NEED HELP!! 1995 Mustang GT with intermittent rough idle/cel.
08-17-2013, 05:43 PM
#1
Thread Starter
Join Date: May 2008
Location:
Posts: 15
NEED HELP!! 1995 Mustang GT with intermittent rough idle/cel.
Bought this car a few weeks ago, got a good deal on it. 95 GT 5spd with 138k. All stock except for Cervins ram air hood and no exhaust after the h-pipe. Has some stupid Clifford alarm system on it. Drove this thing around for a few weeks put a few hundred miles on it and it was fine. Ran with a hint of a misfire but it wasn't crazy or shaky. For the few hundred miles I drove it, it never hesitated to start up again and run great nor did I have any CELs.
So..
A week ago I went to the tire shop 3 min away from my house to get a tire mounted. Left to get coffee (drive thru). Came back. Car sat for maybe 5 minutes. Guy put the tire/wheel in my trunk and slammed it. Car started and had a CEL and ran like complete ****. As soon as I hit the gas to drive forward, it died. Started it up again and kept my foot on the throttle till i got home (3 min away). Turned off the car. Turned it back on. Same thing. Turned it off. Jacked it up to make sure everything was visibly ok, it was. Took off the cervinis cold air box and cleaned the filter. This took about 10-15 minutes. Didn't really do anything so I turned it back on and it ran fine, no CEL, no rough idle. wtf...
Decided to drive to chicago to drop off this wheel/tire. Drove perfect all the way there. Turned it off once I got there, gave the guy the tire, spoke to him for under 5 minutes. Went to turn the car on, runs like ****, CEL, rough idle, wouldn't stay running... Took it to a nearby parking lot, played with the fuel inertia switch in the trunk. Let it sit for 5 min, then 10 min, still ran like **** with a rough idle and CEL. So I chanced it home and stopped before every red light, the car died, and I would turn it on and keep on trucking.....
After about 10 restarts, it started up perfectly, no more CEL, no more rough idle. Drove it home normally, stopped by my friends house, didn't turn it off. Got him outside, turned it off for 5 seconds, turned it back on, RAN LIKE ****, CEL ON, ROUGH IDLE. He was stumped too. Drove the car home a block away, turned it off..
At home..
Disconnect a bunch of sensors to see if anything would trigger a different start. Disconnected the EGR, MAF, IAC, IAT, and Intertia Switch.
Did the paperclip trick. Results:
KOEO: 111 = No Fault
KOER: 111 = No Fault
Cylinder test: 9 = No Fault
*During these tests, I noticed that if I turn the key on and the fuel pump primes for 2-4 seconds, the car starts/runs great. If I turn the key on and the fuel pump keeps priming (does not stop priming at all), then the car starts/runs like ****, CEL, rough idle.
---
I've eliminated the MAF, IAC, EGR, Plugs, Wires, Rotor, Cap as culprits.
Tested the TFI by holding a test light on both wires coming out of the ignition coil; test light flashed while cranking for both the good start/run and the crappy start/run like ****. TFI eliminated as a culprit.
Tested the Fuel Pressure. 32-33psi while idling nicely without the CEL. 38-40 while running like ****/CEL on/rough idle. Both instances also went up 8-10psi with removing the vacuum line off the fuel pressure regulator (did not smell like gas either), so.. Eliminated Fuel Pressure Regulator as a culprit.
Tested the #5 pin on the CCRM. While priming (both instances, running great and running like ****) the reading was over 12v. While idling/running (both instances, running great and running like ****) the reading was 13.8v. Eliminated the CCRM as a culprit.
Tested the Fuel inertia switch. 12v on both instances while priming, 13.8v on both instances while running/idling. Eliminated inertia switch as a culprit.
Sprayed carb cleaner around all the vacuum hoses throughout the engine bay, no difference in engine idle. Eliminated vacuum lines as a culprit.
---
Decided to test the CEL with my friends Snap-On scantool. Results:
111 - No Fault
113 - Intake Air Temp Signal High Circuit Open
157 - Mass Airflow Signal Too Low
158 - Mass Airflow Signal Too High
327 - EGR Signal Too Low
334 - EGR Voltage Above Closed Limit
542 - Fuel Pump Circuit Open - ECA To Ground
Considering that I've unplugged a bunch of crap earlier, I didn't think much of any of these codes. Cleared them, tried again, won't give me any codes besides a 111...
-
-
-
Symptoms while running rough/CEL on/idling like ****:
- Will always start
- Will never die (unless I quickly tap the throttle)
- Smells like it is running rich, visible by black smoke
- Passenger side of the engine bay smokes a little (EGR?)
- CEL on
- Idle at 500-600
Where I'm at on this:
1) Would a bad Fuel Filter cause this intermittent problem?
