No Start Hot

kwayne · 03-27-2008, 05:34 AM

I have an 87 7mgte. When cold, it starts and runs fine as long as the ignition is not turned off. Once it's turned off, it has to cool down before it will start again.

I have found two ways to start the car hot. It can be roll started, or it can be started by bypassing the efi main relay with a jumper wire. So far I have replaced the ignitor, ecu, fuel pump, fuel filter, cam position sensor and coil pack. All vacume line have been replaced and all leaking moulded hoses have been replaced.

Does anyone have any ideas?

bunksbbq · 04-02-2008, 08:18 AM

Check the neutral switch. Its located on the transmission, close to the exhust pipes. The heat will cause it to fail, preventing the starter working. After it cools off, the car will start fine. Worst case, it can be bypassed but I don't recommend it. You lose the protection of not starting in gear and cruise control.

CyFi6 · 04-02-2008, 08:32 AM

Does it crank or what? Sounds like youre having issues with your EFI relay, test it and fix or replace it if its bad.

kwayne · 06-10-2008, 07:02 AM

Thanks for all of the help! The problem turned out to be a fault ignition switch. When the car heated up, the switch would fail, causing a loss of power to the efi main relay control side circut. This in effect cuased the fuel pump to shut down. By inserting a jumper wire, bypassing the efi main relay, the car started and ran find. From there, we were able to back track to the ignition switch.

CyFi6 · 06-10-2008, 07:06 AM

glad to hear it worked out and you diagnosed it properly! Something a lot of people have trouble with

03-27-2008, 05:34 AM	#1
kwayne Stock Join Date: Mar 2008 Location: Atlanta Ga Posts: 5	No Start Hot I have an 87 7mgte. When cold, it starts and runs fine as long as the ignition is not turned off. Once it's turned off, it has to cool down before it will start again. I have found two ways to start the car hot. It can be roll started, or it can be started by bypassing the efi main relay with a jumper wire. So far I have replaced the ignitor, ecu, fuel pump, fuel filter, cam position sensor and coil pack. All vacume line have been replaced and all leaking moulded hoses have been replaced. Does anyone have any ideas?

06-10-2008, 07:02 AM	#4
kwayne Stock Join Date: Mar 2008 Location: Atlanta Ga Posts: 5	No Start Hot Thanks for all of the help! The problem turned out to be a fault ignition switch. When the car heated up, the switch would fail, causing a loss of power to the efi main relay control side circut. This in effect cuased the fuel pump to shut down. By inserting a jumper wire, bypassing the efi main relay, the car started and ran find. From there, we were able to back track to the ignition switch.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
87 Supra won't start	RNEMESiS42	MKIII Supra	3	06-25-2011 06:30 PM
Car wont start hot	carfanatic89	MKIII Supra	41	03-30-2009 10:58 PM
My car decides when it wants to start	carfanatic89	MKIII Supra	16	02-12-2008 07:50 PM
Car Died...where to start?	Jrew	MKIII Supra	4	10-26-2007 02:19 PM
no start	87supraguy	MKIII Supra	5	03-23-2006 07:31 AM

04-02-2008, 08:18 AM	#2
bunksbbq Stock Join Date: Jun 2007 Location: Honolulu Posts: 2	Check the neutral switch. Its located on the transmission, close to the exhust pipes. The heat will cause it to fail, preventing the starter working. After it cools off, the car will start fine. Worst case, it can be bypassed but I don't recommend it. You lose the protection of not starting in gear and cruise control.

04-02-2008, 08:32 AM	#3
CyFi6 3" Exhaust Join Date: Oct 2007 Location: SLO Posts: 234	Does it crank or what? Sounds like youre having issues with your EFI relay, test it and fix or replace it if its bad.

06-10-2008, 07:06 AM	#5
CyFi6 3" Exhaust Join Date: Oct 2007 Location: SLO Posts: 234	glad to hear it worked out and you diagnosed it properly! Something a lot of people have trouble with