Running rich...part two.
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Racer
Joined: Aug 2011
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From: Littleton, Colorado
Running rich...part two.
Yeah, I know what you're thinking..."not this guy again !!!"
OK... a few weeks away from trying to diagnose my rich running problem on the 90 C4 and I now will have nothing but time for the next week or so caring for an ill family member. I'll start again fresh and update daily what's been checked and the results.
I need your help people !!! Please...
I'm going to very meticulous and document each step I take, the values of any measurements (volts, ohms, etc...), and the results .
In a nutshell...
Car = 1990 C4 with TPC supercharger (no intercooler, yet)
Manual transmission
Have new FTC1-016 from Split Second (controls 7th injector and retards timing) and new PSC1-001 (modifies signals from AFM to run larger injectors).
Also have Zeitronix ZT-2 to monitor wideband O2, fuel pressure, and manifold pressure.
I have verified that the wideband is functioning properly and is accurate.
The car was dialed in via the PSC1 with the 30lb injectors and was running fantastic for a month, then the next morning...
... starts fine, AFR's around 14-14.7 then after 10-15 seconds the AFR's fall to 10.3-10.5 over the next 30 seconds. This is at idle.
Does not go over 11 during a short drive.
I have verified that the PSC1 and FTC1 are functioning properly.
I do not have a resistance box yet and do not have an oscilloscope.
A good multimeter, I do have.
Hit me up with your suggestions before I rip out the entire harness and DME and replace it with a standalone. I'm very tempted to do this for more than one reason, but if the problem is mechanical then I'll still have the problem, won't I?
Thanks for all your help.
Derek
OK... a few weeks away from trying to diagnose my rich running problem on the 90 C4 and I now will have nothing but time for the next week or so caring for an ill family member. I'll start again fresh and update daily what's been checked and the results.
I need your help people !!! Please...
I'm going to very meticulous and document each step I take, the values of any measurements (volts, ohms, etc...), and the results .
In a nutshell...
Car = 1990 C4 with TPC supercharger (no intercooler, yet)
Manual transmission
Have new FTC1-016 from Split Second (controls 7th injector and retards timing) and new PSC1-001 (modifies signals from AFM to run larger injectors).
Also have Zeitronix ZT-2 to monitor wideband O2, fuel pressure, and manifold pressure.
I have verified that the wideband is functioning properly and is accurate.
The car was dialed in via the PSC1 with the 30lb injectors and was running fantastic for a month, then the next morning...
... starts fine, AFR's around 14-14.7 then after 10-15 seconds the AFR's fall to 10.3-10.5 over the next 30 seconds. This is at idle.
Does not go over 11 during a short drive.
I have verified that the PSC1 and FTC1 are functioning properly.
I do not have a resistance box yet and do not have an oscilloscope.
A good multimeter, I do have.
Hit me up with your suggestions before I rip out the entire harness and DME and replace it with a standalone. I'm very tempted to do this for more than one reason, but if the problem is mechanical then I'll still have the problem, won't I?
Thanks for all your help.
Derek
Drifting
Joined: Aug 2010
Posts: 2,274
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Yep, if it is mechanical the prob wont go away.
However, It still seems like an electrical issue.
If you have checked and verified everything the next thing I want to see is the waveforms. I would also like to see if it's not something else just over looked.
The way I understand it, is this is a reoccurring problem that was fixed for a while with some additional componets and new updated piggyback controler.
I also understand that you have bypassed the 7th injector all together and got the same results.
Does it make boost and how much?
Have you had an exhuast gas anylizer at the tail pipe to confirm what the AFR is seeing?
Have you checked the 7th injector, leak, stuck?
and you are using the stock AFM?
The PSC1-001 just modifies the fuel signal. It doesn't care what injectors are used. And it's adjustable?
However, It still seems like an electrical issue.
If you have checked and verified everything the next thing I want to see is the waveforms. I would also like to see if it's not something else just over looked.
The way I understand it, is this is a reoccurring problem that was fixed for a while with some additional componets and new updated piggyback controler.
I also understand that you have bypassed the 7th injector all together and got the same results.
Does it make boost and how much?
Have you had an exhuast gas anylizer at the tail pipe to confirm what the AFR is seeing?
Have you checked the 7th injector, leak, stuck?
and you are using the stock AFM?
