no power, dies at full throttle

[Rc 415]

Ok, so I got my carb runnin, the truck idles great, but when I'm driving it, it has no power at all, it will get louder when i push the pedal, but it wont move much faster, it doesnt put me back in my seat at all, and it will sometimes even die if i push the pedal all the way down too quick, anyone know what kind of carb adjustments can cause/fix this? It really struggles on hills too.

[xtreme80]

I would start by taking a look at your accelerator pump. Seems like that would cause the same or similar symptoms.

[Mickey_D]

Or your fuel filter.

Actually, thinking about it, it sounds like your float is too low.

[cjracing15]

I would look for a vacuum leak.

[Rc 415]

Originally Posted by xtreme80

I would start by taking a look at your accelerator pump. Seems like that would cause the same or similar symptoms.

I thought of that, I actually just put in a new one and I'm pretty sure its not the problem.

Originally Posted by Mickey_D

Or your fuel filter.

Actually, thinking about it, it sounds like your float is too low.

Fuel filter is brand new, and the float level hmm that may have something to do with it, I'll have to take a look.

Originally Posted by cjracing15

I would look for a vacuum leak.

Gunna have to take a look for this too, I did eliminate a few smog things while I was working under there

[Malo83]

Originally Posted by Rc 415

I thought of that, I actually just put in a new one and I'm pretty sure its not the problem.


Fuel filter is brand new, and the float level hmm that may have something to do with it, I'll have to take a look.


Gunna have to take a look for this too, I did eliminate a few smog things while I was working under there

Did you get a Check Engine light at any time, and what did you eliminate smog wise?

[Rc 415]

Originally Posted by Malo83

Did you get a Check Engine light at any time, and what did you eliminate smog wise?

I have a code 34 now, the map sensor is getting low voltage, could that be my problem here? As far as smog, I took out the parts that attached to the smog pump, and the manifolds, and a few vacuum lines too. Could the timing be off causing this problem?

[jermasaurus]

map sensor could definately be your problem. I would start there. I think you get that code if your vacuum line to the sensor is missing of damaged

[Rc 415]

Originally Posted by jermasaurus

map sensor could definately be your problem. I would start there. I think you get that code if your vacuum line to the sensor is missing of damaged

well the vacuum line is there, and it has no leaks, but I have some strange new info. It was the timing causing my problem. See, It all started when I realized that my distributer was actually very very loose, in fact the bolt was not tightened at all, but the truck seemed to have decent power and run fairly well. so, I set the timing the old fashioned way, turning the vibration dampener with a socket and wrench, I noticed that the timing indicator had a chalk mark on mark 4 advanced, so I lined up the line on the vibration damper with the 4 advanced, set the distributer cap so that the rotor was directly under plug #1, and I double checked 2 times that it was correct. Anyway, so I started it, checked it with a timing light, and sure enough the line on the vibration damper was lining up with the chalk make made on the indicator. the truck idled great, but had a bid of a hard time starting, and unfortunately my truck had no power at all, felt like i couldnt get it going down the road at all. So what I did, I placed the dist cap back to where it was when it was loose, but I tightened it down this time. Now by turning it back to where it was I retarded the timing quite a bid, so far, that I can no longer see the line on the vibration damper coming around, it is not at 0 or even at 12 on the before section on the indicator. But, the truck has its power back again, it starts way better, and idles good, albeit a little fast I think. Now, I can not figure this out at all, it has me completely stumped, anyone have any ideas? By the way my dist cap has no vacuum advance.

[jermasaurus]

Not sure what year and setup your truck is.

If it is a carb with HEI, then there should be mechanical and vacuum advance i think. No electronic advance from a PCM. So you are dealing with base timing.

If the motor and dampener are original, then it is possible that the outer ring of the dampener has shifted on the rubber portion or is in some way ot aligned to the middle.
That would make your timing mark seem off.

[Rc 415]

Originally Posted by jermasaurus

Not sure what year and setup your truck is.

If it is a carb with HEI, then there should be mechanical and vacuum advance i think. No electronic advance from a PCM. So you are dealing with base timing.

If the motor and dampener are original, then it is possible that the outer ring of the dampener has shifted on the rubber portion or is in some way ot aligned to the middle.
That would make your timing mark seem off.

its a 83, carbed, hei, the motor is a gm goodwrench 350 put in about 10 years ago

[Malo83]

Rc, I have the same 83 as yours and with the Computer you need to set up the base timing, to do it properly you have to disconnect the Comp from the Distributor, you should have a 4 pin connector coming off the distributor, disconnect it and have the truck warm and set the timing at 8 deg on the pointer, adjust the idle speed screw to 550/600 rpms once that is done reconnect the 4 pin connector, the timing will change but leave it alone. you might want to reflash the computer by removing the ground cable from the battery and reconnect it a couple of times.

