[font size="1" color="#FF0000"]LAST EDITED ON 12-Feb-01 AT 01:42 PM (EST)[/font][p]I have an 89' F-150. 300 6 cylinder and c-6 trans. The check engine light flashes like crazy when accelerating. It does not flash when at idle or when slowing down. It does not matter if the truck is in gear or out of gear. It only flashes when pushing down on the accelerator. There is no rythem to the flashes. It does not seem to show any peticular code. Anybody have any ideas?

Jakegypsum // Ford fleet, soup to nuts.

 

Sounds like what mine was doing. I'd check for a vacuum leak, and/or the EVP Sensor.

 

Thanks Cgl. I will look into it. Jake.

Jakegypsum // Ford fleet, soup to nuts.

 

Jake, I have that exact same problem on a 1989 F-150 4x4 302 Aod, during WOT. I've come to suspect that because the truck has no preheater or convertor, that the computer is getting a lean or rich reading from the O2 sensor. I replaced it once, with the same symptoms. If you have a code reader, you might get some info from it.

 

Thanks Pastmaster. I think that is what I will do. I do feel that it could be the O2 sensor. Seems to me that I may have replaced that once already on this truck a long time ago. I just don't remember the crazy flashes. I have done so many different things to different trucks, I kind of loose track after a while. I am also going to check the EVP sensor that cgl suggested. I did find a worn mark in a vacuum line but it was very very minor. The rest of the vacuum system seems to check out good. Thanks. Jake.

Jakegypsum // Ford fleet, soup to nuts.

 

 

[font size="1" color="#FF0000"]LAST EDITED ON 13-Feb-01 AT 11:04 PM (EST)[/font][p]Cgl, I did find a worn spot on the vacuum line going to the brake booster. At first when I found it I did not think that it was a problem. I did cut that section out of the line and spliced the two sections of it together. Doug at work, the person who normally drives this truck, says that there is a noticable inprovement in the way the truck handles. A smoother running engine and quicker shifts on the automatic trans. Once again, it is crazy how you don't realize how bad your truck is running until you change something around. I have had similar problems with other pickups but never really thought about on this one. I still have the flash so I plan on plugging it in to a computer in the near future to check the sensors. Thanks.

Jakegypsum // Ford fleet, soup to nuts.

 

Jake:

I'll bet you it's a bad EGR valve. My '88 did that, and it also surged at b/w 1,600 and @ 2,100 RPM, but only surged on the "overrun," i.e., when you lift throttle. Now I have a 5 speed, so this "chucking" was very noticeable as it caused the whole driveline to "lash" back and forth, like you were alternately lifting and then gassing it again. You probably wouldn't be able to notice surging on deceleration with that slushpump, er, I mean, autobox.

I pulled either a "32" or a "33" code out of it, and the book that came with the code puller said it was either the EGR valve or the electronic positioning sensor bolted to the valve. Is that what you meant by the EVP? (I can't remember and don't feel like looking it up....)

Anyway, I FOUND an EGR sitting on a truck in the junkyard (yes, I do seem to find a lot of loose parts just sitting there lately, but this was a good one) and that fixed the surging and the check eng. lite. However, some 4 months and thousands of miles later, it's doing it again, surging and flashing the "Check Engine" light. Happily I removed two good looking valves from the junkyard last weekend, and I will bolt one one shortly and let you know.

I'd like to know if you find it's the EGR when you pull the codes. My truck was run hard and put away wet well before I got it, but after I changed that EGR it ran VERY smoothly, 'till just lately.

What? Buy NEW maintenance parts? I'd be afraid my truck would get used to it, that's why!

Later. Peter

 

On my 88 302 the flashing during acceleration stopped by just taking the EVP sensor out, moving the pin in and out while measuring resistance and putting it back in. How about that?

 

Bigsix, I am not sure but I don't think it is the EGR valve. The truck never ran bad at all and it never "surged" or "chucked". I do know what your talking about because I have had that type of problem with my 83' and both 86's. Bolt the new valve on and be done. I do know that when I repaired a vacuum line on this truck the other day, there was inprovement on the operation of the truck. Unexpected inprovement. I do plan on putting this truck on a computer and I am going to check the EVP and O2 sensors. We have been busy at work and I have not been able to get back on the truck. I will post my results as soon as I get the chance. Thanks a lot for your input and I don't blame you for using EGR valve's off of trucks out of the salvage yard. The new one's can be very expensive. Thanks again.

Jakegypsum // Ford fleet, soup to nuts.

 

Hey,
I just got my truck back from the shop for the same problem. What they said is that a valve that has something to do with the gas/air mixture was stuck and would stay open. It is not a major problem, nor is it necessary to fix right now, but in time it can lead to some minor problems, such as not passing smog tests and having to get a new Cat. Convertor. That is all.

 

Jake:

You’re welcome, and sounds like a plan! Let us know how you make out. I know vacuum problems can be a b****.

For my fellow recyclers (yard rats?): The two EGR’s I got recently came off of ’86 vans, and here’s the P/N: E7TE-9F483-C2A. The reason I pass this on is that the “interchange software” at the salvage yard doesn’t list EGR’s, so you’re on your own. However, the Ford Parts Dept. near me told me this P/N is one of (apparently several?) correct EGR’s for my ’88 F150 4.9 5-spd. Mazda. So surprisingly, we have some flexibility here, when scavaging.

Just tryin’ to save .02 for once, instead of throwin’ mine in all the time!

BigSix

 

I realise this is a very old thread, but I am having the same problem with my F150. Glad of the possible suggestions as to what is the problem. Waiting to get it towed to the garage next week.

As an aside, and for informational purposes, the problem coincidentally began on the same day I received my annual AAA renewal in the post. It was due August 4th, so I belled them and renewed. I decided to upgrade from the Classic, which I have used for years, to the Plus plan because the garage I am going to try to use now is 12 miles from home. (Have had a very difficult time finding anyone who will work on an 1989 model).

Asked them to set up a tow for the next morning. I was stunned by what they said. They said, if you use your membership before 7 days have elapsed, you will be charged $10 extra per mile for any miles over 7. I said, no, wait, I just upgraded my membership, so I have coverage up to 100 miles away, and I have been a AAA member for 40 years. Said it did not matter and expect to pay extra if I did not wait 7 days. I was both appalled and furious. This will be the LAST year I ever do business with AAA again.

 

Best suggestion is starting your own new thread.

Until you read the codes, you or anyone else, is guessing at the root cause. Guessing will thin your wallet very quickly.

 

My truck is a 1989, so a computer cannot diagnose much on it. Guessing is primarily what I am stuck with. Someone told me the truck is worth a good bit of money, so I am going to try to sell it, but until I do, it is all I have to use, so I need to have it repaired. I am the original owner. Bought it brand new in 1989. It has been a great truck. I cannot say I did not get my money's worth out of it.