Base timing question...
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Safety Car
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From: Poop land
Base timing question...
Coolant temps were up in the 220s today on the way home and was trying to figure out my pinging problem at low rpms under load (40 mph, 1200 rpms, OD engaged, converter locked). I was stuck in traffic for a good while so of course coolant temps would rise. When I got home, I retarded my base timing from 12 to 6 degrees, then 3 degrees for the hell of it to see if it would still ping. When the base timing was at 3 degrees, why does the car idle at 400 rpms and stall out when the pedal is pressed down?
Not that I would ever leave the base timing at 3 degrees, but what's making the car wanna backfire, pop and stall out when I get on it with that low base timing? Isn't the base timing of those old F-bodies set at like 0 degrees???? Are TPIs really supposed to have at least 6 degrees of timing in order not to stall out?
Not that I would ever leave the base timing at 3 degrees, but what's making the car wanna backfire, pop and stall out when I get on it with that low base timing? Isn't the base timing of those old F-bodies set at like 0 degrees???? Are TPIs really supposed to have at least 6 degrees of timing in order not to stall out?
Race Director
Joined: Sep 2000
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From: The Top of Utah
Originally Posted by kopbet89c4
Coolant temps were up in the 220s today on the way home and was trying to figure out my pinging problem at low rpms under load (40 mph, 1200 rpms, OD engaged, converter locked).
Originally Posted by kopbet89c4
Isn't the base timing of those old F-bodies set at like 0 degrees???? Are TPIs really supposed to have at least 6 degrees of timing in order not to stall out?
RACE ON!!!
Thread Starter
Safety Car
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From: Poop land
So then, why will my car stall out if timing is at 4 degrees or less? I set it to 0 just to see what would happen. The engine would turn on briefly then 2 seconds later stall out. It sounded like a MAF problem and had the same effect. Pushing the gas had no effect on the rpm. Basically it wouldn't rev or even idle once started.
Then I set it up to 12 degrees like it has always been at and the car bacame 100% drivable again. I'll just have to use 89 octane from now on or it will ping. I've been filling up the car with 87 octane for the past couple of weeks... so maybe the combined effect of the 220 degree coolant temp, the timing and the low octane gas contributed to this pinging problem.
But I'm still confused as to why the car wouldn't idle worth a damn when I put the timing at 0 degrees....
Then I set it up to 12 degrees like it has always been at and the car bacame 100% drivable again. I'll just have to use 89 octane from now on or it will ping. I've been filling up the car with 87 octane for the past couple of weeks... so maybe the combined effect of the 220 degree coolant temp, the timing and the low octane gas contributed to this pinging problem.
But I'm still confused as to why the car wouldn't idle worth a damn when I put the timing at 0 degrees....
Race Director
Joined: Sep 2000
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From: The Top of Utah
Originally Posted by kopbet89c4
So then, why will my car stall out if timing is at 4 degrees or less? I set it to 0 just to see what would happen. The engine would turn on briefly then 2 seconds later stall out.
Originally Posted by kopbet89c4
It sounded like a MAF problem and had the same effect. Pushing the gas had no effect on the rpm. Basically it wouldn't rev or even idle once started.
Originally Posted by kopbet89c4
Then I set it up to 12 degrees like it has always been at and the car bacame 100% drivable again. I'll just have to use 89 octane from now on or it will ping. I've been filling up the car with 87 octane for the past couple of weeks... so maybe the combined effect of the 220 degree coolant temp, the timing and the low octane gas contributed to this pinging problem.
Originally Posted by kopbet89c4
But I'm still confused as to why the car wouldn't idle worth a damn when I put the timing at 0 degrees....
RACE ON!!!
Melting Slicks
Joined: Jun 2004
Posts: 3,032
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2 quick comments...
While trouble shooting a pining problem I had with my '85, I set the timing to 0*. It was a bandaid, but it worked in stopping the ping until I found the real cause of it & fixed the problem. Mine idled (not well, but it would idle).
You mentioned you stalled out when you drop the timing. If I'm remembering my posts right... didn't you say you introduced a vacuum leak into the system a long time ago? Would that not cause some stalling when the timing is dropped back to spec...
While trouble shooting a pining problem I had with my '85, I set the timing to 0*. It was a bandaid, but it worked in stopping the ping until I found the real cause of it & fixed the problem. Mine idled (not well, but it would idle).
