Weird no start problem
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5th Wheeling
Joined: Aug 2016
Posts: 48
Likes: 4
Weird no start problem
1995 F-150 XLT 4x4, 178k mi
Good fuel pressure, fuel pump engages at KOEO, new air filter and strong spark at plug wires. Truck cranks really well but won't start. I had to replace the battery so all codes the truck had was wiped. The truck stopped running last week, then began running fine for two days, now won't start again. I pulled the ECM and physically it looks fine, no burn marks or other obvious problems. I have no idea what to do now.
Good fuel pressure, fuel pump engages at KOEO, new air filter and strong spark at plug wires. Truck cranks really well but won't start. I had to replace the battery so all codes the truck had was wiped. The truck stopped running last week, then began running fine for two days, now won't start again. I pulled the ECM and physically it looks fine, no burn marks or other obvious problems. I have no idea what to do now.
Lead Driver
Joined: Jul 2007
Posts: 7,868
Likes: 9
From: Rhode Island
Does the CEL turn off while cranking, and when you stop cranking, do you hear the fuel pumps run for a second afterwards?
Does the engine run on starting fluid?
Does the engine run on starting fluid?
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5th Wheeling
Joined: Aug 2016
Posts: 48
Likes: 4
The CEL comes on KOEO, stays on during cranking, stays on afterward. After the initial 1-2 second pump sound with KOEO I don't hear it again after cranking. Sometimes with KOEO I'll hear the pump sound once then after a while I'll hear it again.
I didn't have starting fluid but I took the air intake off and tried with carb cleaner and no start.
I didn't have starting fluid but I took the air intake off and tried with carb cleaner and no start.
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Lead Driver
Joined: Jul 2007
Posts: 7,868
Likes: 9
From: Rhode Island
The CEL comes on KOEO, stays on during cranking, stays on afterward. After the initial 1-2 second pump sound with KOEO I don't hear it again after cranking. Sometimes with KOEO I'll hear the pump sound once then after a while I'll hear it again.
I didn't have starting fluid but I took the air intake off and tried with carb cleaner and no start.
I didn't have starting fluid but I took the air intake off and tried with carb cleaner and no start.
If it didn't start with carb cleaner being sprayed right in the throttle body, then you likely are not getting spark either - which would point to a faulty PIP sensor in the distributor.
Thread Starter
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5th Wheeling
Joined: Aug 2016
Posts: 48
Likes: 4
Just what I feared, we've entered auto repair I know nothing about. I found this page, I assume these tests will work to diagnose my ICM and PIP:
http://easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/ignition-control-module-tests-1
I'll do these tests and report back. Sounds like this is my problem though.
http://easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/ignition-control-module-tests-1
I'll do these tests and report back. Sounds like this is my problem though.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
When you changed the battery did you replace the battery cables also?
If so do you still have a large wire running from the NEG (-) post of the battery to the fender?
Why not just watch this video then, it is for 1996 but it will work for your 1995 truck also:
/
If so do you still have a large wire running from the NEG (-) post of the battery to the fender?
Just what I feared, we've entered auto repair I know nothing about. I found this page, I assume these tests will work to diagnose my ICM and PIP:
http://easyautodiagnostics.com/ford/...module-tests-1
http://easyautodiagnostics.com/ford/...module-tests-1
/
Thread Starter
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5th Wheeling
Joined: Aug 2016
Posts: 48
Likes: 4
I definitely hit a wall here.
I followed the steps here:
http://easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/ignition-module-tests-3
I checked for spark at the distributor cap. I got 1 initial weak spark then nothing during cranking. I installed a new ignition coil and tested for spark there; same result. So I tested for 12v at the coil and I got a lil over 11v during KOEO.
I also installed a new ICM and checked the switching signal as directed on the page. The LED test light came on during KOEO then stayed off during cranking. According to the page this means that either the PIP sensor is bad or the ICM is bad. Since it's a new ICM I tested the PIP signal and I got a flashing test light. So it's not a bad PIP sensor either.
So what the heck is it? My battery is reading 12.10v
I really don't want to drop hundreds at a garage but I have no idea what's happening here.
I followed the steps here:
http://easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/ignition-module-tests-3
I checked for spark at the distributor cap. I got 1 initial weak spark then nothing during cranking. I installed a new ignition coil and tested for spark there; same result. So I tested for 12v at the coil and I got a lil over 11v during KOEO.
I also installed a new ICM and checked the switching signal as directed on the page. The LED test light came on during KOEO then stayed off during cranking. According to the page this means that either the PIP sensor is bad or the ICM is bad. Since it's a new ICM I tested the PIP signal and I got a flashing test light. So it's not a bad PIP sensor either.
So what the heck is it? My battery is reading 12.10v
I really don't want to drop hundreds at a garage but I have no idea what's happening here.