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1991 burb expectations

My 91 with a 350 and 4l80e was a dog when towing my boat. The engine would run hot and with the boat and hill I would have to turn the AC off and slow down. It would not recover until we were going down the other side. Even on flat ground it run more then 230.

Likewise, it had no power and seemed like something was wrong. I was thinking clogged cat but that wasn't it. It was the fact that it was almost 20 years old and weighed more then 4500 pounds. Then put a 3200 pound boat behind in the summer heat.

My long term solution was a new motor. I've always loved K5 and Suburbans and knew this was going to be my keeper so I put a 383 in it. I also added a 4 core radiator while doing it.

The Burb never get's over 190 pulls the boat up 6 percent grades and will still pick up speed.
 
vdubnut said:
hey all,

been a member for a while but just upgraded my membership....

A few Questions for you all....

1. I have a 91 burb that i bought about 3 yrs ago for our family camping trips and various projects around the house. it was a 1500 and i bought another salvage burb and took the axles, driveshaft, brakes, leaf springs, etc., off and swapped them onto mine. What im wondering is what to expect performance wise from the burb. I bought a 3000 lb. 20 ft travel camper that i have been pulling with it....but i feel like i have to push it really hard just to travel at a reasonble pace on the freeway.. if i hit any headwind or any slight grade, my speed goes way down and im pushing it even harder. Am i expecting too much from the old 350tbi or do i have a worn out motor. the truck has a 350 700r4 trans, with a crane rv cam, jacobs headers, no cat, msd cap rotor and wires....4:10 gears, stock 3/4 ton springs, 33x12.5x16.5 tires...engine work done by PO.

2. torque converter lock...is it typical for the torque converter to unlock with the slightest increase in the throttle? it seems like it should stay locked until the demand is greater. in fact my old 84 burb would downshift into 3rd and stay locked, only come unlocked when it was almost floored....

I really love the truck...we've always had one in the family since i was a baby so they're in my blood....i love the look of the 91 and it runs really well, but towing my trailer gets stressful since i have to push it so hard all the time...i can maintain 55 in 3rd gear, but 4th at 65 is tough to keep.

thoughts?

thanks
jamie.
Click to expand...

Jamie,

I've got a V1500 '90 Burb with some very minor upgrades (CFM Tech TB spacer, injector pod spacer, salad bowl under the air filter housing) to the engine. It rides on stock axles with 3.73 gears driven by a 700R4 tranny. I have had that thing loaded with 8 adults and a 2000 lb trailer and not had a problem when driving on the freeway (I-15 and I-80). It does slow on long uphill sections (like the climb from Scipio to the summit south of town), but that's to be expected.

I would seriously look into the tune of your engine. If you have the mods you do and you are still running the stock chip, you may see a moderate improvement with a new chip.

As for the tranny, you can put a shift kit in it to help with the TCC staying engaged longer. However, if the tranny is original and has over 100K on it, you may be fighting the tranny itself. May be time for a rebuild.

Kevin
 
as far as heating up...not at all...it runs cool all the time and barely goes up even pushing it hard. I am going to do a "tune up" checking timing, doing plugs, check compression, etc see what improvement i can get.

When you say loaded with 8 people and a 2000 lbs trailer...and it slows...On that section of road after Scipio over the summit....i have to go down to 2nd gear and hold about 35-40 mph....3rd wont maintain on that hill... how about you?

what do you recommend as far as a "new chip" goes? how much improvement and how much does one cost?
 
Tune it up and Check your timing. Be sure to disconnect the timing bypass wire. If you set timing without disconnecting the wire the timing wil be way off.
New fuel filter would also be a very good idea when you do a tuneup.
An adjustable fuel pressure regulator will help. I usually run around 13-14 psi when I tow a lot. Any mods you do the throttle body will help.
This some good stuff to get a little more power[URL]http://marine-performance-parts.com/gmtbiperformance.aspx I am running most everything on th...ttp://www.cfm-tech.com/GM_tbi_tuning_tips.htm
Read the Tuning tips pages on the bottom left corner of the page. It will help you understand TBI and how to get a bit more power out of it.
 
vdubnut said:
as far as heating up...not at all...it runs cool all the time and barely goes up even pushing it hard. I am going to do a "tune up" checking timing, doing plugs, check compression, etc see what improvement i can get.

