Made a small timing adjustment, now it won't start.


Active Member
Jan 9, 2022
Southern California
For the long back story of the car, click here:
Old Mustang with EEC troubleshooting

The above thread sort of stalled out when I had to take time off the project. I thought I was close to a proper running car when it blew a fuel line and my Dad had some new braided lines made. After removing the braided lines and getting new ones made the car was off for some weeks.I fired it up and we seemed to be back to square one. I'm back looking at it in another week and the car fired up and did not shut off after starting. Yay!, but the idle is not consistent and too low. I thought I would try a small turn of the distributor one way and the other to see if the timing was a little off. With the car running, I did that, listening for an idle improvement. I did not remove the SPOUT plug. Nothing seemed better and then the car died. It wouldn't fire up, so I removed the plug and kept moving the distributor a little and got it to fire once long enough to move a tiny amount and it died again. I gave up trying to find the sweet spot. I'm not moving it much at all so I can't be far off. Is there something I should have done before trying to adjust the timing on a car with around a 1989 top end that my 1965 Mustang knowledge just messed up?
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You can't fiddle with the timing with the spout plugged in, it makes the computer mad. Unhook the battery and turn the head lights on for a few minutes, turn the lights off and hook the battery up, start it up and get it up to operating temp, pull the spout and check the timing.
You may need to do a 'base idle reset' if it idles too low.
There is a procedure for that too, you can't just turn the idle screw.
Yep, I'd say it got mad. I let is sit for 45 min while I did something else and it started. I'll look up the " base idle reset " . Previously, Dad had a Ford idle adapter plate between the Air bypass valve and the throttle body. ( I think that's what the thing on the front side of the throttle body is called. ) You could turn some allen screws to adjust the idle, since the engine it's all bolted on is not stock.
OK, it's the idle control valve on the front side of the throttle body.

" Base idle reset. Disconnect the IAC and pull the SPOUT and set the idle to 600-700ish. Reset the ECU, plug the IAC and SPOUT back in and let it relearn idle.
I get steps 1-3. I need to see where to adjust the idle though. Is reseting the the ECU as simple and unplugging the battery for a while?
First thing I would do is unhook SPOUT connector and set timing at 10*. Plug in SPOUT and warm up the car. Disconnect battery to reset the computer. Then unhook SPOUT and IAC and set idle with throttle screw to 600 +/-. Then follow the rest of the instructions on base idle reset.
The worst thats ever happened to me is the advance and retard wasnt synced for the new distributor setting but a quick pull then shutdown replug then restart cures that....LOL

If the car got that far out of whack twisting the distributor with the Spout plugged in and is a 5 speed Id say to check to see the resistance between pin #4 on the ECU plug to pin #2 on the TFI module plug....

You should see 22kohms of resistance with meter set to 200k .............

If you see a 0.00kohms you need to either add a resistor or replace the one thats shorted to "OPEN"


The other possibility is that your ground wire to the engine block to the frame needs to be stronger and you may need to clean the 2 dedicated ECU ground wires that are behind the battery attached to the unibody stacked up on top of each other.........

Depending on the age of the engine and its mileage & when the T-Chain was done last along with thrust plate you may have enough wear to cause the camshaft to walk back n forth putting pressure on the lower bronze bushing wearing it into an oblong pattern and when you moved the distributor you could of shorted the distributor shaft to ground....

If this is the case just changing the distributor is a temporary fix....very temporary if the car is a 5 speed because with the wobble you have yourself uncontrollable variable timing going on until its fixed..

Good Luck
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Well, since this is a 1965 Mustang with a 302 and the the intake and electronics from a 1989 Mustang that my Dad put together, I may have to hunt for stuff. Some devices didn't make the trip from the salvage yard donor. It's an automatic.