[Rc 415]

Originally Posted by Malo83

Rc, I have the same 83 as yours and with the Computer you need to set up the base timing, to do it properly you have to disconnect the Comp from the Distributor, you should have a 4 pin connector coming off the distributor, disconnect it and have the truck warm and set the timing at 8 deg on the pointer, adjust the idle speed screw to 550/600 rpms once that is done reconnect the 4 pin connector, the timing will change but leave it alone. you might want to reflash the computer by removing the ground cable from the battery and reconnect it a couple of times.

Thanks!!! One question though, how do I set the idle speed screw to that setting approx? Oh and 8 deg before or advance? I'm guessing before...

[79Silv4x4]

Originally Posted by Rc 415

well the vacuum line is there, and it has no leaks, but I have some strange new info. It was the timing causing my problem. See, It all started when I realized that my distributer was actually very very loose, in fact the bolt was not tightened at all, but the truck seemed to have decent power and run fairly well. so, I set the timing the old fashioned way, turning the vibration dampener with a socket and wrench, I noticed that the timing indicator had a chalk mark on mark 4 advanced, so I lined up the line on the vibration damper with the 4 advanced, set the distributer cap so that the rotor was directly under plug #1, and I double checked 2 times that it was correct. Anyway, so I started it, checked it with a timing light, and sure enough the line on the vibration damper was lining up with the chalk make made on the indicator. the truck idled great, but had a bid of a hard time starting, and unfortunately my truck had no power at all, felt like i couldnt get it going down the road at all. So what I did, I placed the dist cap back to where it was when it was loose, but I tightened it down this time. Now by turning it back to where it was I retarded the timing quite a bid, so far, that I can no longer see the line on the vibration damper coming around, it is not at 0 or even at 12 on the before section on the indicator. But, the truck has its power back again, it starts way better, and idles good, albeit a little fast I think. Now, I can not figure this out at all, it has me completely stumped, anyone have any ideas? By the way my dist cap has no vacuum advance.

I had an '83 where the outer ring of the damper actually 'slipped' around the inner ring and the marke on it were useless. I could set the timing 'on the mark' and it ran like crap. I took to setting the timing by a vacuum gauge.

[Rc 415]

Malo83 you are a god I did everything you said, and it runs like a champ now! Thanks a bunch!

[Malo83]

Glad everything worked out for you that's what this place is all about

[Rc 415]

Thanks again, after driving it for a good 30 min to work today, right when I shut it off, it did that kinda slow dying noise, you know like the cylinders were still firing but really slow about to die, then it made a clunk kinda noise and stopped. it did it when I got home and shut it off too. but if I start it up right after that and turn it on, it doesnt do it, anyone have any insight on that?

[redrat]

It sound like your timing is off now. But im not sure if you should advance or retard it. I know one of these guys whould know..

[Malo83]

Sounds like it's Dieseling, carbon buildup in the cylinders still burning after you turn it off. Also double check all your emissions that you took off have been sealed or capped off to prevent any type of vacuum leak, double check your Base timing making sure that the Dist. didn't move. the easiest way to clean out the carbon is to trickle water down the carb at high RPM, the steam will clear out the carbon, do one side at a time. GM also has a top end cleaner that you can use to clean out the cylinders.

[swb85]

Getting your timing right probably raised your idle speed, and now it may be too high, try slowing it down a bit and I bet it quits dieseling.

[Ivan D.]

Originally Posted by 79Silv4x4

I had an '83 where the outer ring of the damper actually 'slipped' around the inner ring and the marke on it were useless. I could set the timing 'on the mark' and it ran like crap. I took to setting the timing by a vacuum gauge.

What you should do ASAP is junk this damper and get a new one, preferably an OEM unit - you do NOT want that damper to fly apart on you.

[Rc 415]

Originally Posted by Malo83

Rc, I have the same 83 as yours and with the Computer you need to set up the base timing, to do it properly you have to disconnect the Comp from the Distributor, you should have a 4 pin connector coming off the distributor, disconnect it and have the truck warm and set the timing at 8 deg on the pointer, adjust the idle speed screw to 550/600 rpms once that is done reconnect the 4 pin connector, the timing will change but leave it alone. you might want to reflash the computer by removing the ground cable from the battery and reconnect it a couple of times.

Malo when you said 8 degrees did you mean advance or retard

[xtreme80]

Originally Posted by Rc 415

Malo when you said 8 degrees did you mean advance or retard

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