What age and mileage was your car when the LH module failed?
03-30-2006, 05:58 AM
#31
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Hi Tails
It is very difficult to know what has happened to a car over the years, unless you were lucky enough to own one from new.
My theory is that the semiconductor technology used in the "tile" has a poor static charge tolerance. Eventually they fail. There is no doubt that failure can be accelerated by faults/abuse.
My replacement units are designed with lots of protection :-)
It is very difficult to know what has happened to a car over the years, unless you were lucky enough to own one from new.
My theory is that the semiconductor technology used in the "tile" has a poor static charge tolerance. Eventually they fail. There is no doubt that failure can be accelerated by faults/abuse.
My replacement units are designed with lots of protection :-)
03-30-2006, 06:28 AM
#32
Rennlist Member
On the plus side, my '88 has had no issues with its LH in 70KKm - and I have a spare '91GT LH that has been used to keep another '89 running for a couple of months ( until we sent the dead one off for John to rebuild 
.
I ran the 'GT' LH in my car for a month or so to evaluate any performance gain from the different eprom .... none apparent; however, the GT EZK spare remains in the S4 in place of the original as there was some more 'zap' available as sensed by the butt-o-meter.
John, on the comment re. mechanical shock sensitivity, would it be worthwhile to consider mounting the LH module on rubber isolation feet within the two module bracket ... and run a separate case ground strap?? The bracket itself allows precious little space to maneuver into position, and has a locating pin in the rear; however, there is 'air' space available around the LH within its bracket position.
.I ran the 'GT' LH in my car for a month or so to evaluate any performance gain from the different eprom .... none apparent; however, the GT EZK spare remains in the S4 in place of the original as there was some more 'zap' available as sensed by the butt-o-meter.
John, on the comment re. mechanical shock sensitivity, would it be worthwhile to consider mounting the LH module on rubber isolation feet within the two module bracket ... and run a separate case ground strap?? The bracket itself allows precious little space to maneuver into position, and has a locating pin in the rear; however, there is 'air' space available around the LH within its bracket position.
03-30-2006, 07:24 AM
#33
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I have to put in my 2 cents . Even though I don't own one , in my experience I've seen them fail as early as 40,000 miles up until today which then the sky is the limit . I think you guys for the most part are the current owners and not always the 1st to have the problem
As far as carrying an extra . I would , but then why not an lh relay, fuel pump relay , etc.... These thingsare a problem . I've never seen a pre 87 fail . Why is that John ?
P.s. John thanks for taking care of the last one for us . It's working fine .
As far as carrying an extra . I would , but then why not an lh relay, fuel pump relay , etc.... These thingsare a problem . I've never seen a pre 87 fail . Why is that John ?
P.s. John thanks for taking care of the last one for us . It's working fine .
03-30-2006, 07:37 AM
#34
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Hi Garth,
It may be that might work for the mechanical shock problem.....BTW you don't need to ground the case to the cradle/car chassis as it gets all its grounds through the cable forms.
Hi Jim,
The pre 87 cars use the LH 2.2 series ECUs, which don't have the dreaded "tile" circuit. (neither do any of the EZK units, early, or late).
In general these are much more relaible, but I have known them to fail when stored on a shelf with open pins on the connector. Always store them with pins shorted together with some aluminium foil for safety.
Glad to hear the customer is happy :-)
It may be that might work for the mechanical shock problem.....BTW you don't need to ground the case to the cradle/car chassis as it gets all its grounds through the cable forms.
Hi Jim,
The pre 87 cars use the LH 2.2 series ECUs, which don't have the dreaded "tile" circuit. (neither do any of the EZK units, early, or late).
In general these are much more relaible, but I have known them to fail when stored on a shelf with open pins on the connector. Always store them with pins shorted together with some aluminium foil for safety.
Glad to hear the customer is happy :-)
03-30-2006, 05:31 PM
#36
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Originally Posted by Garth S
I ran the 'GT' LH in my car for a month or so to evaluate any performance gain from the different eprom .... none apparent; however, the GT EZK spare remains in the S4 in place of the original as there was some more 'zap' available as sensed by the butt-o-meter.
My LH failed at 90,000 klms and the car is 16 years old.
03-30-2006, 06:26 PM
#38
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S4 and newer 928 LHs (35 Pin versions) fail at a much greater rate than their older 25 pin brothers (US '85 to '86 models), I have observed some failures of the 25 pin type.
