injection issue 7mge need guru help.

[1933beer]

the problem
The car is missing, #5 injector does not inject gas. I have checked spark its good. engine fault code was 25. I have verified all other cylinders work. I have verified I have 12volts between red wire and ground with ignition on. on injector #5. we did not get connectivity between ppine of white wire and main wire( where it is spliced into the wiring harness).

what I have done last

We replaced the section of wire that is tied into number 3 injector to include new female pin ( white wire). We put every thing back together and still number 5 does not get gas. I de pinned the 12vt side (red wire) and ran 12vlts to the injector when the car was running no change. We then (to verify we hand a good wire from # 5 injector to the ECU did a ohms test and it is good from the pin on the injector to the ecu. the injector works if I run wires direct to I have spark at that cylinder. I have to assume that if #3 injector is working fine that it is not the ECU. What am I missing? What Else could it be? HELP!

a little back history

We this summer replaced the engine with a JDM engine after original went out in May. this car had sat for 4 years and the PO did a bad job on a rebuild that he never finished. we got it last spring and put it back together and replace tons of pars. I have read the TSRM and used the wiring diagram to help me trouble shoot the issue. I have to long threads on Supra forum about this project. I am at a lost as to what else I can do. and son that is loosing hope that he will ever drive this car as it should drive.

thanks for help.

 

[Piratetip]

How are you determining that the injector is not firing? Noid light? Audio Scope? Inspecting Spark Plug? Other?
Have you swapped injectors around on the rail to see if the misfire follows the injector or stays on #5?
This will give you a clue as to what to check next.

Have you checked the resistance of each injector yet and compared against spec? (unplugged from harness)
Spec- 2.0 - 3.8Ω (For GTE engine)

Code 25 is for an A/F Lean Condition
Could be multiple issues:
http://www.cygnusx1.net/Supra/TechTips/engine_error_codes.aspx

 

[1933beer]

How are you determining that the injector is not firing? Noid light? Audio Scope? Inspecting Spark Plug? Other?
Have you swapped injectors around on the rail to see if the misfire follows the injector or stays on #5?
This will give you a clue as to what to check next.

Have you checked the resistance of each injector yet and compared against spec? (unplugged from harness)
Spec- 2.0 - 3.8Ω (For GTE engine)

Code 25 is for an A/F Lean Condition
Could be multiple issues:
http://www.cygnusx1.net/Supra/TechTips/engine_error_codes.aspx

I have a non turbo

 

[1933beer]

Ok I put this in the wrong section my bad. I checked all injectors before putting them into the engine. All new seals. I can pull the plug wire off of 5 and the car does not change how it runs. When I pull the plug on the rest of the cylinders the car misses more. I confirmed number 5 cylinder has spark. New cap rotor and plugs. I even tried a different plug no change. I had found that I didnt have connectivity on the white wire to number 5. 5 and 3 share the same pin on the ECU. 3 has connectivity and is working. I pulled and u did the wiring harness saw where the white wire on 5 injector was spliced. No connectivity so I replaced. I really thought we had found the problem. Put it all back together no change. I can flood the cylinder with gas if I run a separate wire for the white wire. It act as ground that it should be getting from the ECU. That tells me injector is working. It get a higher reading for ohms across the injector but the others to next to it read the same.

 

[Piratetip]

This question still applies no matter what engine you have.

Have you swapped injectors around on the rail to see if the misfire follows the injector or stays on #5?
This will give you a clue as to what to check next.

 

[Nick M]

Check for fuel on the spark plug.

 

[1933beer]

This question still applies no matter what engine you have.

Have you swapped injectors around on the rail to see if the misfire follows the injector or stays on #5?
This will give you a clue as to what to check next.

I have not swapped around injectors. The injectors were cleaned and I tested them before putting them in. If I can get fuel to go into the cylinder by connecting it directly to ground it works right?

 

[1933beer]

Check for fuel on the spark plug.

I will check for fuel on the plug. Would this mean it is over squirting?

 

[Piratetip]

I have not swapped around injectors. The injectors were cleaned and I tested them before putting them in. If I can get fuel to go into the cylinder by connecting it directly to ground it works right?

No, it might not be able to open in the ms time commanded by the ECU.
Could be a sticky pintle, weak / damaged coil, mismatched Ω between 3 & 5, or other issues.

Making assumptions for a diagnosis is never a good idea.

What are each individual injectors Ohm readings?
1-
2-
3-
4-
5-
6-

7M-GE wiring TCCS
http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=54

 

[1933beer]

I don't know how he got 18 before I do know that the digital meter I had broke and the old analog he used was giving him 10 -12. I picked up a new cheap meter and it gave me the readings below. 5 was different but not by much

No, it might not be able to open in the ms time commanded by the ECU.
Could be a sticky pintle, weak / damaged coil, mismatched Ω between 3 & 5, or other issues.