The PSC1-001 just modifies the fuel signal. It doesn't care what injectors are used. And it's adjustable?
Last edited by Makmov; Jul 17, 2012 at 01:19 PM.
Thread Starter
Racer
Joined: Aug 2011
Posts: 362
Likes: 2
From: Littleton, Colorado
Yep, if it is mechanical the prob wont go away.
However, It still seems like an electrical issue.
If you have checked and verified everything the next thing I want to see is the waveforms. I would also like to see if it's not something else just over looked.
The way I understand it, is this is a reoccurring problem that was fixed for a while with some additional componets and new updated piggyback controler. The original problem from back in Febuary was that the original ecu from TPC quit working properly. FTC1 was the replacement. Never had the rich condition before. I would think that if it was related to the 2 piggybacks installed, it would not have run so well for a solid month.
I also understand that you have bypassed the 7th injector all together and got the same results. = Correct
Does it make boost and how much? = Yes, at this altitude, 3psi max
Have you had an exhuast gas anylizer at the tail pipe to confirm what the AFR is seeing? = No, but did have a friend with a zeitronix in his car and we switched sensors and display units. Values did not change due to the swap in either of our cars.
Have you checked the 7th injector, leak, stuck? = Removed fuel line to 7th entirely, no change.
However, It still seems like an electrical issue.
If you have checked and verified everything the next thing I want to see is the waveforms. I would also like to see if it's not something else just over looked.
The way I understand it, is this is a reoccurring problem that was fixed for a while with some additional componets and new updated piggyback controler. The original problem from back in Febuary was that the original ecu from TPC quit working properly. FTC1 was the replacement. Never had the rich condition before. I would think that if it was related to the 2 piggybacks installed, it would not have run so well for a solid month.
I also understand that you have bypassed the 7th injector all together and got the same results. = Correct
Does it make boost and how much? = Yes, at this altitude, 3psi max
Have you had an exhuast gas anylizer at the tail pipe to confirm what the AFR is seeing? = No, but did have a friend with a zeitronix in his car and we switched sensors and display units. Values did not change due to the swap in either of our cars.
Have you checked the 7th injector, leak, stuck? = Removed fuel line to 7th entirely, no change.
Last edited by dkcaims; Jul 17, 2012 at 01:11 PM.
Drifting
Joined: Aug 2002
Posts: 2,557
Likes: 14
From: Dallas, TX
I didn't realize you also have the PSC1 manipulating the AFM. This would affect fuel and AFR since the DME uses the AFM (now being manipulatd by the PSC1) to determine the amount of fuel to get into each cylinder. Have you verified the operation of the PSC1 or check to make sure you're getting the proper signal to the DME?
When it's running rich, can you smell it? or does it back fire? I imagine running at 10.7 would result in some very nasty smelling fumes.
When it's running rich, can you smell it? or does it back fire? I imagine running at 10.7 would result in some very nasty smelling fumes.
Drifting
Joined: Aug 2010
Posts: 2,274
Likes: 3
Yeah, it's like the whole load signal shifted for some reason on the PSC1
They are kind of stinky when they are that fat.
Okay I will just trying to wrap my head around this a little bit more.
It doesn't alter the mapping it just moves the whole map slightly, and the condision would be as the result of less rpm than it thinks it has or actually the load signal less than what it should be sending.
They are kind of stinky when they are that fat.
Okay I will just trying to wrap my head around this a little bit more.
It doesn't alter the mapping it just moves the whole map slightly, and the condision would be as the result of less rpm than it thinks it has or actually the load signal less than what it should be sending.
Last edited by Makmov; Jul 17, 2012 at 02:00 PM.
Thread Starter
Racer
Joined: Aug 2011
Posts: 362
Likes: 2
From: Littleton, Colorado
[quote=axl911;9692859]I didn't realize you also have the PSC1 manipulating the AFM. This would affect fuel and AFR since the DME uses the AFM (now being manipulatd by the PSC1) to determine the amount of fuel to get into each cylinder. Have you verified the operation of the PSC1 or check to make sure you're getting the proper signal to the DME? = yes, the PSC1 does change the voltage signal the proper amount(s) when changing the fuel map. What's odd is that after a month of running great (AFR's where they should be), this problem begins. The fuel map has not changed and the voltage signal to the DME plug has not changed (still the same values as when it was running great.
