New 91 Chevy owner!

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

PaulyJ

Newbie
Joined
Feb 28, 2021
Messages
14
Reaction score
27
Location
Idaho
Ok, I spent a better part of the day messing around with the truck. First I bolted the Y pipe back on the manifolds with some new hardware. Put on new PCV valve, throttle position sensor, plugs and wires. I was hoping I fixed the lack of power going uphill problem, but sadly I did not. Anyone have any guesses as to what the issue might be? Here are some pics of the old TPI and plugs.

You must be registered for see images attach


You must be registered for see images attach


You must be registered for see images attach
 

mars2878

I'm Awesome
Joined
Feb 11, 2016
Messages
1,283
Reaction score
885
Location
massachusetts
Besides checking out fb mktplace or craigslist for parts or part outs, try:
Full-service yards car-part.com
Self-serve yards row52.com

A helpful tool @ row 52 that I like is that I can get email/text alerts for new arrivals that fit my search parameters.
 

PaulyJ

Newbie
Joined
Feb 28, 2021
Messages
14
Reaction score
27
Location
Idaho
More fun! Yesterday I had a friend come over to get me going in the right direction trying to figure out this mystery problem. We tried driving it around and it had a small miss and backfiring when he put on any gas. He took off the distributor cap and it looked really good, so we dug around and noticed that someone had taken off a vacuum hose and plugged it with a screw. The hose goes into the back of the TBI and is supposed to T down into the intake manifold behind the TBI. The T in the hose had a screw in it and the intake manifold end was left open, so it was sucking in air. We fixed that and the engine immediately ran better. We still haven't pinpointed the mystery lack of power issue, but he drove it around the block and he is thinking something to do with the transmission but he said the truck feels like it wants to go but really wont go higher than 20 mph.

You must be registered for see images attach
 

SouthernYankee

OBS Enthusiast
Joined
Sep 21, 2020
Messages
62
Reaction score
158
Location
North Carolina, USA
Great looking truck for the price!! Welcome to the forums.

Have you put a decent tank of gas in it yet? It could be bogging down due to poor fuel. Also can you rev it high at all? It could be the transmission, might be stuck in first or something like that. Best of luck. I look forward to where this goes!


Sent from my iPhone using Tapatalk
 

PaulyJ

Newbie
Joined
Feb 28, 2021
Messages
14
Reaction score
27
Location
Idaho
Great looking truck for the price!! Welcome to the forums.

Have you put a decent tank of gas in it yet? It could be bogging down due to poor fuel. Also can you rev it high at all? It could be the transmission, might be stuck in first or something like that. Best of luck. I look forward to where this goes!


Sent from my iPhone using Tapatalk

Actually I spoke to the previous owners today lol. They said they believe it is the detent cable that goes to the transmission. I guess because its lifted the cable might not be long enough? Does that seem like it could be it?

It revs just fine when its sitting in park.
 

thinger2

I'm Awesome
Joined
Jul 6, 2019
Messages
1,562
Reaction score
3,935
Location
Tacoma
Welcome to the forum!
1500 bucks is a good deal.
But, a word of caution. A 91 has a 700r4 transmission. The cable from the throttle body to the trans isnt a "detent cable"
Its a "Throttle valve cable"
usually known as a "TV" cable.
And it must be set up correctly.
Do not just start randomly adjusting that cable. You need to follow the factory procedure.
If you dont, you will smoke that transmission.
Sometimes within a block or two.
Dont **** around with half assing a 700r4. it will bite you.
It is an easy to do adjustment once you know how to do it and have inspected the cable and the linkage and brackets.
I dont think your performance problems are related to the transmission.
It sounds like and from the pics it looks like 42 monkeys have been at this truck with random bullshit advice.
The first thing I noticed was those plugs look like somebody gapped them with a forklift. They are not good.
And never trust a "pre gapped" plug
They are pre gapped if the guy in China did each and every one correctly.
They dont.
You need to start with 3 things.
Inspect each and every vacuum line on the throttle body and make sure that they are connected to the proper port.
I would just replace them all.
Next, you need to set your base timing back to zero degrees at top dead center.
First, you need the #1 piston at top dead center on the compression stroke.
Then, take a look at the timing mark on the balancer to see if it shows TDC.
On the passenger side of the firewall is a plastic cover.
Under that cover are several wires.
One of those is a tan wire with a black stripe.
That is the distributor reference wire
You need to unplug that wire before you set base timing.
I will bet you a case of beer of your choice that it is not at TDC and has been screwed with by knuckleheads in an attempt to "make er run"
Fix the vacuum leaks, make sure distributor is in correctly.
Set it to tdc .
And dont **** around with the tv cable untill you know how to do it.
I know, this sounds like a lot of overwhelming bullshit.
But it really isnt.
Its actually a pretty damn simple system.
Dont let anyone convince you that you need to spend more on equipment than you paid for the truck.
Bullshit.
If you can understand how to figure out online gaming, if you ever get called up by us olds farts because we beat the computer with a hammer and it still wont work?
If you get how you can scan **** with your phone and random people drop **** on your porch?
If you get that ****
Tell me.
I have no friggen clue.
The moral of the story is dont let any of the "gatekeepers" try to beat you down.
You can do this. Its easy but its old.
Ill help out in any way I can.
Ill even trade you.
If I help you get it to run,
You explain to me what in the flying **** a voip link is and why I need it and how its worth my time to get one of those damn things and do I need to go to walmart to get what ever that is.
You got this brother.
Its old, but its easy.
 

