89 V2500 seems to lack power going uphill.

[Ditch Wicked]

My 89 v2500 with the 5.7 and THM 400/3L80 cant seem to get out of its own way going uphill. Max going uphill with no load is around 50-55. I am not sure what transfer case I have, and the rear end is a 4.11. When towing a 93 K3500 on a heavy trailer I was pegged out at 35MPH. Is there anything I can do to improve this, or is the EPA to blame? If this is posted in the wrong forum, please let me know and I will move it to the correct one.

 

[bucket]

Just mild hills, or long, mountain passes?

 

[YakkoWarner]

Are you running TBI or a carb? I'd expect a 1989 to be TBI but maybe not. If you do have TBI, are you getting any errors on the service engine light?

 

[Ditch Wicked]

Just mild hills, or long, mountain passes?

Long mountain hills. I live just over the top of the Tecate divide. So, its downhill going East or West, and long uphills getting home.

 

[Ditch Wicked]

Are you running TBI or a carb? I'd expect a 1989 to be TBI but maybe not. If you do have TBI, are you getting any errors on the service engine light?

TBI, 5.7, 3l80, 4.11 diffs.

 

[fast 99]

possible restricted exhaust? check with vacuum gauge

 

[bucket]

Long mountain hills. I live just over the top of the Tecate divide. So, its downhill going East or West, and long uphills getting home.

You may very well have some amount of lost power somewhere, but I don't think you are too far off for a TBI 350 pulling a heavy Suburban up a long and steep incline.

 

[Snoots]

Clogged catalytic converter.

 

[Ditch Wicked]

possible restricted exhaust? check with vacuum gauge

Exhaust is clear. Has a small partial crack in the DS exhaust manifold that seals up once the manifold heats up. I plan on replacing the stock manifolds with headers once I get out of CA this spring.

 

[Ditch Wicked]

Clogged catalytic converter.

Cat is clear.

 

[Ditch Wicked]

You may very well have some amount of lost power somewhere, but I don't think you are too far off for a TBI 350 pulling a heavy Suburban up a long and steep incline.

I was afraid of that. It does have almost 160k miles on it and the previous owners don't seem to have cared much for maintenance schedules. I was talking to the wife about it, and she not being a car person, I described it as "its like the motor is tired". I guess I will need to pull it and do a rebuild before I put headers on it. Going to be fun towing it cross country with a 93 K3500 with a 7.4 and 4l80-e. Might be looking for a couple 700R4's later this year.

 

[bucket]

I was afraid of that. It does have almost 160k miles on it and the previous owners don't seem to have cared much for maintenance schedules. I was talking to the wife about it, and she not being a car person, I described it as "its like the motor is tired". I guess I will need to pull it and do a rebuild before I put headers on it. Going to be fun towing it cross country with a 93 K3500 with a 7.4 and 4l80-e. Might be looking for a couple 700R4's later this year.

I wouldn't go that far yet. It would be wise to check things like fuel pressure, injector spray pattern, condition of ignition system, timing, etc. Timing alone can make a big difference.

 

[Rusty Nail]

ya. timing

 

[Ditch Wicked]

I wouldn't go that far yet. It would be wise to check things like fuel pressure, injector spray pattern, condition of ignition system, timing, etc. Timing alone can make a big difference.

Fuel pump was replaced 2 months ago, Injectors replaced and TBI rebuilt 4 months ago, Ignition system was all replaced 6 months ago except for the distributor (cap, rotor, Ignition module,wires plugs, relays, neutral safety switch, and ignition switch) and ECM. It went to my mechanic today and had an oil change and had oil pressure, fuel pressure, vacuum, timing and a visual inspection done. He even gave ole girl a colonoscopy to see if the cat was clogged. His conclusion was " its an 89 chevy 350 with a 3 speed trying to move a suburban uphill against gravity, CARB, and the EPA". Thanks for all the insight, and questions to ask.

 

[peats]

My Blazer came with a 350 that lost power like yours. Changed cam and timing chain, nothing else and it's been running very strong for 40k miles in my '81 square.