code 31
Thread Starter
Joined: Nov 2003
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code 31
Im getting a code 31 on the tester on my 88 F150 302 4 speed. it says Evap control systen under minimum voltage. Any ideas on where to lok for the cause. Im guessing the EGR valve position sensor but I dont know much about this injection yet. Any help will be appreciated. merry Christmas to you all
Senior User
Joined: Dec 2003
Posts: 354
Likes: 1
From: Memphis, TN USA
Most of the time if you are getting a code pertaining to the EGR, it is just usually a clogged EGP pipe and passage ways. Try cleaning the EGR pipe and passage ways and see if that error would come up after you first clear the error and clean the EGR.
Senior User
Joined: Dec 2003
Posts: 354
Likes: 1
From: Memphis, TN USA
You really don't have to take the EGR apart and dismantle it to clean it.
Just the pipes and the passage ways where the EGR takes in the hot air from the exhaust and the pipe goint into the intake.
I'm not sure if you have heard of a "Top End Cleaner". GM has made a "Top End Cleaner" and it's on a can to clean carbon buildup.
However, a brand called SeaFoam can do the same.
I would recommend to try to clean away any carbon build up in the engine.
Use a $6 Seafoam Motor Tune-Up. 1/3 in fuel tank, 1/3 in oil crankcase, 1/3 in intake vacuum (use the brake booster vacuum hose with a funnel while the engine running). Let it set for 30 minutes, the longer the better. I'd recommend driving it at night at less traffic highway and push the throttle at WOT for a few seconds. There would be a lot of smoke and the other driver thinks they have a fog situation.
Get an oil change after that.
Just the pipes and the passage ways where the EGR takes in the hot air from the exhaust and the pipe goint into the intake.
I'm not sure if you have heard of a "Top End Cleaner". GM has made a "Top End Cleaner" and it's on a can to clean carbon buildup.
However, a brand called SeaFoam can do the same.
I would recommend to try to clean away any carbon build up in the engine.
Use a $6 Seafoam Motor Tune-Up. 1/3 in fuel tank, 1/3 in oil crankcase, 1/3 in intake vacuum (use the brake booster vacuum hose with a funnel while the engine running). Let it set for 30 minutes, the longer the better. I'd recommend driving it at night at less traffic highway and push the throttle at WOT for a few seconds. There would be a lot of smoke and the other driver thinks they have a fog situation.
Get an oil change after that.
New User
Joined: Oct 2003
Posts: 6
Likes: 0
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I got the same code a few weeks ago. I had just replaced my EGR valve and EVP sensor ( installed on top of the EGR valve). When it was all done I got the code 31. So I started replacing parts further down the chain with no luck getting the code to go away. Turns out that the parts I bought from the local store weren't built with the same toloerences as fords. The pin on the EVP sensor was about a 1/8" too short to engage the EGR valve. I had to pay the local ford dealer $250 to find this out. That sucked.
Thomas
Thomas
