1990 350 motor

[1990k5fan]

Changed the fuel filter today. Not much of a performance increase. Helps on start ups now. Car used to take a few ticks and now it only takes one.

Called the exhaust shop and I'm going to go up there on friday morning. Hopefully the cat brings some more performance.

Also, I'll try and check the timing tonight when I go to my gf dad's shop. How were the carbs that came stock with these cars? Would I get a big improvement with a new carb?

 

[Can Can]

Man, you're killing me. It's not a car, it's a TRUCK!!!!

Secondlly, if your truck is stock, it doesn't have a carb. It's fuel injected. TBI, to be precise.

Have you checked your injector spray pattern yet?

 

[tRustyK5]

I just want to add one tidbit regarding the crate engine you linked to. Those hp and tq numbers are not SAE net like your truck is rated which is why those numbers appear higher. SAE net is the rating as the motor is installed in the truck with all accessories installed and running. If you bought that crate and installed it you'd be right back here complaing that your truck isn't any snappier than it was before...

Rene

 

[1990k5fan]

Man, you're killing me. It's not a car, it's a TRUCK!!!!

Secondlly, if your truck is stock, it doesn't have a carb. It's fuel injected. TBI, to be precise.

Have you checked your injector spray pattern yet?

Sorry about that. . You know what I meant.
I'll look into how to check the injector spray pattern when I get home.

 

[tiger9297]

This thread makes me tired.

 

[1990k5fan]

http://coloradok5.com/forums/showthread.php?t=201862

Thanks :P.

 

[user]

wrong gearing

I think you went the wrong way on the gearing; the lower the ratio the higher the gear, hence higher top speed and/or better gas mileage. If you went from 3.73 to 4.1 you went the wrong way - also you've got to have the same ratio in the front as the rear, or you're likely to break something in the drivetrain when you put it into 4wd. I'd suggest 3.08 if you don't do towing, or 3.42 if you do.

 

[1990k5fan]

I think you went the wrong way on the gearing; the lower the ratio the higher the gear, hence higher top speed and/or better gas mileage. If you went from 3.73 to 4.1 you went the wrong way - also you've got to have the same ratio in the front as the rear, or you're likely to break something in the drivetrain when you put it into 4wd. I'd suggest 3.08 if you don't do towing, or 3.42 if you do.

I wanted more power not mpg.

 

[rjfguitar]

I think you went the wrong way on the gearing; the lower the ratio the higher the gear, hence higher top speed and/or better gas mileage. If you went from 3.73 to 4.1 you went the wrong way - also you've got to have the same ratio in the front as the rear, or you're likely to break something in the drivetrain when you put it into 4wd. I'd suggest 3.08 if you don't do towing, or 3.42 if you do.

What the???.......

He's nearly perfect with 4.10's, if anything 4.56's would really be nice since he doesn't do much freeway driving.

3.08 gears are one of those things that we wish could be "uninvented." In my book they rate right up there with VX gas and nuclear war heads on the "lets forget we built this" list.

They are junk, they are gas eaters in town and motor bogging junk on the freeway. As far as 3.42's.... they are basically as bad and are nearly worthless too.

 

[1990k5fan]

Got the computer read tonight and had the EGR valve replaced. The hesitation got smaller and hopefully will be even less when I get my restrictive Cat changed for a high flow one.

 

[W7NB]

3.08 gears are one of those things that we wish could be "uninvented." In my book they rate right up there with VX gas and nuclear war heads on the "lets forget we built this" list.

They are junk, they are gas eaters in town and motor bogging junk on the freeway. As far as 3.42's.... they are basically as bad and are nearly worthless too.

I'm running 3.42's right now, but only have 33's. I get the same economy as everbody else - 10 or 11 in town and mid teans on the highway. It wouldn't matter if I had 4.56's to me - I still would not tow a 4k pound load like my boat in overdrive with my 700R4. Thats just asking for a burnt tranny in my book unless you have a STOUT built 'R4 and a big tranny cooler.

I think the ultimate gearing for a 350TBI/700R4 used as a combo DD/trail truck is 3.73's with 33's and 4.10's with 35's. It puts 65mph right in the middle of the power band and will probably get the "best" fuel economy we should expect when driving the lifted equivalent of an aerodynamic brick wall.
Of course when one goes to 38's or 40's the whole 1 ton axle thing comes into play in a big way, and it's time for 4.56 and up gears.

On the other hand, if you are building a pure trail rig that will never see pavement (my dream when I replace my current pickup) then gearing changes completely. So what if it's doing 3800 rpm in OD to do 55 - you want crawl and grunt, not cruise and economy.

Just my somewhat educated 2 cents, so take it for what it's worth. I DO agree that 3.08's may well be the closest to hell you can get

 

[1990k5fan]

Getting the cat changed tomorrow for $135 including the cat. I'm stoked :].

