Home » Public Forums » GMCnet » will not idle
| will not idle [message #280696] |
Thu, 25 June 2015 10:28  |
pzerkel
Messages: 212
Registered: September 2007
Location: Salisbury, IL
Karma: 0
|
Senior Member |
|
|
In the never-ending saga of "one thing leads to another" (see "belts - size vs. quality" thread)...
So after finding a belt that fits and installing it I noticed one of the water hoses was rubbing against the belt. I zip tied it out of the way, and that put enough a bend in one of the lines attaches to the "T" that one of the hoses is starting to kink. My understanding is that I can fix that by getting some "kink resistant hose". It is a hose about 11" long coming from the intake manifold running to a "T" near the a/c compressor.
I took the zip tie out and tried to situate things so that the hose was not rubbing the belt and the other hose was not kinked. I could just get it, but would never trust it to stay put driving down the road. The hoses need to be supported somehow IMO.
So I tried to start it. It would start, but would not idle at all. It just kept sputtering and would die after a few seconds. I could keep it running if I kept my foot in it though. Honestly it has never idled well, but usually better than this (esp after it runs for a few minutes).
I kind of knew that I had carburetor issues, but as long as it ran and drove, I did not want to "fix" it. Anyway now, I cannot keep it running (at idle anyway). So I started looking around the carburetor. I found two lines unconnected. Based on where the other ends were, I suspect one was supposed to be connected to a port on the passenger side valve cover, and the other was probably to the charcoal canister. I hooked up the one to the valve cover, I need to get under it to reach the charcoal canister.
I also took this oppurtunity to figure out what the ID code is on my Quadrajet. It is 17058254. This is interesting to me because I have a 1978, but it has a 455. My research indicates that 17058254 was a "GMC MH" carburetor (but for a 1978 403). So I suspect that whichever PO installed the 455, just took the carburetor off the old 403, and bolted it up to the 455?
Also, worth noting is that this engine has an Edelbrock intake manifold.
I am pretty sure my choke has never really worked right since I had the coach. So after trying to educate myself some from the manuals and googling "Quadrajet choke". It appears to me that what used to be the heat tube going from the manifold to the chock has been cut, crimped (mostly) closed and just sort of sitting there attached only to the carburetor.
Can anyone tell me if the Edelbrock intake even has a place to attach the heat tube to? If not, what other options do I have?
I am starting to wonder if it is time to think about getting the carb rebuilt (I would likely send it one of the Jim's or DIck Patterson). But even if I do that, I think I have other issues with vacuum lines and choke tubes that need to get solved also. If I do send the carb out, what kind of issues is it going to cause being the 17858254 was from a 403 and is now on a 455?
I guess I will start with the kinked water hose, re-attaching the line to the charcoal canister. If that it gets it to idleing better, I will probably continue with troubleshooting the a/c. But whether that gets it idling okay or not, I think I need to decide what further steps I should take re the carburetor.
Oh and all this looking around, I am realizing just how ugly hoses and wires are routed. Most of the spark plug wires are just dangling (some dangerously close to the exhaust manifold IMO). I guess one just works on these things one item at a time.
I think I should change my sig to "not a car guy, but trying not to be a car idiot"
Paul Zerkel
'78 Eleganza II
Salisbury IL (near Springfield)
|
|
|
|
| Re: will not idle [message #280702 is a reply to message #280696] |
Thu, 25 June 2015 11:18  |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
|
Senior Member |
|
|
for what it is worth, I ended up sending my carb to jimB when I figured out I had a locked up power valve, and probably some other problems. for the stated rebuild price I shipped it to him in a box of parts(I took it partially apart and realized i did not have the skill to put it back together, and he returned it back with an electric choke a couple weeks later, all I had to do is run a wire from an ignition source to the new electric choke. I am not sure if Dick tosses the heat tube type mechanical choke or not.
I would have had a local re-builder do my carbs normally, but since I had no history of my carb I sent it out to a GMC person, that assured me the bushings were fine, and other issues were looked at, that a cleaning/rebuild might miss. I was dealing with less then 5mpg, and I did not want to chance anything. fix the carb, and then I can take that out of the equation and worry about other things.
I installed the carb when I got it back, and I had to do zero adjustments to it. Been idling, and ect.. ever since. a couple presses on the gas pedel, and the engine fires right up, and I can drive away almost immediately.
that is just my experience.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
|
|
|
|
|
|
| Re: will not idle [message #280708 is a reply to message #280707] |
Thu, 25 June 2015 11:57 |
appie
Messages: 902
Registered: April 2013
Location: denmark
Karma: 2
|
Senior Member |
|
|
Hello paul
Now I am not a spicialist on this. But I am getting some experience
I would say before spending money on a carb rebuilt. Start with getting everything right. If you have major vacuum leakes you will never have it idle right
So connect all vacuum hoses. Make sure ypu have gas. Adjust your ignition making sure you have enough voltage and the advancce systems work
Add a electric shocke. If you have no experience on these things find someone to teach you. You will need this knowledge!
