Pressure at WOT

[TrboHead]

Ok...here is my problem.

I am only able to get about 150-160 lbs. of line pressure at WOT while driving down the road at full throttle or even if I try stalling the car sitting in the driveway. If I check the pressures while the car sitting still and manually pull on the TV cable then they all seem ok. I can get 275 lbs. max in reverse manually pulling the cable but if I jump in the car and try to stall it by foot brake I can only get about 150-160 lbs.

Here are the pressure readings at 1000 rpm.

low Max

Park 100 110
N 105 245
R 200 275 nice
O/D 102 250
D 105 250
2 235 235
1 240 240

The only thing I noticed was that 1 and 2 gear did not seem to change if any from low to max. I don't know if this is normal or not. I do run a Transright transbrake in the car. Just put new clutches/bands/seals in it. I don't know exactly where to start looking or test. I have already changed the TV punger spring from a white spring(Art Carr?) to a green(Transgo) spring. The car shifts very nice at this point with no power(0 boost) but I know I will burn up clutches if I don't chase this problem down.

PR valve next?

I'm stumped.

Larry

 

[WE4]

Well, My stab is....

Either TV out of adjustment , but you have cked that,,, Hrmm or you are cavitating it but stalling it will do it too? Sitting still? That puzzles me. If fluid was flowing away from sump it would do that, But sitting still is odd. And , pressures look good. hrrrmmm

 

[TrboHead]

Well,

Could it be a flow problem when rpm builds? Cooler lines kicked? Pulling air in other that filter? When I rev the motor up and try to stall it slowly I notice that it builds pressure with just a little gas, rpm about 1800, but when I push the peddle any farther I can almost here a slight noise(flushing fluid sound) as I see the pressure snap to about 150 and stay there even if I push the peddle to the floor. This is so weired. I can step out of the car and pull on the TV cable and get 250 psi with it idleing. Could the PR valve be stuck? It maybe giving me a high pressure with low rpm but when I push on the converter the flow doesn't keep up?

Puzzled
Larry

 

[WE4]

Just out of curiousity?

What converter are you running? Did it have a lube tube?

 

[TrboHead]

I'm running the Art Carr non LU. What's a lube tube?

BTW - I pulled the PR valve out. It wasn't stuck at all and looks fine to me. Transgo Kit shows that you need to grind on it and take one of the ridges down. Mine didn't have this mod done so I ground it down and will see what this does. It also had a black spring and not the Transgo green spring. I know I probably need to put in a new bigger PR valve anyway.

Larry

 

[WE4]

Well....

I disagree. PR circuit is NOT the problem. It is in TV somewhere. Art carrs converters dont have what I asked so we will drop that. I would still drive with test gauge and see how it gets back to 150. Under throttle or after a second or... however. I just dont know where to have you start. but there is defintely something up . I need to think....

 

[77 cruiser]

Check that TV

Are you sure you`re getting max. TV, cause you say when you pull it by hand the press. comes up. Have someone mat the gas & see if the TV cable is tight.

Jim

 

[WE4]

Sure does sound like that , doesnt it, but he said he cked that. I was thinking the same thing.

 

[TrboHead]

That is what I thought. I made sure it was as tight as possible at WOT before checking the pressures several times.
At one time I actually put the car in gear(OD) idleing with the emergency brake on and stepped out of the car disconnected the TV cable from the throttle. Pulled TV all the way and got about 245 psi at idle. I then gave it a little gas at the throttle while still pulling and holding on the TV cable(not very safe but wife was busy). It drops to about 150 psi.

It's almost like I get pressure at idle(~1000 rpm) with TV pulled but as soon as I rev it up a bit the pressure drops. Could I have a problem with the pump but it's not really showing signs of this until the volume increases?

My TV set up looks fine. I'm using the Transgo Bootstrap Green spring with one shim(.030) between the spring and the TV plunger. Could I have the TV plunger Bushing turned around?

TV set up as so: TV spring(tiny spring), Throttle valve, Green spring with strap inside, shim, TV Plunger, TV Plunger Bushing and then pin.

Larry

 

[TrboHead]

Updated pressure at 1500 rpm

Well......

Now I checked the PR(TV Boost Valve) to see what I had in there. It's a .470 (stock).
Checked the pressures again but decided to run the car at about 1200-1500 rpm in all the gears. This may tell the story.

Gear Low Med Max
P 95 95 98
R 175 175 180
N 110 150 235
OD 110 150 160
D 110 150 160
2 175 175 180
1 175 175 180

Does this mean I can put a .570 PR in and fix my problem? I don't why I can get so much pressure at idle compared to 1500 rpm. WOT pressure is what I need to concern myself with. This may be normal. I sure hope this is my problem. I don't know what I'm doing. Just trying to keep it all together. I'm going to sit back and digest all this before I make another move.

You guys are great

Larry

 

[WE4]

Something is still not quite right.

Tv Boost is still low, next to non existant. The neutral vs park thing is very interesting. They should follow each other. You got a good one there. I would need to "nose around" to see what was up. If you like, I can send you a "test" pr set up to see if anything changes. At this point CHANGE is what you are looking for. If so we will go from there. If not , Then I got to look elsewhere for the culprit or a sign. Let me know ...

 

[TrboHead]

Test PR set would be great!!! I need a .570 setup anyway. I will call you Monday morning. Change would be good. I feel much better that we are closer anyway.

BTW I ran some new pressure numbers making sure the fluid was hot and rpm was rock solid at 1500 rpm. I wanted to double check Reverse and Nutueal reading. Each gear I started from the Park positon. I pulled the TV cable by hand as hard as I could stand but noticed I could get a pair of pliers and probably get a little more pull out of the cable. Maybe I need to recheck these numbers by pulling max TV with a set of pliers. I really hate the thought of pliers on my car.

Gear Low Max
P 85 85
R 170 190
N 105 210
OD 105 210
D 105 175
2 145 150
1 130 140

Thanks a bunch!!

Larry