73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: alfreema on March 13, 2012, 08:43:48 pm
-
Total newb here, but wanting to learn!
BEGIN LONG STORY -- FEEL FREE TO JUMP TO END LONG STORY TO GET TO THE POINT
1976, Chevy Camper Special with a 454. This baby was purchased by my great uncle who died, passed it to my grandfather who died and passed it to my mom. She doesn't want to die just yet so she quickly gave it to me. :D
Anyhow ... it sat on my grandpa's farm for a looooong time while he was alive and unable to live by himself and it just weathered away. I decided to go check it out one day and when I flipped open the lid a rodent so large I can only describe it as Ratzilla was standing on the radiator staring me down eye-to-eye. He was determined that I wouldn't eat him, and I was determined not to poop myself.
After the standoff I was able to inspect and that Godforsaken rat had chewed through every dang hose and copper wire in the joint.
So I decided I wanted to restore this rusty, weathered, rat food back to it's former glory. I had it towed to an electrical shop to get all the critical wiring redone and then to a mechanic to get it running fairly nicely. Then I spent way too much on a near cab-off restoration (we did everything EXCEPT take the cab off -- I should have went ahead and done that). Then I took it down and had a whole new interior put in.
END LONG STORY, BEGIN THE POINT
All was well for a while. Then several weeks ago my wife was driving (I know, I know, don't say it), and it started "surging" on her badly while she was on a highway. I had it towed to a Chevy dealer and they were unable to get it to repeat. So after a while I just went down and rode with a tech and it cut out once early in the ride and that was it. We just chalked the one slight cut out to "warming up".
Well I dropped off the tech and proceeded to drive home and sure enough at about the 7 mile mark it starts cutting out on me. My wife described it as a surging but now I know why. It would cut out, and then suddenly get power again creating a surging sensation. But really it's just cutting out.
Instead of hauling the thing back to the Chevy dealer, who somehow wasn't able to reproduce what I was able to reproduce after the very first time driving it since we dropped it off, I'd like to troubleshoot this thing myself if at all possible. That might be a big IF.
Soooooo ... what is the absolute first thing in diagnosing this problem? I'd like to take a very methodical approach and start with the most obvious things to check and proceed from there.
Where do I begin? (And please understand I don't know squat about any of this, but I am willing to ask a lot of questions and keep trying).
Thanks!
-
First... gas filter Due to the age, next would be the rubber lines connecting the gas tank to the steel lines. If both checks out then the fuel pump may be getting weak. That should get you started..
-
Sounds like a misfire. Tune it up and check the integrity of the ignition system. Simple test, warm it up and then wet the ignition wires with a squirt bottle. See if it runs worse.
-
Ok, guys! I'll start with the gas filter tomorrow and see what happens.
-
I'm thinking misfire as well. A tune could definatley be in order if it hasn't been done recently. So get some plugs and wires. When you do this inspect your plugs for condition, gap, color and consistancy- this can tell you a lot about how the engine is running, fuel wise. If this doesn't solve it and nothing out order on the spark plug inspection, I would consider replacing the distributor. They have become inexpensive and it would save a lot of trouble shooting and it would all be fresh. You could easily spend double on distributor parts and end up not solving the problem. However do inspect you cap and rotor before-hand(inspect the contacts and the plastic for cracking).
-
OK I poked around quite a bit and for the life of me I cannot find the fuel filter. I managed to find a small fuel filter inside a component that sticks out from and is connected directly to the carburetor, so I will replace it (it didn't look gunky at all or anything but I am not sure if you'd be able to tell if it was bad or not by visual inspection). But I can't imagine that that is the only fuel filter on this truck?
I started from the fuel tanks (it has two), and worked my way forward and followed the hoses to what looks like is probably a fuel pump bolted to the front-passenger side of the engine. From there a line comes out and goes into the carburetor, but there just isn't a fuel filter other than the one I described earlier.
Thoughts?
-
Sounds like your on the right track. Factory is just the fuel filter in the carb. Personally I cut in another in the fuel line before the carb, but some old habits are hard to break. The carb filter is perfectly adequate.
There is also a "sock" on the sender in the tank. Not something I'd change for the sake of changing, but if the senders have to be pulled for any reason, check them.
Check what Vile posted, that sounds like the likely culprit. Though what your doing should be done eventually (your not "wasting your time")
-
OK I swapped out that filter and the engine isn't running any better (didn't think it would, but like it was said, this needed to be done anyway). On to Vile's steps now.
-
Sounds like a misfire. Tune it up and check the integrity of the ignition system. Simple test, warm it up and then wet the ignition wires with a squirt bottle. See if it runs worse.
