Dropped rpms mid- drive
#1
Track Day
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Hey-I will try to make this as brief as possible
strange thing seems to be happening with my 1983 911sc
3 weeks ago-
proceeded into an intersection shifting into 2nd-car died and coasted to a stop-turn the key but engine wouldnt turn over-let sit for awhile(while waiting for a tow) right in front of lincoln center!-still nothing
(unfortunately) i am in nyc-had it delivered to manhattan motors by the tow co.
only because it was dead-i typically use Cheech at Rennwerke in elmsford,ny
this will kill you-after 3 hours of diagnostics they decided it was the ignition coil
and replaced it to the tune of $1250.-yep-ouch
(please do not ever go there)
the next 2 weekends put many miles on the car with no problems
yesterday-driving back home from vacation about 3 hours away
car running fine-all of the sudden the tach drops to zero!
car coasting-i shift through gears frantically and move to the right
am hitting the gas-pump-pump-and can hear it rev but rpm dead and no movement
then-tach jumps back to normal and car takes off
well - it happened three more times in the next hour (but not in the last 2)
i guess im asking for advice on many levels
contact manhattan motors and get pissed-say"figure this out for free!"
OR--do i have someting all together different going on
take it to cheech in elmsford(with tow truck on speed dial)
and forget the money blown
i hope someone has a good idea advice? idea whats happening?
thanks a lot
David
strange thing seems to be happening with my 1983 911sc
3 weeks ago-
proceeded into an intersection shifting into 2nd-car died and coasted to a stop-turn the key but engine wouldnt turn over-let sit for awhile(while waiting for a tow) right in front of lincoln center!-still nothing
(unfortunately) i am in nyc-had it delivered to manhattan motors by the tow co.
only because it was dead-i typically use Cheech at Rennwerke in elmsford,ny
this will kill you-after 3 hours of diagnostics they decided it was the ignition coil
and replaced it to the tune of $1250.-yep-ouch
(please do not ever go there)
the next 2 weekends put many miles on the car with no problems
yesterday-driving back home from vacation about 3 hours away
car running fine-all of the sudden the tach drops to zero!
car coasting-i shift through gears frantically and move to the right
am hitting the gas-pump-pump-and can hear it rev but rpm dead and no movement
then-tach jumps back to normal and car takes off
well - it happened three more times in the next hour (but not in the last 2)
i guess im asking for advice on many levels
contact manhattan motors and get pissed-say"figure this out for free!"
OR--do i have someting all together different going on
take it to cheech in elmsford(with tow truck on speed dial)
and forget the money blown
i hope someone has a good idea advice? idea whats happening?
thanks a lot
David
#2
Quit Smokin'
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Sounds like a lot of money for just a coil! Are you sure they didn't replace the whole Bosch CD ignition unit? Replacing the while unit for $1250, although not cheap, is much more in line than replacing the coil. How did they justify the money spent? What is the labor rate? I would answer those questions before I decided to take the car back. If they screwed you last time, they will probably do it again no matter how mad you get.
It sounds like your problem is definitely electrical. The first thing I would check is that the Bosch CDI is plugged in firmly. I have had mine come partially unplugged, and cause problems like you describe. It's hard to say without seeing the car, but the problem actually could be in the ignition switch itself.....
It sounds like your problem is definitely electrical. The first thing I would check is that the Bosch CDI is plugged in firmly. I have had mine come partially unplugged, and cause problems like you describe. It's hard to say without seeing the car, but the problem actually could be in the ignition switch itself.....
#3
RL Technical Advisor
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David,
Ryan offered some excellent suggestions. You need to see exactly what they replaced and recheck all the CD box and coil connections before proceeding further.
Ignition switches are known to fail on high-mileage cars and those are not expensive (the electrical portion).
If you have now have a silver coil, those are the current Bosch replacements and have been problematic. See if your regular shop (Rennwerke) can swap a known, good used black Bosch one in there for a 3-4 day test, assuming that everything else checks out OK.
Ryan offered some excellent suggestions. You need to see exactly what they replaced and recheck all the CD box and coil connections before proceeding further.
Ignition switches are known to fail on high-mileage cars and those are not expensive (the electrical portion).
If you have now have a silver coil, those are the current Bosch replacements and have been problematic. See if your regular shop (Rennwerke) can swap a known, good used black Bosch one in there for a 3-4 day test, assuming that everything else checks out OK.
