
Another option might be to have a different person look at it with tuning software.
10-26-2005, 12:12 PM
#4
Launching!
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Err... I think I am being misunderstood.
1) On pump gas (92) the car does not like anything more than 19* timing, commanding anymore timing and the car will get KR and start to pull some timing so.....
2) This is when I thought MAYBE it was seeing some false knock, so THAT is when I tried 115 octane then went back to the dyno and tried more timing and did find that the car does have a little bit of false knock.
3) So we shut off the knock sensors (to make sure the car doesn't try to pull timing on us) and commanded 26* (just like everyone else runs with this combo) and we only gained 6 hp with 6 more degrees.
I know my car doesn't have diesel like compression and doesn't need race gas, but it was a measure I took just to make sure I could command more timing and check to see if any KR I was getting was false (since we know the gas is good enough)
Even with the adding timing the HP didn't go up alot, so......
The question is could the tune on my computer be corrupted a little bit and cause this to happen. It has been suggested that I take it to a dealer and have them reflash it and enter my tabels mannually again.
Anyone heard of this?
Hope this clarifys things!! Sorry!!
1) On pump gas (92) the car does not like anything more than 19* timing, commanding anymore timing and the car will get KR and start to pull some timing so.....
2) This is when I thought MAYBE it was seeing some false knock, so THAT is when I tried 115 octane then went back to the dyno and tried more timing and did find that the car does have a little bit of false knock.
3) So we shut off the knock sensors (to make sure the car doesn't try to pull timing on us) and commanded 26* (just like everyone else runs with this combo) and we only gained 6 hp with 6 more degrees.
I know my car doesn't have diesel like compression and doesn't need race gas, but it was a measure I took just to make sure I could command more timing and check to see if any KR I was getting was false (since we know the gas is good enough)
Even with the adding timing the HP didn't go up alot, so......
The question is could the tune on my computer be corrupted a little bit and cause this to happen. It has been suggested that I take it to a dealer and have them reflash it and enter my tabels mannually again.
Anyone heard of this?
Hope this clarifys things!! Sorry!!
10-26-2005, 12:56 PM
#5
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I think I would start with the fuel side. First off, the
basics like a new fuel filter and a fuel pressure check.
Short fuel is a good way to pick up pinging under load
(WOT). If possible watch the fuel pressure on the
dyno and record idle and if possible, RPM increments
(like every 1000 or 2000, but be sure to catch the
redline fuel pressure at least). See fuel fade more than
usual? Do you have wideband mixture data?
Next thing I would look at is misfires-current on all 8
across a WOT pull. Here you're looking for something
that might indicate a single injector being short on
squirt, a bankwise lean condition, anything that would
result in an at-the-cylinder fueling issue despite good
rail pressure.
What is the character of the WOT knocks? Have you
peeled back the knock attack & decay so you can see
the true KR activity? Looked at knock detect numbers
instead of KR timing and tried to make sense of that
against the idle baseline detects or light throttle
acceleration? Or is it just 4 degrees, bang!, and stuck
with it all the way off because it won't bleed down
quick enough and jumps up too far, the instant you
mash the throttle?
basics like a new fuel filter and a fuel pressure check.
Short fuel is a good way to pick up pinging under load
(WOT). If possible watch the fuel pressure on the
dyno and record idle and if possible, RPM increments
(like every 1000 or 2000, but be sure to catch the
redline fuel pressure at least). See fuel fade more than
usual? Do you have wideband mixture data?
Next thing I would look at is misfires-current on all 8
across a WOT pull. Here you're looking for something
that might indicate a single injector being short on
squirt, a bankwise lean condition, anything that would
result in an at-the-cylinder fueling issue despite good
rail pressure.
What is the character of the WOT knocks? Have you
peeled back the knock attack & decay so you can see
the true KR activity? Looked at knock detect numbers
instead of KR timing and tried to make sense of that
against the idle baseline detects or light throttle
acceleration? Or is it just 4 degrees, bang!, and stuck
with it all the way off because it won't bleed down
quick enough and jumps up too far, the instant you
mash the throttle?
