Have a 93 f150 5.0 5spd that is constitantly getting 10mpg average even after changing plugs wires rotor cap fuel filter thermostat and adjusting timing..so i pulled codes and got these when it was cold. 1 21 24 52 67 .. Then after being warmed up only got 1 52 33 34... So can someone help explain what these codes are ? i can find referance to 33 ..EGR malfunction which i cant figure out because the egr works. This truck really has me scratching my head.

 

Also replaced TPS..this truck runs very smooth and never misses only thing it does is idles high for the first 30 secs when i fire it up.. but the IAC been replaced recently also.

 

Ford ? OBD Trouble Codes
if you did the key on engine on test, you need to turn the wheel, turn off overdrive if you have the button, press the brake, the heat should off for this test.
check the vacuum canister (coffee can) and make sure there is no rusted holes underneath it
do this test correct and the 52 code should disappear
codes 33 and 34 are EGR

 

I made a shorting out connector to get codes to flash turned key to accessory had everything turned off. Coffee can dealio.. finally someone used a term i know! Thank you sir!! Ill go check right now .. barely any rust on anything on this truck but ill look! Thanks

 

what i did, i bypassed the valve that turns on the egr valve by the ignition, connecting the 2 vacuum lines together (green and black) with the green vacuum line disconnected at the egr and put a vacuum gauge at the end of the green one to confirm i had no vacuum leaks. then i hooked it back up the way it was.

 

There is no Code 1.......that means your flash count is probably off.

 

Was the engine running when you did this test? If so, all that means is you have vacuum. Zero indication if there is a leak in the line..

 

Alright went back and checked codes after having the truck un hooked all night an having replaced the Oxy sensor and that Electrical part that sits on top of the EGR... So now i have a code 52 1 and 33...and yes ive sat there 4 times now and it blinks once than nothing for 4 secs than goes to 3 3 ... So the original owner said he had the EGR disconnected?? yet when i follow the tube its welded to the exaust pipe ... Any suggestions? Im damn near ready to just fold and take this to a shop to see what they can do for the gas mileage..

 

Code 52,
Power steering switch, 302 should but does it still have one? its possible the pressure hose was replaced and the switch wasn't put in place/replacement hose didn't include its port. Might be plugged in but not connected to the pressure hose for example.

Anyway its saying it never changes state, either always open or always closed.

You should find out which one is the case as always "on" would increase idle speed, always "off" wouldn't be problem provided it doesn't attempt to stall idle speed maneuvers.

Code 33,

Is telling you the egr valve doesn't open. Could be caused by a vac leak might be a dead EVR or faulty electrical connections to it.

Couple ways to test it and one of the simplest quick and dirty tests would be to take a jumper wire and ground out the brn-pnk wire at the EVR with the engine idling (it'll have two wires to it, you don't want the red wire).
If the motor stumbles when you ground out that circuit the EGR valve can and will open, it has vacuum to it as well as power and the EVR functions as it should.

If it doesn't then you need to get into the problem in more depth, verify vacuum routing verify key "on" power to the EVR (that red wire) and that the EGR valve itself isn't froze up.

You can test the EGR valve by applying vacuum to it while the motor idles, if the motor stumbles when you do so the valve is working it is not froze up.
If it doesn't move it's either froze up or its diaphragm is ruptured.

If the valve is fully closed and remains that way, that is not a problem in of itself and not the cause of poor fuel econ.


Code 1,

The single flash you see is the separator code "10" between the KOEO self test and CM codes that you would see if using a code reader, the zero isn't represented in the results when using the flash the MIL method. Wanted to mention that so you'd understand that is normal and what you should have seen.

 

Awesome thank you for this detailed write up. I took the egr off and cleaned it eveything worked with a hand held vaccum.. So ill check electrical. And as for power steering switch how does that effect idle? Forgive my ignorance but that seems odd..also where do i locate this item?

 

Power steering switch will be in the pressure hose between the power steering pump and steering gearbox.

The 302 is the only engine that has one, when you turn the wheel the load on the engine increases can make it stall/near stall. They put a switch in the pressure line to tell the computer the driver is turning the wheel, it increases idle speed slightly to offset any possible stall condition that could tend to create.

With a strong motor you probably don't need it unless of course without it you notice it tends to near stall those conditions.

You don't want the switch closed all the time as it would hold an increased idle speed, something you do not want for obvious reasons.

 

Hmmm very interesting ill have to go look right now.. This truck does have a odd idle when i fire it up.. Idles high for about 20-30secs then drops to normal.. and if you take off without letting the idle drop first it will die at every stop..And i replaced TPS and IAC trying to fix it.

 

A 1993 truck should be giving 3 digit codes, not 2 digit, which is probably why your count is off.

 

3 digit?? Nope.. Even the fancy scanner the shops use came up with the same codes im counting with a jumper

 

Thank you Danr1 the plug was off and taped up i never would of noticed it.. Plugged it in now code 52 is gone!!...but now i got a code 22 after driving and re checking..this truck..