It is a 45 minute drive but I'll be saving like 200 bucks so it is worth it.
<3 this place :]

 

[4X4HIGH]

Getting the cat changed tomorrow for $135 including the cat. I'm stoked :].

It is a 45 minute drive but I'll be saving like 200 bucks so it is worth it.
<3 this place :]

Did you talk to Alan? If so did you mention my name and shop? At $135.00 including the CAT not a bad guess on my part since i had mine done 5 years ago and was only off by $10.00.

 

[4xcrazy]

Let's all just hope this is the main problem,,,,otherwise I am just going to suggest....

 

[76zimmer]

Let's all just hope this is the main problem,,,,otherwise I am just going to suggest....

 

[rjfguitar]

I'm running 3.42's right now, but only have 33's. I get the same economy as everbody else - 10 or 11 in town and mid teans on the highway. It wouldn't matter if I had 4.56's to me - I still would not tow a 4k pound load like my boat in overdrive with my 700R4. Thats just asking for a burnt tranny in my book unless you have a STOUT built 'R4 and a big tranny cooler.

I think the ultimate gearing for a 350TBI/700R4 used as a combo DD/trail truck is 3.73's with 33's and 4.10's with 35's. It puts 65mph right in the middle of the power band and will probably get the "best" fuel economy we should expect when driving the lifted equivalent of an aerodynamic brick wall.
Of course when one goes to 38's or 40's the whole 1 ton axle thing comes into play in a big way, and it's time for 4.56 and up gears.

On the other hand, if you are building a pure trail rig that will never see pavement (my dream when I replace my current pickup) then gearing changes completely. So what if it's doing 3800 rpm in OD to do 55 - you want crawl and grunt, not cruise and economy.

Just my somewhat educated 2 cents, so take it for what it's worth. I DO agree that 3.08's may well be the closest to hell you can get

I disagree, I've got 4.10's with 35's and it basically sucks. Too low on the freeway, plenty tall for in town.

I've got 4.10's and 31's on my K30 with a 454.... perfect gearing for all around use.

I said the same thing once, that 3.73's were about right for everything underneith a 36", and even told a local guy I met that he was crazy running 4.56's with 35's and non OD trans. I had 3.73's with 33's...ran good, towed ok, I couldn't complain. Until... I drove more trucks with much lower gearing and relized how much better they ran without loosing any mileage, now I sing a different note....

3.42's with 33's may or may not deliver better mileage than if you had 4.10's. Bogging a motor doesn't do anything for mileage, but good vaccuum does though at a better RPM. In town is likely to favor a set of 4.10's with 33's, you'll use less foot to get moving and accelerate better when making a pass or what not.

 

[W7NB]

3.42's with 33's may or may not deliver better mileage than if you had 4.10's. Bogging a motor doesn't do anything for mileage, but good vaccuum does though at a better RPM. In town is likely to favor a set of 4.10's with 33's, you'll use less foot to get moving and accelerate better when making a pass or what not.

I feel like such a dolt

Living in the FI age I have pretty much forgotten about the value of a vacume gage for performance measurement. I have one in my tune up box- I think I'll see about running a vacume line into the cab and hooking it up to see if I'm fooling myself on the performance - I have been strictly looking at RPM's at a given speed, but as you say, if you have to dog it all the time to keep the RPM's up economy goes down the toilet.

Thanks for the reminder!

 

[txfiremank5]

Let's all just hope this is the main problem,,,,otherwise I am just going to suggest....

Well, even if it's not the "main" issue, I bet it will help if it's still the stock cat.

 

[1990k5fan]

Did you talk to Alan? If so did you mention my name and shop? At $135.00 including the CAT not a bad guess on my part since i had mine done 5 years ago and was only off by $10.00.

I called and asked for Alan but he wasn't there. I had the other guy who answered it give me the price of 135 cash. I told him about you and that you said they'd hook it up with 135 bucks.

It has to be a good improvement over the stock one.

Hitting freemont up tomorrow since I don't have any school.

 

[rjfguitar]

I feel like such a dolt

Living in the FI age I have pretty much forgotten about the value of a vacume gage for performance measurement. I have one in my tune up box- I think I'll see about running a vacume line into the cab and hooking it up to see if I'm fooling myself on the performance - I have been strictly looking at RPM's at a given speed, but as you say, if you have to dog it all the time to keep the RPM's up economy goes down the toilet.

Thanks for the reminder!

It can be a toss up. Your 3.42's might help mileage out if you can get out on the freeway and run 80mph, but that can be hard to average. I remember when I had 3.08's and 33's, it was an utter dog under 60mph and I usually had to downshift to gain momentum, but over 75mph and it would run! Regardless, for most of us that is useless. I don't know who in their right mind would want to use one of these trucks as serious commuters.