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Glenn
Glenn, Senior Master Ford Tech
Category: Ford
Satisfied Customers: 1745
Experience:  26 years exp with Ford Products, ASE Master Auto & Truck + advanced engine perf L1/L2 Gas & Diesel
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I have a 98 f150 with a 4.6L V8 that started running rough ...

Customer Question

I have a 98 f150 with a 4.6L V8 that started running rough and backfireing(intake, exhaust?. It just started happening after it
got really cold one night and I thought the fuel lines had froze up.
I had trouble getting it started but now It's starts great, but within a few seconds it's starts roughing rough and backfiring. Replaced the plugs and found two that were fouled and all the rest look brown like it's running rich. No improvement, could it be the fuel pressure regulator?
Submitted: 7 years ago.
Category: Ford
Expert:  Glenn replied 7 years ago.

hi john,

I would start with pulling codes from pcm. Autozone will pull them free. You would need a fuel pressure gauge to check for excessive pressure, but this would generally affect all cylinders so its not likely your problem.

Do you remember which cylinders had the fouled plugs? if you dont, unplug injectors one at a time trying to locate miss] I would start there with a compression test, backfires are usually valve timing related. This engine can spit a cam follower off, especially cold &/or using the wrong oil [requires 5w20], not changing it often enough [sludge]

let me know what you find and I will continue helping you.

Customer: replied 7 years ago.
Reply to Glenn's Post: Glenn, I checked the old plugs and it's old lucky
number 7 thats fouled out. so I pulled the fuel
injector connector off 7 and the backfireing when
away after 15-20 seconds. But the engine runs even rougher at idle with that injector disconnected. Maybe it's a leaky injector?
I'll have to pick up code reader tommorrow
after work and get back to you with what I find
out.

Thanks So Far!
John
Expert:  Glenn replied 7 years ago.

A fuel pressure gauge would ge helpful to check for leak down. See if they loan any out.

compression gauge!

Glenn, Senior Master Ford Tech
Category: Ford
Satisfied Customers: 1745
Experience: 26 years exp with Ford Products, ASE Master Auto & Truck + advanced engine perf L1/L2 Gas & Diesel
Glenn and 7 other Ford Specialists are ready to help you
Customer: replied 7 years ago.
Reply to Glenn's Post: I guess it could be a bad cylinder yead valve?
A compression check would help to find that out, but what should the compression be on that engine?
Expert:  Glenn replied 7 years ago.

John it should be around 150 . Just keep posting your results and I will keep helping you. I try to check my questions at least every couple hours.

Glenn, Senior Master Ford Tech
Category: Ford
Satisfied Customers: 1745
Experience: 26 years exp with Ford Products, ASE Master Auto & Truck + advanced engine perf L1/L2 Gas & Diesel
Glenn and 7 other Ford Specialists are ready to help you
Customer: replied 7 years ago.
Glenn,
I scanned the fault codes and got a P0307, which is cylinder no. 7 misfire detected. I cleared the code and took the truck around the block and the engine light did not come on yet. The intermitant backfire still exists and the idle is little rough. The big issue is when put the trans in gear, Thats when it starts missing. I think the catalytic converter is plugged. Before I changed plugs, I had to drive the truck 175 miles with the plug fouled. what do you think?
Expert:  Glenn replied 7 years ago.

Hello again,

John you need to check compression on #7..I attached the tsb that I think might have happened. Its not the cat converter!

