[Duncan95Gt]

I've got a 1995 GT 5 speed so here the story I drive it daily and one day I went to start it and the fuel pump didn't prime at this time I had already replaced the TPS for rough idle and was working toward the IAC getting replaced so all I could think to do was cycle the key and after a few times it primed and I went to work not an issue for a few days then it became a daily issue I had to continue driving it no matter what well 3/1/23 I had the same issue in the morning I tapped on the iac with a screw driver it clicked the pump cycled and went to work after work it wouldn't do anything my boss ran a jumper to the iac red wire from the battery and the iac opened and the pump primed and I got the car home I've REPLACED THE IAC AND THE PLUG TOO AND STILL NOTHING HELP ME PLEASE FIGURE THIS OUT
So I tried to do the eec test to see if it'll give me codes it does not respond at the relay by the computer I get 0.17v and ohms of the relay were 1.1 also I did other multi meter tests and have low voltage to everything except the fuse blocks and the coil that show 12.38v so I don't know what to look at I'll add everything info wise I have been through

 

[Duncan95Gt]

Only the pin shown has power with key on

 

[mercenvy]

You can't test it like that. The ECU needs to be installed and then you can backprobe it.
As far as i know the fuel pump should prime with the key regardless of the IAC.
I'd start looking at fuel pump circuit, or ECU might be bad.

It must be difficult trying to diagnose electrical problems with all that trash on the floor.

 

[dmw_4814]

You can't test it like that. The ECU needs to be installed and then you can backprobe it.
As far as i know the fuel pump should prime with the key regardless of the IAC.
I'd start looking at fuel pump circuit, or ECU might be bad.

It must be difficult trying to diagnose electrical problems with all that trash on the floor.

I agree; I don't think the IAC valve has anything to do with the on/off state of the fuel pump. If it starts running when the IAC valve is tapped on, that's got to be pure coincidence.

Yikes! That IS a lot of trash! 😲

 

[mercenvy]

Install the ECU, check that it is getting power. This should be pin #1 yellow wire. Use a pin from the back side. When the key is turned, there should be power to fuel pump relay For about 5 seconds. Relay will also click.

 

[Victor112487]

Might check to make sure you even have power to the relay box I think the real question is did someone righ something up to make something else work the same thing happened on my for f150 in order to turn on the fuel pump the light switch had to be on that was just one of the many things. I seen crazier stuff also so make sure someone didn’t tamper with the stock harness or relays cause who knows maybe some one tried to upgrade the fuel pump and wired it to something the shouldn’t have. if your keys on you fuel pumps on you idle air control valve just controls how much air is going in at an idle. It’s all part of the evap system