3rd post
Thread Starter
|
Senior User
Joined: Aug 2005
Posts: 123
Likes: 0
3rd post
I've posted questions on this forum a few times but I'm still having a difficult time with this truck. It's a 94 F250 with a 5.8 with 94K miles. I've replaced the inline fuel filter, TPS, cap, rotor, plugs, wires and even the coil, I've also applied fuel injection cleaner. The truck sat for quite a while and I've put a new tank of gas in but it still cuts out at idle and under acceleration. I've been all over the Internet looking and reading and I've even contacted a tech at our local Ford dealership. They suggested checking the fuel pressure and maybe even the ignition. Questions are, do you check the fuel pressure from the stem on top of the fuel rail that looks like a tire stem? secondly, when they say check the ignition, is that the timing? Thanks again in advance.
Jerry
Jerry
Postmaster
Joined: Apr 2008
Posts: 4,802
Likes: 1
Timing don't usually slip, but you can check it, it should be at 10*BTDC with the SPOUT connector unplugged. I'm thinking they mean either just basic stuff like plugs and wires and coil (all of which you already got replaced), or the TFI module on the side of the dizzy, at 94k miles you ain't quite yet at the point where you should be expecting a TFI module failure, but it's a known problem and can cause all sorts of weirdness.
Fuel pressure like Virto said is checked at the shrader valve, for a MPFI system (like you have) you should be seeing 35-40psi at idle.
Fuel pressure like Virto said is checked at the shrader valve, for a MPFI system (like you have) you should be seeing 35-40psi at idle.
Thread Starter
|
Senior User
Joined: Aug 2005
Posts: 123
Likes: 0
fuel test and numbers
OK, I bought an INNOVA fuel injection pressure test kit. I hooked up the hose to the schrader valve, turned the key on and the fuel pump primed and the gauge peaked at 40 PSI and then gradually dropped out to 0. Next, I turned the engine on and it ran at 32 PSI steady, I then pushed the throttle down and only then would the pressure climb to 39 or 40 PSI, after I released the pedal it would drop back down to 32 PSI. After I ran the test I pushed the release valve on the test gauge and no fuel drained out. Any ideas or suggestions would be greatly appreciated.
Jerry
Jerry
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
Your test indicates the FPR is operating normally, though the pressure should not drop when the fuel pump stops or the engine is shut off, this may indicate a leaking injector.
You next step should be to pull the codes.. if you haven't done so already. Ford Fuel Injection
Also clean the IAC valve on the side of the throttlebody, and find a dark place where you can view the motor running with no ambient light(inside a garage at night with the lights off. If you see a light show from the plug wires they should be replaced.
You next step should be to pull the codes.. if you haven't done so already. Ford Fuel Injection
Also clean the IAC valve on the side of the throttlebody, and find a dark place where you can view the motor running with no ambient light(inside a garage at night with the lights off. If you see a light show from the plug wires they should be replaced.
Trending Topics
Fleet Mechanic
Joined: Mar 2005
Posts: 1,603
Likes: 1
From: St Louis
You may also want to check plug wire routing. It is another known issue of the trucks for the plug wires to crossfire and cause a miss. The suggestion of checking your timing on a warm idle engine will help make sure the engine is firing at the right spot.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
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
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Postmaster
Joined: Apr 2008
Posts: 4,802
Likes: 1
Jerry, your fuel pressure looks good, the pump seems to be working fine and the pressure regulator doing its job. I agree with Conanski tho, it shouldn't go down to zero, it drops down a bit but not that much down...
Junior User
Joined: Nov 2006
Posts: 74
Likes: 0
i have the 88 f-250 4x4 460 c6.when i would drive it felt like i was running out of fuel but pick back up an go again,taking off from a stop it would sputter an take off,then it got this attitude ill start when i want,anyway come to find out it was the stator inside the dist.went to the bone yard pulled one out its ran every since.you may want to hollow out your cat.convert. depending on your smog laws where you live,where i live there are no laws but your own.
Thread Starter
|
Senior User
Joined: Aug 2005
Posts: 123
Likes: 0
Thanks
Thanks again all of you guys for you help and suggestions. I ran an OBD1 code reader from INNOVA and found no trouble codes. I did replace the plug wires, plugs, cap and rotor etc. I haven't checked the timing yet, I think that's the only thing I haven't checked. It's really bugging the hell out of me that this truck is so full of trouble and trouble shooting. It could very well be the stator in the distributor, I'll also check the EGR valve etc. as you guys have suggested.
Jerry
Jerry
Postmaster
Joined: Apr 2008
Posts: 4,802
Likes: 1
Jerry, just so you know, the TFI distributors are pretty expensive, so be prepared for a low-triple-digit sticker shock. Dunno if the parts are sold separately. Your problem however does sound very much like how my Lincoln was acting up when the TFI module was going bad, my engine is a 5.0 SEFI and its EEC-IV system is damn near identical to what your 5.8 runs off. To pull the TFI module off the distributor you'll need a special tool that costs about $5 and is usually in stock at Advance Auto Parts, same store can usually test the module for you as well, and sell you a new one if it comes down to it. The module I put in my car was a GP Sorensen unit for $30-something, and it's been working just fine. A note of caution here - never buy an electronics piece made by a company named Wells (found at AutoZone usually), their sensors are okay but the TFI and HEI modules have caused many a truck to get stranded on the side of the road.
Postmaster
Joined: Apr 2008
Posts: 4,802
Likes: 1
TFI stands for Thick Film Ignition, or something like that. The TFI module is the plastic doohickey that sits on the side of the distributor and has a 6-wire harness plug into it. Read here on how it works:
http://www.autozone.com/servlet/UiBr...3d801abd3a.jsp
Read this article for some ideas, remember a 5.8 (351) is just a long-stroke 5.0 (302):
FordMuscle Webmagazine - Tales of the big & ugly Work Truck. 1989 F-150 5.0L Project Truck
http://www.autozone.com/servlet/UiBr...3d801abd3a.jsp
Read this article for some ideas, remember a 5.8 (351) is just a long-stroke 5.0 (302):
FordMuscle Webmagazine - Tales of the big & ugly Work Truck. 1989 F-150 5.0L Project Truck