sootnsmoke

Did my first towing with the new to me truck in my signature. Very disappointed and I am not sure the truck is gonna work out but thought I would check in with everyone to see if I am missing something or not. Truck is completely stock, has 102K orig miles. Right before the short towing trip I just changed air filter and oil/filter. The lift pump was changed a few thousand miles ago (have previous owner shop receipt) Fuel filter was changed 3,000 miles ago by previous owner (have shop receipt). No extra gauges installed currently. Engine starts right up, does not smoke under load. Towing my 5K LB trailer going down level ground at 65 mph no issues and only partial throttle needed. With stock 235/85/16 tires, 4.10 gears and the Getrag in 5th gear the RPMs should be around 2100 or so. When a slight grade comes on (probably only 3% or so), I need to keep the pedal floored WOT to maintain 60 MPH. Truck sometimes even looses a couple mph to 57 and barely stays there at WOT during that slight grade. When back on level ground there is no problem maintaining 65 to 70 and WOT is no longer needed. No smoke under load so I assume boost is adequate for amount of fueling. I also assume the stock governor spring is not defueling at 2000 rpms and 60 MPH, correct? To me that says either injection pump or fuel pressure issue due to clogged fuel filter or lift pump even though both don't have many miles on them. Since this is my first 12 valve, perhaps this is all they are good for when towing 5K lb stock? Is this the case or do I need to start hunting for issues?*

Onemoparnut

You are right on the edge of the rpm limit so it could be starting to defuel. The gov is at 2200 so it will start to defuel before that trying not to let the rpm get above that. Try putting a 3200 spring in it they only cost 20 bucks and they are a great improvement. Are u sure you are turning 2100 in fifth at 60 mph seems like a lot of rpm.

1STGENFARMBOY

Well there will probly be several people coment so here is oppinion.

You could do one of two things, it sounds like your truck is probly on fine working order.
there really made to tow in 4th, but you could do a few mods and get the extra power you need to tow in 5th but then you may have trans problems, as the manual sugestes towing in 4th i believe.

you can run a cummins at 2,500rpm all day long with no ill effects.
will your fuel consumption suffer ? ? maybe some, but it will get the job done and keep on going.

i have an auto trans so someone with a 5spd that tows will chim in i hope.

Dar

sootnsmoke

I don't have a tach but I ran a gear ratio/rpm calculator and with the 5th gear getrag ratio with my tires and 4:10 gears, 2000 rpm at 60 MPH is correct. Not sure about the factory spring defueling at 60 mph as I can floor it unloaded and run right to 70 mph with no issue. On another note, I can only lightly and briefly hear the turbo when shifting gears and cannot hear any turbo whistle when flooring it in 5th? Don't know if that is typical for stock motor and turbo in a 92?

Richie O

A stock truck is a total dog. Its normal. Been there, done that 4 times over.

1STGENFARMBOY

come on Richie give him some advice, as you of all people know how the hog eats the cabbage.

Dar

Richie O

Just wanted him to know, its most likely running normal. I had every intention of leaving my 92 totally stock and run the snot out of it towing. That lasted one trip, then the wrenches came out. I was so unhappy with the bog monster after having trucks that would turn the engine to a wasted pile of slag metal on demand.

sootnsmoke

I just can't believe a truck like this could come out of the factory stock and not be able to pull a 5k lb camper more than 55 mph up a 3% grade. Not to mention requiring WOT to do it.

brainfade

The performmance sounds a little soft to me. 5K isn't much for one of these trucks, it should do better than 57mph.

I'd start by checking the throttle linkage to be sure it's getting full travel. It's common for wear and cable stretch to reduce the fueling. While you're in there back out the high idle screw, the one the throttle hits when floored, that will often make a big difference. By the way, the stock settings have the engine defueling around 2700 rpm.

If those adjustments don't get you where you need to be check the sticky at the top of the page for more performance related and in depth adjustments. There is a lot to be had for free or really cheap.

sootnsmoke

Had someone press pedal to floor and checked throttle position. It goes completely to the stop. Just want to check everything to make sure it is correct before I start changing things and configuration

soggy

Where in WA do you live? Like other people have said, it sounds like a stock 1st gen, there are many cheap or free upgrades you can do to get more power out of it.

BILTIT

Sounds about right, i am not familiar with what a 3% grade is but i know pulling my 2500-3000lb camper up a good incline 5th gear really cannot hold it. You need to use 4th when climbing hills etc.

I would atleast get a boost gauge as you may have leaks. Do as above instructed, check throttle linkage and remove the full throttle stop screw.

Remember these engines were very de-tuned from the factory for warranty reasons back then. 160hp/400ft.lb is not much power by todays standards but fortunatley we can extract more power with a few turns of some screws.

snowjoker

Throw a fuel pin in and turn the pump up a little and you should not have any issues pulling 5k... hell ive had that much in the back of mine and it pulls fine being an auto with stock tranny and converter

whiskers

I agree that it sounds about right. I had a '90 stock with 3:55's though. it hauled a 3k camper just fine but had to go to 4th on big grades in the Rockies just to maintain 45-50mph. Went to a 10k 5th wheel and it wouldn't maintain 55 on level ground. Sold it and went to a ford 6.0 and it wouldn't do much better. Went to a '91 and the difference was night and day. And after a bit of tweaking it would pull the 10k pretty well, but never in 5th. had to go to a gear vendors overdrive to make it work in the right rpm zone. I've put one on every truck since and would go without one. But you can get a lot more out of that stock engine with research and a little coin. if you can get it up in the 250HP range it will pull your rig just fine.

Thiss

Sounds like a dog. How much do you want for it. I will help you out and give you 3k for the down payment on a new one and you can run out and buy a new one with a $500 dollar a month payment. After all everyone should have car payments, right? Then you can race up the hills with the weekend warriors pushing the trailers far too fast. Ok all sarcasm aside, turn it up. Find a close member on here who is close who knows what they are doing and you will be able to get all the power you really need for cheap.