F-150 ECM Memory Lost or ?
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F-150 ECM Memory Lost or ?
My 1989 F-150 4.9L, EFI, 2X4 of 385,007 miles was running great, until a no-start required me to change the starter solenoid thus disconnecting the battery for about 15 minutes. Now it starts fine but it stumbles bad accelerating, occasional back-fire in the intake, very low power & MPG about 5. A few years ago I replaced the battery and it did the exact same thing but one short drive of a few miles and it was back to normal. This time after 5 trips of about 10 miles each, it may run normal for a few minutes then back to bucking, stumbling, etc. Is there any way to retrain the memory (other than driving) or just replace the ECM? Any other cause? I'm afraid to continue driving it for fear of damaging the drive train or getting rear ended. All help is very much appreciated... Thank you.
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From: Easton,Ks
You should always hang a 9V battery on the cigarette lighter plug when unhooking the battery.
The only time to not do this is when you are changing a sensor for the EEC Computer and you want it to relearn the sensors. Other than that you can have a lot of problems as you have found out.
What happens is you more than likely have a bad sensor that is so far out of specification that the computer would not accept the reading from it and you were running on the last known good reading from that sensor. Now that you unhooked the battery the computer lost that last good reading and the sensor is bad so the computer can only run from a factory set value.
You need to run both computer tests (KOEO & KOER) and post the codes back here and we will try to help you find the bad sensor(s).
A new computer will not help in your case.
If you do not know how to run the self-tests than go to:
Ford Fuel Injection How To Run a Self-Test
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The only time to not do this is when you are changing a sensor for the EEC Computer and you want it to relearn the sensors. Other than that you can have a lot of problems as you have found out.
What happens is you more than likely have a bad sensor that is so far out of specification that the computer would not accept the reading from it and you were running on the last known good reading from that sensor. Now that you unhooked the battery the computer lost that last good reading and the sensor is bad so the computer can only run from a factory set value.
You need to run both computer tests (KOEO & KOER) and post the codes back here and we will try to help you find the bad sensor(s).
A new computer will not help in your case.
If you do not know how to run the self-tests than go to:
Ford Fuel Injection How To Run a Self-Test
/
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Thank you for getting back to me. I ran the KOEO but the engine was cold (25 degrees). Maybe I should have brought it up to operating temperature? Ran the test 3 times, codes are: 21 - 24 - 67. Both the ECT and ACT show on the list as out of self test range, .3 to 3.7 volts. I did not depress the clutch to close the start switch, probably why the 67. I tried the KOER, could not get it to flash any codes. Engine was stumbling and trying to stall. Will try again tomorrow. Thanks again for helping me.
Larry
Larry
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Brought up to operating temperature, stumbled the whole time at any RPM, held clutch down and ran both sets of codes following the instructions:
KOEO: 11 - 11
KOER: 11 - 11
After the EOER ran, the stumbling stopped, idled & accelerated okay. I did not drive it due to the blizzard & digging out. Will drive it tomorrow.
When it acts up it runs like it has a major vacuum leak. When it decides to run okay, it happens quickly, there's no in-between.
Could the ERG be sticking?
KOEO: 11 - 11
KOER: 11 - 11
After the EOER ran, the stumbling stopped, idled & accelerated okay. I did not drive it due to the blizzard & digging out. Will drive it tomorrow.
When it acts up it runs like it has a major vacuum leak. When it decides to run okay, it happens quickly, there's no in-between.
Could the ERG be sticking?
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From: Suffolk, VA USA
Run individual diagnostics on the sensors, particulary the Engine Coolant Temp sensor (ECT). That sensor can fail, essentially by getting "stuck" within its acceptable operating range. It will never throw a code, but can cause the ECU to enrich the fuel mixture when not appropriate, causing the drivability issues you're describing. In your case, it sounds like the ECT could still be reading cold when the engine is at operating temperature.
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Checked wires & cap, all dry. Intake clear. Started up fine, missed and stumbled during warm up for about 5 minutes, then like a switch was thrown it ran smooth & accelerated normal. I drove it about 5 miles, it ran great. Got on the interstate, it went up to 65mph perfectly. Then, just like a switch was thrown, it started to miss, stumble, buck & jerk, backfiring in intake, speed fell off. Sounded like the driveshaft was going to fly out. I downshifted from 5'th to 4'th & floored it, 2,000 RPM to about 2,500 it seemed not as noticeable & it would accelerate. After a few up shifts & downshifts to control my speed, the problem stopped and it ran fine for about 10 miles. About a mile from home then it started up again. Pulled in my driveway, shut it off. Then I ran the KOEO & KOER again, 11 - 11, all normal. Never did get a check engine light during or after the bucking.
I can try changing the ECT sensor. Again I appreciate all the help.
I can try changing the ECT sensor. Again I appreciate all the help.
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Fleet Owner
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From: Easton,Ks
Does it do it on the other tank if you have two fuel tanks?
Sounds like it going lean, maybe the fuel pump?
Sounds like it going lean, maybe the fuel pump?
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From: Suffolk, VA USA
There are a lot of different things that can cause the symptoms you're describing. The ECT was just one suggestion. I don't advise throwing money at any part until you do some more diagnostics. Bill K asked about possible fuel starvation. I recommended you run diagnostics on the sensors. He, I, or anybody else who chimes in could be right, but you're the only one who has the capability to narrow it down. Get a good manual. Run the tests, and find the problem rather than reaching at straws. Here's a link that will lead you to the some sensor tests.
Ford Fuel Injection
Also, don't forget to give all wiring and vacuum lines a good visual check as well as a "wiggle" test to try to replicate symptoms.
Ford Fuel Injection
Also, don't forget to give all wiring and vacuum lines a good visual check as well as a "wiggle" test to try to replicate symptoms.
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Thanks Bill K & Bill. This afternoon I removed & plugged the vacuum line to the EGR, same problem. About two months ago my front tank fuel pump quit going up a mountain. I switched to the rear tank and drove away. Figuring with 384,000 miles the high pressure pump was getting tired, I changed it and the filter. The rear tank pump is original, still haven't replaced the front tank pump.
A neighbor mentioned the pick-up coil in the distributor as a possible cause?
I wiggled vacuum lines and wiring with it running, listened close for vac. leaks, etc. I'll run some of the sensor tests and try to narrow it down. I really appreciate your help......Thank you.
Larry
A neighbor mentioned the pick-up coil in the distributor as a possible cause?
I wiggled vacuum lines and wiring with it running, listened close for vac. leaks, etc. I'll run some of the sensor tests and try to narrow it down. I really appreciate your help......Thank you.
Larry
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From: Easton,Ks
The PIP sensor in the distributor (it is not a pick-up coil, no coil in it) would not do this. When the PIP sensor goes bad the engine stops running and will sometimes restart after it has cooled down.
However the TFI (ICM) module on the side of the distributor can cause this problem also.
However the TFI (ICM) module on the side of the distributor can cause this problem also.
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