97 F250 7.5L cold engine problems
Thread Starter
|
New User
Joined: Dec 2013
Posts: 2
Likes: 0
97 F250 7.5L cold engine problems
Kinda pulling my hair out with this problem: Just put in a '96 engine with 85,000 on it ran great and all that. Just recently it started missing really bad when the engine was cold but once it warmed up it ran beautiful. Now it'll start right up, run good for a few seconds, then sputter and die. Any gas I give it usually kills it. To add to the problem, I noticed if I have my headlights on it doesn't run quite as bad. Still it always smooths out and runs great when the engine warms up. Also the battery drains when it's just sitting there overnight. Computer does not read any codes. This has everyone I ask stumped!
Already replaced mass air flow sensor, coolant temp sensor, IAC valve, spark wires, distributor cap, alternator, and coil. Fortunately most of that came off the '97 engine I jerked out. Also during the engine swap I removed the smog pump and bypassed the EGR valve. It ran beautifully for the first few months after the engine swap and then this problem came about. Any ideas??
Already replaced mass air flow sensor, coolant temp sensor, IAC valve, spark wires, distributor cap, alternator, and coil. Fortunately most of that came off the '97 engine I jerked out. Also during the engine swap I removed the smog pump and bypassed the EGR valve. It ran beautifully for the first few months after the engine swap and then this problem came about. Any ideas??
Senior User
Joined: Oct 2013
Posts: 282
Likes: 0
"Computer does not read any codes", or "Computer does not read any codes other than 111"? There is a difference.
I'd be suspecting the fuel pressure regulator, or FPR. One check I would make is to remove the vacuum line while the engine is running and see if it leaks any gas. If it does it's failed and needs to be replaced.
Next I'd check the fuel pressure with a fuel pressure gauge at the Schraeder test port on the fuel rail. I'd be looking for between 35 and 45 PSI with the ignition on, engine off, and fuel pump line in the EEC test connector grounded. (There is a picture of the connector here, with the fuel pump pin identified.) I'd want to read between 30 and 45 PSI with the engine running and the fuel pump pin ungrounded, and I'd want to see fuel pressure increase between 5 and 10 PSI when I disconnected the vacuum line from the regulator.
I'd be suspecting the fuel pressure regulator, or FPR. One check I would make is to remove the vacuum line while the engine is running and see if it leaks any gas. If it does it's failed and needs to be replaced.
Next I'd check the fuel pressure with a fuel pressure gauge at the Schraeder test port on the fuel rail. I'd be looking for between 35 and 45 PSI with the ignition on, engine off, and fuel pump line in the EEC test connector grounded. (There is a picture of the connector here, with the fuel pump pin identified.) I'd want to read between 30 and 45 PSI with the engine running and the fuel pump pin ungrounded, and I'd want to see fuel pressure increase between 5 and 10 PSI when I disconnected the vacuum line from the regulator.
Last edited by broke vet; Dec 8, 2013 at 06:24 PM. Reason: Wordsmithing
Senior User
Joined: Oct 2013
Posts: 282
Likes: 0
It could be. I'm still wondering about the lack of codes, though.
Just so we're on the same sheet of music -- your truck has a test connector under the hood like the one shown at the top of the page at Fuel Injection Technical Library » How To Run a Self-Test , right? I'd hate to be missing the boat because I'm thinking OBDI when your truck is OBDII.
Just so we're on the same sheet of music -- your truck has a test connector under the hood like the one shown at the top of the page at Fuel Injection Technical Library » How To Run a Self-Test , right? I'd hate to be missing the boat because I'm thinking OBDI when your truck is OBDII.
Last edited by broke vet; Dec 14, 2013 at 11:21 PM. Reason: Moving a picture
Thread
Thread Starter
Forum
Replies
Last Post
Kiernan
1968-Present E-Series Van/Cutaway/Chassis
2
Apr 24, 2017 01:44 PM
ProdigyMS
1987 - 1996 F150 & Larger F-Series Trucks
3
Nov 19, 2013 02:57 PM
duback66
1987 - 1996 F150 & Larger F-Series Trucks
8
Jun 27, 2006 04:08 PM
