Car Cranks but Won't Start
#1
Car Cranks but Won't Start
First, I've searched high and low for someone who has an issue like mine, but I cannot find any clues.
Problem: Was driving the car a week and a half ago, stopped at a light and the car cut off. Tried to restart it, and it cranks hard, but absolutely will not start.
Tests:
- Sprayed Starting fluid into the intake - Car starts to crank and run. Great I've got spark
- Checked the fuel pump ECU - It has been bypassed already
- Replaced fuel pump - Installed a Supra Pump
- Checked the EFI 30A fuse - Intact, checked continuity, good reading, still replaced it. No start
- Checked power at the fuel pump with the Relay in place - .6v
- Removed the EFI relay and jumped pins 2 and 4 - 12v power to the fuel pump, engine starts, but runs rough
- Replaced EFI relay with brand new unit - No start, .6v at fuel pump
- Checked ground continuity to the fuse box and the engine - Good grounds
- Checked power from the negative battery terminal to the left side(3 below) of the 30A EFI fuse - .6v
Any ideas? Am I looking at needing a new ECU?
All voltage readings were taken with the key in the ON position.
FYI, Pic of EFI Relay pins that were jumped:
Problem: Was driving the car a week and a half ago, stopped at a light and the car cut off. Tried to restart it, and it cranks hard, but absolutely will not start.
Tests:
- Sprayed Starting fluid into the intake - Car starts to crank and run. Great I've got spark
- Checked the fuel pump ECU - It has been bypassed already
- Replaced fuel pump - Installed a Supra Pump
- Checked the EFI 30A fuse - Intact, checked continuity, good reading, still replaced it. No start
- Checked power at the fuel pump with the Relay in place - .6v
- Removed the EFI relay and jumped pins 2 and 4 - 12v power to the fuel pump, engine starts, but runs rough
- Replaced EFI relay with brand new unit - No start, .6v at fuel pump
- Checked ground continuity to the fuse box and the engine - Good grounds
- Checked power from the negative battery terminal to the left side(3 below) of the 30A EFI fuse - .6v
Any ideas? Am I looking at needing a new ECU?
All voltage readings were taken with the key in the ON position.
FYI, Pic of EFI Relay pins that were jumped:
Last edited by mrmj2u; 05-31-17 at 08:27 PM.
#2
checked your actual ECU? leaking capacitors can be the root of such a cause, I hate to be that guy of the thread but these cars have alot of commons issues that can be solved by ECU replacement or repair.
#3
Was hoping that there would be another thing to check, before spending the money on a new ECU.
#4
When you get the car started with the starter fluid, how does it run? It could be a problem with your AFM, Cam/Crank Angle Sensor, Injectors, possibly your TPS or Idle Air Control Valve, My good friend had avery similar issue only a few weeks back in his VR4 Galant and all it needed was some cleaner over his AFM and Throttle Body.
#5
When you get the car started with the starter fluid, how does it run? It could be a problem with your AFM, Cam/Crank Angle Sensor, Injectors, possibly your TPS or Idle Air Control Valve, My good friend had avery similar issue only a few weeks back in his VR4 Galant and all it needed was some cleaner over his AFM and Throttle Body.
When the EFI relay pins were jumped, the injectors started hum immediately, the fuel pump started and then when I turned the key to START the engine it started. It sputtered really bad and wouldn't idle over ~350 RPMS. It ran very smooth as I revved it, though.
Last edited by mrmj2u; 11-21-17 at 11:48 AM.
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#8
It does sound like a fuel issue but could possibly be Airflow related, though that would usually mean it runs a bit rough once you get it going. If its revving smoothly and the fuel pump and injectors are operating fine it could possibly be a sensor or airflow issue. Have you worked your way through the Air system?
#10
It does sound like a fuel issue but could possibly be Airflow related, though that would usually mean it runs a bit rough once you get it going. If its revving smoothly and the fuel pump and injectors are operating fine it could possibly be a sensor or airflow issue. Have you worked your way through the Air system?
There are no codes showing, the only time the CEL lights up is when the EFI pins are jumped. Otherwise there is no CEL when turning the car on.
I've jumped the E1 with TE1 and the CEL does not light. I'm seriously thinking that its the ECU.
Last edited by mrmj2u; 06-01-17 at 06:12 AM.
#11
My '97 just cut off going down the street. Checked everything figuring fuel pump, or my ECU, was dead. Hooking up a meter to the OBD2 port would not read anything. Meter said "no communication" with the ECU. Might be worth you doing that just to check. I bought a replacement ECU from a salvage yard and it fired right up.
ps: The previous owner parked the car in the hot sun way too much. (my back seat and speakers are toast) I figure all that heat helped take out the ECU.
ps: The previous owner parked the car in the hot sun way too much. (my back seat and speakers are toast) I figure all that heat helped take out the ECU.
Last edited by jmblimo; 06-05-17 at 04:39 PM.
#12
My '97 just cut off going down the street. Checked everything figuring fuel pump, or my ECU, was dead. Hooking a meter to the OBD2 port would not read anything. Might be worth you doing just to check. I bought a replacement ECU from a salvage yard and it fired right up.
ps: The previous owner parked the car in the hot sun way too much. My back seat is toast. I figure all that heat helped take out the ECU.
ps: The previous owner parked the car in the hot sun way too much. My back seat is toast. I figure all that heat helped take out the ECU.
#14
The problem was with the ECU. The new-to-me ECU arrived today, popped it in, plugged the battery in and the car roared back to life!
Do you guys think it can be fixed? It looks really bad to me. Seems like a good idea to have a spare lying around.
Thanks for your suggestions guys!
#15
Send it out for a rebuild... Always good to have a spare ECU as it is not a part easy to get.....
Either Tanin
http://www.taninautoelectronix.com/1992-1995-SC400-SC300-Lexus-SC400-ECU-ECM-Rebuild-p/lexus_ecu_repair.htm
or
Darryl
http://www.lexuspartsplus.com/ecu-services.html
Either Tanin
http://www.taninautoelectronix.com/1992-1995-SC400-SC300-Lexus-SC400-ECU-ECM-Rebuild-p/lexus_ecu_repair.htm
or
Darryl
http://www.lexuspartsplus.com/ecu-services.html