Anyone know about LM1/LMA-3 Perf. Tuning Systems?
06-23-2005, 11:48 AM
#16
Rennlist Lifetime Member
Loren,
My experiences have been otherwise. We recently had a car in that did have a midrange issue. Air was going around and causing a lean enough spot in the midrange that the car dove off on power.
In regards to the harness, we have repaired three cars in the last year with this issue. They were intermittent based on the movement of the chassis and where the break was. The car was fine some times and not others. This is an age thing, not a routing issue like the 993..
My experiences have been otherwise. We recently had a car in that did have a midrange issue. Air was going around and causing a lean enough spot in the midrange that the car dove off on power.
In regards to the harness, we have repaired three cars in the last year with this issue. They were intermittent based on the movement of the chassis and where the break was. The car was fine some times and not others. This is an age thing, not a routing issue like the 993..
06-23-2005, 10:26 PM
#17
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Thanks Stephen...
I had failed to mention that in addition to the rough running, I also did have a minor idle miss as well. Intake nuts were confirmed to be tight, however, the intake was then removed and the ever so thin phenolic spacer was replaced as I understand this too can conribute to the idle/and running problem. It did fix the idle miss, but not the intermittent rough running. The harness is still a potential unknown as far as I'm concerned.... It could be where the demon is hiding...
Loren~ Thank you VERY MUCH for your input! I spoike to Curt again today and looked over his briefcase sized active diagnostic tool. the "AutoForce EFI 8400" was purchased by curt around '84 for $10,000. That was a TON of dough back then!! This tool was designed specifically for the 3.2 DME controlled motor. It connects inline with the harness, and works with the motor running. It has a readout for every single pin in the harness. It will read voltage incoming and outgoing as well. The tool was connected, and th car driven with the rough running present. The meter showed no problems with the entire system...
We are completely perplexed by this diagnostic nightmare, and are absolutely open to any and all suggestions from all... No matter how silly you think, as those are the most often overlooked!
I did try removing the air filter, and holder, and sprayed a can of intake cleaner in and around the butterfly with the motor running. The problem again went away, but was mildly returning by the end of my 5 mile test drive... Again, I remind you that the problem is intermittent.... COuld it in fact be a very dirty AFR meter element polluted opr compromised by K&N filter element oil?? WHo knows... I will be driving more miles on the car tomorrow, and we'll see if the demon shows up again...
Pat
I had failed to mention that in addition to the rough running, I also did have a minor idle miss as well. Intake nuts were confirmed to be tight, however, the intake was then removed and the ever so thin phenolic spacer was replaced as I understand this too can conribute to the idle/and running problem. It did fix the idle miss, but not the intermittent rough running. The harness is still a potential unknown as far as I'm concerned.... It could be where the demon is hiding...
Loren~ Thank you VERY MUCH for your input! I spoike to Curt again today and looked over his briefcase sized active diagnostic tool. the "AutoForce EFI 8400" was purchased by curt around '84 for $10,000. That was a TON of dough back then!! This tool was designed specifically for the 3.2 DME controlled motor. It connects inline with the harness, and works with the motor running. It has a readout for every single pin in the harness. It will read voltage incoming and outgoing as well. The tool was connected, and th car driven with the rough running present. The meter showed no problems with the entire system...
We are completely perplexed by this diagnostic nightmare, and are absolutely open to any and all suggestions from all... No matter how silly you think, as those are the most often overlooked!
I did try removing the air filter, and holder, and sprayed a can of intake cleaner in and around the butterfly with the motor running. The problem again went away, but was mildly returning by the end of my 5 mile test drive... Again, I remind you that the problem is intermittent.... COuld it in fact be a very dirty AFR meter element polluted opr compromised by K&N filter element oil?? WHo knows... I will be driving more miles on the car tomorrow, and we'll see if the demon shows up again...
Pat
06-24-2005, 12:09 AM
#18
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Loren,
Sorry I forgot to address each of your questions...
Here goes~
Sorry I forgot to address each of your questions...
Here goes~
Originally Posted by Lorenfb
First, your problem is very unlikely related to a mechanical engine problem. (I WOULD AGREE!)
Next, let's understand what's been done:
1. replaced the head temp sensor (YES)
You could just bypass it by jumping the white connector with a paper clip.(??? NOT SO SURE ABOUT THIS ONE... WOULDN'T THAT SEND THE COMPUTER AN OPEN LOOP READING, MAKING THE ENGINE QUIT?)
