Efi doesnt work anymore

When the engine is running have you checked the temperature at each exhaust port looking for a colder cylinder?

Vacuum connected is about 35, haven't disconnected it. I don't have a heat gun to check that. Thanks guys

This would be a good time to have a Quarterhorse, it would be nice to be able to see and record data to get to the bottom of this.

Where do I get one and how much?

Normally I stock them, but I just sent my last one out. So http://www.moates.net/quarterhorse-for-fords-p-199.html?cPath=63

Sent from my SCH-I545 using Tapatalk

Video's aren't uploading

And of course it didn't die this time.


https://youtu.be/qLCZVZEQk1I

Thats good, it not dieing, maybe it is learning. Maybe the previous wiring issue threw some really bad plot data and thats why it died, now it is learning to do it right.

It sounds great when running right.

Did you try the throttle blips and reading for codes?

Compression in all cylinders is what?

I'd still like to see that fuel pressure closer to 40 than 35 with vacuum disconnected. So many issues relate to how the injectors see the pressure, or more accurately, how the computer knows the injectors should be seeing 38-39, not 35. And it's trying like a son of a gun to correct by richening the tables. Thats a FPR on the fuel rail issue or is this a non return system? This is why fuel pressure and fuel flow are usually the very first step to diagnose the older EFI systems.

Sounds like IAC is doing it's job, but something out of the blue is throwing it for a loop. I don't think it sounds like a bad IAC which hunts around or surges in my experience. You mentioned differing voltages there, do you have another IAC you could try but not right now?

The vacuum reading is odd, why good, but then low. Is your brake booster hooked up during this? If it is, try it without that hooked up. You checked for vacuum leaks, using some wd40 or carb cleaner?

So my thought next on the list is, do the tests in that article i linked and read codes. Then, even with the wonky idle, get it onto the street for a learning cycle. Then maybe try a different IAC.

It's a return system, I think the high vacuum is messing with the pressure. Tried the iac off my full size and it does the same thing. Ran it without the booster to rule that out and also checked for leaks with some mass air cleaner. I'll try and get it out in the neighborhood tonight.

The vacuum is doing what its supposed to do. Without it connected what is the pressure?

I bet it's 39psi without vacuum.


Drive it around and let it do a learning cycle, you are familiar right?

Was about to take it for a test drive when I remembered one of the rear calipers is seized, so it's going to have to wait till this weekend.

I had 2 EFI issues on my install that I threw a ton of parts at and I had no codes. One I found by watching my engine run in the dark and I found a bad spark plug arcing to the header that correlated with my drivers side miss. Changed the spark plug and my miss was gone. So watch your engine run in the dark and look for an arc correlating with your stumble under the dash and in your engine bay.

My second efi issue was where mine would stumble and then the idle would raise for a few seconds and then lower like it does when you first start them. I was doing something one day to my glove box and I noticed I could make my bronco stumble and the idle would raise for a few seconds and return to normal when I was moving the harness by the computer, I could even make it die. I took the harness apart in that area looking for a cut wire or short in that area and found none. I then decided to put some electrical grease on the computer pins to see if that was it and 1 year later it has not done it again.
I like to twist and ruff up my wiring trying to make the connection problem show up.

First test drive went successful, idle serge has gone away, but it still wants to idle at 1100 in park.

Second test drive was longer and I made it home lol. Still has a high idle and started a slight miss when I left for home. Otherwise all went well!