Stumbling / missing / surge ?
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New User
Joined: Aug 2004
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Stumbling / missing / surge ?
I'm new to the forum and desperately need help with my 1994 E-250 van with 5.8L engine (127,000 miles).
Engine starts and runs smoothly, but at random times engine seems to "hiccup" or "briefly stall" - regardless of whether idling, at low speed and high speed. I'm sure I'm not describing symptoms correctly, but will appreciate any help and suggestions you can give me. Here's what I've done so far:
Pulled codes
Key On - Engine Off
111 System Passed
Key On - Engine On
111 System Passed
No Continuous Memory Codes
Replaced the following:
Distributor Cap (Motorcraft)
Rotor (Motorcraft)
Spark Plug Wires (Motorcraft)
Spark Plugs (Motorcraft)
Vaccuum Hoses
Purge Valve (Motorcraft)
Throttle Position Sensor (Auto Zone)
Idle Air Control Valve (Auto Zone)
Fuel Pressure Regulator (Pep Boys)
Tested EGR Valve for leakage with vacuum pump. Applied 6 in-Hg to valve and EGR held vacuum.
Tested EGR Valve Position Sensor: Resistance with vacuum fluctuated between 5,500 to 100 ohms and reference voltage on harness side @ 5 volts. Both were OK as indicated in Haynes Repair Manual.
Need help quickly -- PLEASE!!!!
Engine starts and runs smoothly, but at random times engine seems to "hiccup" or "briefly stall" - regardless of whether idling, at low speed and high speed. I'm sure I'm not describing symptoms correctly, but will appreciate any help and suggestions you can give me. Here's what I've done so far:
Pulled codes
Key On - Engine Off
111 System Passed
Key On - Engine On
111 System Passed
No Continuous Memory Codes
Replaced the following:
Distributor Cap (Motorcraft)
Rotor (Motorcraft)
Spark Plug Wires (Motorcraft)
Spark Plugs (Motorcraft)
Vaccuum Hoses
Purge Valve (Motorcraft)
Throttle Position Sensor (Auto Zone)
Idle Air Control Valve (Auto Zone)
Fuel Pressure Regulator (Pep Boys)
Tested EGR Valve for leakage with vacuum pump. Applied 6 in-Hg to valve and EGR held vacuum.
Tested EGR Valve Position Sensor: Resistance with vacuum fluctuated between 5,500 to 100 ohms and reference voltage on harness side @ 5 volts. Both were OK as indicated in Haynes Repair Manual.
Need help quickly -- PLEASE!!!!
Elder User
Joined: Feb 2004
Posts: 638
Likes: 7
From: Birmingham, AL
kodabear,
I would check the fuel pressure with a gauge and replace the fuel filter. The ignition module is a common problem with these vans. It is in the fender well on the driver's side behind the battery.
I had a similar problem with mine for a while but it seems to have self corrected. I suspect the ignition module was the problem. It would usually give trouble after a long run on the highway in hot weather. If it begins to act up again I will carry a can of electronics cold spray with me and spray the module while the engine is not running right. That will cool the module, and if it begins to run right, tell me that it was being adversely affected by the heat.
Older Fords had the module mounted on the distributor and later models have them relocated to remote locations due to heat issues. I think that the small engine compartment of the van may still present enough heat in some circumstances that the module is affected.
Gene
I would check the fuel pressure with a gauge and replace the fuel filter. The ignition module is a common problem with these vans. It is in the fender well on the driver's side behind the battery.
I had a similar problem with mine for a while but it seems to have self corrected. I suspect the ignition module was the problem. It would usually give trouble after a long run on the highway in hot weather. If it begins to act up again I will carry a can of electronics cold spray with me and spray the module while the engine is not running right. That will cool the module, and if it begins to run right, tell me that it was being adversely affected by the heat.
Older Fords had the module mounted on the distributor and later models have them relocated to remote locations due to heat issues. I think that the small engine compartment of the van may still present enough heat in some circumstances that the module is affected.
Gene
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New User
Joined: Aug 2004
Posts: 5
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Gene,
I took the van to a mechanic who checked the fuel pressure and the coil. Both were OK. Mechanic also checked codes with several different computers, and nothing came up. He said it seems to be a fuel related problem, because when he added propane to the air intake, the engine smoothed out and ran nicely.
At his suggestion, I replaced oxygen sensor and will take van back to him tomorrow so he can clean the fuel injectors.
The ignition control module is located on the fender well (driver's side) behind the battery. I'll pick up some spray tomorrow and test it as you suggested.
Thank you so much for your help. Other suggestions will be appreciated, and I'll let you know what happens tomorrow.
Helen
I took the van to a mechanic who checked the fuel pressure and the coil. Both were OK. Mechanic also checked codes with several different computers, and nothing came up. He said it seems to be a fuel related problem, because when he added propane to the air intake, the engine smoothed out and ran nicely.
At his suggestion, I replaced oxygen sensor and will take van back to him tomorrow so he can clean the fuel injectors.
The ignition control module is located on the fender well (driver's side) behind the battery. I'll pick up some spray tomorrow and test it as you suggested.
Thank you so much for your help. Other suggestions will be appreciated, and I'll let you know what happens tomorrow.
Helen
Elder User
Joined: Feb 2004
Posts: 638
Likes: 7
From: Birmingham, AL
Mine never set codes when it was running bad either. If you think it is heat related, then the spray may help to isolate it by returning the ignition module or other electronic component to a cooler temp.
The mass air sensor is somthing else that can cause simalar symptoms when it's sensor wires get dirty.
Good luck with it and let us know what you find out.
Gene
The mass air sensor is somthing else that can cause simalar symptoms when it's sensor wires get dirty.
Good luck with it and let us know what you find out.
Gene
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New User
Joined: Aug 2004
Posts: 5
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Instead of a mass air flow sensor, my van has a manifold absolute pressure (MAP) sensor of the frequency type. Voltage was correct. When I removed the vacuum line from the sensor, the engine idle speed increased -- AND RAN SMOOTHLY!!
Is this a good sign?? Or a normal reaction for this procedure???
Anyone???
Is this a good sign?? Or a normal reaction for this procedure???
Anyone???
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