73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: mk_tacticalranch on June 23, 2015, 05:16:56 pm
-
I have a friend bringing over their 1976 chevy truck 4x4 3/4 ton 350 manual. The issue is the truck recently starting dying every time they turn. I have never heard this happen before. Any tips on where to start? I was thinking about replacing the power steering pump and belts and going from there.
Thanks
-
Does it die when your turning the wheels while sitting still ?
Or while turning a corner when driving ?
If it's sitting still it might just need the idle speed bumped up a little
Sent from my iPhone using Tapatalk
-
It dies while making the corner while driving.
-
Replace fuel filter first. Then go to the pump and take off the rubber supply line. Fire up the air compressor and blow air back to the tank. Drop the tank and check out the sending unit and tank. Replace if necessary. Probably the strainer in the sending unit is loaded with crap or rust. As the owner makes a turn the stuff slides up and plugs the strainer. That would be my guess.
This is assuming the idle just doesn't need adjusting up.
I would leave the power steering alone.
-
Float height adjustment?
-
Not that there is anything wrong with Don5's ideas. If the filter in the tank is clogging around corners, it's going to a very brief clog, as soon as you straighten out, the fuel will slosh back. It would need to be sucking up debris constantly to clock up. A brief corner turn is not long enough for the screen to clog and then drop fuel pressure enough to kill the engine. Being as you said it dies only when turning a corner and not any other time, I dought a clogged pick up screen is your issue. The tank to carb distance is to far to cause instant pressure drop and stalling.
What carburator do you have? Stock Quadrajet? I heard from another veteran site member that it is common, in carburetors, for fuel to slosh or debris to fall into the jets (I think) during cornering, causing an instant drop in fuel supply, stalling the engine. Debris usually getting in the carb from clogging, torn, dirty or worn fuel filters and/or torn or missing or deteriorated screens on the pick up tube.
It would be better to check the fuel filter and monitor fuel pressure during the stalling event to ensure proper pressure up to the carb. This will help isolate where the problem is, i.e. in tank, before the pump, after the pump, or in the carb.
-
I will now go back in the corner and quietly watch from now on...
-
I will now go back in the corner and quietly watch from now on...
Get out of the corner.
Your trouble shooting thoughts are valid.
-
Thank you everyone. I start digging into the truck tomorrow. I assume its the stock carb. I will try all of your suggestions and leave the power steering pump alone, for now. :)
Thank you again. Ill let you know how it goes
~Mellisa~
-
Very well may be a float issue or carb needs rebuilt. Assuming nothing was done to the truck to bring this on.
Fuel filter first as mentioned, tune up. readjust mixture and idle speed.
Does he smell gas when this happens?
Does it restart easy?
Sent from my iPhone using Tapatalk
-
The truck has been sitting for a few months. It does smell of gas and will not easily start after it dies. It takes many tries before it fires up.
-
Don5, your thoughts are fine, your ok there, just too far down the line without doing some tests and locating the issue.
Mk, how long is a fuel months? 3 months is not a huge deal, six months perks some attention, 9 months, close to a year? That's when you begin to question the quality of the fuel as well.
Please let us know about the model of carb, how long it sat, old gas or new gas in tank? When it finally fires back up after stalling, does it just fire up and run easily or does it stumble, hesitate and require putting your foot on the gas or something to get it to finally start and sputter to life and run? When the truck is running and driving, how well does it run and drive? Good sometimes, bad others, has issues when cold, has issues when hot, hesitations or bogging while driving, accelerate and cruise smoothly? These are all important to help narrow down and properly repair the issue.
-
LTZ- Fuel in the primary tank is new, couple weeks old. Fuel in the aux tank is old, old. I havent had a chance to drive it but I will tomorrow if it fires up. I will post answers to your questions then. Thank You
Mellisa
-
Ok cool. Also, if it runs for you, see if it stalls on just 1 tank or the other or both. 1 more question to the list haha.
-
Don5, your thoughts are fine, your ok there, just too far down the line without doing some tests and locating the issue.
Mk, how long is a fuel months? 3 months is not a huge deal, six months perks some attention, 9 months, close to a year? That's when you begin to question the quality of the fuel as well.
Please let us know about the model of carb, how long it sat, old gas or new gas in tank? When it finally fires back up after stalling, does it just fire up and run easily or does it stumble, hesitate and require putting your foot on the gas or something to get it to finally start and sputter to life and run? When the truck is running and driving, how well does it run and drive? Good sometimes, bad others, has issues when cold, has issues when hot, hesitations or bogging while driving, accelerate and cruise smoothly? These are all important to help narrow down and properly repair the issue.
If the truck has difficulty starting after its been ran its time for a carb rebuild. This is generally happening due to heat soak causing fuel to evap to fast or the fuel wells leaking and draining the float bowl.
Honestly with how simple it is to rebuild a qudrajet (Except getting the choke to work properly again) there is no reason why any old quadrajet should NOT be rebuilt.
-
ok, here is what I have found so far: It started on the first try. Sounds like it is struggling to breath or get fuel. It will barely stay running without pressure on the gas pedal. It drove alright while i was on the gas, wanted to die when i down shifted or let off the gas. Nothing changed while i was going around corners. ::) Carb is 4BBL Holley. Stock for the truck? I am going to clean the fuel lines and tanks. There has been gas sitting in it for over a year, (The truck has been driven maybe 5 times in the past year) they just topped off one tank a few weeks ago. The idle is crap on both tanks. I didnt drive it far, (the brake lines are shot so no brakes but that's another thread!) I did make sure I drove in 1st, 2nd, 3rd and reverse. Turned both directions.
Ill do regular maintenance (tune up, oil change, etc.) after/during that. Carb rebuild after that. Am I missing anything?
Thanks
~Mellisa~
-
Sounds like you just about covered it. Thanks for all the info, it definitely sounds like a fuel supply issue. 4 barrel carbs are stock for these trucks. Not as holley units tho, the stock carbs are Quadrajets. A fuel pressure reading will definitely be the best course of action at this point. I would install a fuel pressure gauge just before the line goes into the carb. Then depending on the reading go from there, but it sounds like your on the right track with the fuel system. Just make sure you fix this issue before doing the other stuff, unless the other stuff is required to repair this issue. Good job! Your getting there!
-
Blown power valve in holleys can cause idle problems. Causes over rich mixture
Sent from my iPhone using Tapatalk
-
Blown power valve in holleys can cause idle problems. Causes over rich mixture
Sent from my iPhone using Tapatalk
This is true. Since she plans on rebuilding the carb, that will get checked.
-
Thank you guys for the help! I am going to rebuild my carb on my burb too! My friends pick up is disaster. After deeper inspection, the plan is pull the motor and sell the rest as parts! Looks like I have a 350 to completely rebuild! I'm excited!
-
Enjoy and good luck!
Sent from my iPhone using Tapatalk
-
Sweeet! Sorry it kinda ended that way but sometimes that's the way it goes with old vehicles, some times you have to know when to go forward or abort and start again on something else. Have fun! Your welcome.