runs high rpms then dies

[hondo]

just got my cj back together after doing a ton of work to it (new used intake, exhaust manifolds air injection system egr, basically all of the smog related parts) and when i tryed starting it again it ran for 10-15 seconds at about 2000rpm then stops, i have checked for vacuum leaks carb tunning checked inside the carb. and am still at a loss nothing i do seams to change anything. i would apreciate any help i am trying to get it at the exhaust shop by tomorrow.

 

[hondo]

fuel pressure is at 6psi. i also tried messing with the mixture but still no change

 

[Torxhead]

Figure out if it is running out of gas or spark. Does it start right back up?

 

[hondo]

it takes a couple seconds of cranking and pumping the gas pedal a couple times but not to the point where i would say its hard to start. i took the top off the carb to see if the float was jammed and the fuel bowl was full. also tryed disconnecting the fuel line and cranking and it spits out fuel.

 

[Lumpy Grits]

When it dies-
Does it act like it flooded out, or someone turn'd off the ign switch?
LG

 

[hondo]

more like someone turned the ignition off. i tryed a different carb and the idle was high but it was staying running and surging almost dieing then going high rpms then almost dyeing

 

[Lumpy Grits]

How hot is the coil when it dies?
Your SURE, that you have no vacuum leaks...
LG

 

[hondo]

not totally shure there are no vacuum leaks i am now back to the idea that there is. thinking it has something to do with vacuum lines going into and out of the spark cto (threaded into the thermostat housing) i have the middle line (marked d) hooked up to the vacuum advance, the outer line (marked 1) hooked up to the manifold vacuum source, and the one closest to the thermostat housing (marked 2) was left open because the service manual didn't have a clear picture of where it went. it now looks as if #1 goes to a tcs solenoid (left side of the carb hooked up to manifold vacuum and ????) and #1 gets hooked up to vacuum source and a solenoid vacuum valve, which gets hooked up to ?????. thanks

 

[Lumpy Grits]

Not a clue on vac. line routing on yours. Wish I had an ans for you.
Did you take any pictures before tear-down?
LG

 

[hondo]

wouldn't have done any good there werent any vacuum lines on it when i got it.

 

[SMizar]

I would try plugging all the vaccum ports and starting from there...


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[Posi]

spark CTO switch

top line - to non linear valve
middle line - to vacuum advance
bottom line - to manifold vaccuum

The EGR, EGR CTO switch, charcoal canister, and top line (of 3) on the non linear valve are all ported vacuum. All else is manifold vacuum.

Don't leave any lines open. Check the carb base and intake manifold for leaks, I'm assuming all lines are new. I use a propane torch to check for leaks, fast and clean. Testing with gas only, no flame.

 

[hondo]

non linear valve?? how do you use the torch to find leaks? thanks

 

[Torxhead]

Another way to check for leaks would be spraying on WD-40, as a rise in rpms would indicate a vacumn leak.

 

[Posi]

non linear valve?? how do you use the torch to find leaks? thanks

Use the torch just like you would any other spray. Turn the torch on and point the nozzle at any potential leaks (don't light). If there is a leak the idle will increase. No need to soak your engine down, just personal preference.

If your missing the linear valve cap off the top outlet on the spark CTO switch.

 

[hondo]

ok worked on it some more looks like it is actually flooding out as every now and then you can see gas splashing out of the carb, last time actually catching fire. i tryed changing out the egr with a spare that i have and it is still doing the same thing. i will try capping the third port on the spark cto. i think if i can ever get it to stay running long enough i will try the torch method, something about a dirty oily engine bay that annoys me.

 

[hondo]

plugged the final port on the spark cto and there was no change

 

[Torxhead]

A flooding out can be from a stuck needle & seat assy or an out of adjustment float. If either of these conditions exist, you will see lots of gas down the throat of the carb, whereas normally there will be a fine spray.

 

[hondo]

ok i think i figured it out, i used a different spacer for between the intake and carb off of a ford 390 (only one i could find short of ordering online) which has ports in the bottom which were going through holes in the gasket and creating a vacuum leak and causing it to not suck the fuel into the intake and it spraying out the top. i have ordered a new plate from summit racing and i should now whether its right or not tomorrow when it gets here. will let you now how it works. thanks

 

[Posi]

Do you have a vacuum gauge? If so post up your psi, then again after you install the new gasket. If you don't have one their not expensive and a great tool to own.