2) How can I rule out the Ignition Coil?
3) How do I completely rule out the Fuel Pump, or have I already ruled it out?
4) Would a bad ECT Sensor cause this?
5) Would a bad IAT Sensor cause this?
6) Would a bad PIP/Stator cause this?
7) Could there be some sort of safety net in the Clifford Alarm wiring that puts the car in limp mode? (Very unlikely, but worth a mention)
THANKS FOR READING THIS THROUGH GUYS!
So..
A week ago I went to the tire shop 3 min away from my house to get a tire mounted. Left to get coffee (drive thru). Came back. Car sat for maybe 5 minutes. Guy put the tire/wheel in my trunk and slammed it. Car started and had a CEL and ran like complete ****. As soon as I hit the gas to drive forward, it died. Started it up again and kept my foot on the throttle till i got home (3 min away). Turned off the car. Turned it back on. Same thing. Turned it off. Jacked it up to make sure everything was visibly ok, it was. Took off the cervinis cold air box and cleaned the filter. This took about 10-15 minutes. Didn't really do anything so I turned it back on and it ran fine, no CEL, no rough idle. wtf...
Decided to drive to chicago to drop off this wheel/tire. Drove perfect all the way there. Turned it off once I got there, gave the guy the tire, spoke to him for under 5 minutes. Went to turn the car on, runs like ****, CEL, rough idle, wouldn't stay running... Took it to a nearby parking lot, played with the fuel inertia switch in the trunk. Let it sit for 5 min, then 10 min, still ran like **** with a rough idle and CEL. So I chanced it home and stopped before every red light, the car died, and I would turn it on and keep on trucking.....
After about 10 restarts, it started up perfectly, no more CEL, no more rough idle. Drove it home normally, stopped by my friends house, didn't turn it off. Got him outside, turned it off for 5 seconds, turned it back on, RAN LIKE ****, CEL ON, ROUGH IDLE. He was stumped too. Drove the car home a block away, turned it off..
At home..
Disconnect a bunch of sensors to see if anything would trigger a different start. Disconnected the EGR, MAF, IAC, IAT, and Intertia Switch.
Did the paperclip trick. Results:
KOEO: 111 = No Fault
KOER: 111 = No Fault
Cylinder test: 9 = No Fault
*During these tests, I noticed that if I turn the key on and the fuel pump primes for 2-4 seconds, the car starts/runs great. If I turn the key on and the fuel pump keeps priming (does not stop priming at all), then the car starts/runs like ****, CEL, rough idle.
---
I've eliminated the MAF, IAC, EGR, Plugs, Wires, Rotor, Cap as culprits.
Tested the TFI by holding a test light on both wires coming out of the ignition coil; test light flashed while cranking for both the good start/run and the crappy start/run like ****. TFI eliminated as a culprit.
Tested the Fuel Pressure. 32-33psi while idling nicely without the CEL. 38-40 while running like ****/CEL on/rough idle. Both instances also went up 8-10psi with removing the vacuum line off the fuel pressure regulator (did not smell like gas either), so.. Eliminated Fuel Pressure Regulator as a culprit.
Tested the #5 pin on the CCRM. While priming (both instances, running great and running like ****) the reading was over 12v. While idling/running (both instances, running great and running like ****) the reading was 13.8v. Eliminated the CCRM as a culprit.
Tested the Fuel inertia switch. 12v on both instances while priming, 13.8v on both instances while running/idling. Eliminated inertia switch as a culprit.
Sprayed carb cleaner around all the vacuum hoses throughout the engine bay, no difference in engine idle. Eliminated vacuum lines as a culprit.
---
Decided to test the CEL with my friends Snap-On scantool. Results:
111 - No Fault
113 - Intake Air Temp Signal High Circuit Open
157 - Mass Airflow Signal Too Low
158 - Mass Airflow Signal Too High
327 - EGR Signal Too Low
334 - EGR Voltage Above Closed Limit
542 - Fuel Pump Circuit Open - ECA To Ground
Considering that I've unplugged a bunch of crap earlier, I didn't think much of any of these codes. Cleared them, tried again, won't give me any codes besides a 111...
-
-
-
Symptoms while running rough/CEL on/idling like ****:
- Will always start
- Will never die (unless I quickly tap the throttle)
- Smells like it is running rich, visible by black smoke
- Passenger side of the engine bay smokes a little (EGR?)
- CEL on
- Idle at 500-600
Where I'm at on this:
1) Would a bad Fuel Filter cause this intermittent problem?
2) How can I rule out the Ignition Coil?
3) How do I completely rule out the Fuel Pump, or have I already ruled it out?
4) Would a bad ECT Sensor cause this?
5) Would a bad IAT Sensor cause this?
