View Full Version : still stuck

04-29-2013, 01:52 AM
My 90 celica gts 5 speed 2.2. Having problems with my fuel injectors not grounding right whick means my ecu acting up already replaced it once it worked for couple days. Any reasons it could be doing this wiring? Grounds? Any have this problem. I have the federal emissions computer

04-29-2013, 02:38 PM
It's likely a bad ground. How did you determine it to be the injectors? What lead you to change the ECU? Have you used a digital multimeter to troubleshoot the problem?

Check the ECU ground wire on the back of the intake manifold for damage. There is a flow chart in the BGB on the home page you can use to troubleshoot the issue using a multimeter. Open the MFI & SFI Systems link then click on troubleshooting with a voltmeter/ohmmeter.


04-29-2013, 05:15 PM
I used a noid light and power probe check the wiring from the computer. But I still need go through the grounds. Im need check the ecu ground wire and take your work on using that link and thanks.

04-29-2013, 11:09 PM
IIRC the ECU is what grounds the injectors.
They get 12v from the black/red IG on wire. Then the ECU grounds them as it wants them open. Of course the ground goes through the ECU grounds to the chassis. If you're having trouble with all of them and you've swapped with a known good ECU then yeah, take a look at the ECU grounds. Should be white/black wires [2] running to the rear of the intake manifold. They get worn out/corroded on the manifold end.

04-30-2013, 01:18 PM
Alright thanks. I'll check them this weekend then when i get time. Check them grounds for sure.

05-08-2013, 09:41 PM
the ground wire looks intact from what i can see on the back of the intake manifold

05-08-2013, 10:47 PM
Check the ecu ground.

05-09-2013, 06:14 AM
Yeah, I'd actually do a resistance check on that ECU ground. It may look fine, but it could still not be functioning properly.

05-09-2013, 04:24 PM
Ill try that next now thanks.

05-25-2013, 02:47 AM
Have you checked the MAP sensor? I thought my injectors or ECU was acting up, but it turned out to be my MAP sensor. My car would drive fine when I gave it gas, but as soon as I let up on the pedal it would act like it wasn't getting enough gas and then stall. What are your symptoms?

06-15-2013, 01:12 AM
This is a long shot but you don't happen to have one of those IAT chip modules. I bought my 93 GTS and it had one on it. The first thing I did was remove it and resoldered the connection. I chased every sensor and my wiring for days trying to find why my car ran like shit. I finally replaced the ecu and everything has been fine since. I believe that module shorted something in the ecu and I had repaired the connecting before testing it for a short.

It could be a loose ground if it is an on again off again issue but that would only make the new ecu work by coincidence. If it was a bad ground I don't think the second ecu would have worked either. Sounds to me like you have a short that is taking out the ecu. I would take a multi meter and check every wire to the ecu for a short.