injectors wont open

ae86_7mgte

New Member
Mar 26, 2008
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kaiserslautern, germany
Hi my name is kyle im new to this site, i live in kaiserslautern germany. i have an AE86 which i have put a 7mgte into. I bought a motor from a 89 supra with a 5 speed, i bought it without hearing it run. big mistake, so when i got the motor in the care , wired it up nicely and got it running it leaked all over and so i changed all the main seals, so that was good then number 5 cylinder was dead, so i just went ahead and pulled the motor out and fully rebuilt it,IE new pistons arps everywhere MHG new gaskets. bored .5 over. so mechanically the motor was now great. so i put the motor back in the car primmed the oil system, went to fire it up and nothing, it fired a few times just burning the cold start injector fuel. so i have pinpointed it down to the injectors are not opening, i rigged up my cold start valve to run constant just so i could barely get enough fuel to let it idle , just enough so i could check ignition timing, which is dead on. so i hooked the cold start back up normally, i have checked the injectors they ohm out fine and open perfect with my homade tester harness ( just one at a time so i hear them click open)
so basically all injectors are fine and fuel pressure is just fine, the EXACT problem are the injectors just simply dont open, so i have checked both terminals in the injector plugs and both read 12 volts with ignitoin on. i have ohmed basically every wire there is , so im confident the harness is just fine, the engine is very well grounded,( three heavy zero gauge grounding straps)
the ecu pins all check out the grounds are all fine and all the power in to the ecu is just fine, i have opened the ecu twice just to check for any things that look damaged, and everything looks perfect. the only thing i can possibly think of is A the ecu is bad but has no physical signs of damage, B the maf is stuck on fuel cut for some reason and not letting the ecu open injectors due to it thinking its overboosting, even when trying to start lol. or the tps is making a fuel cut and telling the ecu to turn off the injectors. so i am completely LOST like i said it would fire up before i rebuilt the motor and now they siply wont open. so if ANYONE can figure this out they are a straight genius to me. well thanks for any input kyle
 

Nick M

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Sep 9, 2005
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Power is constant when the EFI circuit is operating correctly. The ECU grounds the injectors in groups of two to fire them. Check power first, it is easy.

Are you sure the system is wired correctly? Including the circuit opening relay?
 

ae86_7mgte

New Member
Mar 26, 2008
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kaiserslautern, germany
Nick M;971188 said:
Power is constant when the EFI circuit is operating correctly. The ECU grounds the injectors in groups of two to fire them. Check power first, it is easy.

Are you sure the system is wired correctly? Including the circuit opening relay?

yes 100% wired correctly, and yes i do understand how the injectors work, and like i said, before wired exactly the same it ran, and i have all the proper power entering the ecu how it should, this is why im so lost, eveyrthing is correct, i just need to know what sensor is possbly keeping the ecu from firing the injectors
 

Nick M

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Sep 9, 2005
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ae86_7mgte;971198 said:
yes 100% wired correctly, and yes i do understand how the injectors work, and like i said, before wired exactly the same it ran, and i have all the proper power entering the ecu how it should, this is why im so lost, eveyrthing is correct, i just need to know what sensor is possbly keeping the ecu from firing the injectors

You have made statements in direct contention with each other.

It is the cletus sensor that shuts down injectors. If you know how it works, then what are you asking? No sensor shuts off injectors, as you are describing. If the cam position sensor gives rpm and engine postion, fuel and spark are delivered together. It might run kind of lousy, but it will still run.
 

ae86_7mgte

New Member
Mar 26, 2008
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kaiserslautern, germany
IE. the tps sensor when u let of the gas it cuts injectors while rpm is dropping then kicks them back on, and what im asking is what your opinion is, all i can do is state the facts and , all i can see is for some reason it WILL not run as the injectors do not open what so ever,
 

Nick M

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Sep 9, 2005
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So you think you have engine decel fuel cut while cranking huh? Did you check codes yet as asked? Do you see one for no STA?
 

Buddafucco

Beef Supreme
Mar 3, 2007
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I got a jdm motor, put it in, wouldn't start, clogged injectors. I put a power probe to the injector wires at the ecu, pumped the power threw them while cranking and eventually it stumbled and then started.
 

gaboonviper85

Supramania Contributor
Jan 13, 2008
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Nick M;971706 said:
So you think you have engine decel fuel cut while cranking huh? Did you check codes yet as asked? Do you see one for no STA?

He said it has to actually run to throw a code.... He can't even get it to turn over so can he get a code as of yet? He mentioned this already in this thread.


And he he tested the injectors himself and they were fine... Don't really know how well he tested and or if they have been flow tested but I doubt all 6 injectors would be so full of crap that none even let enough fuel out to atleast run like crap lol.
 

Buddafucco

Beef Supreme
Mar 3, 2007
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The car doesn't have to run to throw a code.
My motor had 6 clogged injectors. I thought I just said that. It is a possibility if the motor has been sitting around long enough.
 

sneakypete

Regular Member
Jul 18, 2007
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Central NJ
all you have to do is connect a jumper in the diagnostic box to t1 and e01 and turn the key to acc. the check engine light should flash steadily if there are no codes. the car doesnt have to be running
 

Nick M

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Sep 9, 2005
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gaboonviper85;971785 said:
He said it has to actually run to throw a code.... He can't even get it to turn over so can he get a code as of yet? He mentioned this already in this thread.

So if that is the case, how is a code 11 set with no power to the ECU?

He said the only change is the engine swap, now it doesn't run. Yet he did all the wiring correctly. :nono:
 

gaboonviper85

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Jan 13, 2008
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that's just what he said... I think its an obvious wireing problem.. But if you actually read his posts he did say it won't throw codes it hasn't run long enough to generate a code