TSB
00-26-1
  • ENGINE - ROUGH IDLE/MISS AFTER START-UP DURING COLD AMBIENT TEMPERATURES LESS THAN -12 DEGREES C (10 DEGREES F) - VEHICLES BUILT 3/1/1996 THROUGH 7/31/2000
  • NOISE - FROM ENGINE - ROUGH IDLE/MISS AFTER START-UP DURING COLD AMBIENT TEMPERATURES LESS THAN -12 DEGREES C (10 DEGREES F) - VEHICLES BUILT 3/1/1996 THROUGH 7/31/2000
Publication Date: DECEMBER 8, 2000

FORD:1997-1999 F-250 LD
1997-2000 ECONOLINE, EXCURSION, EXPEDITION, F-150
1999-2000 F SUPER DUTY
LINCOLN:1998-1999 NAVIGATOR

ISSUE:

Some vehicles equipped with a 4.6L, 5.4L, or 6.8L engine may exhibit a rough idle/miss after start-up in cold ambient temperatures (less than -12°C/10°F). This may be caused by a roller finger follower(s) being dislodged from the valve. This may result in damage to the camshaft, roller finger follower, valve, retainer, etc. A procedure is now available to service this condition.

ACTION:

Inspect and replace any worn or damaged engine valve components and install new retaining clip and lash adjuster for service. Refer to the following Service Procedure for details.

SERVICE PROCEDURE

Perform normal engine diagnostic routines before opening valve covers. If the valve train is suspect, remove the valve covers and look for Roller Finger Follower(s) (RFF) that may have become dislodged.

  1. Inspect the following parts that may have been damaged by any dislodged roller finger followers:
    • Cam lobes (chipped or grooved)
    • Valve stem tips (mushroomed, metal displaced, or bent)
    • Roller finger followers (chipped or grooved)
    • Inspect valve guide only if its corresponding RFF or valve stem tip is damaged.

    Replace damaged parts as necessary.

  2. If follower(s) are damaged, replaced as necessary, otherwise re-use followers in same location as removed from head.
  3. Remove all intake and exhaust lash adjusters from the engine and replace with service-only Lash Adjusters (YL3Z-6500-AA). Refer to the appropriate Workshop Manual, Section 303-01B for service procedures and tooling necessary to compress the valve springs and remove the roller followers.

    NOTE:REFER TO FIGURE 1 FOR INSTALLATION OF THE NEW RETAINING CLIPS (YL3Z-6A539-AA), TO THE ROLLER FINGER FOLLOWER.

     

  4. Using a valve spring compression tool, install followers and the attached retaining clips by pushing clips onto lash adjuster.

    NOTE:THE CLIP IS NOT REMOVABLE FROM ADJUSTER ONCE IT HAS BEEN SNAPPED INTO PLACE. IF THE ENGINE NEEDS TO BE SERVICED AT A LATER DATE, REMOVE THE RFF BY BENDING UP THE CLIP. LEAVE LASH ADJUSTER IN THE ENGINE WITH THE CLIP WHILE REMOVING THE FOLLOWER. THEN REMOVE THE LASH ADJUSTER FROM THE HEAD AND SNIP/CUT THE CLIP FROM THE LASH ADJUSTER. REPLACE WITH A NEW CLIP ON FOLLOWER DURING INSTALLATION.

     

  5. Check valve train for proper assembly and reinstall valve covers as outlined in the Workshop Manual, Section 303-01B.


PART NUMBERPART NAME
YL3Z-6A539-AARetaining Clip - Roller Finger Follower
YL3Z-6500-AALash Adjuster

OTHER APPLICABLE ARTICLES:

NONE

Customer: replied 7 years ago.
Glenn, What will the compression radio be if the one of the valves is not opening? I assume it would be lower than 150. I'll have to pick up a compression tester, the one I have won't fit on this engine. I have a 1970 GTO with a pontiac 400 that I used to drag race. I think I rather be working on that engine instead. but enough dreaming.
Expert:  Glenn replied 7 years ago.

John, you know it might be faster just to pull that valve cover and inspect it. The popping back noise just has to be a valve issue.

If you do the compression just compare it to 5 & 6.

Customer: replied 7 years ago.
Ok you win, I'm pulling the valve cover. I'll get back to you as soon as it's off
Customer: replied 7 years ago.
I can see rocker arm off. I'm still having trouble getting the valve cover all the way due
to the exhaust pipe going from the intake to the exhaust manifold. I took the pipe off the intake but since I live in the rust belt in insn't ever coming off the exhaust manifold, any ideas? I think I need to fully inspect the valve train. are you going to around tomorrow? I could probably use some help looking over the damage and fixing it. I make it work your while, you have been right on so far. I going to forward the deposit right now
Expert:  Glenn replied 7 years ago.