What is interesting is that I have seen many Bosch-sourced replacement LHs (these were installed prior to the current owner knowing the history) also fail - these are identified as "made in Spain" in pre 1990 models - vs. modules that have made in Germany on the label. One can ponder why this happens, but it may indicate that "shelf life" for replacement modules is an issue.
What is interesting is that I have seen many Bosch-sourced replacement LHs (these were installed prior to the current owner knowing the history) also fail - these are identified as "made in Spain" in pre 1990 models - vs. modules that have made in Germany on the label. One can ponder why this happens, but it may indicate that "shelf life" for replacement modules is an issue.
03-30-2006, 07:20 PM
#39
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'89 GT, LH death in 2003 at 120k miles during 6-month long on-stands repairs
'91 GT, Original LH (yes, I'm sure) still operating at 79k miles.
'94 GTS, Original LH (fairly sure), Replacement EZK at 45k miles, 56k miles total.
Spare LH goes with me on long trips (along with spare relays)
'91 GT, Original LH (yes, I'm sure) still operating at 79k miles.
'94 GTS, Original LH (fairly sure), Replacement EZK at 45k miles, 56k miles total.
Spare LH goes with me on long trips (along with spare relays)
03-30-2006, 08:28 PM
#41
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88 S4 with unknows history.
Running at 130k miles. Probably till tomorrow then she will just click.
Spare Jetronic module in hand.
Bosch 928.618.123.13
Made in Spain.
Spare been sitting in it's box. Rattling around in it's box without packing protection.
Think mebbe it should be tested if failure may be time related.
No sell-by or use-by date on box.
Ernest (NYC)
Running at 130k miles. Probably till tomorrow then she will just click.
Spare Jetronic module in hand.
Bosch 928.618.123.13
Made in Spain.
Spare been sitting in it's box. Rattling around in it's box without packing protection.
Think mebbe it should be tested if failure may be time related.
No sell-by or use-by date on box.
Ernest (NYC)
03-30-2006, 11:55 PM
#42
Rennlist Member
90 GT original LH w/143k... although with an interesting history...
I'm the 2nd owner, bought it w/64k and ALL records. On my drive to DEVEK days 2001, car would not hold idle or rev after a stop halfway between LA and SF (GT had approx. 90k at that time). Marc Thomas to the rescue drove the 200 miles from SF with Louie Ott's spare LH, popped it in and viola, back to normal (BIG thanks again Marc and Louie
)
After DEVEK days, drove back to Phoenix with Louie's LH installed. Louie needed it back, so just for the heck of it, I put the original LH back in and it's been there ever since (53k+ worth).
So, still not sure what happened, but it may have been just the big connector and plugging and unplugging it did the trick?!?
Rick Redpath
90 GT, Guards Red, Black/Grey, 143k
I'm the 2nd owner, bought it w/64k and ALL records. On my drive to DEVEK days 2001, car would not hold idle or rev after a stop halfway between LA and SF (GT had approx. 90k at that time). Marc Thomas to the rescue drove the 200 miles from SF with Louie Ott's spare LH, popped it in and viola, back to normal (BIG thanks again Marc and Louie
)After DEVEK days, drove back to Phoenix with Louie's LH installed. Louie needed it back, so just for the heck of it, I put the original LH back in and it's been there ever since (53k+ worth).
So, still not sure what happened, but it may have been just the big connector and plugging and unplugging it did the trick?!?
Rick Redpath
90 GT, Guards Red, Black/Grey, 143k
03-31-2006, 05:25 AM
#43
Rennlist Member
Hi Rick,
If the windshield (windscreen) drain hole is blocked, water can get into the LH/EZK 35 way connectors.
I've seen some where the pins have rotted through !
As the contacts are self cleaning to some extent, then a quick unplug/plug in may help clear some mild corrosion.
Check carefully for any water ingress.....
If the windshield (windscreen) drain hole is blocked, water can get into the LH/EZK 35 way connectors.
I've seen some where the pins have rotted through !
As the contacts are self cleaning to some extent, then a quick unplug/plug in may help clear some mild corrosion.
Check carefully for any water ingress.....
03-31-2006, 11:16 AM
#44
Rennlist Member
i was told it is an age thing. not a usage thing. a chip in the unit acually oxidizes inside its epoxy case and fails. it happens over time, not with use. this is why it ia also a bad idea to buy a used one. I know i guy that fixes them, PM me if you need the info