When you say loaded with 8 people and a 2000 lbs trailer...and it slows...On that section of road after Scipio over the summit....i have to go down to 2nd gear and hold about 35-40 mph....3rd wont maintain on that hill... how about you?

what do you recommend as far as a "new chip" goes? how much improvement and how much does one cost?
Click to expand...

Sorry about taking so long to get back...I've been on the north slope of the Uintas for the past week.

As far as being loaded down as I described, it drops into 3rd and can typically maintain 40 or so mph without too much strain. I must also qualify that my tranny is a Goodwrench rebuild with less than 30,000 miles on it and that the trailer I towed was very low profile. It didn't rise past the belt line of the Burb. I imagine that your trailer is much taller and as such you are experiencing a lot more aerodynamic drag.

For a chip, check out www.TBIchips.com for more info. As of late, I have been corresponding with Brian about some future upgrades to the Burb. He has been more than helpful in answering my questions. I imagine around $300 is what a chip would cost.

Kevin
 
Thunder said:
Tune it up and Check your timing. Be sure to disconnect the timing bypass wire. If you set timing without disconnecting the wire the timing wil be way off.
New fuel filter would also be a very good idea when you do a tuneup.
An adjustable fuel pressure regulator will help. I usually run around 13-14 psi when I tow a lot. Any mods you do the throttle body will help.
This some good stuff to get a little more power[URL]http://marine-performance-parts.com/gmtbiperformance.aspx I am running most everything on t...ttp://www.cfm-tech.com/GM_tbi_tuning_tips.htm
Read the Tuning tips pages on the bottom left corner of the page. It will help you understand TBI and how to get a bit more power out of it.
Click to expand...
What he said I'm thinking your timing must be way off,make sure you disconnect that timing bypass wire the brown plug on the main harness right by the firewall, even a motor with lower compression from high miles should pull like a 350.
 
I would get a chip from tbi chips ( I have one of his chips for the 383 I have in my 91 burb ) before I would buy a new ECM from the dealer.
Tarey
 
update....

I checked the timing on the burb this past Sunday. If i did things correctly, the timing was way off! with the wire plugged in the timing mark was about a inch beyond the 14 degree mark...with it unplugged it was right at 14. seeing as the timing changed a bunch when i unplugged the wire, i figured i had the right wire (bypass wire). anyway i adjusted the timing back to zero with it unplugged, which slowed the idle down considerably, and then plugged the wire back in...which did nothing. so i shut off the truck and disconnected the battery, reconnected the battery, then checked it again and the timing was back up around 12-14 deg. is this typical? then when i unpluged it again the timing was back at zero. so i did the battery disconnect again to reset the computer and then left it alone.

seems to run fine, sounds slightly different, like maybe there was slight pinging before and now there isnt. I took it from Salt lake city, up to Jackson Hole WY over the last few days. I was really hoping that there would be significant improvement, but it seemed to pull about the same.

the only other oddity is that the day before adjusting the timing, i re-charged the A/C and drove 15 miles to a friends house. when i left, my service engine soon light came on?!? this was the first time it has ever came on in my ownership of it. while doing the timing i had disconnected the battery a couple of times and so the light was back off. i then drove it on this trip and had no light all the way to Jackson. but then on day 4 going up a dirt road it came on again.. im guessing the O2 sensor or something? i need to find some info on how to check the code i guess.
 
Checking the trouble codes is really easy. Go to the TBI Injection section of the boards. There's a sticky at the top called "TBI trouble codes". It tells you how to pull the codes from the computer with a paperclip and it describes what the code numbers are.
 
If you are towing a 3000 lb trailer you should not be towing in OD. It will kill a 700r4 trans.
Also if your CEL came on you should check the codes to see what is going on.
 
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