Gary Lewis Posted January 20, 2021 Share Posted January 20, 2021 Since I don't have a tachometer, how do I know if I lost tach sensor signal? When it happens again, what do I do to see if the pumps are still on? I have a fuel pressure tester, should I keep that in the truck and when it shuts off just coast over on the shoulder and screw the pressure tester on? It is PIP instead of tach that tells the ECA where the engine is in its revolutions, as shown below. And I don't know what happens if it loses PIP and then regains it. I don't see why the engine wouldn't refire, but I don't know. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 20, 2021 Share Posted January 20, 2021 What you're calling the TFI (Thick Film Ignition), I called the Ignition Control Module - they're the same thing. We installed a new one - Motorcraft - with the new distributor. Do you really think it could be a bad TFI/ICM when both the distributor and TFI/ICM are new? There are two different TFI systems, if you install the wrong module you have problems. The first was Push Start (PS) these trucks will run -with locked timing- if you unplug the SPark Out ("spout") connector. The Computer Controlled Dwell (CCD) will not. Then, there's also the possibility the electrolytic caps on the engine management computer are leaking. Heat affects them also. But they don't usually come back. Link to comment Share on other sites More sharing options...
ScubaSteve Posted January 20, 2021 Share Posted January 20, 2021 My truck doesn't have a tachometer - does that mean the EEC-IV doesn't use a tach signal? I was calling it the Tachometer signal but as the other guys have clarified its the PIP signal. Either way I was loosing the signal from the distributor and my fuel pumps were shutting off. I found several damaged wires in my harness when I did the repair so I cant say exactly what wire or wire color fixed it. Not sure if this is your problem but its something to look into. Link to comment Share on other sites More sharing options...
MarkThomas Posted January 20, 2021 Author Share Posted January 20, 2021 It is PIP instead of tach that tells the ECA where the engine is in its revolutions, as shown below. And I don't know what happens if it loses PIP and then regains it. I don't see why the engine wouldn't refire, but I don't know. I can't get my code reader to work, but last June I was able to download codes the old fashioned way from the procedure in Chiltons using a volt meter and a jump wire. If a PIP were lost, would that show up in the codes? Link to comment Share on other sites More sharing options...
MarkThomas Posted January 20, 2021 Author Share Posted January 20, 2021 There are two different TFI systems, if you install the wrong module you have problems. The first was Push Start (PS) these trucks will run -with locked timing- if you unplug the SPark Out ("spout") connector. The Computer Controlled Dwell (CCD) will not. Then, there's also the possibility the electrolytic caps on the engine management computer are leaking. Heat affects them also. But they don't usually come back. Here's a discussion talking about what you're saying I think: https://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml They're saying if the PIP or SPOUT are intermittently grounded it results in stall...similar to what I'm experiencing. Link to comment Share on other sites More sharing options...
MarkThomas Posted January 20, 2021 Author Share Posted January 20, 2021 There are two different TFI systems, if you install the wrong module you have problems. The first was Push Start (PS) these trucks will run -with locked timing- if you unplug the SPark Out ("spout") connector. The Computer Controlled Dwell (CCD) will not. Then, there's also the possibility the electrolytic caps on the engine management computer are leaking. Heat affects them also. But they don't usually come back. Just talked to the tech that helped me get it going, he didn't repair any wires near the TFI connector, his were coil wires and such. So, here's a thought I could buy a new TFI connector: https://www.wiringproducts.com/electric-module-socket-wire-assembly-1-pc.html or https://www.amazon.com/1986-1993-Mustang-Distributor-Module-Harness/dp/B00BXOSY6E/ref=sr_1_3?dchild=1&keywords=TFI+Connector&qid=1611159210&sr=8-3 Replace the TFI connector, that would have all new parts from the distributor out except for most of the PIP/SPOUT wire to/from the EEC IV. I might get lucky and the bad connection is in or near the connector. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 20, 2021 Share Posted January 20, 2021 Just talked to the tech that helped me get it going, he didn't repair any wires near the TFI connector, his were coil wires and such. So, here's a thought I could buy a new TFI connector: https://www.wiringproducts.com/electric-module-socket-wire-assembly-1-pc.html or https://www.amazon.com/1986-1993-Mustang-Distributor-Module-Harness/dp/B00BXOSY6E/ref=sr_1_3?dchild=1&keywords=TFI+Connector&qid=1611159210&sr=8-3 Replace the TFI connector, that would have all new parts from the distributor out except for most of the PIP/SPOUT wire to/from the EEC IV. I might get lucky and the bad connection is in or near the connector. You could replace the plug, but if I were going there I would remote mount it, and solve an ever present problem with these ignitions*, as I said. If you have an analog multimeter you can ohm out the spout wire from the distributor plug to the firewall, while flexing it around. You might turn up an intermittent open circuit. Link to comment Share on other sites More sharing options...
MarkThomas Posted January 20, 2021 Author Share Posted January 20, 2021 You could replace the plug, but if I were going there I would remote mount it, and solve an ever present problem with these ignitions*, as I said. If you have an analog multimeter you can ohm out the spout wire from the distributor plug to the firewall, while flexing it around. You might turn up an intermittent open circuit. I will likely take you up on that, and checking the wiring to the firewall is also good practice. A near break or short to ground could be in the wiring to the firewall. Since I'll be splicing those wires anyway, might as well check all of it. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 20, 2021 Share Posted January 20, 2021 I will likely take you up on that, and checking the wiring to the firewall is also good practice. A near break or short to ground could be in the wiring to the firewall. Since I'll be splicing those wires anyway, might as well check all of it. Don't miss Jim's recommendation to remote-mount the TFI. Ford had fits with them until they took them off the distributor and put them on the fender where it is cooler. Link to comment Share on other sites More sharing options...
1986F150Six Posted January 20, 2021 Share Posted January 20, 2021 Don't miss Jim's recommendation to remote-mount the TFI. Ford had fits with them until they took them off the distributor and put them on the fender where it is cooler. https://www.fourwheeler.com/how-to/electrical/1708-how-to-relocate-the-tfi-module-on-older-ford-efi-v8s/ Link to comment Share on other sites More sharing options...
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