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Starts right up, but won't stay running.

howiebilt

Bronco Buddah
Joined
Jan 22, 2002
Messages
3,460
Loc.
Newton
Replace the ignition switch , take a couple shots of whatever flavor you like and post up in the morning ;)

Oh , I know what you're thinkin' ... that howiebilt is such a comedian ...

SeRiOuSlY- put a new ignition switch in that bronco right now and drive it to work tomorrow:cool:


Glad I could help ;D ;D

Howiebilt
 

j.r.nice

Bronco Guru
Joined
Feb 8, 2004
Messages
1,615
man I'm really confused now, but I'll try anything at this point!

I'll bet you are - even I am.

I am going back to what you indicated before and basing my questions and suggestions on that. You start it and it runs for 2 seconds then cuts off UNLESS you open the throttle and speed it up.

1) If you run it at higher RPMs (around 2000 up)
- will it stay running for as long as you hold the throttle open ......i.e. it doesnt shut off?

2) If running at about idle or just above (800 -1500) will it stay running if you "goose" the throttle just a little?

3) did the guy who rebuilt the carb have experience? ...with Edelbrocks? ......is he any good (sorry if this sounds bad, but a lot of guys rebuild carbs and really dont know what they are doing)

After I read your reponses I'll give an educated guess. Realize - it's very hard to diagnose stuff on a bulletin board. It's hard enough to do live.

J. R.
 

Fast Pat

New Member
Joined
Oct 17, 2007
Messages
37
Loc.
Flowood, MS
Are you holding your gas can apparatus higher than the carbeurator? It will require gravity to feed if it is not connected to the fuel pump.
 
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OP
Dachy

Dachy

Full Member
Joined
Jun 30, 2004
Messages
262
Loc.
San Diego, CA.
The truck will run as long as you hit the throttle.. even lightly. the moment you stop giving it throttle, it dies about a second or two later.

The guy who rebuilt the carb has never really rebuilt one before :p and it was kinda thrown together (we were pressed for time in his defense) so it may not be completely clean.

The gas can is higher than the carb (when I was running it that way). Either today or tomorrow afternoon I'll hook up the fuel pump and gas tank, look for the air bleeds and shoot some carb cleaner in there and see if it makes a difference. Then dig in deeper and figure out this idle circuit and clean that as well.
 

j.r.nice

Bronco Guru
Joined
Feb 8, 2004
Messages
1,615
Good, then your problem is in the idle circuit.

Could be as simple as an incorrectly adjusted mixture screw or a float level. Could also be something inside the carb clogging the idle circuit.

Have you turned the idle mixture screws? there should be two.....usually they are adjusted by turning the clockwise to close them (dont turn them hard after they bottom out)and then back them out 1 - 1 1/4 turns. I am not sure about Edelbrocks.

edit: link to page 4 items 61
http://www.edelbrock.com/automotive_new/misc/tech_center/install/1000/1921.pdf
 
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howiebilt

Bronco Buddah
Joined
Jan 22, 2002
Messages
3,460
Loc.
Newton
My bad ... :-[

I thought I read that it would start and die right away and it didn't matter what you did to the throttle ... where did I get that ?:?

forget the switch and get that fuel pump hooked up , I would like to know what happens when there is some pressure on the fuel line instead of gravity flow .

sorry again for throwing that switch thing at ya ... ;D


howiebilt
 
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OP
Dachy

Dachy

Full Member
Joined
Jun 30, 2004
Messages
262
Loc.
San Diego, CA.
well my fuel pump is no good :mad:
going to have to get another one of those..

also I was reading my Centech instructions and it mentioned that you should buy a ballast resistor that match's your coil. Well, I have a Mallory 29440 Coil and a stock ballast resistor so I'm trying to figure out which one I need. Additionally, in the troubleshooting it states that if the vehicle starts up and dies, you have an ignition or ballast resistor problem. I don't think that really is the problem cause it runs with throttle but might as well get the right ballast resistor for it.

Anyways, looks like I have a great weekend ahead of me :p
 

73azbronco

Contributor
Bronco Guru
Joined
Nov 11, 2007
Messages
7,796
You have NO fuel pump, mech or elec hooked up? I don't see how your filling the bowls even with gravity feed, need to get some pressure, I think 5-7psi.
 
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Dachy

Dachy

Full Member
Joined
Jun 30, 2004
Messages
262
Loc.
San Diego, CA.
okay so now I have the fuel pump installed and working properly, drawing gas from the tank. that didn't fix it.

I've tried three different carburetors, two of them which were off running vehicles, one that was rebuilt.