When it's running rich, can you smell it? or does it back fire? I imagine running at 10.7 would result in some very nasty smelling fumes. Yes, burns my nose if I get too close. No, does not back fire. Idles just fine, just rich. I tried changing the fuel map to lean it out and yes it does lean it out, but then the idle speed jumps to 1,600 and some surging occurs. Your may know the following, but for the benefit of others...
That's probably because the voltage reading is lower than the DME is programmed to see. If you're familiar with the PSC1, a value of 10 across all the cells is neutral (no changes to the signal from the AFM). Each full number changes the voltage signal by .25 volts. You can fill the cells with values from 0-20 (take away up to 2.5 volts or add 2.5 volts). So a value of 8 drops it .50 volts and a value of 13 increases it by .75 volts. You can change the values in tenths.
However, since the DME is programmed to see a value of .25 to 4.6 volts from the AFM and if at idle you normally have a value of .6 volts (that figure I'm still trying to figure out, the volts at idle unmodified), if you modify the signal too much (below .25 volts) the DME might just be cycling the injectors on and off since it's a value it's not programmed to see. The bottom line is that the map is the same as when it was running great, but now it's just rich. Puzzling...
Long winded I know... sorry.
When it's running rich, can you smell it? or does it back fire? I imagine running at 10.7 would result in some very nasty smelling fumes. Yes, burns my nose if I get too close. No, does not back fire. Idles just fine, just rich. I tried changing the fuel map to lean it out and yes it does lean it out, but then the idle speed jumps to 1,600 and some surging occurs. Your may know the following, but for the benefit of others...
That's probably because the voltage reading is lower than the DME is programmed to see. If you're familiar with the PSC1, a value of 10 across all the cells is neutral (no changes to the signal from the AFM). Each full number changes the voltage signal by .25 volts. You can fill the cells with values from 0-20 (take away up to 2.5 volts or add 2.5 volts). So a value of 8 drops it .50 volts and a value of 13 increases it by .75 volts. You can change the values in tenths.
However, since the DME is programmed to see a value of .25 to 4.6 volts from the AFM and if at idle you normally have a value of .6 volts (that figure I'm still trying to figure out, the volts at idle unmodified), if you modify the signal too much (below .25 volts) the DME might just be cycling the injectors on and off since it's a value it's not programmed to see. The bottom line is that the map is the same as when it was running great, but now it's just rich. Puzzling...
Long winded I know... sorry.
Thread Starter
Racer
Joined: Aug 2011
Posts: 362
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From: Littleton, Colorado
Yeah, it's like the whole load signal shifted for some reason on the PSC1 = but nothing has shifted, the map has not changed. I've verified that
They are kind of stinky when they are that fat.
Okay I will just trying to wrap my head around this a little bit more.
It doesn't alter the mapping it just moves the whole map slightly, and the condision would be as the result of less rpm than it thinks it has. = The PSC1 does not alter the true fuel maps in the DME, it simply modifies the voltage signal that the DME receives from the AFM. Tricks the DME into thinking their is more or less air coming through the AFM and then adds more or subtracts fuel respectively.
They are kind of stinky when they are that fat.
Okay I will just trying to wrap my head around this a little bit more.
It doesn't alter the mapping it just moves the whole map slightly, and the condision would be as the result of less rpm than it thinks it has. = The PSC1 does not alter the true fuel maps in the DME, it simply modifies the voltage signal that the DME receives from the AFM. Tricks the DME into thinking their is more or less air coming through the AFM and then adds more or subtracts fuel respectively.
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Drifting
Joined: Aug 2010
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Yeah, it's like the whole load signal shifted for some reason on the PSC1 = but nothing has shifted, the map has not changed. I've verified that
They are kind of stinky when they are that fat.
Okay I will just trying to wrap my head around this a little bit more.
It doesn't alter the mapping it just moves the whole map slightly, and the condision would be as the result of less rpm than it thinks it has. = The PSC1 does not alter the true fuel maps in the DME, it simply modifies the voltage signal that the DME receives from the AFM. Tricks the DME into thinking their is more or less air coming through the AFM and then adds more or subtracts fuel respectively.
They are kind of stinky when they are that fat.
Okay I will just trying to wrap my head around this a little bit more.
