Greg, you know better'cuz he's in a *smog* state
... no big block for DR, without getting an exemption and getting the attention of the DMV.
-- A
I was being sarcastical.....
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
RPM's too low at 65 mph, what's up with that?
- Thread starter Desert Rat
- Start date
I was being sarcastical.....
Desert Rat
Fetch the comfy chair
I think Sonora Pass is about that, maybe a little less. The distributor is a brand new MSD HEI. The fuel filter is brand new. In fact, mechanical fuel pump is also new and I installed a helper electrical pump in the rear to keep the lines full to avoid any possibility of gas overheating in the metal lines during slow driving. One thing that did happen this last trip was that on the way down I was having trouble maintaining idle. I kept stalling out when I would take my foot off the gas to brake. Finally in Sonora, I adjusted the idle screw to bring the RPM's up which solved that problem.
Yes to both
Neutral would make the truck not go very fast at all. Unless you were pointed downhill
High means the '205 is runnign at its original ratio; Low means you're doubling the gear ratio of the '205, i.e. 4:1 and 2:1 for "lo" and "hi" on the sticks.
-- A
I was being sarcastical.....
There are certain advantages to owning REALLY old trucks -- like all of yours, or my '74's.
Anyway, maybe the stumbling is a carb issue? I have a good guy up here, but I think Scott has somebody down in Fremont who's good too... prolly worth it.
::shrug:: I'm headed down to DR's shortly to check out the tach, and I'll give forth my expert (
) prognostication on how the truck runs too.-- A
Desert Rat
Fetch the comfy chair
With the rear in H and the front in neutral on the NP205, I should be running 1:1 right? Provided the NP203 is in H.
1:1 for the t-cases ... but the tranny is .7:1 in OD. It's 1:1 in 3rd.
Tranny
4 .7:1
3 1:1
2 1.63:1
1 3.06:1
First Tcase (203)
2:1
1:1
Second Tcase (205)
2:1
1:1
So your net is, in OD-hi-hi .7x1x1 = .7:1.
In 1st-lo-lo,. 3.06x2x2 = ~12:1.
Then account for the 4.56:1 in the axle, etc etc.
-- A
If you put any piece of your drivetrain in neutral then you aren't supplying any power to the wheels.
Also is your carb jetted correctly for the altitude? I am willing to bet that your carb is running too rich due to the altitude and most likely needs adjusting as well. Are you running a quadrabog?
Desert Rat
Fetch the comfy chair
DrEmu came over and we checked the tach with a meter. It is reading about 100-150 rpm slow at lower speeds and 150-200 slow at higher revs. So, at 65 mph in OD, I am actually running around 1800-2000 rpm, which is about right from what I'm reading. DrEmu thinks it is a carb issue. I tend to agree. You can get the tranny to kick down when you stomp on it, but the truck doesn't seem to have much power. I'm thinking the Edelbrock Q-jet needs an adjustment or a re-build. I'm leaning towards it running too lean, but sometimes it smells like it is running rich. DrEmu, throw me Scott's info, as well as your Concord connection.
k20
3/4 ton status
Wait, so you are running an electric and a mechanical fuel pump at the same time? If I were you I would ditch the mechanical (when it goes bad it just fills up the crankcase with gas anyway), and just run the electric. And if possible, use a regulator with a return fitting, and have it return to the tank (how I have mine setup, still using the tbi in tank pump, and a regulator so I can run a carb, with no mech pump). That will solve any vapor lock issues. How it is now, if I aint missing anything, say at low idle, the engine is using minimal fuel, the mechanical pump aint pushing that much fuel, and the electric pump is still sitting there screaming away heating up. The electric pumps are cooled by the fuel going through them, so whatever fuel is basically sitting in it is overheating.
The electric pump you added, it is for a carb setup correct? If it is just a generic fuel pump, it could be that it is for a fuel injected engine and is pushing 40-60psi to the mechanical pump, and causing some screwy stuff there. If it is a carb pump, check that it is functioning properly, could be it isnt pump and the mech pump is attempting to draw fuel through a locked up pump.
Just some thoughts I have
The electric pump you added, it is for a carb setup correct? If it is just a generic fuel pump, it could be that it is for a fuel injected engine and is pushing 40-60psi to the mechanical pump, and causing some screwy stuff there. If it is a carb pump, check that it is functioning properly, could be it isnt pump and the mech pump is attempting to draw fuel through a locked up pump.
Just some thoughts I have
Driving with a doubler on the street you want both the 203 and the 205 in high range which is a 1:1 ratio. The 700R4 on the other hand when it's in OD it is a .7 overdrive.
Desert Rat
Fetch the comfy chair
The electric fuel pump is just a helper pump that runs a low pressure 4-7 psi. It is working properly and the mechanical pump is new. With the low pressure coming from the rear pump, it shouldn't be causing any problems with the mechanical pump. Running a rear helper pump is common in rigs where vapor lock are a problem. I think I'm going to take it to either Fremont or Concord, two places that have Q-Jet carb shops and have them play with it.
Desert Rat
Fetch the comfy chair
By the way, I need the info on your connection in Fremont for carb work.
Dremu has it for you.
Also ditch one of the fuel pumps and i'll bet your problem goes away.
Desert Rat
Fetch the comfy chair
It was worse without the helper pump. Of course, it didn't help that I had dual exhaust and one pipe ran right along the frame rail too close to the gas lines. I've dumped that in favor of single exhaust now. This Blazer has been gutless since the day I bought it. I've swapped in a new MSD ignition, headers and new fuel pump to no avail. DrEmu had the name of the shop in Fremont, but I can't find any info on it in the yellow pages.
Nor-Cal Carburetor Co
(510) 796-5474
4461 Peralta Blvd
Fremont, CA 94536
(510) 796-5474
4461 Peralta Blvd
Fremont, CA 94536
Desert Rat
Fetch the comfy chair
Thanks much.
FYI
I have a 95 Ford with a 460 E4OD tranny and a doubler with 4:10 axle gears with 35s
The whole setup is gearing wise very near what you have. I end up using the 1:1 gear in my tranny a LOT. Going down the Intersate at 75 is fine in OD but the slightest hill and I kick it down to the 1:1 gear.
I bet you need more motor or lower gears.
I have a 95 Ford with a 460 E4OD tranny and a doubler with 4:10 axle gears with 35s
The whole setup is gearing wise very near what you have. I end up using the 1:1 gear in my tranny a LOT. Going down the Intersate at 75 is fine in OD but the slightest hill and I kick it down to the 1:1 gear.
I bet you need more motor or lower gears.
Have you verified that the seconondaries (i.e. "4 barrels") are actually opening, or at least are adjusted to open at the correct time? A buddy got a rebuilt q-jet a couple years ago and when he first installed it the secondaries would not open, almost like they were stuck.
Also, have you verified that you are getting 100% throttle opening at the carb? I have also seen this issue after people have installed a new carb and the linkage is not adjusted right and therefore only getting partial throttle even with the foot planted to the floor.
Also, have you verified that you are getting 100% throttle opening at the carb? I have also seen this issue after people have installed a new carb and the linkage is not adjusted right and therefore only getting partial throttle even with the foot planted to the floor.
Desert Rat
Fetch the comfy chair
I'm thinking the problem does lie in the Q-jet. I don't think the secondaries are opening at all. I think the tranny is kicking down when I stomp it, but that's it. I'm going to have a good carb shop go at it and see what happens.
I've offered up my help a couple times already for various problems you've had but you don't seem to want my help otherwise i would have offered here this time. 
