Engine/Transmission (1998.5 - 2002) Throttle Buzzing

[SConklin]

Just reinstalled the head, and twins. The truck's been down for about 4 months, sitting in one spot, until I got everything put back together. Previously, this was not an issue until I put everything back on.



When the engine is running, there is a loud buzzing noise coming from the engine. It is intermittent, and light at idle, and speeds up to a steady buzz (sounds like a loud bumble bee in the engine) as the throttle is pressed.



The throttle cable is routed tighter now since the change - seems to have an slight S-curve to it now for some reason. I'm not sure why, or how it was before. I suspect something with the APPS/throttle, but I don't know.



Anyone else have any experience with this, or an idea what it might be? I've played with different switches in the cab, moved the cable around, varied engine load, etc. I still does it the same - seems dependent on the throttle position.



Not sure if it matters, but I have a MAD ECM, high idle switch (turned off), and FASS too (running 15-17psi all the time). The VP44 was just replaced right before taking my truck down. Also, there is a vent problem in the tank, (will not vent its pressure), and the truck seems to have a hard time starting initially when the motor is cold, which it did not have before.

 

[SConklin]

I rerouted the APPS line to make it straighter, and re-grounded the wires from it, and cleaned it up. Still nothing. No one has any insight?



Skyler

 

[csutton7]

is it the FASS system---



is the fan belt routed right---



alternator--



turbos--



or maybe the vacuum pump or powersteering pumps are going out--



vp44--





hard starting can be too high of fuel pressure or not enuff------



this is going to seem dumb, but I have to ask--do you have the FASS plumbed right--the return line is really the return lie and the feed is the feed--not opposite---



so you have new VP44, new head gasket, orings, studs, twins and the FASS has been on for awhile right???



---take a broom handle or stethascope and see if you can pinpoint the buzz--



because you've done so much and the truck has been sitting for awhile it may be tuff to pinpoint things--has the truck been garaged and kept warm during the winter or not---if not some of these things could be caused due to the weather(coldness)--



who did the work on the truck---chris