1998 explorer xlt 4.0, Had a bad valve seal, now loud on take off, lost power

Dan1977 · April 25, 2015

Hi everyone (my first post).. Well little background. The trucks throttle cable broke off and the engine revved up to 6-7000 rpm's for about 5 secs before I turned the key off. After that I had smoke coming from the engine. Turned out it was a valve seal. So he replaced that with some tool that goes down into it. so u dont have to take off the valve cover. I also had the throttle cable replaced, and he replaced the hole thing. Im not sure whats it called but there was a little black box with that too.

So anyway, Im getting this faint puttering/light ticking that sounds like its coming from right in front of my drivers side feet, that only happens when u give it gas and stops completely when u let off the gas. I also really cant here it at idle even at 3000rpm's, its only under load. The gas peddle even seems to shake a little when u gun it. It also seems to not have the power it use to have, and is much louder on take off. (he said he checked the compression and that was good) Any Ideas? =]]

It also has a EVAP Gross leak, I didnt think that would be part of it but maybe it is. TY for any help

my98nnj · April 25, 2015

Which engine is in your truck? If you have the V8 you most likely have a cracked exhaust manifold.

lobo411 · April 25, 2015

Is it knocking/pinging? Here's someone else's video of pinging:

https://www.youtube.com/watch?v=JA0cH_vRABg

I'm not an expert on this, but my guess would be that a lot of oil got past the bad valve seal before you could have it fixed. Supposedly, a carboned-up combustion chamber can cause pinging. You could try running some techron. Worth a shot...won't hurt anything.

Dan1977 · April 26, 2015

my98nnj said:
Which engine is in your truck? If you have the V8 you most likely have a cracked exhaust manifold.

Its a v6 with overhead cams, It could still be the exhaust manifold right? Ill have to look.

Dan1977 · April 26, 2015

lobo411 said:
Is it knocking/pinging? Here's someone else's video of pinging:

https://www.youtube.com/watch?v=JA0cH_vRABg

I'm not an expert on this, but my guess would be that a lot of oil got past the bad valve seal before you could have it fixed. Supposedly, a carboned-up combustion chamber can cause pinging. You could try running some techron. Worth a shot...won't hurt anything.

Sounds more like a rattling, but also like the engine is working harder to get going. And it does not do it while idling even when i rev the engine up to 3000rpms. I could just be the way he put in the throttle cable, but im not sure why that would be. I gotta go back to him and see what he thinks, but I will try that Techron, couldnt hurt. It was also alot louder when pulling my boat. IDK maybe its nothing, but i dont remember hearing it before that valve seal went.

my98nnj · April 26, 2015

V6 SOHC - Well known for timing component failures, could possibly be your problem. If by chance he took the cam out, specials are needed to time it. If it's not timed correctly, it could run, but with a loss of power.

2000StreetRod · April 26, 2015

Comments

Dan1977 said:
. . . The trucks throttle cable broke off and the engine revved up to 6-7000 rpm's for about 5 secs before I turned the key off.

If the throttle cable broke the engine speed would have dropped to idle. I suspect that the throttle plate return spring broke. The PCM has an engine speed limiter. The stock setting is 6250 rpm.

Dan1977 said:
. . . Turned out it was a valve seal. So he replaced that with some tool that goes down into it. so u dont have to take off the valve cover.

In my experience there is no possible way to replace a valve seal without removing the valve cover. It is possible (and common) to replace a valve seal without removing the valve.

Dan1977 said:
I also had the throttle cable replaced, and he replaced the hole thing. Im not sure whats it called but there was a little black box with that too.

The throttle plate return spring is part of the throttle body.

Is the "little black box" the thing in the photo below attached to the throttle body and with the wires attached?

If so, that's the throttle position sensor (TPS).

Dan1977 · April 27, 2015

"

2000StreetRod said:
If the throttle cable broke the engine speed would have dropped to idle. I suspect that the throttle plate return spring broke. The PCM has an engine speed limiter. The stock setting is 6250 rpm."

----Well that sounds about right, what happened (from my perspective) the foot peddle was stuck and would not go down after driving it for about 2 mins (after it sat for a few months) so I pushed harder and maybe it was the spring but it just snapped and the peddle dropped to the floor rpms were prob right at 6250

"In my experience there is no possible way to replace a valve seal without removing the valve cover. It is possible (and common) to replace a valve seal without removing the valve."

----Thats prob what he did, he said he broke his tool trying to replace the valve seal, but I think he meant he didnt have to remove the camshaft when I asked, so im sure he removed the cover. Ive read that the valves in this truck cannot be adjusted is that correct?

"The throttle plate return spring is part of the throttle body.
View attachment 83549
Is the "little black box" the thing in the photo below attached to the throttle body and with the wires attached?"

----No it was a black box about 3-4" long by 2" wide 1.5" high. He got a used throttle cable from someone and this was part of the old one he had left in the truck. I have no idea what it was, was just a rectangular box. i was thinking that might be mounted under my feet somewhere. Im going to have to inspect more. I have a car I drive most of the time, the truck is manly used for towing my boat, but it was in really good shape. so id hate to be doing harm.

View attachment 83550
If so, that's the throttle position sensor (TPS).

2000StreetRod · April 27, 2015

valve lash

Valve lash or clearance between the valve stem (B below) and the roller cam follower (rocker arm) is controlled by the hydraulic lash adjuster (A below).

As you stated, it is not mechanically adjustable.

Was the box the item identified in the photo below?

Is so, that's the cruise control servo. Its cable connects to the throttle body.

Dan1977 · April 27, 2015

Was the box the item identified in the photo below?
View attachment 83573
Is so, that's the cruise control servo. Its cable connects to the throttle body.[/QUOTE]

Yep that exactly what it was, My cruise control was out too so thats why he had that part. Never fixed it though. Well I can rule that out now, thx

1998 explorer xlt 4.0, Had a bad valve seal, now loud on take off, lost power

Dan1977

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lobo411

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Dan1977

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