A buddy of mine checked it with a timing light while I cranked it to see if it was 'jumping' or moving irregular, still looked fine and the engine sounds fine when it's running.

I'm really starting to lose my marbles here! Any other suggestions?
 

HoosierDaddy

Contributor
Bronco Guru
Joined
May 29, 2006
Messages
2,773
When I installed my performer rpm , I had vacuum leaks several times (ran just like yours is doing) with as many different gasket sets , all felpro blues. Then I read the install manual for the intake and it stated nice and clear "Do not use the blue felpros" , changed to a normal felpro gasket , and it ran fine thereafter.
Otherwise , I'm thinking carb issues.
 

howiebilt

Bronco Buddah
Joined
Jan 22, 2002
Messages
3,460
Loc.
Newton
3 different carbs and it still doesn't idle ...


vacuum leak somewhere preventing the idle





howiebilt
 

mustangtoby

Bronco Guru
Joined
Nov 28, 2007
Messages
1,757
Loc.
southwest Colorado
Sounds like vacuum to me, also. I have tried the starting fluid trick, but you can also use wd-40. I have also sealed carb gaskets with a little silicone (in a pinch), use it sparingly.
 

mustangtoby

Bronco Guru
Joined
Nov 28, 2007
Messages
1,757
Loc.
southwest Colorado
Sounds like vacuum to me, also. I have tried the starting fluid trick, but you can also use wd-40. I have also sealed carb gaskets with a little silicone (in a pinch), use it sparingly.
 

ohpoo2

Contributor
Sr. Member
Joined
Dec 21, 2005
Messages
873
I tryed to read all the posts but did not see if you tried to advance the timing to keep it running. Like you all say it does sound like vac also.
 

HoosierDaddy

Contributor
Bronco Guru
Joined
May 29, 2006
Messages
2,773
Just to clarify the starting fluid trick , works best with two people. One keeps the motor running as slow as possible the other sprays starting fluid around the intake gaskets and carb gaskets . Use very little fluid , if you get a backfire and you have been hosing that thing down , BOOM !
At any rate the motor will pick up it's idle once you have found the leak , as it is inhaling an ignitable vapor through the leak.
as suggested earlier , check all theasy stuff first , carb base gasket , vacuum "nipples" or other various plugs.
 
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Dachy

Dachy

Full Member
Joined
Jun 30, 2004
Messages
262
Loc.
San Diego, CA.
When I installed my performer rpm , I had vacuum leaks several times (ran just like yours is doing) with as many different gasket sets , all felpro blues. Then I read the install manual for the intake and it stated nice and clear "Do not use the blue felpros" , changed to a normal felpro gasket , and it ran fine thereafter.
Otherwise , I'm thinking carb issues.

HoosierDaddy I think you have the answer! I pulled the intake manifold today and found a blue felpro gasket. On top of that, I found clear silicone sealing the ends of the intake manifold, big gobs of the stuff. It looks like the same stuff you use in bathrooms when installing a new sink or something. Do they make clear automotive silicone or is this some Previous Owner hijink?

I'll be ordering a new intake manifold gasket tomorrow (thats when my buddy who can get me a sweet discount works at the part shop), a fel-pro printoseal is what I found to be the appropriate gasket for an rpm performer intake manifold.

I figure this is why the bronco sat for 10 years before I bought it, maybe the P.O. couldn't get it running right either. Or maybe when I started it the first time it blew the gasket loose so it didn't seal right or something which would cause a vacuum leak.

Either way I hope this fixes it, if not, I should have replaced this gasket in the first place anyways seeing as how the truck has sat for 10 years without being started. :p We'll know sometime this weekend or next week whether or not it works!
 

HoosierDaddy

Contributor
Bronco Guru
Joined
May 29, 2006
Messages
2,773
After a gasket change , it would sometimes run until the motor cycled hot/cold a time or two. (with the improper gaskets ).

Ditch the cork end gaskets completely and buy a tube of permatex "The Right Stuff !" or Ultrablack.
I just had a chance to use both recently , I think I'm really liking "The Right Stuff". Not to take away from Ultrablack , which I had to remove from a surface after it had cured , it seemed to adhere really well also , the right stuff just seemed a little denser/firmer once it had cured.
A clear automotive sealant ? , unknown to me. Do an intake manifold gasket search here , you'll find a lot of useful info.
Oddly enough , this same issue is what caused mine to sit abandoned in the garage or storage unit for ten years also. As of last week , I'm fuel injected and loving it ! :)
Let us know how it works out for you.
 
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