Yes both have been changed with new harness wires as well. Last year the ECM relay had really bad connections. I was monitoring the fuel pump relay with a tester light and the engine was shutting off before the relay would close. So I know the fuel pump relay is not bad. Yes I have changed that part twice in the past. Can leave you stranded when they open up. I can monitor the ECM relay for the fail condition next. Also when I measured the high end of the coil I was measuring 15K ohms. Post above said between 7 - 11 Kohms. I did not check it cold. I will make that measurement and see what it reads after not running. I checked the original coil and at cold it is 65K ohms. That was a ford OEM coil. I check a number of times yesterday and I have spark during this no run condition. I am starting to think it is on the fuel side of the issue not that I have spark under this condition. Has anyone had a fuel pump ack up like this? Low pressure fuel pump and new gas tank last year, so I hope it is not that one.

 

Measured the coil at cold ambient temp and is 1 ohm on low side and 7.4K ohms on high side. When engine stalls coil reads 1.5 ohms on low side and 15.5k ohms on high side. It doubles. I was still getting good spark out of the coil using my spark plug tester when it was hot. Coil replacement is a NAPA coil.

 

Looks to me like the secondary side of the coil has an issue. New or not it looks bad to me with those secondary readings. Regardless what the spark tester is showing.

 

Just for *****s & giggles, leave the cap off whatever tank you're running from & see if it stays running.

 

ok I will try the gas cap test. Maybe a defective gas cap causing a fuel flow problem.

 

IMO there's no way a gas cap could cause your problems. There's pictures of a Bronco gas tank (probably in a thread somewhere on FSB) that got sucked into a pancake because the vapor canister system failed in a way that applied engine vacuum to the fuel tank. The truck obviously still ran with engine vacuum working against the pump.

Have you tried unplugging (via the electrical connection, not the hose) the MAP right as it starts dying?


Have you unplugged the battery (reset the computer) and then retested for codes?

 

Tried with gas cap removed still stalled after about 20 minutes. Checked EEC relay as well and that was operating properly. Looks like a bad new coil. IC24. Checked the spark at the number 1 plug and was weak and missing some times. Coil changes resistance on the secondary from 7k ohms to 15.5 k ohms. Under warranty so I am going to get a new one tonight and change it out. Its a Napa Echlin coil. I have had good luck with Napa parts to date. Just could be a bad one.

 

I did disconnect the battery when I changed the distributor. So that should have reset codes. Checked codes again and not getting anything. I have not tried disconnecting the MAP sensor on engine stall. I can try that. It stalls like shutting the key off, Then has a real hard time trying to restart. Noticed RPM gage just spins when trying to restart. Once it cools down for a few minutes it will start right up and run for a short while then stall again.

 

Its worse in warm weather, it runs longer when cool/from cold start, you've changed all ignition related parts, it ran longer without the cap on than it had before???

Yes/no?

If yes, you've got a fuel delivery issue somewhere.

Right. But there ARE situations where where evap systems failure cause fuel to stop flowing, especially in EFI. And just because...

doesn't mean it can't & does not happen.

 

My truck has been doing the same thing, so I look forward to finding out what you find. If I manage to get some free time I'll work at troubleshooting too and add any details if I have success. Good luck!

 

Where did you get the new distributor from??

Reason why I ask, is because I had the pick-up coil go bad in my truck last March and leave me stranded. I cheaped out and bought a whole new distributor (brand unknown) from eBay and it lasted for a whole five minutes before it went bad and I couldn't get the truck to start again, I'm not kidding, just five minutes!

Went and got this one from the Zone and have had no problems since months later.

Duralast Gold New/Distributor BDLG-FD08- Read1Reviews onDuralast Gold New #BDLG-FD08

 

Ordered an ignition coil from Pertronix D3003 and it throws sparks. Installed it and started the truck up. Again after fifteen minutes the truck shut down and did not want to start. Acted like a fuel issue, since all the ignition parts are new and working. New distributor is from CARQUEST via Auto Palace who just bought them out in my town. Came with new ignition module as well. Checked the PIP signal going to the ignition module and it was strong. Old one was barely visible when check. Not getting any computer codes in the engine off state. I have done as much as i can. Taking it to my mechanic who can look at the fuel side of the problem. Gas cap did not make any difference. Will let you know what my mechanic can find.

 

we have a 89 5L at work that did something similair and it got worse as it wormed up it was a broken vacuum line and rotted cap at the vacuum tree that supplies the fuel pressure regulator .. just simply wasnt getting enough vacuum to fully open the regulator and once the idle was down there was no vacuum so dies

 

 

I’m also having the same issue with my 1987 ford f150 4.9l I6. Anyone ever figure it out? Already replaced everything in fuel and ignition system.