OK, so my father and I replaced the spark plugs last year and gapped them. And it was running really nicely for quite a while. But just to be clear on this step, you want me to spray both ends of the ignition wires while the truck is running to see if it starts running rougher, correct? I mean spray the distributor and then spray the sides of the engine, essentially?
-
Sounds like a misfire. Tune it up and check the integrity of the ignition system. Simple test, warm it up and then wet the ignition wires with a squirt bottle. See if it runs worse.
OK, so my father and I replaced the spark plugs last year and gapped them. And it was running really nicely for quite a while. But just to be clear on this step, you want me to spray both ends of the ignition wires while the truck is running to see if it starts running rougher, correct? I mean spray the distributor and then spray the sides of the engine, essentially?
Your looking for a break in the wires or a short in them, by spraying them like stated, if you do have a wire with the above mentioned problem, the truck will instantly run rougher and you will be able to tell that you have a bad or bad wires.
-
hows your engine ground?
-
Okay, I decided to hold off on this project until my new carburetor came in from http://www.nationalcarburetors.com/ so that I could swap that out and then begin the ignition tests. Well it came in yesterday and is wrapped in clear plastic so that I can easily compare it to the older one.
The old carburetor has a fuel filter in the front going straight in but the replacement carburetor has a 90 degree elbow. I think there might be enough slack to reroute the fuel line to make the 90 degree bend, but I am wondering if I have the wrong carburetor? Also my current carburetor has a fairly long arm sticking out on the driver side with two linkages hooked up. The new carburetor has a connection for only a single linkage (I think I could gang the two linkages on the same one).
I'm just not sure if I have the right carburetor. Should I open the new one and see if I can make it work, or call 'em up and return it?
-
I know two people that have had bad experiences with national carbs. If you open it they won't return it. First person said the carb wouldn't idle and this was a tbi. The second had the same problem you have being a diff carb and it also wouldn't idle. One would think that because national carbs does sell there carbs through autozone... the quality would be good. I guess maybe these were mishaps. Idk good luck. But remember if that's not what you paid for once you open it your stuck
-
Wulp, that might just be a good enough reason to return it then. Where's a better bet to get an exact replacement?
-
What year is your old carb you are compairing to the new one?
-
Or better yet what are the carb #s on the side (170...)
-
I would check the previously mentioned things before adding to your problem with possibly incompatible parts. Did you perform a tune-up or check the wires? Spray the wires like suggested, and another free check is to let it run in the dark and watch for lightning under the hood.
-
Also id check the oil pressure, choke operation( make sure its opening), ignition timing, do you here any tapping or sound like a coffee pot ( detonation) from under the hood when it cuts out?
-
i think Cadillac carbs have the fuel line out the side
-
The truck is a 76 Camper Special with a 454 and the original carburetor.
-
(http://contentinfo.autozone.com/znetcs/additional-prod-images/en/US/aol/C9279/2/image/4/) does it look like that
-
Sorry I missed some of the earlier posts when I responded earlier.
OK I see the sense in not swapping the carbs until I run the other quick tests, so I will try that this week.
I could not find any carb numbers on the side. I only see "Rochester QuadraJet" as you would expect. Where are the numbers I am looking for?
The new carburetor somewhat similar to that one, at least the fuel filter coming out at a 90 degree angle from the front is the same.
Here is a photo of mine:
(http://img7.imageshack.us/img7/4466/carb1q.jpg)
-
The #s should be behind the throttle linkage on the body of the carb going vertical. Looks like it maybe a buick, pontiac, or olds carb as the fuel inlet is straight out front
-
the pic i posted is a cadilac/olds
-
The truck is a 76 Camper Special with a 454 and the original carburetor.
Doesn't look it from the pic
-
sounds like a loose battery ground to me. try cleaning the ground and making sure its tight.
-
my carb on my 79 is a side inlet also, the original carb was and the one we replaced it with is also...also at the junkyard every truck i saw had the side inlet from 1976ish up
-
The truck is a 76 Camper Special with a 454 and the original carburetor.
Doesn't look it from the pic
Interesting, maybe I am completely wrong, but what makes you think it's not original? My great uncle bought the truck brand new and passed it to my grandfather, where it sat on his farm for a very long time (due to him not being able to drive). It only has 64kmiles on it (my great uncle pulled a camper and traveled a lot in the summers, but also became ill and couldn't drive it much). I can't imagine there was a need to swap he carburetor in that time frame, but it certainly may have happened.
One other side note, I think this may have been a late model 1975 that was just tagged as a '76 for VIN purposes. I can't remember why, but something lead me to believe that. Is that even possible? Would it make a difference in the carburetor?
Side note: A guy I had do some body work on it did an awful job spray-painting the engine block and put a crappy coat of some rubber-looking stuff on the valve covers (both of which really torqued me). He didn't charge me for it, but I'd rather he didn't touch it at all.
