Loosing Boost Pressure - Please help (1 Viewer)

[FAWN 80]

Hi All

I have a 1992 Landcruiser 80 Series (1HD-T) Auto and ever since my last 4wd trip, boost has been fluctuating and cannot hold max psi for long.

I feel it begins after the car is properly warmed up (15-20 minutes into the drive)

The car will get to 9PSI (my max) and suddenly drop, then go back up ect ect sometimes it wont go back up at all until i let off the throttle for a few seconds then get back onto it.

Some people have suggested boost leaks, others have mentioned wastegate issues. I am just confused as to what it would be and why it is only really after an extended drive and will be perfect up until then. Was also very sudden after this trip.

Any advice at all would be deeply appreciated.

Thanks

 

[Delta VS]

Can you feel a difference in power when this happens? Could it be just the gauge?

 

[FAWN 80]

Can you feel a difference in power when this happens? Could it be just the gauge?

Unfortunately it is very noticeable. Definetely not the gauge.

 

[Delta VS]

Do you have access to an air compressor to put air pressure to the waste gate and intake system? Pressurizing the system then spraying soapy water and looking for bubbles, or using one of those smoke systems (like 100$ on amazon) are the common ways to find boost leaks.

Have you pulled intake off to see condition of compressor wheel on turbo, and how easily it spins?

Probably your best place to start, then check for boost leaks and put pressure to the waste gate line to see if it's actuating correctly/leaking.

10 psi plenty for testing purposes.

 

[FAWN 80]

Do you have access to an air compressor to put air pressure to the waste gate and intake system? Pressurizing the system then spraying soapy water and looking for bubbles, or using one of those smoke systems (like 100$ on amazon) are the common ways to find boost leaks.

Have you pulled intake off to see condition of compressor wheel on turbo, and how easily it spins?

Probably your best place to start, then check for boost leaks and put pressure to the waste gate line to see if it's actuating correctly/leaking.

10 psi plenty for testing purposes.

Would a boost leak only affect the drive when warm though? That's what is confusing me. No issues in the first part of the drive even when warm. You have to be getting on it a for a good 5-10 minutes before it will do it.

 

[Delta VS]

Would a boost leak only affect the drive when warm though? That's what is confusing me. No issues in the first part of the drive even when warm. You have to be getting on it a for a good 5-10 minutes before it will do it.

seems like a good place to start. Possible once a boot is warmed up it stretches or something. Leaks would be a good thing to rule out any time there is a boost issue.

 

[FAWN 80]

seems like a good place to start. Possible once a boot is warmed up it stretches or something. Leaks would be a good thing to rule out any time there is a boost issue.

Okay, will see if my mechanic can do the test for me. I have had the injector pump rebuilt 3 months ago and was perfect since until now. Would this have something to do with it potentially?

 

[Delta VS]

Okay, will see if my mechanic can do the test for me. I have had the injector pump rebuilt 3 months ago and was perfect since until now. Would this have something to do with it potentially?

If the pump has boost referenced fuel (there would be a small line from head/intake to top of injection pump), that system could be sticky or something. That is not unheard of. As the engine builds boost, it pushes air on a diaphragm that changes fuel rate. If that was somehow stuck, it would keep the pump from pushing out full fuel.

 

[Delta VS]

Okay, will see if my mechanic can do the test for me. I have had the injector pump rebuilt 3 months ago and was perfect since until now. Would this have something to do with it potentially?

got a pic of the pump on the engine?

 

[FAWN 80]

got a pic of the pump on the engine?

I don't unfortunately the car is at home right now. It is the standard pump fully rebuilt to factory spec. A couple of people have pointed me to the pump as maybe being the issue. Going to have to have a chat with the people who rebuilt it and get their opinion.

 

[Delta VS]

I don't unfortunately the car is at home right now. It is the standard pump fully rebuilt to factory spec. A couple of people have pointed me to the pump as maybe being the issue. Going to have to have a chat with the people who rebuilt it and get their opinion.

good plan

 

[AussieHJCruza]

What brand fuel filter is in it? Have seen (very rarely) aftermarket filters simply not flowing enough fuel. If she's starving for fuel she won't make boost.

Do you have an EGT gauge? If you do, what's it doing when the engine is loosing boost?

 

[mudgudgeon]

If a boost leak is causing an immediate loss of power, there's a high chance you could here this.
It can sound like a whistle, or like a cat meowing.

Fuel issues could also explain it. Or air in the fuel.

When there's a loss of power, does it stumble or misfire when you put foot on the pedal?
Do you see any white smoke from the tailpipe when it loses power and you still trying to accelerate?