It doesn't alter the mapping it just moves the whole map slightly, and the condision would be as the result of less rpm than it thinks it has. = The PSC1 does not alter the true fuel maps in the DME, it simply modifies the voltage signal that the DME receives from the AFM. Tricks the DME into thinking their is more or less air coming through the AFM and then adds more or subtracts fuel respectively.
Correct it's not doing anything to the true DME map, but in a sense it moving the whole map rich or lean depending on the adjusted value.
Thread Starter
Racer
Joined: Aug 2011
Posts: 362
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From: Littleton, Colorado
Drifting
Joined: Aug 2010
Posts: 2,274
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Man, it sure seems like a bad load signal either from the AFM or something in the DME. I did read that a out range signal will make the DME go screwy.
Or the speed sensor is misreporting.
Still would like to see the waveform to see it is what is to be expected or narrower. e.g. faster than normal pulse. I suspect it is. Obviously it's a globe issue.
I guess I would take the FTC1 completely out of the loop including removing the injector and capping it off.
By pass the PSC1 and see if you can get a good baseline on the car componets. At least then we know if its the car or one of the piggybacks.
and I am coming up with it should be about 1 volt at idle.
Or the speed sensor is misreporting.
Still would like to see the waveform to see it is what is to be expected or narrower. e.g. faster than normal pulse. I suspect it is. Obviously it's a globe issue.
I guess I would take the FTC1 completely out of the loop including removing the injector and capping it off.
By pass the PSC1 and see if you can get a good baseline on the car componets. At least then we know if its the car or one of the piggybacks.
and I am coming up with it should be about 1 volt at idle.
Last edited by Makmov; Jul 18, 2012 at 02:47 PM.
Thread Starter
Racer
Joined: Aug 2011
Posts: 362
Likes: 2
From: Littleton, Colorado
Man, it sure seems like a bad load signal either from the AFM or something in the DME. I did read that a out range signal will make the DME go screwy.
Or the speed sensor is misreporting.
Still would like to see the waveform to see it is what is to be expected or narrower. e.g. faster than normal pulse. I suspect it is. Obviously it's a globe issue.
I guess I would take the FTC1 completely out of the loop including removing the injector and capping it off.
By pass the PSC1 and see if you can get a good baseline on the car componets. At least then we know if its the car or one of the piggybacks.
and I am coming up with it should be about 1 volt at idle.
Or the speed sensor is misreporting.
Still would like to see the waveform to see it is what is to be expected or narrower. e.g. faster than normal pulse. I suspect it is. Obviously it's a globe issue.
I guess I would take the FTC1 completely out of the loop including removing the injector and capping it off.
By pass the PSC1 and see if you can get a good baseline on the car componets. At least then we know if its the car or one of the piggybacks.
and I am coming up with it should be about 1 volt at idle.
I'm going to run a few more tests on the AFM now...
Thread Starter
Racer
Joined: Aug 2011
Posts: 362
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From: Littleton, Colorado
No Chris...
What I did was start the car, let it idle and slowly forced the barn door closed (plastic cover over wiper arm/track removed) and AFM's climbed to 14.0
Only moved the barn door an eighth inch or so and in turn lowered the voltage, which in turn reduces the fuel injector pulse.
After lunch I'm going to measure the voltage at idle directly at the AFM and at the DME plug with the PSC1 taken out of the loop.
Last time I checked it was 1.4 volts.
Have not seen a definitive value in Porsche documentation for a 964 as to what that voltage reading should be at idle (800-850rpm), but other Porsche owners have mentioned .6 to .8 volts at idle (944 I think).
Would a weak spring in the AFM cause the barn door to be opening too far and in turn sending a faulty signal to the DME?
Makes sense to me...
What I did was start the car, let it idle and slowly forced the barn door closed (plastic cover over wiper arm/track removed) and AFM's climbed to 14.0
Only moved the barn door an eighth inch or so and in turn lowered the voltage, which in turn reduces the fuel injector pulse.
After lunch I'm going to measure the voltage at idle directly at the AFM and at the DME plug with the PSC1 taken out of the loop.
Last time I checked it was 1.4 volts.
Have not seen a definitive value in Porsche documentation for a 964 as to what that voltage reading should be at idle (800-850rpm), but other Porsche owners have mentioned .6 to .8 volts at idle (944 I think).
Would a weak spring in the AFM cause the barn door to be opening too far and in turn sending a faulty signal to the DME?
Makes sense to me...