Gary Lewis Posted December 22, 2022 Share Posted December 22, 2022 So... today we pulled the radiator because the new one is due tomorrow during the blizzard. While we were at it I pulled the throttle body to clean it up because the inside was filthy. I decided since it was off we should install the new Motorcraft TPS we had laying around. The old one tested to be in spec, but while we were in there why not. We also had a new EGR, actuator and gasket branded Motorcraft laying around. We had the piping that went to the exhaust as well. That came in handy because I had to take the air hammer to the old one to get it off. All of that went back together fine. I don't think this will solve the problem though. Funny story: I was rocking the crank while watching the dizzy rotor yesterday. I just had the cap laying willy nilly on the dizzy with the rotor exposed. I called Gary to discuss the events of the diagnostics. He suggested I do the fuel filter to leave no stones unturned. So I ran to the parts store to get one. Came back, battled with the retainer clips and it was installed. I turned the key a few times to prime the system. Then cranked away with no start. Primed again and cranked away with no start. Then it dawned on me I never put the cap on the dizzy. I looked under the hood to see the cap was in the perfect position to absolutely shred the rotor. So back to the parts store. When I put it in the truck fired right up. Here's hoping it was the EGR 'cause I can't see what else in what you did that it might have been. But, I sorta doubt it. Like we said on the phone, this sounds electrical. To die at the end of the drive and to shut off as if someone flipped a switch doesn't seem mechanical. And then to start again 30 minutes later screams electrical. Link to comment Share on other sites More sharing options...
mat in tn Posted December 22, 2022 Share Posted December 22, 2022 Here's hoping it was the EGR 'cause I can't see what else in what you did that it might have been. But, I sorta doubt it. Like we said on the phone, this sounds electrical. To die at the end of the drive and to shut off as if someone flipped a switch doesn't seem mechanical. And then to start again 30 minutes later screams electrical. not trying to just keep shot gunning possibilities but the fuel pump relay comes to mind, and I have also had a fuel pump work great cold then quit on its own schedule. I think you said two tanks and that would be specific to one tank, but they do share the same relay. if you have a thermal gun you could check for excessive heat at the relay. Link to comment Share on other sites More sharing options...
Bruno2 Posted December 22, 2022 Author Share Posted December 22, 2022 not trying to just keep shot gunning possibilities but the fuel pump relay comes to mind, and I have also had a fuel pump work great cold then quit on its own schedule. I think you said two tanks and that would be specific to one tank, but they do share the same relay. if you have a thermal gun you could check for excessive heat at the relay. Well , here is my deductive reasoning. The truck is only doing this under a load. It wont do it running parked in the driveway. However, as soon as you put it in gear it starts to act up with poor throttle response, rough/poor idle and then dying with extended crank no start and then eventually starting . I dont think a faulty relay would cause anything except the dying and no re start. The "under load" condition is making me think ignition related. This is when the ignition system is stressed and I have had bad ignition components cause misses and poor idle in other vehicles. I dont necessarily think it's a spark ignition problem, but I do think it's probably based in the ICM since it controls fuel delivery also. Link to comment Share on other sites More sharing options...
mat in tn Posted December 22, 2022 Share Posted December 22, 2022 Well , here is my deductive reasoning. The truck is only doing this under a load. It wont do it running parked in the driveway. However, as soon as you put it in gear it starts to act up with poor throttle response, rough/poor idle and then dying with extended crank no start and then eventually starting . I dont think a faulty relay would cause anything except the dying and no re start. The "under load" condition is making me think ignition related. This is when the ignition system is stressed and I have had bad ignition components cause misses and poor idle in other vehicles. I dont necessarily think it's a spark ignition problem, but I do think it's probably based in the ICM since it controls fuel delivery also. have you tried a different coil? Link to comment Share on other sites More sharing options...
Bruno2 Posted December 22, 2022 Author Share Posted December 22, 2022 have you tried a different coil? Not yet, I am going to install this Motorcraft ICM I have. Supposedly tjis.is the component that communicates injector timing and spark timing. Link to comment Share on other sites More sharing options...
Bruno2 Posted December 26, 2022 Author Share Posted December 26, 2022 Well , here is my deductive reasoning. The truck is only doing this under a load. It wont do it running parked in the driveway. However, as soon as you put it in gear it starts to act up with poor throttle response, rough/poor idle and then dying with extended crank no start and then eventually starting . I dont think a faulty relay would cause anything except the dying and no re start. The "under load" condition is making me think ignition related. This is when the ignition system is stressed and I have had bad ignition components cause misses and poor idle in other vehicles. I dont necessarily think it's a spark ignition problem, but I do think it's probably based in the ICM since it controls fuel delivery also. Replaced the Ignition Control Module (ICM) today or what Bill Vose calls the TFI module. I think this did the trick. Everything seems normal. Test drove it for several miles and about 30 minutes with no failure. Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 26, 2022 Share Posted December 26, 2022 Replaced the Ignition Control Module (ICM) today or what Bill Vose calls the TFI module. I think this did the trick. Everything seems normal. Test drove it for several miles and about 30 minutes with no failure. Yippee! Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted December 26, 2022 Share Posted December 26, 2022 Replaced the Ignition Control Module (ICM) today or what Bill Vose calls the TFI module. I think this did the trick. Everything seems normal. Test drove it for several miles and about 30 minutes with no failure. If your old ECU had blown caps and one was missing a leg there's no way the truck could have run well, so that was a good find and replacement regardless. TFI modules can be finicky, and like I said the diagnostic equipment is rare. I'm glad to hear that your truck is working again! Link to comment Share on other sites More sharing options...
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