I’m I have an interesting problem that I can’t figure out. I’ve been trying to diag an engine stalling issue for awhile now. Basically when the engine is hot and you push the clutch in to come to a complete stop it begins to surge and eventually shuts off or jumps back to life. It isn’t intermittent, happens every time I drive it. I have no codes, aside from a boost control solenoid code (I have a Gillis valve). I’ve fixed all vacuum/ boost leaks. IAC valve is new and cleaned of any carbon, IAC has a new connector. Coolant temp sensor is functioning and has a new pigtail for better pin fitment. VAM works and I can watch voltage change as I open the air door. TPS is working and idle voltage is set at 0.9v. All ignition related items are new from motor craft and I’ve verified spark, fuel and air. Ignition timing is on point.
I now believe my issue is not base engine related but electrical. I’ve checked my resistance on all of my signal return wires (black white wire pin 46 on eec) and my voltage reference (orange white wire pin 26 on eec). Vref is showing 5 volts and my signal return depending on my sensor shows accurate voltages. However I did find a some ancient wire splice at my eec that tapped into my black white signal return wire. For some reason the brown white wire pin 30 of the eec was spliced into it. I fixed the splice and returned the brown white wire to the existing wire in the harness (somewhere in the harness they splice together from factory as shown in wiring diagrams). However when I did this repair, after I finished and turned the car on the rear lamp out and head lamp out lights were on, on my system sentry. I went to verify my lights works and they did. Oddly enough when I push the clutch in now the lights on the system sentry turn off. Then I release the clutch they turn back on.
My thoughts are that somewhere my clutch pedal switch and the wires that go to the system sentry are grounded out somewhere and are causing my engine stalling issue. Maybe it’s adding resistance to my vref or it’s interfering with my signal return somehow. Also one last thing there is a second two wire connector coming off my clutch engage switch (black white and grey yellow) I can’t find where it plugs into. The red dark blue wire is plugged in and goes through a main harness. Not sure if this matters.
Man electrical problems are the worse. A thought or two for you, can you bypass the clutch interlock switch and tuck it out of the way? To me, that would take it out of play and tell me it's something else. Also, you might want to check fuel pressure and power to the pump. My thinking is as the pump is working and getting hot it may be putting out less pressure and causing a strange idle. I feel your pain as electrical problems are my biggest nightmare when it comes to cars.
1988 Turbo Coupe, Black/Black, 5 Speed, Moonroof, T3/T4, ported E6, 255LPH, Kirban, Stinger Exhaust, MGW shifter, K&N, Gillis valve, BP1.5, PIMPx, Koni's
1964 Ford Galaxie 500XL, 390 6V, Big Solid cam, Headers,3.89's, 4 Speed, Vast and fast
1960 Ford Starliner, 292 Y Block, 312 4bbl intake, headers, 3 Speed, slow and low
Is your car a factory 5 speed or did you change it from an automatic?
I swapped the 5 speed into my car and I have the exact same issue when pressing the clutch in except my car doesn't stall. When I press the clutch pedal the RPMs drop from 13-1400 to right at 1,000 but only when the car is cold. When the car gets hot it idles fine. Also, the rear light out warning light is one when the clutch is released but goes out when the clutch is pressed in. It's been more annoying then anything so I haven't figured it out yet. I posted a thread about it here and I'm almost convinced it has to do with how the clutch switch and sentry are wired into the ECU. If I ground the circuit, idle is fine and the sentry lights stay out but it causes a short when trying to start the car. I think it could be a pin location difference or maybe something internal to the ECU, I'm leaning towards the pin location.
When I figure it out I'll post it here but I've been busy and it hasn't kept me from enjoying the car.
(08-08-2023, 10:32 AM)Kuch Wrote: Man electrical problems are the worse. A thought or two for you, can you bypass the clutch interlock switch and tuck it out of the way? To me, that would take it out of play and tell me it's something else. Also, you might want to check fuel pressure and power to the pump. My thinking is as the pump is working and getting hot it may be putting out less pressure and causing a strange idle. I feel your pain as electrical problems are my biggest nightmare when it comes to cars.
I haven’t been able to check fuel pressure when it’s hot/running. I’ve checked it many times and it pumps right up to 35 psi and holds steady. If this matters, I had originally thought that the coolant temp sensor was the cause, car would run great until warmer up. Shut it off hot and try to restart it and the car would fire up and die immediately. New sensor and a new pigtail and that’s fixed but still have the problem with it bogging down when coming to a stop.
(08-09-2023, 03:15 PM)spittinfire Wrote: Is your car a factory 5 speed or did you change it from an automatic?
I swapped the 5 speed into my car and I have the exact same issue when pressing the clutch in except my car doesn't stall. When I press the clutch pedal the RPMs drop from 13-1400 to right at 1,000 but only when the car is cold. When the car gets hot it idles fine. Also, the rear light out warning light is one when the clutch is released but goes out when the clutch is pressed in. It's been more annoying then anything so I haven't figured it out yet. I posted a thread about it here and I'm almost convinced it has to do with how the clutch switch and sentry are wired into the ECU. If I ground the circuit, idle is fine and the sentry lights stay out but it causes a short when trying to start the car. I think it could be a pin location difference or maybe something internal to the ECU, I'm leaning towards the pin location.
When I figure it out I'll post it here but I've been busy and it hasn't kept me from enjoying the car.
The car is a factory 5 speed but I’m also the 4th owner of the car and the history of it is still unknown. When I get a chance I could post some photos of what my clutch switch looks like for reference. I’ve also noticed the car bogs down way more when on the brake, then I push in the clutch to come to a stop as compared to just coasting to a stop. Maybe this is something I’ve over looked but I’m on the factory tevvis system and I’m pretty sure it doesn’t use engine vacuum. Also my car only ever idles at around 1000 rpm cold or hot. When it’s hot the idle is much more stable and less choppy.
I've got the stock automatic computer in my car and I've thought about changing it out for a manual but then I've got a pimpX waiting to go in so I'm not excited about spending the $150 for a manual just to put it on the shelf in a few months. I'd still like to try it though.
(08-19-2023, 09:36 PM)Jeff K Wrote: Any chance someone put in an automatic tranny PCM in the car? What is the code on the PCM? Should be an LA3 computer.
The one in the car says LA 2 and I have a LA(no numbers next to it) pcm a friend gave me. My car is a 1987 not sure if they change between 87 and 88.
