Help with tranny and boost issue

[fairlady2jz]

Hello everyone I recently aquired a 2001 lightning and I've been fixing a few bugs but now I'm a bit stuck. I have the infamous boost issue. The selenoid actuates up and down when I rev it by the hood. When I drive it I hit the gas and the truck becomes violent and it moves hard, yet I only see about 1 psi in the boost gauge. Yes i have checked my lines and also tested my boost selenoid, could I have a bad boost gauge or a lightly faulty boost actuator?

My second issue is the transmission, it shifts smoothly but when I'm driving and I get into the overdrive gear the truck begins to buckle and the more I accelerate the worst it get. Any help would be appreciated.

The mods to the best of my knowledge are long tube headers with full exhaust, full intake with throttle body and maybe heat exchanger with pulleys not sure on these last two

 

[Dusten]

Hello everyone I recently aquired a 2001 lightning and I've been fixing a few bugs but now I'm a bit stuck. I have the infamous boost issue. The selenoid actuates up and down when I rev it by the hood. When I drive it I hit the gas and the truck becomes violent and it moves hard, yet I only see about 1 psi in the boost gauge. Yes i have checked my lines and also tested my boost selenoid, could I have a bad boost gauge or a lightly faulty boost actuator?

My second issue is the transmission, it shifts smoothly but when I'm driving and I get into the overdrive gear the truck begins to buckle and the more I accelerate the worst it get. Any help would be appreciated.

The mods to the best of my knowledge are long tube headers with full exhaust, full intake with throttle body and maybe heat exchanger with pulleys not sure on these last two

You really need to figure out the mods first. Stay out of boost until you figure it out, or you're going to have a very expensive mistake.

The shutter under load in od is likely a misfire. I'd start with a tune up, and fuel filter. That said, don't do the tune up until you figure out what pullies are on the truck. Post some pictures of the pullies and I'll let you know.

If the solenoid operates in park, it likely works all the time. My guess is either the line is plugged our you have a leak before the boost gauge. Is it the stock gauge?

 

[fairlady2jz]

This is the truck and the pulleys, they seem stock to me from the research that I've done. Let me know Thanks.

 

[fairlady2jz]

I did the egr delete and this is my vacuum/boost line set up which I believe is correct. I also did a boost check with my compressor starting from the black line coming off the lower driver plenum port and the gauge showed boost.

I decided to check the line that goes to the rear of the boost gauge and it was ok but I found this vacuum/boost line just hanging there loose.

I traced it down to this, which I have no clue what its for, any guess?

I cranked on the engine and you can hear a suction sound coming from the open end.

then I did this to the open end

which resulted in this

Now while capping off that end I drove the truck and under full throttle I was able to see full boost, but if I released the open end and drove it then I would get the normal vacuum reading and once full throttle barely 1 pound. Any help would be appreciated, thank you.

 

[Dusten]

Your underhood vacuum setup looks correct.

That setup under the dash looks like the setup that runs to the stock gauge, when someone t's into it with aftermarket gauges. the black line runs to where the T is and is normally just run to the stock gauge. that T and clear line likely went to an aftermarket gauge. The black line you are plugging with your finger goes to the stock gauge. I would remove that T and clear line, and hook it up correctly.

You do infact have stock pullies. I would replace the plugs with OEM plugs gapped at .042(stock gap). Replace the fuel filter too just for good measure and then give the truck a drive. If you didn't have a tune for the EGR delete you should have a check engine light by now.

 

[fairlady2jz]

ok ill give that a shot, ill contact you once I do so. thanks for all the help and happy new year.