Making assumptions for a diagnosis is never a good idea.

What are each individual injectors Ohm readings?
1- 3.5
2- 3.5
3- 3.5
4- can't get to
5- 4.1
6- 3.6

7M-GE wiring TCCS
http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=54

We put on a new O2 sensor and it improved how the car runs under load. so I even put in our other Amf meter. I put another plug in and no change we ran the car a few miles pulled the plug and the number 6 plug. 6 was hot and 5 was noticeably cooler. I could grab it with bear hands 6 not. at idle the car runs nice just the slight miss. I have new injector connectors on there way. I should get them on the 31. I will de pin #5 and replace connector. I don't think it will fix. if not we will pull the injector and replace with another one we have. while we are in there for the 5th time we will replace the rest of the connectors.

 

[hvyman]

Do you have continuirty from inj 5 to the Ecu? Or to inj3?

 

[1933beer]

Do you have continuirty from inj 5 to the Ecu? Or to inj3?

We have continuity on both after we replaced the section of wire. But still 5 is not working. That is the real head scratcher.

I am a little more confused now that my reading for a na are that of a turbo.

 

[hvyman]

Both are the same.

It's a simple circuit.
http://www.cygnusx1.net/supra/Library/TEWD/MK3/manual.aspx?S=Main&P=46

If you have 12v to the injector. Your good.

If your have a ground controlled signal from the Ecu then your good.

If you have a misfire on cylinder 5 such as a headgasket or something else. Then your not good.

You could wire no3 to no5 and vise Versa and repeat the results. If it was an i he ruin issue then wiring the no3 injector temporarily to the no5 injector wiring then the problem should change to the no3 cylinder. If it doesn't then it means your no5 cylinder is faulty to something other than wiring to injectors, the Ecu, or the injectors them selfs.

7m are prone to headgasket which could cause a miss on cyl 5.

Verifying that it's actually 5 not firing injector is rather important.

 

[1933beer]

I don't think the head gasket is bad. This engine is a jdm with a new headgasket. I checked the torque when I got. We have re sealed the engine and put in a new oil pump. If the connectors don't do anything I will check the compression. If it happens to be bad I will scream but then use my warantee. To have another one sent.

 

[1933beer]

We go the new connectors and put one on number 5. No change.

Hyvman I have direct wired the injectors on 5th cylinder to verify it is squirting gas.

I think at this point I will ensure we have good compression.
I will then try to jumper directly from 3 to 5. There is not enough length to swap 3 and 5. I may try to do something as I would like to eliminate the injector as the problem or the wiring.

 

[1933beer]

update we checked compression and it is good not the issue. We removed the fuel rail and replaced the injector on #5 cylinder. We replaced the rest of the connectors going to the injectors put it all back together and we have the same issue number 5 is dead. I pull the spark plug wire and no change.

I don't know what else to do the cylinder has compression spark a different injector that ohms out 3.5 like the rest of the cylinders. I can ohm connectivity between white wires on 3 and 5 I pull 12volts between red wire and ground with the ignition in the on position. ECU has to be good or else #3 cylinder would not work either.

I am open to any ideas.

 

[Nick M]

I will check for fuel on the plug. Would this mean it is over squirting?

Just checking to see if it is wet or dry. Many people, including good techs, somehow miss it and think something is wrong or right, only to see the plug and go "oh".

I'm not saying don't do the checks.

 

[Nick M]

I can ohm connectivity between white wires on 3 and 5 I pull 12volts between red wire and ground with the ignition in the on position. ECU has to be good or else #3 cylinder would not work either.

I am open to any ideas.

You can have 1 strand of 100 intact and show no resistance on the ohm meter. If you have power, 3 is firing, then the connection from the injector to the splice has to be bad. Or, the info given is incorrect.

 

[hvyman]

If the fuel injector is firing then it's not a fuel issue. Pulling the clip on the injector while it's running means it's missing either fuel spark or air.

What was the compression numbers?

Are you sure it's getting spark?
Try swapping coils and see if the problem moves.

 

[1933beer]

We got the new connectors and put one on number 5. No change.

Hyvman I have direct wired the injectors on 5th cylinder to verify it is squirting gas.

I think at this point I will ensure we have good compression. 180 plus
I will then try to jumper directly from 3 to 5. There is not enough length to swap 3 and 5. I may try to do something as I would like to eliminate the injector as the problem or the wiring.
I tried to post the above a few days ago.

Update to that up date. Compression is good. we replaced the rest of the connectors. We replaced # 5 injector. We put everything back together. And still 5 is dead I was out of ideas. Then I figured I could remove #5 connector and jumper 3 and 5. No luck.

So I called a Toyota master techician and I have ordered some new toys. A noid light kit and camera I can hook up to my phone and look at the inside of the cylinder. The noid light will confirm the signal is getting to the injector.
I hope this tells me something useful.