John the only thing you can due is soak it down with pentrating oil. If you can heat it up with torch would help. I don't know if you have air tools, we would use a long air chisel to break the nut loose. See if you can hit your wrench with a hammer. Straight into nut, not trying to losen. [you will strip it otherwise] I'd tell ya to take the exhaust manifold off but you will probably have just as much hassle with all those studs.

You may end up having to replace that EGR exhaust supply line. I think they are around $40

WHEN you do get the cover off, just inspect the cam, the lash adjuster and end of valve for damage. They RARELY damage anything else. You can pop them back in with a hammer and dull chisel. ARE you using 5w20 oil???? if not, GET some and change it. Is there any sludge build up??

I live in Texas and dont have to deal with this often. I have to work sat, but I will try to check on your question every couple of hours.

Customer: replied 7 years ago.
Glenn, I got the exhaust pipe off and I have the
rocker arm in my hand. I'm not sure how to tap it back in. Are you suggesting to tap it back in from the top near the lash adjuster? The lash adjuster is still in place and the roller on the rocker will not fit between the lash adjuster and the camshaft. Does the lash adjuster need to come out? Please advise.

Thanks
Expert:  Glenn replied 7 years ago.

Hi John,

Is the rocker OK? no flat spots on roller, spins with no binding. The cam not worn or rough? Is there any sludge build up?

You will need to bump engine over and get the cam lobe straight up for that valve. Your suppose to use a valve spring compressor tool to push the valve down a little so you can slide that follower [is what its actually called] IN . It's hard to explain, you get it on the valve side right up to the lash adjuster and basically pry it back in while pushing down on the valve a little.

If you want to private message me your phone number I'll try to explain it on the phone.

Customer: replied 7 years ago.
Glenn, I looked it over and everything looks ok, no worse for wear and no sludge. It looks like it just fell out. I had just changed the oil the day before and the only thing I had around was some 10w-30. wouldn't you know it , I was out of town for the weekend and the truck was outside for the nite and it dropped to -15F. Will it happen again if I use 5w-20? I don't think I've ever used anything thinner than 5w-30w with that engine and I bought the truck new.(now 115,000) I used to pull a fifth-wheel camper with it and I wanted some ensurance that the engine would not overheat.(6800lbs) I also have an older bmw(211,000) and the German engineers like the oil right out of the barrel.(20w-50) I guess I need to believe the owners manual a little more. But I did get the follower back in just the way you said. And I will try and finish it up tonight or early tomorrow.
Expert:  Glenn replied 7 years ago.

That's Great to hear, I would definitely use the 5w20 in the winter, This engine has very tight tolerances when new [measured in TEN thousand's] that is why it calls for such a thin oil. AND never over the 5w30. You might get better mileage with the 20.

We use nothing but the 5w20 at my dealership and we are in texas as I mentioned before. I see alot of trailer hitches and no problems from heat.

Customer: replied 7 years ago.

Glenn,

The truck runs great. No more missing and I do have 5-20 in the engine now. Is it the valve that sticks open that causes the follower to fall out? How many times have you seen this happen in other triton engines? You should give me your E-mail for future reference. I plan on keeping the truck for awhile and I also have a mercury Villager mini-van with 155,000, so I think I might be busy working on these vehicles as they get older. Do you know anyone that knows anything about older BMW's? The OBC won't turn on the passager side headling on a 1991, 535i.

Thanks,

John

Expert:  Glenn replied 7 years ago.

Hi John,

Thanks again, I will be able to help you on the villager but post those bmw questions to the general cars section. You can always private message me from this site.

The problem seems to be caused by lack of oil flow, thats why I kept asking about sludge. and yes it is common.

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