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Posted

Truck starts, idles, and accelerates off idle fine. Problems start when shifting into 4th and 5th gear. Which is approximately 40/45mph. Anyyhing beyond that and the truck just starts spitting, sputtering, coughing and popping out the exhaust. 9 times out of 10, flooring the gas pedal makes the symptoms worse. It accerates somewhat normal one out of ten times when I mat it, but it doesn't last long.

 

It also seems to start at a specific point in the throttle travel. Which would make me think it is the TPS, but I have replaced and adjusted it according to Cruiser's instructions with no change. Ive done it many times so I'm confident I did it right.

 

Need to test fuel pressure, think the pump is original, but unsure.

 

Figure it's either, TPS, MAP,  or fuel pump. Ballast too.

Posted

Did you move your distributor lately? If so, check indexing. Also, could be cross fire in the distributor cap during advanced timing situation (upper RPM's).

Posted

Sounds a lot like when my fuel pump died. It was much better when the truck was cold but got worse as it heated up over the course of a day. 

Posted

I would check pressure like stated above. under more load like in 4th and 5th gear you will see issues like you stated when you have low pressure. The fuel injector has hard time keeping up when you are running below about 22 psi. If it is low pressure than you have a few things to check. the fuel pressure regulator fuel filter, hoses in the tank, than the fuel pump its self. 

 

I see the hoses in the tank fall apart all the time with the ethanol that is put in the gas now days.

Posted
4 hours ago, omega_rugal said:

weird, a bad pump will no let you revup enough to get to 4th or 5th gear... sounds like a timing issue...

When my fuel pump went initially I started noticing issues above 3000rpm, getting worse and worse. I was on a road trip through the middle of nowhere and by the time I was stopping at every single parts store to try to find a new pump, I was struggling for 2000rpm. I could still hit 60mph, it just took a looooooooong time. Right before I changed it as fast as I could do was almost a minute to get to 30mph. But it still would get to 60 if I was incredibly gentle with the skinny pedal. 

Posted
20 hours ago, gogmorgo said:

When my fuel pump went initially I started noticing issues above 3000rpm, getting worse and worse. I was on a road trip through the middle of nowhere and by the time I was stopping at every single parts store to try to find a new pump, I was struggling for 2000rpm. I could still hit 60mph, it just took a looooooooong time. Right before I changed it as fast as I could do was almost a minute to get to 30mph. But it still would get to 60 if I was incredibly gentle with the skinny pedal. 

 

revving up under load i meant...

Posted

Update:

 

Fuel pressure is good. 30/32psi idling w/vac, 40psi without vacuum, pressure instantly jumps several psi when you rev it.

 

NOTE: I conducted this test after the truck had sat for several days and was totally ice cold. Going for drive now to warm it up and test again.

Posted

Update:

 

Back from short drive. Syptoms the same, but are all over the place. Sometimes going slow. 35mph try to accelerate and it won't, sometimes high mph like 45 to 55. Then one time it accelerates smoothly all the way up to 80mph. 

 

The one thing that is consistent is it always does it when trying to accelerate or maintain speed.

 

I don't know what happened the first time I tested the fuel pressure, but when I tried again I could not get it to work. It seems like something is missing from the fuel pressure tester, something that was supposed to depress the Schrader valve. How it worked the first time I have no idea, because nothing has changed between then and now.

 

I decided to take out the Schrader valve, AFTER bleeding off pressure from fuel rail. I noticed while bleeding it there was a lot of air coming out.

 

Have a video, going to try and upload it and post a link.

 

Also, found a small vacuum leak. The smaller feed line for the vacuum ball had broken off leaving it just sucking air. I found where it attached to the intake and capped it. Don't think that it was causing any real issues, but figured I might as well.

Posted

if your getting al lot of air, I bet you need to check the hose in the tank.

Get the vacuum ball line fixed. It supply's the vacuum for everything that needs it, like 4 wheel drive.

Posted
40 minutes ago, dvitha said:

if your getting al lot of air, I bet you need to check the hose in the tank.

Get the vacuum ball line fixed. It supply's the vacuum for everything that needs it, like 4 wheel drive.

 

Ya it's got to be sucking air from somewhere. But I'm not convinced it is the source of the problem.

 

Don't need vacuum for anything anymore. A/C doesn't work and don't need heat. Front axle swap to a non CAD D30 also.

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