Engine/Transmission (1994 - 1998) Cranked Down Gov Springs???

[biggy238]

I started a truck yesterday on a local lot. . 1997 5 speed manual. . Single cab 4X4.



I thought it should have been a 215 pump. . I didn't look under the hood because of the snow.



Anyway. After it warmed up... I tached it. . My brother had driven it the week before. He told me it would Tach to 3400rpm but didn't have any power.



I free-wheeled it to 3400 with the trans in nuetral, but what caught my attention. . When you let off the throttle the motor shuts off until it drops atleast 500rpm, and then fuels itsel again and idles. . I did this atleast 10 times at different RPMs just to confirm what it was doing.



I didn't drive it because of the weather, but I wanted to ask what it would act like if someone had just cranked down the stock governor springs.



Does that sound likely??

 

[CashD]

I just bought a 98 12valver and it's still bone stock. it's identical to what you describe. it does have a 215 pump,, and the power is normal for a stock truck. the pump is a virgin (breakoff screw still in place). i can rev to about 3400 and when i let off it comes down normally but drops to about 700 before idling back up to 750-800 range. doesn't do it once it's warm,,, and when i say warm i mean driven a mile or so.

 

[obert]

Alot of mechanical gov'd engines do that cold, Iv herd a few even a little warmed up.



When I read the title I was hoping to see the answer to the above question. would it hurt to "tweak" them a little on an old engine for the sake of wear? would they bind and actauly limit flyweight travel if gone too far??

 

[DWitcher]

I'd like to know the BAD results from cranking down the gov springs because all the 3 and 4 gsk's do is hold the gov weights. I'm not talking about bottoming the gov screws either.

 

[MLee]

I think that you need to drive it and see where it starts to de-fuel. I took mine down "1" click and got a couple hundred more RRRRs out of it and raised the fuel cut of a little. It also brought up the Idle about 50 rpm. But if static high rpm was 3200 this might already be done. If you are very careful you can remove that break of screw with out messing it up.

just my penny's worth.

Marv.

 

[JoshPeters]

On a Diesel, when you decelerate the engine, the pump will litterally shut the fuel off. So a Free Rev to 3400, and when you let out... . it sounds like it shut off... . is normal.



A free rev to 3400 your pretty brave on stock valve springs on a truck you don't know! I wouldn't trust the factory tach that much!



Josh

 

[Forrest]

I've got the 4k springs & when it's cold & I let off from low rpm, under 2k, taking it easy & pulling up to a stop sign, you get a 'bounce' like you're describing. The idle dips below normal & comes back up.



I wish it'd do it all the time. I explain it as "it's not stock BABY"!



Governor spring bounce ... it's a wonderful thing.

 

[biggy238]

I think I described it inaccurately. When you let off of the throttle, the truck doesn't deccelorate in a natural way... If it is turning 2000rpm say... constantly, and you let off the throttle, it doesn't just naturally idle down to the low idle speed... It falls dead for about 500rpm... So between 2000 and 1500 rpm the engine is dead, and it almost feels like it tries to counterrotate, then, the fuel comes back in and idles it down to low idle.

It's wild to me... Mine slows itself like any engine should, at a predictable rate. This one flat lines for several hundred RPM and then catches itself and idles down.





As for taching someone else' truck... . Being a 12 valve it shouldn't rev out far enough to damage itself... . If it can, they should be telling you up front that it can do so.

 

[JoshPeters]

As for taching someone else' truck... . Being a 12 valve it shouldn't rev out far enough to damage itself... . If it can, they should be telling you up front that it can do so.

So every used car lot you can walk up to a car start it, and stand on the throttle till it stops reving?



Redline is there for a reason.

 

[biggy238]

The Governor is there for a reason.



And beyond that, just how many cars do you think are still on the road that are capable of reving until they pop?



Anyway, It's beside the point. The truck Revs higher than is should and then stumbles back down to idle. I just wanted to know if someone had messed with the Gov. Springs and if it was a mild fix, or if something was wrong with the injection process rather that the gov. assembly.

 

[JoshPeters]

The Governor is there for a reason.



And beyond that, just how many cars do you think are still on the road that are capable of reving until they pop?



.

All Gas engines are quite capable of blowing.

Done it a few times.



No engine is designed to sit at or beyond redline for any REAL length of time. You say Still on the road, well that would go back to the old Muscle cars, the 80's etc. I will bet all the money I have, you take an old Chevy 350 and hold your foot on the floor till it stops climbing, Your going to have issues. Floating valves, or worse.



If you came to the shop I work at, and did that to ANY of our lot cars, you'd be removed from the vehicle and asked to leave. I'm sorry I think it's very disrespectful to do something like that to someone elses vehicle. Do what you want to yours.



Ok, I'm done. I won't be replying anymore. There is no point.



Josh

 

[biggy238]

and hold your foot on the floor till it stops climbing, Your going to have issues. Floating valves, or worse.

A situation that is completely out of context with what I did. Along with the implication that what I did was totally immoral and I needed to be reprimanded.



Yes It MIGHT have damaged it. .

 

[obert]

... ... . so how 'bout those governor springs?

 

[biggy238]

I never did go back and drive it in good weather... . They moved it to the front of the lot. . I'd like to see where it stops fueling. . that would eb a great indicator.