Keep one in the glove box for future failures.
2. all vacuum lines replaced/checked(YES)
3. new cap, rotor, & wires(YES
4. checked fuel pressure
How about monitoring it under load when problem occurs?(YES AND YES)
5. replaced DME relay & ECM(YES, AND SWAPPED A PERFECTLY GOOD ONE FROM ANOTHER PERFECTLY GOOD RUNNING CAR. PROBLEM STILL PRESENT.)
6. replaced O2 sensor (YES)
Could have just disconnected it to isolate it. Will run fine with out it.
7. replaced AFM & filter (AGAIN SWAPPED AFM FROM DONOR CAR WITH COMPLETE AIR BOX & FILTER AS WELL... PROBLEM STILL PRESENT.)
You did mean an AFM & NOT MAF which was only first used on the 993.
Things not mentioned:
1. ignition coil (CHECKED OK, BUT SWAPPED WORKING UNIT FROM DONOR CAR... PROBLEM STILL PRESENT)
Did you check the strength of the spark. S/B > 25mm at coil wire to engine ground. (YES)
2. Monitor DME voltage when problem occurs.(BOTH INBOUND AND OUTBOUND FROM DME CHECKED OK)
3. speed sensor voltage, ref sensor can be disconnected after engine starts to isolate it. (SENSOR CHECKED OK WITH EFI8400, DIDN'T REPLACE, BUT SUPPOSE WE COULD TRY)
4. clean all electrical connections & solder ones that are just crimped, e.g. grounds(WHEN I MENTIONED SOLDERING TO CURT, HE GOT A SILLY DUMB GRIN ON HIS FACE... WHILE IT COULD BE A CRIMPED OR BAD SOLDER JOINT, THERE COULD BE HUNDREDS OF DIFFERENT CRIMPED CONNECTIONS CONTRIBUTING?? YET THE EFI8400 SHOWS NO VOLTAGE ANOMALIES WHATSOEVER... )
5. clean all connectors, e.g. AFM connections(DID)
6. monitor injector rail voltage while driving (DID)
Most likely cause; lean fuel enrichment.(THAT'S WHAT IT FEELS LIKE!) Although, you say that the AFM was replaced, (SWAPPED)
did the problem re-occur as before? (YES) Your problem is typical of a sticking/lagging AFM. (COULD THIS BE WHY THE PROBLEM TEMPORARILY WENT AWAY AFTER FLUSHING THE AREA WITH INTAKE CLEANER? WOULD THAT HAVE POSSIBLY CLEANED SOME GRIME OFF OF SENSORS THAT ARE PAST THE BARN DOOR? ALSO WET THE BARN DOOR AXIS.)
You do mention on Pelican that you sprayed something into the intake that solved
the problem for a short time, right? (YES... ACTUALLY REPEATED THIS PROCESS AGAIN TODAY, BY REMOVING THE FILTER HOLDER FOR BETTER ACCESS. I SPRAYED HALF A CAN OF INTAKE CLEANER DIRECTLY IN AT THE BARN DOOR WITH THE ENGINE RUNNING 1-2K RPM'S. CLOSED IT UP, AND THEN RAN THE CAR FOR ABOUT 5 MILES. THE ROUGHNESS THEN MOVED TO ABOUT HALF AS BAD, BUT AT 4K RPM instead... AT A CONSTANT 3K RPM IN 3RD GEAR, ~50MPH, THE ENGINE FELT LIKE IT WOULD SURGE A LITTLE BIT. TOUGH TO KEEP IT RIGHT AT 3K. AFTER A FEW MORE MILES OF DRIVING, THE ROUGHNESS AT 4K DECREASED BY HALF, BUT THE SURGE WAS STILL PRESENT AT 3K... AGAIN, AS THIS PROBLEM HAS ALWAYS BEEN AN INTERMITTENT ONE, I DON'T KNOW THAT THIS IS REALLY HELPING MATTERS... I WILL PUT MORE MILES ON TOMORROW, AND SEE WHAT HAPPENS...)
If so, this confirms the problem being related
to a fuel starvation/ lean problem, or affecting the AFM.
Try reading the Diagnostics page ( www.systemsc.com/diagnostic.htm ) for additional insights.
By-the-way, who's your mechanic in Brea, as I know/work with most SoCal Porsche shops?
Next, let's understand what's been done:
1. replaced the head temp sensor (YES)
You could just bypass it by jumping the white connector with a paper clip.(??? NOT SO SURE ABOUT THIS ONE... WOULDN'T THAT SEND THE COMPUTER AN OPEN LOOP READING, MAKING THE ENGINE QUIT?)