You mentioned you stalled out when you drop the timing. If I'm remembering my posts right... didn't you say you introduced a vacuum leak into the system a long time ago? Would that not cause some stalling when the timing is dropped back to spec...
Last edited by mikey whipreck; Aug 14, 2006 at 09:27 PM.
Thread Starter
Safety Car
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From: Poop land
Originally Posted by mikey whipreck
2 quick comments...
While trouble shooting a pining problem I had with my '85, I set the timing to 0*. It was a bandaid, but it worked in stopping the ping until I found the real cause of it & fixed the problem. Mine idled (not well, but it would idle).
You mentioned you stalled out when you drop the timing. If I'm remembering my posts right... didn't you say you introduced a vacuum leak into the system a long time ago? Would that not cause some stalling when the timing is dropped back to spec...
While trouble shooting a pining problem I had with my '85, I set the timing to 0*. It was a bandaid, but it worked in stopping the ping until I found the real cause of it & fixed the problem. Mine idled (not well, but it would idle).
You mentioned you stalled out when you drop the timing. If I'm remembering my posts right... didn't you say you introduced a vacuum leak into the system a long time ago? Would that not cause some stalling when the timing is dropped back to spec...
Yes, the car would start up, but then stall immediately. Like I said, even when I was pushing the gas down, it didn't even rev up. The gas pedal had no effect.
Drifting
Joined: Jan 2002
Posts: 1,261
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From: Middle River MD
Originally Posted by mikey whipreck
2 quick comments...
While trouble shooting a pining problem I had with my '85, I set the timing to 0*. It was a bandaid, but it worked in stopping the ping until I found the real cause of it & fixed the problem. Mine idled (not well, but it would idle).
You mentioned you stalled out when you drop the timing. If I'm remembering my posts right... didn't you say you introduced a vacuum leak into the system a long time ago? Would that not cause some stalling when the timing is dropped back to spec...
While trouble shooting a pining problem I had with my '85, I set the timing to 0*. It was a bandaid, but it worked in stopping the ping until I found the real cause of it & fixed the problem. Mine idled (not well, but it would idle).
You mentioned you stalled out when you drop the timing. If I'm remembering my posts right... didn't you say you introduced a vacuum leak into the system a long time ago? Would that not cause some stalling when the timing is dropped back to spec...
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Thread Starter
Safety Car
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From: Poop land
Originally Posted by CFI-EFI
Because you have retarded the timing too far. Maybe you didn't understand my first post. The base timing is the starting point. If the conditions call for 18° of advance, the ECM advances the timing by 12°. That, added to the base of 6°, gives the engine the 18° it needs. IF you change the base timing, there is no way for the ECM to know. It will add timing in the amount the prom is programmed to add, for what ever the existing conditions call for. If the base is at 12° as you've been running, the above example will result in 24°, instead of the 18° called for. If you have the base set to 0°, you will end up with only 12°, where you needed 18°.
You are starting to introduce new stuff, here, that wasn't in the opening post. I don't understand what you are driving at.
The lugging of the engine was the cause of the pinging, which is normal. You never want to lug an engine as you described in your opening post. As a double check, you may want to verify the timing mark on your damper. If the ring has spun or moved, your timing readings are off, and not really what you think they are.
That is what engines do. More advance, faster idle. See above.
RACE ON!!!
You are starting to introduce new stuff, here, that wasn't in the opening post. I don't understand what you are driving at.
The lugging of the engine was the cause of the pinging, which is normal. You never want to lug an engine as you described in your opening post. As a double check, you may want to verify the timing mark on your damper. If the ring has spun or moved, your timing readings are off, and not really what you think they are.
That is what engines do. More advance, faster idle. See above.
RACE ON!!!
When I was "lugging" the engine, I was actually trying to get it to downshift. But it didn't on its own. I had to manually downshift it in order for there to be less load on the engine, plus I was trying to pass a slow moving semi.
Are you saying if there is too little timing, the engine will have part throttle drivability issues?
I am not trying to introduce new issues here. I was simply comparing my "low timing + stalling" problem to a MAF problem I had like 14 months ago.
You ask why? Because their effects are identical.
