Checked injector pulse?
Hi Guys,
I have done a hunt around the internets trying to solve my problems with no success.
Full run down on the situation:
ADM AE86 converted to JDM Bigport 4age, with full body loom (Has Relays exc)/ engine loom / JDM Fuel Tank. All from the same imported car. Viewed running before purchase.
• Now its cranking over fine... I am keeping the battery well charged.
• Spark is certainly there... We successfully arced plugs on a metallic surface.
• I suspect its not getting any fuel. Pump can be heard priming and there is certainly fuel pressure on both sides of the rail.
• It will cough and splutter with a bit of "Start ya Bastard" increasing the blame for the fuel system.
• After cranking the motor for a fair while we removed the plugs to check for wetness. Plugs were bone dry.
• I suspected crappy engine earths and cleaned/sanded all mating surfaces (Engine bay was painted before installation).
• Vacuum lines "should" all be correct... Everything that is not being used has been blocked off (has power steering nipples on throttle body exc).
It will most likely be something simple that I have missed, or plugged in incorrectly no doubt.
I need to get this thing going ASAP, any hints would be muchly appreciated!
Cheers, Corey
Checked injector pulse?
Bridge a test light on the injector terminals and crank it, the light should pulse in rhythm with the fuel.
If it passes that, you could have stuck injectors. I've heard a brisk tap on them can free them up sometimes depends how long they sat. Its a nice idea to clean them anyhow. The mobile guys are fine, they do it all in front of you its a nice education.
I assume you've done all the basics like set up the timing with a timing light? Physically inspected to see if you pinched a line flat while wrestling in the motor?
Check for ignition power on one side of the fuel injector plugs. Having spark means the ecu is wired correctly and the coil / ignition system is working.
The ecu provides the earth to the injectors when it is their turn to fire.
Ae86 Drivingclub - Toyota AE86 Car Club where AE86 | KE70 | Toyota 86 / GT86 | Subaru BRZ | Scion FRS owners
Thanks for the feedback guys!
I dont have a LED test light to check for an injector pulse, I will grab one in the next couple of days.
If it comes to it, I will get a mobile mech lol.
It was run probably 8 months ago. You wouldn't think they would be blocked in that period of time.
I will try with what Matt has suggested first and check for power at the injectors. Apparently I should see battery voltage correct?
Does the ECU earth all the injectors? Or only 2? I read that somewhere?
Could someone explain to me how the COR works regarding firing the fuel pump. It seems to only prime once ignition is switch off for a few seconds. Is this normal? Should it be priming constantly under cranking?
I also have read mixed opinions of this.
Cheers guys!
Timing has been untouched since I saw it running 8 months ago, but I have not thrown a timing light on it yet. It definitely seems like a fuel problem
Yes you should see 12v at the injectors with the ignition on. On the bigport motors the injectors are batch fired, so you should have continuity between two of the injectors.
As for how does the Fuel open circuit relay works, think of it as 2 seperate relays.
1. When cranking - Power to the starter motor is provided from the barrell, to the ecu (STA Pin) , cold start injector and also the "Trigger" input of the open circuit relay.
2. When running, the ECU knows the motor is running and the ecu will provide an earth for the second relay via the FP pin.
When either relay is happy, the blue wire that runs to the fuel tank has power and the pump runs.
I've seen bigports where you move the dizzy and the fuel pump will be activated.They also prime for a couple of seconds when you turn the ignition on.
Ae86 Drivingclub - Toyota AE86 Car Club where AE86 | KE70 | Toyota 86 / GT86 | Subaru BRZ | Scion FRS owners
If the plugs are wet with fuel after some cranking then the problem could be as simple as old fuel.
To avoid flooding the engine you could remove the cold start injector plug after you have cranked it for a while, the cold start injector works when the starter motor is engaged, too much cranking equals too much fuel.
First step is to make sure all of the plugs are clean and dry and then crank the engine to see if they get fuel on them.
As suggested, might be dirty/old fuel. When I did my 4A KE70 the injectors were dirty which caused similar issues. I pulled them out and cleaned them (spare plug with wires stripped used to open them and an 044 hooked up directly to injector) after that the motor ran sweet...
How did it go?
Did you get it to run?
What was the issue?