Good luck
Appie
eleganza 76 "Olga" now sadly sold
6 wheel discbrake
Quadrabags
Springfield stage 2 462 olds
Manny tranny
( pictures at http://www.gmcmhphotos.com/photos/g6489-olga.html
Fulltiming in Europe july 2014 til july 2016
Denmark
|
|
|
|
| Re: will not idle [message #280722 is a reply to message #280708] |
Thu, 25 June 2015 19:14 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
|
Senior Member |
|
|
Eletric choke would be an excellent choice. Interesting that P.O. put a 403 carb on the replacement 455. I do not know all the ramifications of that change, but would not be my first choice. Perhaps you can chase a swap.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
|
|
|
|
| Re: will not idle [message #280730 is a reply to message #280696] |
Thu, 25 June 2015 20:45 |
pzerkel
Messages: 212
Registered: September 2007
Location: Salisbury, IL
Karma: 0
|
Senior Member |
|
|
update...I hooked up the vacuum line to the port on the left valve cover, and for now plugged the line that I believe should be going to the charcoal canister. I then started it up, it idled much better. This at least let me drive it up on my set of ramps.
It was getting dark, but now it should be easy enough to get under it to hook up the canister. Plan is to replace the kinking coolant hose this weekend, and get the charcoal canister hooked back up this weekend. After that gets done, I will see how it runs and decide what I want to do with the carburetor.
As has been posted here by others, it really is amazing how much difference a couple of disconnected vacuum lines can make in how it runs.
Paul Zerkel
'78 Eleganza II
Salisbury IL (near Springfield)
|
|
|
|
| Re: will not idle [message #280737 is a reply to message #280730] |
Thu, 25 June 2015 22:07 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
|
Senior Member |
|
|
pzerkel wrote on Thu, 25 June 2015 19:45update...I hooked up the vacuum line to the port on the left valve cover, and for now plugged the line that I believe should be going to the charcoal canister. I then started it up, it idled much better. This at least let me drive it up on my set of ramps.
It was getting dark, but now it should be easy enough to get under it to hook up the canister. Plan is to replace the kinking coolant hose this weekend, and get the charcoal canister hooked back up this weekend. After that gets done, I will see how it runs and decide what I want to do with the carburetor.
As has been posted here by others, it really is amazing how much difference a couple of disconnected vacuum lines can make in how it runs.
Also. make sure the carb is not loose on the manifold. Most GMC air cleaners rub on the underside of the engine cover and tend to loosen the carburetor resulting in lean idle and vapor lock symptoms.
Bob de Kruyff
78 Eleganza
Chandler, AZ
|
|
|
|
|
|
| Re: will not idle [message #280748 is a reply to message #280737] |
Fri, 26 June 2015 00:19 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
|
Senior Member |
|
|
Bob de Kruyff wrote on Thu, 25 June 2015 20:07
Also. make sure the carb is not loose on the manifold. Most GMC air cleaners rub on the underside of the engine cover and tend to loosen the carburetor resulting in lean idle and vapor lock symptoms.
Bob has an excellent point. However, don't get wrench happy with bolts on the carburetor. They need to be snug but not muscled up on. The carbs are old and over tightening can warp the body and render it useless. If you are in doubt about a possible leak, aerosol carb cleaner sprayed on the suspected leak point will speed up the idling engine if the fluid can be sucked in through a leak.
Don't spray much. Remember, this stuff is very flammable.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
[Updated on: Fri, 26 June 2015 00:20] Report message to a moderator |
|
|
|
|
|
| Re: will not idle [message #280765 is a reply to message #280696] |
Fri, 26 June 2015 08:47 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
|
Senior Member |
|
|
The only place I trust around here (Dollar Carburetor and Electric) gets $375 to properly build a Quadrajet, might as well to give the vendors the binniss >and< make sure it's set GMC specific. It's getting harder and harder to find a carb guru, they're all getting old and/or dying off.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
|
|
|
|
| Re: will not idle [message #280805 is a reply to message #280696] |
Fri, 26 June 2015 18:13 |
Chris Tyler
Messages: 458
Registered: September 2013
Location: Odessa FL
Karma: 7
|
Senior Member |
|
|
After you make sure the timing is right, the distrib weights arent stuck and take care of any more obvious vac leaks, try applying the choke or partially cover the primary side. If it smoothes out you are too lean- so look for more vac leaks [primary throttle shaft bushing is a common problem] or the idle circuit has something in it.
If it is worse, you are too rich and its likely too high a float or a leaking needle and seat
One problem with later Qjets is the idle mixture screws are behind plugs. They can be removed and extensions fashioned so that it can be adjusted to lean/best idle or to compensate
Nice thing about Q jets is that they are very adaptable. If it runs well otherwise you may not need a new carb. The Idle curcuits will be the same, although the screw setting may be slightly different
76 Glenbrook
|
|
|
|
Goto Forum:
Current Time: Sun Sep 29 06:23:52 CDT 2024
Total time taken to generate the page: 0.01192 seconds
|
GMCforum
Search
Help
Register
Login
Home