0 degree base timing + throttle = stall after start up
Bad MAF + throttle = stall after start up
I'm still just curious to know why the car stalls even at 0. So I also thought the ECM already adds timing to correct. It is like the engine "knows" the timing if it stalls from the low base timing. I sure would like to learn more...
Thread Starter
Safety Car
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From: Poop land
Originally Posted by HeeHaw89
So what was the cause of your pinging?
Instructor
Joined: May 2005
Posts: 132
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From: Torrington CT
You did disconnect timing bypass. in following post when i changed the engine on my 85 to an 88 foller block they mistakenly installed a 305 crank whick caused all kinds of hell. We went as far as 4deg before. just curious
Le Mans Master
Joined: Feb 2005
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From: The Motor City
Originally Posted by CFI-EFI
Because you have retarded the timing too far. Maybe you didn't understand my first post. The base timing is the starting point. If the conditions call for 18° of advance, the ECM advances the timing by 12°. That, added to the base of 6°, gives the engine the 18° it needs. IF you change the base timing, there is no way for the ECM to know. It will add timing in the amount the prom is programmed to add, for what ever the existing conditions call for. If the base is at 12° as you've been running, the above example will result in 24°, instead of the 18° called for. If you have the base set to 0°, you will end up with only 12°, where you needed18
I think the consideration you should have is the chip is programmed by Alvin(if I remember right) why would you be trying to put more timing at it anyway?
I'm sure he had it cranked up probably as far as what he would consider reasonable.
Melting Slicks
Joined: Jun 2004
Posts: 3,032
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Originally Posted by HeeHaw89
So what was the cause of your pinging?
My pinging was the result of a two different things - exhaust problems and ignition patchwork, the root cause of which was the former owner I like to call Bubba.
Team Owner
Joined: May 2002
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Originally Posted by kopbet89c4
When I was "lugging" the engine, I was actually trying to get it to downshift. But it didn't on its own. I had to manually downshift it in order for there to be less load on the engine, plus I was trying to pass a slow moving semi.
Are you saying if there is too little timing, the engine will have part throttle drivability issues?
Are you saying if there is too little timing, the engine will have part throttle drivability issues?
My truck runs that way when trying to get it out of overdrive. Getting on it harder will cause it to spit out the intake. Problem is, without a dyno, it's hard to measure total advance on a motor with vacuum advance, because you can't load up the motor.
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From: Poop land
Originally Posted by mseven
And in addition to this, it will add"X"amount of advance globally. Your chip being programmed for say 40* at 3800 would now be at 46*. Does a scan show spark reatard?
I think the consideration you should have is the chip is programmed by Alvin(if I remember right) why would you be trying to put more timing at it anyway?
I'm sure he had it cranked up probably as far as what he would consider reasonable.
I think the consideration you should have is the chip is programmed by Alvin(if I remember right) why would you be trying to put more timing at it anyway?
I'm sure he had it cranked up probably as far as what he would consider reasonable.
Burning Brakes
Joined: May 2006
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From: Richfield Utah
Originally Posted by kopbet89c4
The unusually high coolant temps were to blame from sitting in traffic. My car doesn't like coolant temps over 210 degrees. 220 degrees is a bit much. In it got to 230 and I started hearing the pinging once I got moving. Sounded kinda loud as if I was tapping valve stems together with my hands...
Race Director
Joined: Sep 2000
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From: The Top of Utah
Originally Posted by kopbet89c4
When I was "lugging" the engine, I was actually trying to get it to downshift. But it didn't on its own. I had to manually downshift it in order for there to be less load on the engine, plus I was trying to pass a slow moving semi.
Originally Posted by kopbet89c4
Are you saying if there is too little timing, the engine will have part throttle drivability issues?
Originally Posted by kopbet89c4
I am not trying to introduce new issues here. I was simply comparing my "low timing + stalling" problem to a MAF problem I had like 14 months ago.
You ask why? Because their effects are identical.
0 degree base timing + throttle = stall after start up
Bad MAF + throttle = stall after start up
You ask why? Because their effects are identical.
0 degree base timing + throttle = stall after start up
Bad MAF + throttle = stall after start up
Originally Posted by kopbet89c4
I'm still just curious to know why the car stalls even at 0. So I also thought the ECM already adds timing to correct. It is like the engine "knows" the timing if it stalls from the low base timing. I sure would like to learn more...
RACE ON!!!
