Low power on 97 SC 80

[Waggoner5]

My truck just doesn't run like it should. I have driven other SC trucks and my power seems down. While running down the highway, it takes 1/3 pedal to get it to speed up and it constantly seems like its holding back. I have removed the front shaft and added front hubs and the difflock switch and it won't even spin the tires in the rain, in 2wd. The timing is set to Toy specs, the TPS values are correct at all pedal %s. Its not throwing any codes. Its not clattering like its lean, although it seems like a lean condition. The mileage is around 10.5-10.7 driving it sanely. Any suggestions?

 

[landtank]

check the e-brakes, the bellcranks tend to stick in the on position. If the handle in the cab has some play more than an1/4" or so in it when you pull up on it they're stuck.

 

[cruiserdan]

What is the boost pressure?

 

[clownmidget]

Do you have a boost gauge? If so, how much are you developing?

 

[Big_Moose]

What size tires are you running and / or are you geared to match?

 

[clownmidget]

Dan, you scooped me by 3 minutes...you're just too fast with that h20/meth injection

 

[cruiserdan]

Dan, you scooped me by 3 minutes...you're just too fast with that h20/meth injection

Don't forget the undersize pulley....

 

[clownmidget]

Oh that's it. I'm going out to the garage now to polish my snail...

 

[Waggoner5]

I am doing fuel pressure and boost pressure tomorrow. I am running a 34" tall tire with 4.11:1 gears.
How much boost pressure should I expect? Never thought about the e-brake.

 

[LandCruiserPhil]

Mileage sounds in line.
Any chance of your air intake being restricted?

 

[Junk]

34" with 4.10 should not be much issue especially blown. Other than the above ideas, you don't have a massive exhaust issue do you?

 

[Scamper]

bypass stuck open?

 

[Waggoner5]

It has stock converters, magnaflow muffler and stock tailpaipe. This is the way it came from the PO. I am not happy with the sound or the terrible install but it doesn't leak yet so it stays for now.
Thought about a restriction in the airway so I put a cone filter right on the mass air eliminating the airbox and plumbing. Allowed you to hear the blower better but thats it.
I haven't checked the bypass. Is that a common or conceivable problem?
Thanks for all the responses, keep them coming.
G

 

[Scamper]

I don't think a stuck bypass would be at all common. But since you said it was acting weak, I took that to mean it behaved like it didn't have the SC on it. Hense, maybe the bypass is stuck open, which would prevent the boost.

When you get the boost measured, that will tell you if this is a potential problem or not.

 

[LandCruiserPhil]

<<<Thread Hi-jack>>>

Where do you read the boost presure at?

<<<Hi-jack over>>>

 

[CruisenSurfin]

Maybe your center diff is not locking up? Have you tried it with front driveshaft installed and wheels locked and diff lock switch off?

Jesse

 

[Waggoner5]

I haven't tried the diff lock stuff yet, but the driveshaft is getting a CV and when its done its going back on for a test. I haven't ever heard of a diff lock not locking. When you remove the front shaft, you have to lock the diff or the vis. coupling will kepp the truck from going anywhere. It will move but you can tell that its spinning.
G

 

[clownmidget]

The stuck open bypass results from poorly placed hose clamps. Check George Scolaro's site for a pic (http://george4wd.taskled.com/scharger.html).

Boost can be measured at the port on the firewall side of the intake manifold or at the fuel pressure regulator, by what I've been told. Not certain if there would/should be a difference in which one you use. Anyone with experience on this one?

 

[cruiserdan]

I read mine at the upper intake plenum. there is a plug at the back that you can put a 1/8NPT male fitting into if you open up the threads a touch. You should max out at at least 5 PSI, possibly as high as a touch over 6.


If you tinker with the size of the nose pulley you can easily bump 8 PSI (NOT recommended unless you address fuel delivery, intake air temperature and octane.)

 

[clownmidget]

Dan, that's the one that TRD provides a plug for with the s/c, right? That's where I had intended to measure boost but I've found out that Yomama and Turbocruiser both have theirs measured from a "Y" at the fuel pressure regulator.