1993 928 GTS hesitation
06-05-2012, 09:27 PM
#61
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Long shot but have you checked the two fan power wires where they connect at the special connector on to the battery?
Looks like we are getting somewhere 8>)
Looks like we are getting somewhere 8>)
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Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
06-05-2012, 11:29 PM
#63
Rennlist Member
Colin, you're right-- ignition amps are grounded to GP-III, I was working off the PDF which is a bit fuzzy. Too bad, I was liking that theory...
So we're looking for some kind of interaction between fans and ... something.
Steve, how's the battery? In good shape? Or struggles to hold a charge? What does the voltmeter show at the battery terminals, with engine running (fans off)? And with fans running (e.g. A/C engaged)?
Early or late '93? What's the last four digits of the VIN?
So we're looking for some kind of interaction between fans and ... something.
Steve, how's the battery? In good shape? Or struggles to hold a charge? What does the voltmeter show at the battery terminals, with engine running (fans off)? And with fans running (e.g. A/C engaged)?
Early or late '93? What's the last four digits of the VIN?
06-06-2012, 02:05 AM
#68
Nordschleife Master
Thread Starter
I checked the charging system and battery while up there. No issues found.
There was a kill switch from battery to chassis, this was removed and battery ground cleaned.
Steve has said he's going to try to get the car to me so that I can run further tests on the car and check some of the grounds.
Now that I know there are no ign lead problems etc.
There was a kill switch from battery to chassis, this was removed and battery ground cleaned.
Steve has said he's going to try to get the car to me so that I can run further tests on the car and check some of the grounds.
Now that I know there are no ign lead problems etc.
06-06-2012, 04:54 PM
#71
Nordschleife Master
Thread Starter
It has not been 100% confirmed if it is ign or fuel.
When I hooked up the STII (only while parked), there was a slight hesitation but nothing showed up.
My next step is to drive with the ST hooked up and log it. This MAY tell me what I need to know.
Past that, I am going to put it on the dyno and monitor the ign system carefully to see if there is a fault that can be picked up there.
When I hooked up the STII (only while parked), there was a slight hesitation but nothing showed up.
My next step is to drive with the ST hooked up and log it. This MAY tell me what I need to know.
Past that, I am going to put it on the dyno and monitor the ign system carefully to see if there is a fault that can be picked up there.
06-07-2012, 05:22 AM
#72
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Drove 4 hours this afternoon to bring the car to Colin.
Both rad fan fuses pulled - not one hesitation. Just had to keep an eye on the temp but mostly stayed around 86-87.
The only interesting thing that happened was - I turned the fan controller from 0 to 3 quite quickly, this caused a small multiple hesitation for about 2 seconds. When I dialed the fan controller at a slower pace (maybe a second or 2 between changes) nothing happened.
Interesting...
Both rad fan fuses pulled - not one hesitation. Just had to keep an eye on the temp but mostly stayed around 86-87.
The only interesting thing that happened was - I turned the fan controller from 0 to 3 quite quickly, this caused a small multiple hesitation for about 2 seconds. When I dialed the fan controller at a slower pace (maybe a second or 2 between changes) nothing happened.
Interesting...
06-07-2012, 11:47 AM
#73
Pro
Could this be a bad voltage regulator? It sounds like the alternator and regulator are working fairly well and keeping the battery charged. Maybe the voltage regulation is only having trouble when a significant load change (high current) is seen, resulting in alternator voltage output drops for short periods of time and causing the hesitation effects you are seeing.
