Poor Performance, Loud Throbbing...

floridabob

floridabob

New member
Joined
Dec 8, 2008
Messages
167
Going to try and be succinct on the issues by listing them:
1-poor fuel economy, far worse than before these symptoms
2-Loud thumping/throbbing from Ice Box intake (was always there but now much louder)
3-Tons of smoke vs. before (black)
4-weaker boost on low end, but still winds up to 45 psi

I looked around under the hood some and found on my HTT 3 piece manifold a bolt had fallen out. Fixed that, but very little improvement.

Sounds like an exhaust leak and feels like a loss of power due to lower boost at low end or over fueled...or combo of both.??

Did not seem to get worse steadily, but change overnight.

thanks for any help

bob
 
Ran the valves and #6 exhaust was way out of whack... Now I wonder why?

NO noise from the intake now, whereas I always had it before now. Wonder if the last guy that ran the valves didnt do it properly. Or, since this is my first attempt, if I didnt do it right.
 
More than likely it was the previous owner messing up (did it to my own truck and thought it was a bent pushrod). There aren't any valve seats on your truck to worry about dropping.

If it loosens up again then I'd look at the pushrods and see if they are bent or maybe a cam lobe is starting to wear.
 
floridabob said:
Going to try and be succinct on the issues by listing them:
1-poor fuel economy, far worse than before these symptoms
2-Loud thumping/throbbing from Ice Box intake (was always there but now much louder)
3-Tons of smoke vs. before (black)
4-weaker boost on low end, but still winds up to 45 psi

I looked around under the hood some and found on my HTT 3 piece manifold a bolt had fallen out. Fixed that, but very little improvement.

Sounds like an exhaust leak and feels like a loss of power due to lower boost at low end or over fueled...or combo of both.??

Did not seem to get worse steadily, but change overnight.

thanks for any help

bob
Click to expand...



A loose bolt will usually turn into a burned exhaust manifold gasket. Pre-turbo exhaust leaks have a huge, huge, huge, impact on low end power and turbo spool up. I'd personally buy a set of new exhaust manifold gaskets and a manifold to turbo gasket and replace them all. It's a couple hours work and about $30 in parts but well worth it.

Also, like others have said, keep an eye on any valve that seems to lose lash setting quickly, could be sign of lubrication problems and/or cam/tappet wear, and/or pushrod ball&socket wear.
 
Wear

I pulled the pushrod and the ball is gone on the tappet end. Completely flat and a bit mushed, too. Put in a new pushrod and now I cannot unscrew the adjustment screw enough. Old pushrod worked, should I put it back?
 
sounds like the tit from the old one is still in there! probably mashed into the tappet. when you drop the pushrod into the tappet does it spin smooth and kind of " suck" in?

could try to fish the tit out with a magnet, otherwise you might be taking the tappet out.
 
Spent the day yesterday pulling the pump and the tappet window. Funny thing: no visible tappet damage. Fun way to spend the day. Placed the new pushrod and was able to adjust the valve. Hmmm...We will see.
 
floridabob said:
Spent the day yesterday pulling the pump and the tappet window. Funny thing: no visible tappet damage. Fun way to spend the day. Placed the new pushrod and was able to adjust the valve. Hmmm...We will see.
Click to expand...

You left out that last tidbit about being able to set lash in your other post. If you got the rocker adjusted and it's similar in adjustment to the rest of the valvetrain, it's probably going to be just fine.
 
You must log in or register to reply here.
Back
Top