1993 SC400 Has Died Twice In The Last Month, no warning...HELP!!
07-07-11, 07:26 PM
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1993 SC400 Has Died Twice In The Last Month, no warning...HELP!!
Haven't posted in a while, everything has been okay...within the last month, the car has died two times, the first after a 2.5 hour trip on the interstate in 95+ degree heat (luckily I was a block from the house when it died) turned the final corner on my road, it idled down kind of roughly, then just shut off. I tried to restart for a few minutes, no dice. Went to get other vehicle to tow the final block, about ten minutes passed between dying and getting back, tried it one more time before towing and it cranked, albeit while pumping the gas (which I thought was odd being a fuel injected car)...kept the RPMs up and parked it. Went back out after about 30 minutes, started right up, with no other issues for over three weeks (have been around town as well as on the interstate, still as hot as it was that day).
A few days ago, short trip (~2 miles RT) to the store, on the way back, same thing, only this time, I put it in neutral and it restarted with some gas pedal work again, got back home and it has been fine the last few days, but I am puzzled and my confidence it not very high ATM... I don't want to be in traffic and it dies, etc.
No CEL at all, battery is strong (so not thinking alternator, which is less than a year old, though I do have a slight oil leak from VC gaskets--that ruined the last one--I hope to get that fixed within a few weeks).
I have searched and read some posts on MAF and ECU issues, but these symptoms present a little differently. Any feedback is appreciated.
A few days ago, short trip (~2 miles RT) to the store, on the way back, same thing, only this time, I put it in neutral and it restarted with some gas pedal work again, got back home and it has been fine the last few days, but I am puzzled and my confidence it not very high ATM... I don't want to be in traffic and it dies, etc.
No CEL at all, battery is strong (so not thinking alternator, which is less than a year old, though I do have a slight oil leak from VC gaskets--that ruined the last one--I hope to get that fixed within a few weeks).
I have searched and read some posts on MAF and ECU issues, but these symptoms present a little differently. Any feedback is appreciated.
07-07-11, 07:38 PM
#2
Look into the fuel pump relay. You can very easily by pass this relay by using a jumper on the diagnostic port and drive to see if the issue comes back. I know for a fact that relays often act up during hot weather and as soon as they cool down they resume normal operation.
Next time this happens and you can't get it to start spray some starting fluid if it starts then you know for a fact you aren't getting fuel.
Next time this happens and you can't get it to start spray some starting fluid if it starts then you know for a fact you aren't getting fuel.
07-07-11, 08:01 PM
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Look into the fuel pump relay. You can very easily by pass this relay by using a jumper on the diagnostic port and drive to see if the issue comes back. I know for a fact that relays often act up during hot weather and as soon as they cool down they resume normal operation.
Next time this happens and you can't get it to start spray some starting fluid if it starts then you know for a fact you aren't getting fuel.
Next time this happens and you can't get it to start spray some starting fluid if it starts then you know for a fact you aren't getting fuel.
07-07-11, 09:07 PM
#4
Look into the fuel pump relay. You can very easily by pass this relay by using a jumper on the diagnostic port and drive to see if the issue comes back. I know for a fact that relays often act up during hot weather and as soon as they cool down they resume normal operation.
Next time this happens and you can't get it to start spray some starting fluid if it starts then you know for a fact you aren't getting fuel.
Next time this happens and you can't get it to start spray some starting fluid if it starts then you know for a fact you aren't getting fuel.
07-07-11, 10:24 PM
#6
Yes go ahead and bypass the FP ECU but ONLY using the jumper method, no need to do the hardwire method for diagnostic purposes.
And now I've said this in literally every diagnostic thread I've posted in but - pull your codes!!! There are different types of ECU codes and not all of them will throw an always on Check Engine Light, especially if the condition is not ongoing as it appears to be in this case. However the ECU will store these codes and they will come up doing a diag check here:
How to:
http://www.lexls.com/tutorials/intro/codereading.html
Good luck man!
And now I've said this in literally every diagnostic thread I've posted in but - pull your codes!!! There are different types of ECU codes and not all of them will throw an always on Check Engine Light, especially if the condition is not ongoing as it appears to be in this case. However the ECU will store these codes and they will come up doing a diag check here:
How to:
http://www.lexls.com/tutorials/intro/codereading.html
Good luck man!
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07-08-11, 06:42 AM
#9
I highly recommend against this as a diagnostic process - the jumper bypass is exactly the same thing and doesn't involve cutting wires. IF the jumper bypass succeeds over the course of an oil change, then I'd say go ahead and hardwire it via the FP ECU bypass (12v mod)
07-09-11, 09:57 AM
#13
Or bad ecu. Had it happened to my uncle's SC4. He drove it all the way down to my place (three hours one way) to visit the family, and as he was leaving car just shut off and wouldn't come back on.
And once it did come back on the car ran like straight crap, tried to pull codes, and codes wouldn't come on, replaced it with my spare ecu, fired up and hasn't had a problem since
And once it did come back on the car ran like straight crap, tried to pull codes, and codes wouldn't come on, replaced it with my spare ecu, fired up and hasn't had a problem since