I quick review... Car ran fine for years. Then it would start up, die in less than ten seconds and then could be fired right up again with no issues. My Dad bought a new fuel tank plumbed with an internal fuel pump and pipes for fuel injection stuff to try and fix it. We suspected the patched together equipment with the stock tank may have been to blame. I don't think so, now. I've been trying to get the car running properly for some months as I get time to work on it, with the help of this forum, EEC sent off and repaired. MAF sensor replaced. Throttle body cleaned out. I'm not convinced the wiring job for the engine harness and EEC would be how I would have done it, but, like I said, it ran fine for years.
I took a stab at reseting the idle. I found we had left the key in the run position since since Saturday. ( 4 days ago ), so I had to charge the battery. Once I got it fired up, the idle was surging by about 500 rpm. I turned the idle screw some to keep the car from dying at the low RPMs. I never stopped surging. I let it run for a good 5 minutes.I thought it was running a little faster, and wondered if it was trying to bring the idle down since the high rpm was probably out of spec. That caused the engine to die. I've tried firing it up with the SPOUT plug out and it's still fires and dies. Did leaving it in "run" do something to the ECC?
Having the battery go completely dead was probably enough to reset it. Which is where the new surging idle started. The stored codes are the same codes we get since this car doesn't have all the hardware a proper 89 Mustang would have. 81, 82, 84, 85. It won't run long enough to get fully warm and run more codes with engine on.

As I mentioned above , I read somewhere that leaving the key in the run position with the engine off, for a long period could mess up the computer. Have you run into this? The surging I know have and then the engine shutting off and not being able to re-fire up until it's cold again is new.
No EGR valve and no Canister and maybe the Secondary Air Injection system. I've always gotten those for codes, 81, 82, 84, 85.

The big change is how much the idle surges. Before is was a little unstable and I was going to perform the Base Idle setup. Now, it changes so much it's like there is someone give it gas and letting off. Or, the computer is trying to compensate for something over and over. That it flat out dies at a certain temp and will not start up again, until it is colder is also new. I thought in " cold start " mode it just checks the water temp and air temp sensors and the O2 sensors to determine the basics to stay running.
I'm not sure but I think in cold start up it has a set of perimeters the computer uses.
Lets ask a few questions since this is a transplant.
Are all the factory grounds in place?
there are several that are very important, one in the injector harness, two computer grounds, and one that grounds the engine to the firewall, the locations can be found in the 'surging idle checklist'. Is the ACT sensor present? Is the engine temp sensor present? It is located on the heater tube that runs down the passenger side of the intake.
How is the fuel system configured?
Maybe a pic of the engine compartment would help.
I'll check for the ground locations since this was a top end taken from a donor car, and put it by people I never met years ago, I can't guarantee anything.
The ACT and Temp sensor are present. ( You told me which was which in the other thread. Thanks for that. )
The fuel system is a after market tank that drops in a 65 Mustang and is plumbed for fuel injection. The lines run up the passenger side and into the fuel rail , but without the hard line that has the shrader valve. I have that part now, that we used to test the fuel pressure. The fuel rail and all the injectors are stock from the donor Mustang. I am not happy with the relay that is for the wide open throttle to cut out the A/C and the fuel pump. It's broken and the wires coming up from the bottom are held in place with electrical tape. I haven't been able to find a replacement I can hook into the harness. All the new ones don't use solderless connectors. I may have to wire the spades onto the hard lines and then plug the harness into it. Or... replace the whole harness. My Dad has one from Ford Racing. I never had the guts to swap it out. I may have found the motivation.
I checked the " surging idle " thread. I didn't see where the ground on the injector harness was. I was checking under the dash, where the computer is stuffed behind the glove box. I found a wire that broke off it's solderless connector. I think it may have been a ground but I haven't confirmed that. It ends up connecting to a spot behind the underdash A/C unit. The wire it connected to goes into the harness headed to the engine bay. It has a label on it with the numbers 348. I'll check out some wiring diagrams to see if that makes any sense. I would have started thew car after fixing it, but the battery needed a charge.