#4
Track Day
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thanks guys
i decided to forgo talking to manhattan motors again
chalk it up to a very expensive lesson-
talked to the guy at rennwerke and he said about the same thing
so i am now making my way up to elmsford(35min)
(checking the connections as well)
fingers crossed no tow truck needed....
thanks again
david
ill post outcome for any passers by-
i decided to forgo talking to manhattan motors again
chalk it up to a very expensive lesson-
talked to the guy at rennwerke and he said about the same thing
so i am now making my way up to elmsford(35min)
(checking the connections as well)
fingers crossed no tow truck needed....
thanks again
david
ill post outcome for any passers by-
#5
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Your fuel pump could be dying on you or it could be the relay, the latter being much cheaper and easier to fix..
http://www.pelicanparts.com/cgi-bin/...era%20(1984-89)
http://www.pelicanparts.com/cgi-bin/...era%20(1984-89)
#6
Team Owner
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I can second steves comments about the Brazilian Silver coil .. mine lasted I would say about 2.5 hours of driving time .. it is now a quite expensive paper weight.
The confusing part for me was you saying the engine is reving but the tach is zero and the car is not moving , unless I read it wrong.
The confusing part for me was you saying the engine is reving but the tach is zero and the car is not moving , unless I read it wrong.
#7
Rennlist Member
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David,
Ryan offered some excellent suggestions. You need to see exactly what they replaced and recheck all the CD box and coil connections before proceeding further.
Ignition switches are known to fail on high-mileage cars and those are not expensive (the electrical portion).
If you have now have a silver coil, those are the current Bosch replacements and have been problematic. See if your regular shop (Rennwerke) can swap a known, good used black Bosch one in there for a 3-4 day test, assuming that everything else checks out OK.
Ryan offered some excellent suggestions. You need to see exactly what they replaced and recheck all the CD box and coil connections before proceeding further.
Ignition switches are known to fail on high-mileage cars and those are not expensive (the electrical portion).
If you have now have a silver coil, those are the current Bosch replacements and have been problematic. See if your regular shop (Rennwerke) can swap a known, good used black Bosch one in there for a 3-4 day test, assuming that everything else checks out OK.
What made them change out the coil (or whatever)? (i.e., what did they see within their diagnostic tools to indicate a loss of coil spark? Only saw it on the secondary side of the tranny? Where? How?) At least verify this through (their) quantification (not [their] intuition).
...as a previous poster mentioned: don't get bit by the fuel pump or it's relay...
...maybe an impossibility ("can't be fuel-related?" ,..right?), since the P-wrench has stated that it "was the coil",..................................then they "know" it's not fuel-related,..then (if so,..) .,,,,,,"how-so"? What fuel related items were checked? And how? Maybe, when a P-wrench sees an ignition coil miss then he's considered it "done",..requiring no need to check fuel-related matters (as the coil seems to have fixed (temporarily and in his eyes/tests) the problem? An owner would have to pay for the additional fuel system checks (pressures, line integrity, etc.) when the Wrench seems to have located (isolated) it as an ignition issue.....not sure here. Good communication is the key (and, of course, finding a P-wrench who doesn't mind an owner who's trying to learn things, taking a great sense of ownership).
Sometimes, it's like Physicians (and "protocol")...there are those who look "under" rocks (measure) and the others who go with the stats of elimination/probability (and, probably, experience)......I just hate the 5-10% windows of mis(complete) diagnosis......I do, however, like it when the "gatekeeper" is looking everywhere...all systems go kinda' thing (pay to play).
Best,
Doyle
maybe **** here,..(don't get the wrong impression). I just hate it when the clients' get some partial, piecemeal reply,..much less being "put-off" by a semi-knowledgeable owner....
Questions (and answers) are "fair" game.........
Best,
Doyle
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#8
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Hey-I will try to make this as brief as possible
strange thing seems to be happening with my 1983 911sc
3 weeks ago-
proceeded into an intersection shifting into 2nd-car died and coasted to a stop-turn the key but engine wouldnt turn over-let sit for awhile(while waiting for a tow) right in front of lincoln center!-still nothing
(unfortunately) i am in nyc-had it delivered to manhattan motors by the tow co.
only because it was dead-i typically use Cheech at Rennwerke in elmsford,ny
this will kill you-after 3 hours of diagnostics they decided it was the ignition coil
and replaced it to the tune of $1250.-yep-ouch
(please do not ever go there)
the next 2 weekends put many miles on the car with no problems
yesterday-driving back home from vacation about 3 hours away
car running fine-all of the sudden the tach drops to zero!
car coasting-i shift through gears frantically and move to the right
am hitting the gas-pump-pump-and can hear it rev but rpm dead and no movement
then-tach jumps back to normal and car takes off
well - it happened three more times in the next hour (but not in the last 2)
i guess im asking for advice on many levels
contact manhattan motors and get pissed-say"figure this out for free!"
