no tach, car keeps dying
07-03-2009, 06:13 AM
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no tach, car keeps dying For the past month i have been having problems with the car dyng. It seems to only die when it is warmed up, then it dosen't matter if the car is moving or just idleing, it will just cut out randomly, mostly at low rpms. Then after it dies i can start it right up again and the idle will flucuate a bit, but then the car will be fine again until i get about 20ft, and it dies again. The wierd thing is before it seems the engine completely cuts out, the tach will read 0 rpms, and i can step on the gas pedal, and there will be no engine response, but i can still hear the exhaust which meens the engine is still firing,which i can tell b/c the power steering pump is still running, and then it will die. I have put the car on a scanner, but all i came up with was an emission evap code which makes sense because i have no emissions hooked up on my car, and i kept an eye on my fuel pressure guage and the fp never seems to drop when when the car dies, so i have no idea what is going on, its driving me nuts. Is there anybody who can give me an idea of what could be wrong, any bit of help would be appreciated.
07-03-2009, 10:31 AM
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The car in an LS-1 T-56 swap in an 87 iroc, it ran fine for a long time then one day out of nowhere it would just stall when going to shift. We cannot think of what could be causing this. The problem has gotten progressively worse. The strangest thing is the car worked fine and then for some unknown reason did this on its own. Like was said earlier it does not throw any codes other than emissions codes so we dont even know where to start with diagnosing. When running the engine runs great until it warms up, then it will stall out, and its not a slow process it goes from running to dead instantly, no sputtering. Then starting is difficult although fuel pressure does seem to remain constant through the entire process. We could really use some help with this, anyone with any ideas let us know....the procharger is waiting in the house, help get a progharged ls1 third gen back on the road!
07-04-2009, 09:38 AM
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Everyone always has something to say on this site, how is it when someone really needs help with a problem that we have searched for extensively and cant find any answers no one will even respond with any input besides niko which while the idea was appreciated the car is not an LT-1?
07-04-2009, 10:26 AM
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Everyone always has something to say on this site, how is it when someone really needs help with a problem that we have searched for extensively and cant find any answers no one will even respond with any input besides niko which while the idea was appreciated the car is not an LT-1?
Anyway this is likely a cam sensor or crank position sensor problem. Some scanners may not display a code if it is status pending or immature in the computer. HPtuners will show pending/immature codes..
Problem is that it is intermittent and not throwing codes so it will be a lot harder to track the problem. Sometimes with problems like this the only way to fix it is throw money at parts. But my money would be on the cam or crank sensors because you said the rpms would not register right before it died. Im not sure if the ls1 takes its RPM reading from the crank or cam sensor exclusively or both together, but i have read the tach will die out if the cam sensor goes bad. It will start hard but the engine will run fine and I havnt seen any mention of it making an engine stall... If the crank sensor goes, the engine will not run at all.
If you have hptuners available you could also try and do a crank relearn process and see if that helps at all. It could also help to log while driving if you do have hptuners.
07-05-2009, 12:58 PM
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Yeah I was thinking that it could be either the crank or cam sensor, but they weren't throwing any codes so i wasn't sure. I do not have hptuners, but is there another way to test these sensors with out having to go out and buy new ones? Thanks.
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07-06-2009, 02:52 PM
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Yes, I'm also curious what year LS1 motor it is. The 03 Vettes had a TSB on the cam walking after the plate starts loosening up. I had this happen on my 02 TA is how I know about it. Replaced the sensor (I had the same symptoms as you), worked fine for a day then just died again. Then we found out that the "stock" cam had walked around enough to destory the sensor. Not sure if there is an easy way to check that but if after replacing the sensor, it dies again, something to think about. The cps is at the rear of the engine right behind the intake. Should be pretty easy for you to change out.
07-07-2009, 05:28 AM
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my mototr cam out of a 2002 trans am so that could be the problem. It only has about 25,000 miles on it. Dal1as how many miles where on yours before this happened? If this is the case I guess the only solution would be to replace the came, right?
07-07-2009, 09:13 AM
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I was around 70 grand at the time. I would just change out the sensor first but if it does what I talked about damn right it's time for a cam. You already have the engine open.
02-10-2010, 07:18 PM
#15
tach reads 0 then car dies suddenly I have an issue like yours. the car runs fine but if i have to hit the brakes harder than normal (yellow light for instance) then the tack goes out and the car stalls. Then it will start back up but a little rough. Then it runs fine for a while and randomly cuts out again. I replaced my MAF cause that was the code but then it still happened. I had replaced my cam sensor last year because the same thing was going on but like an idiot i bough a cheepo auto zone cam sensor and allthough no code for the sensor has shown up i have the same symtoms as befor, and like you its sort of a guess as what to do. I will get another cam sensor as has been suggested and i bet that will solve the problem
08-02-2010, 11:00 AM
#17
I have an issue like yours. the car runs fine but if i have to hit the brakes harder than normal (yellow light for instance) then the tack goes out and the car stalls. Then it will start back up but a little rough. Then it runs fine for a while and randomly cuts out again. I replaced my MAF cause that was the code but then it still happened. I had replaced my cam sensor last year because the same thing was going on but like an idiot i bough a cheepo auto zone cam sensor and allthough no code for the sensor has shown up i have the same symtoms as befor, and like you its sort of a guess as what to do. I will get another cam sensor as has been suggested and i bet that will solve the problem
08-02-2010, 11:44 AM
#18
If the tach goes dead, that's telling me the crank sensor is bad (or the wiring to it), at that point the computer doesn't have input from the engine for engine speed, so it just dies.
At least, that's what it sounds like to me. I've never actually dealt with it before so take it with a grain of salt.
At least, that's what it sounds like to me. I've never actually dealt with it before so take it with a grain of salt.
08-02-2011, 11:29 AM
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For the past month i have been having problems with the car dyng. It seems to only die when it is warmed up, then it dosen't matter if the car is moving or just idleing, it will just cut out randomly, mostly at low rpms. Then after it dies i can start it right up again and the idle will flucuate a bit, but then the car will be fine again until i get about 20ft, and it dies again. The wierd thing is before it seems the engine completely cuts out, the tach will read 0 rpms, and i can step on the gas pedal, and there will be no engine response, but i can still hear the exhaust which meens the engine is still firing,which i can tell b/c the power steering pump is still running, and then it will die. I have put the car on a scanner, but all i came up with was an emission evap code which makes sense because i have no emissions hooked up on my car, and i kept an eye on my fuel pressure guage and the fp never seems to drop when when the car dies, so i have no idea what is going on, its driving me nuts. Is there anybody who can give me an idea of what could be wrong, any bit of help would be appreciated.