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Discussion Starter · #1 ·
Hey guys,

So I build my supra from top to bottom, everything engine transmission and also diff.
I'm having trouble starting the car. I can't say exactly what happening but I'll try my best explaining what the problem is.
So first the engine turns but some time it will not start, if it starts it runs fine expect for the rough idle because of the base map, I can drive it no problem. But after a short drive I park it and after a while it will not start, and it will not turn the engine, I can hear the starter click everytime I turn the key but it will not start or turn. After along wait like 30 minutes or more it start and fires up normal.
I changed everything the battery the starter, and even the starter relay. I checked the alternator and it's good showing 14v, checked the ground everything is okay.
After leaving the car for a week, because I was sick. Today I tried to start it to move it and break in the engine. It turn but will not fire up, after 4 failed attempts to start the car, it stopped turning.
I'm so frustrated and I can't figure out the problem. I really need help please.
Here is my mod list
Built engine 2.3l storker
Built head with GSC S2 cams
Mechanical fuel pump
There is a fuel pump in the fuel tank but I did not wire it yet to help with the fuel delivery to the mechanical pump.
IGN1A coil kit
ProEFI pro120
Tweak'd performance wire harness
I tried everything please help
 

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Sounds like a few different things are happening-

When the starter cranks the engine but it does not start:

-Mechanical fuel pumps are not always self-priming - ensure your mechanical pump is self priming. If it is not, it's likely you lost the prime in the fuel system so the pump is just spinning in a bubble of air and not moving any fuel. You should connect the in-tank pump to ensure it's always getting fuel when cranking. Also make sure your in-tank pump has a check valve to prevent the loss of the prime - Some larger electric pumps do not have check valves, such as the Walbro 525. Smaller pumps like the factory Denso TT pump, Walbro 255, Walbro 416/450, AEM etc 320's, all have check valves.

-I'd also check your base map to ensure it has some sort of fuel trim adjustment for engine coolant temp ; if it starts and runs well when cold but hates starting after it's been warmed up, that usually means it needs tuning work there.

When the starter just clicks and does not crank:
-A new battery, starter motor, and even relay is great but the usual failure point there are the cables themselves. Inspect not just the clamps for corrosion or damage but inspect the cables themselves - peel back the cable cover/jacket near the battery clamps and the starter connection and ensure it isn't corroded or damaged there, and clean corrosion & replace it if needed, with special care to clean the metal surfaces that contact the battery post and contact the starter motor.
 
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Discussion Starter · #3 ·
Sounds like a few different things are happening-

When the starter cranks the engine but it does not start:

-Mechanical fuel pumps are not always self-priming - ensure your mechanical pump is self priming. If it is not, it's likely you lost the prime in the fuel system so the pump is just spinning in a bubble of air and not moving any fuel. You should connect the in-tank pump to ensure it's always getting fuel when cranking. Also make sure your in-tank pump has a check valve to prevent the loss of the prime - Some larger electric pumps do not have check valves, such as the Walbro 525. Smaller pumps like the factory Denso TT pump, Walbro 255, Walbro 416/450, AEM etc 320's, all have check valves.

-I'd also check your base map to ensure it has some sort of fuel trim adjustment for engine coolant temp ; if it starts and runs well when cold but hates starting after it's been warmed up, that usually means it needs tuning work there.

When the starter just clicks and does not crank:
-A new battery, starter motor, and even relay is great but the usual failure point there are the cables themselves. Inspect not just the clamps for corrosion or damage but inspect the cables themselves - peel back the cable cover/jacket near the battery clamps and the starter connection and ensure it isn't corroded or damaged there, and clean corrosion & replace it if needed, with special care to clean the metal surfaces that contact the battery post and contact the starter motor.
Thank you for replying

- you are correct. But I add 2 check valves in the fuel line, so it should have fuel in the lines to start the car. I had this problem before and I though the check valves were not working, but I checked them and they are okay. What I did was use a blow to push air through the fuel fill cap just to check of the check valves are working and the fuel came out of the end of the line. Also I add the walbro 450 pump in the fuel tank.

- I will take the car to my tuner and let him check the fuelfuel trim as you suggested.

- The battery is relocated to the back with new cables. I might recheck the ground again tomorrow.

Just now I tried to start it again but it will not turn. I can hear the starter click, but nothing is moving.

I want the car to start so I can start tuning soon
 

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Thank you for replying

- you are correct. But I add 2 check valves in the fuel line, so it should have fuel in the lines to start the car. I had this problem before and I though the check valves were not working, but I checked them and they are okay. What I did was use a blow to push air through the fuel fill cap just to check of the check valves are working and the fuel came out of the end of the line. Also I add the walbro 450 pump in the fuel tank.

- I will take the car to my tuner and let him check the fuelfuel trim as you suggested.

- The battery is relocated to the back with new cables. I might recheck the ground again tomorrow.

Just now I tried to start it again but it will not turn. I can hear the starter click, but nothing is moving.

I want the car to start so I can start tuning soon
I would carefully check the cables used in the battery relocation, check both the ground and the + lead to the starter, it sounds like the cables used for the relocation may not be thick enough, the crimps & connections may be poor, or the ground may not be connected to a thick enough piece of clean bare chassis metal.

I hope you get it fixed soon!
 
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I’d check the start motor high voltage contacts. If the starter relay is a healthy click (energized) and no power is making it to the rotor shaft due to worn contacts the starter motor wont spin to turn the flywheel. I’d pull the starter motor and inspect it.
 

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If you pull the spark plugs does the motor turn over easily? Seen a few motor “builds” where the Machinest and builder has no idea what they’re doing so maybe check the basics first. Also is a cylinder full of fuel? That will stop it from turning over for sure. Also, you should be breaking in your motor on the Dyno under a high load, with testing equipment hooked up to verify it is safe to do so. Idling around with out of whack fuel trims is ruining your hone job and ring seal- would do a leak down after it’s sorted and you may be pulling it apart and honing it again if it’s got a grip of blow by
 

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I've also had the issue with a mechanical pump not being able to generate enough pressure to start the car.

Also, this sounds basic, because it is, but as Jeff pointed out, the battery ground needs to have BARE metal where you secure the cable. If you're concerned about rust, you can use dielectric grease on that connection area. I ran into this on another build a couple years ago, didn't strip off the paint enough where I connected the ground cable, and it wouldn't even crank the engine. Stripped the paint off, and it fired right up.
 
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