Keep one in the glove box for future failures.
2. all vacuum lines replaced/checked(YES)
3. new cap, rotor, & wires(YES
4. checked fuel pressure
How about monitoring it under load when problem occurs?(YES AND YES)
5. replaced DME relay & ECM(YES, AND SWAPPED A PERFECTLY GOOD ONE FROM ANOTHER PERFECTLY GOOD RUNNING CAR. PROBLEM STILL PRESENT.)
6. replaced O2 sensor (YES)
Could have just disconnected it to isolate it. Will run fine with out it.
7. replaced AFM & filter (AGAIN SWAPPED AFM FROM DONOR CAR WITH COMPLETE AIR BOX & FILTER AS WELL... PROBLEM STILL PRESENT.)
You did mean an AFM & NOT MAF which was only first used on the 993.
Things not mentioned:
1. ignition coil (CHECKED OK, BUT SWAPPED WORKING UNIT FROM DONOR CAR... PROBLEM STILL PRESENT)
Did you check the strength of the spark. S/B > 25mm at coil wire to engine ground. (YES)
2. Monitor DME voltage when problem occurs.(BOTH INBOUND AND OUTBOUND FROM DME CHECKED OK)
3. speed sensor voltage, ref sensor can be disconnected after engine starts to isolate it. (SENSOR CHECKED OK WITH EFI8400, DIDN'T REPLACE, BUT SUPPOSE WE COULD TRY)
4. clean all electrical connections & solder ones that are just crimped, e.g. grounds(WHEN I MENTIONED SOLDERING TO CURT, HE GOT A SILLY DUMB GRIN ON HIS FACE... WHILE IT COULD BE A CRIMPED OR BAD SOLDER JOINT, THERE COULD BE HUNDREDS OF DIFFERENT CRIMPED CONNECTIONS CONTRIBUTING?? YET THE EFI8400 SHOWS NO VOLTAGE ANOMALIES WHATSOEVER...
)5. clean all connectors, e.g. AFM connections(DID)
6. monitor injector rail voltage while driving (DID)
Most likely cause; lean fuel enrichment.(THAT'S WHAT IT FEELS LIKE!) Although, you say that the AFM was replaced, (SWAPPED)
did the problem re-occur as before? (YES) Your problem is typical of a sticking/lagging AFM. (COULD THIS BE WHY THE PROBLEM TEMPORARILY WENT AWAY AFTER FLUSHING THE AREA WITH INTAKE CLEANER? WOULD THAT HAVE POSSIBLY CLEANED SOME GRIME OFF OF SENSORS THAT ARE PAST THE BARN DOOR? ALSO WET THE BARN DOOR AXIS.)
You do mention on Pelican that you sprayed something into the intake that solved
the problem for a short time, right? (YES... ACTUALLY REPEATED THIS PROCESS AGAIN TODAY, BY REMOVING THE FILTER HOLDER FOR BETTER ACCESS. I SPRAYED HALF A CAN OF INTAKE CLEANER DIRECTLY IN AT THE BARN DOOR WITH THE ENGINE RUNNING 1-2K RPM'S. CLOSED IT UP, AND THEN RAN THE CAR FOR ABOUT 5 MILES. THE ROUGHNESS THEN MOVED TO ABOUT HALF AS BAD, BUT AT 4K RPM instead... AT A CONSTANT 3K RPM IN 3RD GEAR, ~50MPH, THE ENGINE FELT LIKE IT WOULD SURGE A LITTLE BIT. TOUGH TO KEEP IT RIGHT AT 3K. AFTER A FEW MORE MILES OF DRIVING, THE ROUGHNESS AT 4K DECREASED BY HALF, BUT THE SURGE WAS STILL PRESENT AT 3K... AGAIN, AS THIS PROBLEM HAS ALWAYS BEEN AN INTERMITTENT ONE, I DON'T KNOW THAT THIS IS REALLY HELPING MATTERS... I WILL PUT MORE MILES ON TOMORROW, AND SEE WHAT HAPPENS...)
If so, this confirms the problem being related
to a fuel starvation/ lean problem, or affecting the AFM.
Try reading the Diagnostics page ( www.systemsc.com/diagnostic.htm ) for additional insights.
By-the-way, who's your mechanic in Brea, as I know/work with most SoCal Porsche shops?
