89 bronco 5.0 rich
Thread Starter
|
Senior User
Joined: Jan 2007
Posts: 186
Likes: 1
From: watford, ontario
89 bronco 5.0 rich
sooooo I got a 89 bronco with 5.0 and i just got it e tested and it barley passed it was extremely high on Hc which is unbernt fuel im pretty sure.. i did a complete tune up on it before i took it in which was plugs , wires cap rotor pcv valve, fuel filer checked the timming and replaced my o2 sensor . so anyways i checked my vacume lines and found a couple that were leaking so fixed them ran a koer test and got the code 42 again so i cleaned my throttle body and iac and rechecked my vacume lines again just to be safe. did another koer test and code 42 came back again.. so i checked the fuel pressure and its okay . theres no exhaust leaks my cats arent plugged either.. so im wondering if i hade a bad air charge sensor could it cause it to run rich and i haven checked my coolent temp sensor either if it was reading off that could cause a rich problem too couldnt it??
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
The fuel regulator can supply the proper fuel pressure but it can also have a ruptured internal diaphragm which allows fuel to be drawn in through the vacuum port. Pull the vacuum hose off and inspect it for signs of fuel by smell and a visual test. Cycle the key on/off a few times to see if fuel trickles put that vacuum port.
What do you mean the fuel pressure checked "ok"? What was the pressure at idle? Pressure at idle with the vacuum hose disconnected?
What do you mean the fuel pressure checked "ok"? What was the pressure at idle? Pressure at idle with the vacuum hose disconnected?
Post Fiend
Joined: Jan 2005
Posts: 8,402
Likes: 10
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
Looks like you are on the right track. The PCM relies on several inputs to meter the fuel/air mixture. TPS, MAP, ECT and ACT as well as the O2 sensor in closed loop. Before blindly replacing parts I suggest checking the output signals on the sensors mentioned above, minus the O2 of course.
Ryan has some great reference material here: Ford Fuel Injection
Ryan has some great reference material here: Ford Fuel Injection
Thread Starter
|
Senior User
Joined: Jan 2007
Posts: 186
Likes: 1
From: watford, ontario
ya im going to check the ect and act today there the only ones i havent checked yet soo i really hope one is fubared haha ..
Trending Topics
New User
Joined: Feb 2011
Posts: 13
Likes: 0
Before you get too crazy with diagnistics, start with the basics. When I was faced with a similar issue, I found my truck to be slightly low on coolant. This caused the temp sensors to supply false signals to the computer.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
Thread Starter
|
Senior User
Joined: Jan 2007
Posts: 186
Likes: 1
From: watford, ontario
measured the resistance through the ect at room temp with the dvom on the 200 K ohm scale i got 37.5 and 36.5 k ohms for the act so according to the shop manual there both in spec ..
Fleet Mechanic
Joined: Aug 2005
Posts: 1,462
Likes: 74
From: Hartford, AL
Ford Fuel Injection » Two Digit Codes 33-58 Have a look here.
I knew how to look up the code and am very familiar with FFI. I was just sayin' I haven't looked up. If the code is KOER code 42 I would think you may have a bad o2 sensor although it's new. "No HEGO switching detected always rich". If the CM code is 42, then it is switching but just rich. If the o2 is bad it will read lean which will in turn cause the eec to add fuel making is rich. I would suggest swapping the o2 again. There are also some tests you can do to make sure the o2 is working and check the o2 ground path.
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
You also need to measure the MAP sensor. That one will also trigger a rich or lean condition even if it is off a few hertz. Very narrow operating range.
The TPS can be a contributor, but if it is off you usually get an error code or other symptoms such as weird shifting assuming you have an E4OD.
Thread
Thread Starter
Forum
Replies
Last Post
Coresair
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
33
Jun 22, 2016 06:00 AM
MemOrex
1987 - 1996 F150 & Larger F-Series Trucks
2
Jan 23, 2005 07:22 PM