And lastly -- you guys all rock!! I gave up and took this sucker to a guy with Chevy experience and he swapped out the HEI distributor after testing/inspecting it.
-
My condolences. Well the fuel inlet coming straight out the front instead of a90 degree elbow is a give away. The card isn't a 75 or 76 .the#s are behind the throttle linkage on the drivers side.clean it up and post the#s here.then we can tell you what carb you have.not saying the carb won't run great...
-
Also if its a pontiac rochester carb keep it those were known to be some of the best for power:)
-
My condolences. Well the fuel inlet coming straight out the front instead of a90 degree elbow is a give away. The card isn't a 75 or 76 .the#s are behind the throttle linkage on the drivers side.clean it up and post the#s here.then we can tell you what carb you have.not saying the carb won't run great...
Interesting. Well I will assume it's not original and I will go look for those numbers again. I have looked a few times based on this thread but just couldn't for the life of me see anything (I think I was in too much of a hurry each time). I'll give it a real thorough check this time.
-
http://www.recarbco.com/technical/rochester/qjet.html
-
Total newb here, but wanting to learn!
BEGIN LONG STORY -- FEEL FREE TO JUMP TO END LONG STORY TO GET TO THE POINT
1976, Chevy Camper Special with a 454. This baby was purchased by my great uncle who died, passed it to my grandfather who died and passed it to my mom. She doesn't want to die just yet so she quickly gave it to me. :D
Anyhow ... it sat on my grandpa's farm for a looooong time while he was alive and unable to live by himself and it just weathered away. I decided to go check it out one day and when I flipped open the lid a rodent so large I can only describe it as Ratzilla was standing on the radiator staring me down eye-to-eye. He was determined that I wouldn't eat him, and I was determined not to poop myself.
After the standoff I was able to inspect and that Godforsaken rat had chewed through every dang hose and copper wire in the joint.
So I decided I wanted to restore this rusty, weathered, rat food back to it's former glory. I had it towed to an electrical shop to get all the critical wiring redone and then to a mechanic to get it running fairly nicely. Then I spent way too much on a near cab-off restoration (we did everything EXCEPT take the cab off -- I should have went ahead and done that). Then I took it down and had a whole new interior put in.
END LONG STORY, BEGIN THE POINT
All was well for a while. Then several weeks ago my wife was driving (I know, I know, don't say it), and it started "surging" on her badly while she was on a highway. I had it towed to a Chevy dealer and they were unable to get it to repeat. So after a while I just went down and rode with a tech and it cut out once early in the ride and that was it. We just chalked the one slight cut out to "warming up".
Well I dropped off the tech and proceeded to drive home and sure enough at about the 7 mile mark it starts cutting out on me. My wife described it as a surging but now I know why. It would cut out, and then suddenly get power again creating a surging sensation. But really it's just cutting out.
Instead of hauling the thing back to the Chevy dealer, who somehow wasn't able to reproduce what I was able to reproduce after the very first time driving it since we dropped it off, I'd like to troubleshoot this thing myself if at all possible. That might be a big IF.
Soooooo ... what is the absolute first thing in diagnosing this problem? I'd like to take a very methodical approach and start with the most obvious things to check and proceed from there.
Where do I begin? (And please understand I don't know squat about any of this, but I am willing to ask a lot of questions and keep trying).
Thanks!
I had a 1966 chevy truck that did the same thing to me,What I found was that the truck sat for a long time with gas in the tank,the gas went stale and had curroded the inside of the tank.When I started driving it once and a while,pumping gas into the tank,it started to mix up the corrotion in the tank that would get pulled over the pick up screen and cause it to run all the gas out of the line from the tank to the motor then it would die,like it was out of gas[about 4 miles each time]We would shake the truck and it would start back and go another 4 miles and die again.So I replaced the tank,lines,fuel filter,and rebult the carb and it ran fine ever since.Maybe that is your problam.
-
I have had 3 similar cases to this scenario. All acted like exact same problem on 350 chevy's so I'll get straight to the point and tell you the three quick things to check.
1. Choke flap lose and was sucking shut randomly. This is the easiest thing to test. Simply wire the choke flap open, OR if you're brave like we did, wedge a piece of 3/8 or so fuel line or air compressor hose in the choke flap to keep it open an drive it
2. Fuel tank not getting proper ventilation. Just take your fuel cap off and drive it.
3. Bad ignition control module OR coil. I you're unfamiliar just have someone else check/swap one or both out. More likely to be ign module.
4. Something else that I've had experience with, tho usually they don't act this way, but I'd put a new fuel pump on it.
Regardless you're losing fuel or spark. Check fuel stuff first then ignition stuff and I'd search for lose ground and/or hot wires shorting out.