10-26-2005, 02:31 PM
#6
TECH Senior Member
Check compression/leakdown.
Check spark plugs for fouling (oil or otherwise).
Check PCV and intake manifold for evidence of oil ingestion.
Check fuel pressure across RPM range.
Check misfire counts.
Check injector duty cycles.
Check LTFT's and STFT's (are you leaning out anywhere...?).
After flashing PCM, you should wait 15 seconds with key off.
If flash was corrupted, then PCM would fail the checksum.
Check spark plugs for fouling (oil or otherwise).
Check PCV and intake manifold for evidence of oil ingestion.
Check fuel pressure across RPM range.
Check misfire counts.
Check injector duty cycles.
Check LTFT's and STFT's (are you leaning out anywhere...?).
After flashing PCM, you should wait 15 seconds with key off.
If flash was corrupted, then PCM would fail the checksum.
10-26-2005, 05:10 PM
#7
Launching!
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These last 2 post are the info I am looking for!
We did log fuel pressure on the dyno and it is totally fine. (58psi)
Haven't done a leakdown test yet but, in theory, if it was low on compression wouldn't it like to have abundant timing due to lower cylinder pressure?
I have a catchcan and it has about < 1 oz in it after 1000 miles
I will pull spark plugs out although they are fairly new (<3000 mi) NGK tr55's
There are misfire counts at idle but not at WOT we did log that on a run, if that is what you are reffering to.
AF which we checked with a wideband in the tailpipes was speck on 12.8 across the board which leads me to believe it is not a fuel problem (injector or other such)
Fuel filter is BRAND new.
JIMMEYBLUE... good advice on the knock attack. I think when we try to add more timing it just knocks across the board on the dyno from the minute i stand on it until I let off, that is with anything more than say 20* on pump gas. The thing that puzzels me is the fact that even though we added 6* more timing the car made only 6 more hp with the knock sensors off and on 115 octane. When I do heads I will be sure to check/clean injectors and manifold.
I am getting some heads from TEA and they said to make sure I flash the PCM with a stock file and then manually enter my new numbers, does that seem logical?
Thanks for the replies guys! Sorry so long!
We did log fuel pressure on the dyno and it is totally fine. (58psi)
Haven't done a leakdown test yet but, in theory, if it was low on compression wouldn't it like to have abundant timing due to lower cylinder pressure?
I have a catchcan and it has about < 1 oz in it after 1000 miles
I will pull spark plugs out although they are fairly new (<3000 mi) NGK tr55's
There are misfire counts at idle but not at WOT we did log that on a run, if that is what you are reffering to.
AF which we checked with a wideband in the tailpipes was speck on 12.8 across the board which leads me to believe it is not a fuel problem (injector or other such)
Fuel filter is BRAND new.
JIMMEYBLUE... good advice on the knock attack. I think when we try to add more timing it just knocks across the board on the dyno from the minute i stand on it until I let off, that is with anything more than say 20* on pump gas. The thing that puzzels me is the fact that even though we added 6* more timing the car made only 6 more hp with the knock sensors off and on 115 octane. When I do heads I will be sure to check/clean injectors and manifold.
I am getting some heads from TEA and they said to make sure I flash the PCM with a stock file and then manually enter my new numbers, does that seem logical?
Thanks for the replies guys! Sorry so long!
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10-26-2005, 10:28 PM
#11
Launching!
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Originally Posted by Black02SS
Nevermind I see it now. Its hard to see with the black font.
When you dyno'd the car, did you use a wideband to check the AFR. Maybe the wideband is faulty and the car is actually runing lean causing the KR.
When you dyno'd the car, did you use a wideband to check the AFR. Maybe the wideband is faulty and the car is actually runing lean causing the KR.
If you got "knocked down" into the low octane table, just turning off the sensors probably didn't get out back into the high octane table yet.
Are you guys messing with the low octane table too, or leaving it stock?
Are you guys messing with the low octane table too, or leaving it stock?
10-27-2005, 01:20 PM
#12
Originally Posted by 954RR
I think that the low octane tables are stock. Not sure on that one. I will find out for sure. If I do how long does it take for the motor to recover from the low octane tables?