Check Engine Light Flashing But no Codes.
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Check Engine Light Flashing But no Codes.
I have a 95 EB with a 302 with 190500 miles on it. It has been throwing a check engine light for about a year now. On cold start up the engine will rev up like normal then just when it is going to go down it jumps up to about 1400-1500 rpms and the check engine light will flash. But it doesn't throw any codes. It runs fine other wise, I averaged 15.2 mpg's on my last tank of 87 octane. Mostly city driving. I have had it hooked up to two different type of scanner's while it did the light flashing and every thing but can't get a code to show up.
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From: Coweta,GA, GO DAWGS!!!!!!
Possible ECM problem, most likely PROM. A code is set but the ecm doesn't store it or show it, but the ecm operates normally at all other times. Best way to check this is to set your own code and see if it will record and show that one. Start the engine and let it get to op. temp. pull the coolant temp sensor connector and ground out the wire, like your checking a ect sensor or gauge. This should throw an overheating or out of range ect code. Then recheck the codes. If you still don't get a code after manually setting one you have an ecm fault. If this is the case I wouldn't replace it until the engine starts to act up or run bad.
Also is the truck stock or have you replaced the ecm before? I installed the incorrectly calibrated ecm on my '91 f-150. Ran great and solved the problem I was having but I couldn't get any codes from it, even the ones I set manually.
Also I would clean the IAC and throttle body's if you haven't already.
Also is the truck stock or have you replaced the ecm before? I installed the incorrectly calibrated ecm on my '91 f-150. Ran great and solved the problem I was having but I couldn't get any codes from it, even the ones I set manually.
Also I would clean the IAC and throttle body's if you haven't already.
Hotshot
Joined: Jul 2002
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From: Bend,OR
there are 2 different tests. KOEO and KOER , go to www.fordfuelinjection.com to run both to see what comes up. pull the codes yourself
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I am trying to pull the codes my self, I am using a snap on diagnostic computer and I can't remember what the other brand is.
Even with both of the different name brand computers hooked up while the bronco does the reving up and the check engine light flashes no codes. After it rev's up it stumbles down around 500rpm's and then comes back to normal.
Every thing about the computer is factory. I have never messed with it and when it started doing this I replace the IAC valve because I thought that would fix it but I was wrong.
Even with both of the different name brand computers hooked up while the bronco does the reving up and the check engine light flashes no codes. After it rev's up it stumbles down around 500rpm's and then comes back to normal.
Every thing about the computer is factory. I have never messed with it and when it started doing this I replace the IAC valve because I thought that would fix it but I was wrong.
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From: Chicagoland
Originally Posted by Triple_E_Farms
I am trying to pull the codes my self, I am using a snap on diagnostic computer and I can't remember what the other brand is.
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Unlike MPRICE I used the snap on computer scanner again today and the only code I received was 111 with said was no codes present. The engine didn't act up today. I think I am going to lean towards the pcm getting old. I wonder how much a new pcm will cost?
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From: Coweta,GA, GO DAWGS!!!!!!
I gave $159 for the new one in my '91. That was from ford. Unless it's doig this to where you can't drive the truck I'd leave it be.
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Had the same problem on my 92 it was a vacuum leak where a mechanic put a piece of rubber hose larger than the vacuum line over the line. Took me forever to find it once I replaced with smaller hose problem went away.
