Uphill battle....

[89Suburban]

Since I have redone the heads, the truck has been running great and very strong. There is one issue that I have ran into though. On very, very long and steep upgrades, truck in 2nd gear, and about 3/4 throttle holding speed about 35 mph towing the boat, power starts to die away and I notice the temp gauge start rise, not over heat, just rise up from normal a bit. I have to let off the gas and the power comes back. But when you push into it hard again, it starts the same thing. I am wondering if the fuel supply is weak in those conditions and it's leaning the motor out, causing it to get hot and loose power?

I mean other than in this extreme situation the truck runs great, has plenty of power, timing feels spot on. I think I need to check the fuel filter. I don't remember ever replacing it since I bought it. Isn;t there some kind of screen filters in the TBI unit too?

Thanks for any advice on finding this bug out.

 

[Old77]

Have you ever checked the fuel pump? If I remember right you don't ever run a full tank do you? I'm wondering if when on an incline like that if the pump is having a hard time getting the fuel from the back of the tank Fuel filter replacement is also a good place to start since you said you've never replaced it.

 

[89Suburban]

That fuel pump was replaced last summer, it was before I joined here. Like, August of 2010. I came back to the boat ramp at midnight to pull the boat out and go home and the fuel pump was fried. And the beating on the tank thing ran out of mojo, that's how I got the truck to start for the previous two weeks before that, lol. That was a ****** night.

 

[Old77]

That fuel pump was replaced last summer, it was before I joined here. Like, August of 2010.

I'm just lost without my 89Sub write ups

 

[89Suburban]

I'm just lost without my 89Sub write ups

That would have been a good one, but I let the shop fix it, I need to dig those pics up of it getting towed by the flatbed. I had to call and wake my brother up to come get me and the boat out of there, it was a long night. And I had to leave my Burb sitting in the ghetto, I thought for sure my **** was going to be on cinder blocks the next morning.

 

[HotRodPC]

The warming up in that situation is likley normal and I wouldn't worry bout that part of it. Do keep in mind, its still an older bottom end and very very well worn rings. When you're climbing like that and pulling a load, you're putting more strain on the motor. Those tired rings only can only hold so much compression. It would be my guess its just a tired motor. I wouldn't think any related to fuel at all. If its got a good spray pattern and it does keep running, without chuggin like its running out of fuel, then fuel isn't the problem. I'm guess you're just putting a tired motor under strain and up an incline pulling a load, its likely normal for a low compression motor. What you're describing is not hp loss, its torque loss. Motor is slowly losing its ability for pull power. I woudln't sweat it dawg. Drive it till you can't drive it no mo.

I'd imagine if you could pull your PCV valve, and watch all the blow by come out of the valve cover while climbing that hill pulling the boat, it would be smoking like a freight train.

 

[dhamp]

Just to be clear, on that same steep grade and no boat, she's not affected??

 

[89Suburban]

The warming up in that situation is likley normal and I wouldn't worry bout that part of it. Do keep in mind, its still an older bottom end and very very well worn rings. When you're climbing like that and pulling a load, you're putting more strain on the motor. Those tired rings only can only hold so much compression. It would be my guess its just a tired motor. I wouldn't think any related to fuel at all. If its got a good spray pattern and it does keep running, without chuggin like its running out of fuel, then fuel isn't the problem. I'm guess you're just putting a tired motor under strain and up an incline pulling a load, its likely normal for a low compression motor. What you're describing is not hp loss, its torque loss. Motor is slowly losing its ability for pull power. I woudln't sweat it dawg. Drive it till you can't drive it no mo.

I'd imagine if you could pull your PCV valve, and watch all the blow by come out of the valve cover while climbing that hill pulling the boat, it would be smoking like a freight train.

Let me ask you this, if there is a lot of blow by under that heavy stress situation, could it be choking the engine through the breather hose with crap? It is also very amazing to me that there is no smoke whatsoever coming out of the exhaust during this **** either. First thing I do is look in the mirror to look for blue smoke coming out and there aint ****. Clear as ever.

Just to be clear, on that same steep grade and no boat, she's not affected??

Actually this happened twice, once without the boat too. Very steep half mile grade, 2nd gear on the 700r4, 3/4+ on the throttle holding around 35 mph +/-. Other than that she would blow past anybody on the highway with the boat on if I wanted it to, I mean she will go.

What if the timing was too retarded, would that do this?

 

[bucket]

Sounds like fuel to me. I've had to put a couple pumps in mine too, the aftermarket TBI pumps seem to be "just good enough" when they are new so when they get some age on them, the pressure starts to fall off. What will happen is the power falls off over time and you don't realize you ever had a problem until there's a new pump in there again.

Dropping that 40 gallon tank is a pain, especially with the duals I installed. This last time I just made a access panel in the rear floor (it's not a virgin rust-free truck anymore anyway) and now changing the pump is a 30 minute job, tops. I used the section of floor I cut out as the hatch, and added a flange around it for support, then sealed it up with that tar-tape stuff. Now on long trips I carry a spare fuel pump, since it can easily be changed on the roadside.

 

[Old77]

Sounds very similar to my setup bucket