3VZE losing Power

[Ryan Cave]

Hey guys,

I have a 1990 toyota Pickup. 3VZ-E. 174,000 miles. A few months ago the truck would start to lose power when I put a load on the motor. You don't really notice in first and second gear because those don't really put that huge of a load on. In neutral the truck will rev just fine, when I try to get passed 3000 RPM in third (40-45 MPH) is when I really notice it. The truck loses power. My pedal will be to the floor and it will slowly but surely reach about 50 MPH TOP SPEED. After I let off the throttle, the truck will die.

Things I've done.
- replaced timing belt
- replaced water pump (mine as well since I'm there)
- replaced fuel filter
- checked to make sure fuel pump works (it does)
- checked for a vacuum leak (there is not one)

Next steps:
- the truck will start, but I do feel less pressure from the exhaust and it appears to be smelling like sulfur. Im going to take off the Catalytic converter to see if the issue persists.

While that is happening, any other thoughts?

 

[Mudder]

Check for any codes is a good way to start too the link will help you find how to get the codes then just google ## code for a 3.0

Toyota 92-95 Pickup or 4Runner 3.0L or 93-94 T100 3.0L – OBD Trouble Codes

 

[Ryan Cave]

The catalytic converter was fine. I ran trouble codes and got a ding from the knock sensor. From my understanding that has no affect on this, is that correct?

Any other thoughts?

 

[Mudder]

Oh yes it does. If it's acting up after about 2k rpms it'll cut power because it doesn't want your engine ruined.

 

[Ryan Cave]

Okay. Looks like I'm replacing the knock sensor then. Super duper haha

Before I do a complete tear down,

 

[Ryan Cave]

Sorry, premature sending. Before the complete tear down, anything else. Only code was the knock sensor so I would assume that's the only sensor out.

 

[Mudder]

Could be the wire as well. Toyota does sell new wires for them as they are replaceable. I'd try that before getting a new sensor.

 

[KLF]

The knock sensor harness on top of that engine has a TSB in the system, contact the closest dealer with your vin, they should replace it for free.

 

[pappy]

The knock sensor harness on top of that engine has a TSB in the system, contact the closest dealer with your vin, they should replace it for free.

Geez, talking Martian to the fella.

TSB = Technical Service Bulletin.

 

[Tigerstripe40]

Do yourself a favor.
Put a .44mag slug in it, and swap in a 5VZ-E

 

[KLF]

And there it is. That actually took longer than I thought.

 

[Ryan Cave]

So, Is there a way to bypass the wiring on the knock sensor to see if that is the problem before actually pulling it out?

 

[pappy]

If you pull the wire the truck won't run. Ask me how I know?

 

[ntsqd]

Try disconnecting the exhaust after the cat and see if it still does it. What you're describing is exactly the symptom that I had from a rust-plugged exhaust system.

 

[Ryan Cave]

HAHA the only thing that concerns me is 2 years ago when I got my head gaskets replaced for free by Toyota (praise the lord for factory recalls) they asked me if I wanted to do a knock sensor. They said it was gonna be an additional $400 and I just didn't have the money at the time. Therefore, I said no. A few months later... check engine light came on for the knock sensor. This was about 16 months ago. So I have had a check engine light for a knock sensor for 16 months. Does it make sense that this just started happening?

 

[Ryan Cave]

Thanks ntsgd Ill try that right now !

Thank you all for contributing. Even you, Tigerstripe40 !!