Injectors not firing.

[rickreyburn]

O.K. so I am another one of those that decided to put a supra engine in my pickup truck (84 xtra cab) so I don't really belong here but really am stuck and could use some help. The engine is a 5mge 85 or 86 (the engine has a knock sensor) The engine harness is from a year without the knock sensor but I know its not from an 82 because the distributor had no vacuum advance. My truck was original with a carb so I swapped the entire wiring harness in from the supra. Everything including the dash. I left the original truck ignition switch, wiper etc. When I try to start the truck the injectors do not fire. I have spark and the timing is right because it will run for a short while on starter fluid or gas. I have power to the ecu at the large plug. I can get the injectors to fire by jumping them at the plug that hooks up to the ecu. The injector resistor is good. My AFM is good when I push door fuel pump goes on. My circuit open relay clicks when I turn key. My EFI #1 and EFI#2 relays work. From what I understand this ECU fires by grounding them out when it gets a signal from the rotor inside the distributor. So if I have power at the ecu and power to my injectors and all the wiring is hooked up what is going on? Bad Ecu? not getting signal from distributor. I don't know. The ECU P/N is 89661-14020. it says 5mge M/T right on it. It plugs in fine, the only thing i notice is that where the ecu plugs go is orange and my plugs that go into it are a bannana yellow color. Is there a way to see if my ecu is bad or a way to make sure it is getting the proper signal it needs from the distributor? Any help would be great.

[83CelWA]

Did you make sure to attach the ground harness when putting the engine together? I sits around the lower intake area and looks like a couple wires going to a copper lug.

[rickreyburn]

if you mean the injector/engine harness that grounds to the intake manifold then yes. I dont think thats the problem because I can fire injectors manually from the plug that goes into the ecu. I have also verified that the ecu has power, All components work i.e., AFM,fuel pump, relays, iscv, throttle body, ignition. I think the problem lies within the ecu itself or the circuit that tells it when to fire the injectors. I only have a haynes manual to work with and the wiring diagrams are not the best. I am not 100% on what actually tells the ecu when to fire the injectors. I even looked inside the ecu, and there is no degradation or burnt spots on the board so I dont think thats the problem either.

[whitey408]

http://www.cygnusx1.net/Supra/Library/TSRM/MK2/

here try to route your wire from there. if you think it is still the ECU let me know i got one laying around here somewhere.

GOOD LUCK!!!

[jsn_ayers]

5MGE
89661- 14020 years 8.83 8.84 SUPRA
This may be your problem
You need a 85 89661-22080 ECU and harness or just swap the sensors to 84 on the engine.

[rickreyburn]

Thanks for the link to the TSRM I had no idea this site had that kind of info. I only got thru some of the checks before it started to rain today. I have already found some problems. The TSRM is for an 86 model but it is very similar to what I have. I think I can make it work with what I've got. The main difference I can see Is the AFM wiring.

[83CelWA]

The main difference I can see Is the AFM wiring.

That's right, I forgot about that one. I had the same issue with the first swap in the Celipra and ended up having to swap a wire to another spot on the plug fro the AFM and leave the other one off. I cannot remember who told me about it, but I will look into what 2 wires are involved.

[rickreyburn]

O.k. I have sorted out most of it. I have a 1986 engine with the 83 84 TPS and air flow meter. The car I pulled it from was an 83 but the guy I bought it from said it did not have the original engine. I guess I got lucky because the 86 5mge has a lot of improvements over the earlier years but I am probally cancelling out most of the advantages by having 83 84 sensors wiring and ECU. I guess I have a good platform for upgrades. Still can't get injectors to fire but have cancelled out hardware/wiring conflicts. I noticed that the cold start injector does not squirt either when I crank it. I think the problem has somthing to do with the STA wire from circuit open relay to starter to ECU. I am not getting voltage at ECU STA terminal when cranking. I will be able to dig into it this weekend weather permitting.

[jsn_ayers]

The starter wire runs to the Ignition and the STA wire(black) runs off it before the Ignition ,so you just need a jumper to the ECU from that wire.

http://www.cygnusx1.net/Supra/Library/TSRM/MK2/manual.aspx?S=E&P=3
Page 3 and 4 shows it. It also goes to the open start relay and the #2 EFI relay. Test all those places to see if its open anywhere along the way.

[rickreyburn]

Been a while but found that distributor was one tooth off. Ended up with a 85 p-type with older engine in it. No knock sensor, square tooth timing belt teeth, round instead of D shaped intake runners. Pulled this motor from my pickup and put in the supra where it belongs. I will do an intro thread soon with pics.

[DreadyDiggs]

So...what's become of the pickup?

[rickreyburn]

I have a NA 7mge for the supra that I made my intro post about. This 5mge will go back into the pickup when the 7mge is ready. I am shooting for holiday time frame. I love my pickup but I have a long commute to work and its not the greatest long hauler.