6) Would a bad PIP/Stator cause this?
7) Could there be some sort of safety net in the Clifford Alarm wiring that puts the car in limp mode? (Very unlikely, but worth a mention)
THANKS FOR READING THIS THROUGH GUYS!
Last edited by skymarauder; 08-17-2013 at 05:46 PM.
08-17-2013, 07:45 PM
#2
Thread Starter
Join Date: May 2008
Location:
Posts: 15
Just replaced the fuel filter. Ran great for about 5-6 ignition cycles. Went to a neighbors. Filled up some fresh gas. Went home and again.. fuel pump keeps priming after 2-4 seconds, starts and runs like ****/CEL..
What's next?? How can I eliminate the PIP/Stator? Is it supposed to be 3-6V while running?
What's next?? How can I eliminate the PIP/Stator? Is it supposed to be 3-6V while running?
08-18-2013, 10:17 AM
#4
Thread Starter
Join Date: May 2008
Location:
Posts: 15
Not sure if I know how to mess with it but it's worth a shot.
I tried redoing the KOEO/KOER tests and the CEL does not respond at all (when I turn the key on and I hear the pump keep priming past the 2-4 seconds). Also, when the pump primes after the initial 2-4 seconds, the fan is running too. Maybe this means something?? FP on, fan on, no communication with the test port?? It will communicate and give me a 111 code when the fuel pump primes for 2-4 seconds (resulting in the car running great) just not when it keeps priming (resulting in car running like crap). Someone help!
I've been reading hundreds of old posts across the net. One guy had a similar situation that he described as "flipping a light switch the car would run like crap/cel on/rough idle" and he ended up testing everything but the end result was a bad computer. How do I test a computer on this car? I found a write up but I think it was for a 87-93 not my body style. Any help is greatly appreciated!
I tried redoing the KOEO/KOER tests and the CEL does not respond at all (when I turn the key on and I hear the pump keep priming past the 2-4 seconds). Also, when the pump primes after the initial 2-4 seconds, the fan is running too. Maybe this means something?? FP on, fan on, no communication with the test port?? It will communicate and give me a 111 code when the fuel pump primes for 2-4 seconds (resulting in the car running great) just not when it keeps priming (resulting in car running like crap). Someone help!
I've been reading hundreds of old posts across the net. One guy had a similar situation that he described as "flipping a light switch the car would run like crap/cel on/rough idle" and he ended up testing everything but the end result was a bad computer. How do I test a computer on this car? I found a write up but I think it was for a 87-93 not my body style. Any help is greatly appreciated!
Last edited by skymarauder; 08-18-2013 at 11:26 AM.
08-19-2013, 10:48 AM
#6
5th Gear Member
Join Date: Jul 2012
Location: ohio
Posts: 3,628
You have a wire someplace that has an intermitant break in it. The fan will run by default with the key on when the ecu does not see the ect.
My suggestion is you do the wiggle test... Turn the key on and start grabbing and shaking wire looms till the fan shuts off.
I know it sounds silly but sometimes it is the easiest way to find the problem with wiring.
Check the wiring that goes into the big square plug on the passanger side fire wall.
This is where all the engine stuff plugs in. to the computer harness. Make sure no corrosion is present in the plug it self.
My suggestion is you do the wiggle test... Turn the key on and start grabbing and shaking wire looms till the fan shuts off.
I know it sounds silly but sometimes it is the easiest way to find the problem with wiring.
Check the wiring that goes into the big square plug on the passanger side fire wall.
This is where all the engine stuff plugs in. to the computer harness. Make sure no corrosion is present in the plug it self.
08-19-2013, 11:06 AM
#8
5th Gear Member
Join Date: Jul 2012
Location: ohio
Posts: 3,628
Make sure none of the wires in the self test plug are chaffed and shorting or jumping across one another.
There has to be a wiring promlem somewhere in that area for the fan to come on and stay on even when the car is cold , plus there is a set of terminals you can jump to make the pump run. This is where I would start digging in. The self test terminal also runs through the big square plug on the passenger firewall.
There has to be a wiring promlem somewhere in that area for the fan to come on and stay on even when the car is cold , plus there is a set of terminals you can jump to make the pump run. This is where I would start digging in. The self test terminal also runs through the big square plug on the passenger firewall.
08-19-2013, 11:11 AM
#10
5th Gear Member
Join Date: Jul 2012
Location: ohio
Posts: 3,628
Im not sure that would explain the fuel pump continuing to run , but it could explain the rough idle.
I suspect the 2 are realated in the wiring some place.
But you can test the ect
http://www.oldfuelinjection.com/?p=28
I suspect the 2 are realated in the wiring some place.
But you can test the ect
http://www.oldfuelinjection.com/?p=28