PaulyJ

Newbie
Joined
Feb 28, 2021
Messages
14
Reaction score
27
Location
Idaho
Welcome to the forum!
1500 bucks is a good deal.
But, a word of caution. A 91 has a 700r4 transmission. The cable from the throttle body to the trans isnt a "detent cable"
Its a "Throttle valve cable"
usually known as a "TV" cable.
And it must be set up correctly.
Do not just start randomly adjusting that cable. You need to follow the factory procedure.
If you dont, you will smoke that transmission.
Sometimes within a block or two.
Dont **** around with half assing a 700r4. it will bite you.
It is an easy to do adjustment once you know how to do it and have inspected the cable and the linkage and brackets.
I dont think your performance problems are related to the transmission.
It sounds like and from the pics it looks like 42 monkeys have been at this truck with random bullshit advice.
The first thing I noticed was those plugs look like somebody gapped them with a forklift. They are not good.
And never trust a "pre gapped" plug
They are pre gapped if the guy in China did each and every one correctly.
They dont.
You need to start with 3 things.
Inspect each and every vacuum line on the throttle body and make sure that they are connected to the proper port.
I would just replace them all.
Next, you need to set your base timing back to zero degrees at top dead center.
First, you need the #1 piston at top dead center on the compression stroke.
Then, take a look at the timing mark on the balancer to see if it shows TDC.
On the passenger side of the firewall is a plastic cover.
Under that cover are several wires.
One of those is a tan wire with a black stripe.
That is the distributor reference wire
You need to unplug that wire before you set base timing.
I will bet you a case of beer of your choice that it is not at TDC and has been screwed with by knuckleheads in an attempt to "make er run"
Fix the vacuum leaks, make sure distributor is in correctly.
Set it to tdc .
And dont **** around with the tv cable untill you know how to do it.
I know, this sounds like a lot of overwhelming bullshit.
But it really isnt.
Its actually a pretty damn simple system.
Dont let anyone convince you that you need to spend more on equipment than you paid for the truck.
Bullshit.
If you can understand how to figure out online gaming, if you ever get called up by us olds farts because we beat the computer with a hammer and it still wont work?
If you get how you can scan **** with your phone and random people drop **** on your porch?
If you get that ****
Tell me.
I have no friggen clue.
The moral of the story is dont let any of the "gatekeepers" try to beat you down.
You can do this. Its easy but its old.
Ill help out in any way I can.
Ill even trade you.
If I help you get it to run,
You explain to me what in the flying **** a voip link is and why I need it and how its worth my time to get one of those damn things and do I need to go to walmart to get what ever that is.
You got this brother.
Its old, but its easy.

Hahahaha I love it. I definitely agree, Im not gonna mess with the TV cable myself, Ive learned of a very good mechanic in the area I plan on getting the truck taken to for the transmission. Hopefully, fingers crossed, the previous people didnt already smoke that brand new transmission (why do I get the sinking feeling they did?). Once that gets taken care of I feel pretty good about bringing it home to handle everything else.
 

thinger2

I'm Awesome
Joined
Jul 6, 2019
Messages
1,562
Reaction score
3,935
Location
Tacoma
Hahahaha I love it. I definitely agree, Im not gonna mess with the TV cable myself, Ive learned of a very good mechanic in the area I plan on getting the truck taken to for the transmission. Hopefully, fingers crossed, the previous people didnt already smoke that brand new transmission (why do I get the sinking feeling they did?). Once that gets taken care of I feel pretty good about bringing it home to handle everything else.
You can adjust the tv cable yourself.
Just do your homework first.
Make it run correctly before you psy somebody at the trans shop.
Remember, this is old tech, but its still tech.
And the guy at the trans shop probably doesnt have a clue either.
Get it to run right first.
Then we can talk about transmissions.
I dont think you have a trans problem.
I think you have an engine performance problem related to the tbi or ignition timing or both.
 

PaulyJ

Newbie
Joined
Feb 28, 2021
Messages
14
Reaction score
27
Location
Idaho
It could be the TBI. After we fixed that vacuum line the truck idles smooth with no miss, so that could still be a timing issue?
 
Top