Rich Mixture?
Thread Starter
|
New User
Joined: Aug 1999
Posts: 4
Likes: 0
Rich Mixture?
I have a 92 with a 351 EFI. When the engine heats up and highway speeds are reached, the "Check Engine" light comes on giving a 173 (rich mixture) code. I've replaced the O2 sensor and checked the wiring. I was getting a EGR position sensor error, but it went away with replacement of the EGR valve. Also, and maybe related, when I reach cruise speed (above 2500 RPM), the vents in my dash lose vacuum and air starts blowing though the defroster ducts. This condition reverses when I slow down. Any ideas?
Junior User
Joined: Sep 1999
Posts: 86
Likes: 1
From: near St. Louis USA
Rich Mixture?
my '93 w/ 351 was blowing smoke like a cold diesel. After spending hours trying to find the problem, I found out the fuel pressure regulator's diaphram was leaking fuel into the vacuum system. The engine was sucking raw fuel. Replaced the FPR and no more smoking Bronco!
john
john
Thread Starter
|
New User
Joined: Aug 1999
Posts: 4
Likes: 0
Rich Mixture?
You're right on. I had my fuel pressure checked a month or so ago and I was push 80 psi..should have been @ 38 psi. Replaced it and all is well. Though the vents still act screwy, but I can live with that. Thanks for the reply!!!
Posting Guru
Joined: Jun 1999
Posts: 1,525
Likes: 1
Rich Mixture?
That's right, prolly so.LOL! The vent problem is related to a vacuum problem which has to be fixed first before you go back to the engine problem,which may be causing the problem in the first place.Following the vacuum schematic, check everything out, especially at the vacuum resevoir (RSVR)and back into the dash.There is one vent dashpot under the hood near the pass. side. Also, from the cruise servo back into the dash as well.Don't forget PCV valve also.After that is done,and still gettin' a 173,I'd recommend the ECTS be replaced.Also,a far shot, low fuel pressure will cause the computer to over compensate and hold the injectors open longer when not necessary such as when a fuel filter is restricted.
Phillip
Phillip
Phillip
Phillip