OR--do i have someting all together different going on
take it to cheech in elmsford(with tow truck on speed dial)
and forget the money blown
i hope someone has a good idea advice? idea whats happening?
thanks a lot
David
strange thing seems to be happening with my 1983 911sc
3 weeks ago-
proceeded into an intersection shifting into 2nd-car died and coasted to a stop-turn the key but engine wouldnt turn over-let sit for awhile(while waiting for a tow) right in front of lincoln center!-still nothing
(unfortunately) i am in nyc-had it delivered to manhattan motors by the tow co.
only because it was dead-i typically use Cheech at Rennwerke in elmsford,ny
this will kill you-after 3 hours of diagnostics they decided it was the ignition coil
and replaced it to the tune of $1250.-yep-ouch
(please do not ever go there)
the next 2 weekends put many miles on the car with no problems
yesterday-driving back home from vacation about 3 hours away
car running fine-all of the sudden the tach drops to zero!
car coasting-i shift through gears frantically and move to the right
am hitting the gas-pump-pump-and can hear it rev but rpm dead and no movement
then-tach jumps back to normal and car takes off
well - it happened three more times in the next hour (but not in the last 2)
i guess im asking for advice on many levels
contact manhattan motors and get pissed-say"figure this out for free!"
OR--do i have someting all together different going on
take it to cheech in elmsford(with tow truck on speed dial)
and forget the money blown
i hope someone has a good idea advice? idea whats happening?
thanks a lot
David
Hate to tell you this, but the ignition coil is a $60 part and it's pretty easy to get to, just under the distributior cap. Out of curiosity, how did they break out the parts and labor. Other than the DME relay and fuel pump, it could be the fuel sender or the engine control module, the latter is very expensive, $2k+.
Is it possible your transmission is slipping?
#9
Team Owner
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holy crap if your coil is under your distributor cap you have one really fancy Porsche ... only my Rotor is under there .. my coil is on top of my fan housing
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#10
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Unfortunately, my car isn't that fancy...
#11
Burning Brakes
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And last time I checked 83 SCs do not have DMEs or DME relays.....
The amount of $$ you spent would be about the cost of a new Bosch CDI unit. You can have them rebuilt for $250 to $400 or try you luck on E-bay/salvage yards.....
You didn't mention if you have a factory Bosch unit or a Perma-tune.... I know I sound like a broken record on this topic, but I speak from experience. Perma-tune is crap.... I had this identical problem and after lots of testing of EVERYTHING in the ignition circuit and finding nothing wrong. I swapped the Perma-tune box and blue coil with a bosch unit and black coil and Viola, no more mysterious dying. It will get more frequent as time passes and can be very dangerous if you find yourself in a construction zone with no shoulders and an 18 wheeler behind you.......ask me how I know!! I scored bosch box and black coil on e-bay for $175, somebody up there likes me :-)
BTW - don't let those SOBs get off so easy if they only in-fact replaced the coil, that's criminal what they charged you.
The amount of $$ you spent would be about the cost of a new Bosch CDI unit. You can have them rebuilt for $250 to $400 or try you luck on E-bay/salvage yards.....
You didn't mention if you have a factory Bosch unit or a Perma-tune.... I know I sound like a broken record on this topic, but I speak from experience. Perma-tune is crap.... I had this identical problem and after lots of testing of EVERYTHING in the ignition circuit and finding nothing wrong. I swapped the Perma-tune box and blue coil with a bosch unit and black coil and Viola, no more mysterious dying. It will get more frequent as time passes and can be very dangerous if you find yourself in a construction zone with no shoulders and an 18 wheeler behind you.......ask me how I know!! I scored bosch box and black coil on e-bay for $175, somebody up there likes me :-)
BTW - don't let those SOBs get off so easy if they only in-fact replaced the coil, that's criminal what they charged you.
#12
RL Technical Advisor
#13
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I vote RL911 off of the "Advice Island".....
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#14
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yesterday-driving back home from vacation about 3 hours away
car running fine-all of the sudden the tach drops to zero!
car coasting-i shift through gears frantically and move to the right
am hitting the gas-pump-pump-and can hear it rev but rpm dead and no movement
then-tach jumps back to normal and car takes off
car running fine-all of the sudden the tach drops to zero!
car coasting-i shift through gears frantically and move to the right
am hitting the gas-pump-pump-and can hear it rev but rpm dead and no movement
then-tach jumps back to normal and car takes off
In the middle of his post, he's saying his rpms drop to zero, but he can hear the engine revving, which would not be fuel related...possible a transmission issue.
sounded like he had two different problems.
Last edited by RL911; 07-09-2009 at 09:44 AM.
#15
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In the early part of his post, he says his engine dies, that sounded fuel/ignition related.
In the middle of his post, he's saying his rpms drop to zero, but he can hear the engine revving, which would not be fuel related...possible a transmission issue.
sounded like he had two different problems.
In the middle of his post, he's saying his rpms drop to zero, but he can hear the engine revving, which would not be fuel related...possible a transmission issue.
sounded like he had two different problems.