318 LA high idle issue.

[brandon marsh]

I bought a new edelbrock 1406 carb and a weiand 8007WND intake for my 85 d150 got it all installed and when I start it hits red line immediately when I start it. everything points to a vac leak but ive replaced all the hoses on the intake, used an adapter plate for the carb to the intake and bought all new fittings but it still high idles. ive even adjusted the high idle screw and air and fuel mix screws.


any help is appreciated

 

[Biff]

Are all the vacuum ports blocked off , are the throttle blades closing completely? Did it get dropped and linkage bent ?

 

[brandon marsh]

all the vacuum ports are blocked

Are all the vacuum ports blocked off , are the throttle blades closing completely? Did it get dropped and linkage bent ?

all ports that are meant to be blocked are blocked and I haven't dropped it nor is any linkage bent. I'm really stumped on this

 

[Biff]

Post some pics of your set up ,I’m off to work will check in later ,lots of great advice on here .cheers

 

[brandon marsh]

all the vacuum ports are blocked

all ports that are meant to be blocked are blocked and I haven't dropped it nor is any linkage bent. I'm really stumped on this

im heading to the farm tomorrow ill get more picks

 

[mygasser]

sounds like part of the carb linkage could be caught on the adapter plate/gasket holding the throttle open.
neil.

 

[brandon marsh]

sounds like part of the carb linkage could be caught on the adapter plate/gasket holding the throttle open.
neil.

i just added an adapter plate cause someone suggested that it wasnt clearing the intake on the bottom/underneath. maybe i need a thicker plate?

 

[brandon marsh]

sounds like part of the carb linkage could be caught on the adapter plate/gasket holding the throttle open.
neil.

the adapter i bought was a Weiand Carburetor Sealing Plates 9006 its only 0.063" thick

 

[missing linc]

i just added an adapter plate cause someone suggested that it wasnt clearing the intake on the bottom/underneath. maybe i need a thicker plate?

The adapter plate could be upside down, I just put one on my car last night, I had an open spacer originally, but it didn't really seem to like it, plus Edelbrock recommends a 4 hole and not an open style. I haven't had a chance to drive it yet, my oil pressure line has developed a leak, have to fix that first. What adapter are you using? I have the Edelbrock 2696 pn, and it definitely is not reversible.

 

[ChargedDart75]

Check and make sure the throttle blades are fully shut.

 

[brandon marsh]

The adapter plate could be upside down, I just put one on my car last night, I had an open spacer originally, but it didn't really seem to like it, plus Edelbrock recommends a 4 hole and not an open style. I haven't had a chance to drive it yet, my oil pressure line has developed a leak, have to fix that first. What adapter are you using? I have the Edelbrock 2696 pn, and it definitely is not reversible.

i have a weiand adapter plate PN - 9006

 

[ChargedDart75]

i have a weiand adapter plate PN - 9006

That's an open plate. I doubt it's your issue.

 

[cudamark]

Check to make sure the gaskets seal all the passageways/openings on both side of the adaptor plate. I've seen some setups with gaps that caused a vacuum leak. While the engine it running, spray some WD40 around all the gasket seams and hoses to see if there is a leak.

 

[AJ/FormS]

Did anyone mention the PCV hose? or the power-brake hose? or secondaries hung open?

 

[67Dart273]

It HAS to be air leaking somewhere. Since this is a new? install? of an intake, did you pull the little pins out of the valley crossover? These will "jack up" the intake and prevent it sealing. And it might be some other related sealing issue. Check that the carb is not "jacked" on the flange, AKA interfering with the EGR/ choke well, whatever.

LOLOL This is about the third or fourth thread on this same problem in the last 2-3 weeks

 

[AJ/FormS]

when I start it hits red line immediately when I start it. everything points to a vac leak but ive replaced all the hoses on the intake, used an adapter plate for the carb to the intake and bought all new fittings but it still high idles. ive even adjusted the high idle screw and air and fuel mix screws.

In my experience
An engine with a small DRY air leak
originating NOT in the carb,
(as in at the intake to head gasket, or a base gasket, or hoses)
can idle a little faster than usual; but the more DRY air you give it, sooner or later it will be too much, and then the engine will slow down, and any more air will eventually cause it too stall.
The only way the engine can "hit redline immediately", is if the unauthorized air also has fuel in it. And that points to the air coming in thru the usual channels,namely thru the venturies. And since the 1406 has dry secondaries until the throttles are opening,
Ima guessing
your primaries are not closing.
This does not preclude that the secondaries are not ALSO not fully closed, it only hints that they are.
Make sure the fast-idle cam is 100% disengaged during cranking......... and stays disengaged.
This does not mean "just open the choke".
It means make sure the fast-idle cam is 100%.....
"DISENGAGED".
As in; the fast-idle screw is NOT on any step of the cam, but is in fact, clocked into the disengaged position where there is no cam under it. You may have to manually put it there, and figure out how to keep it there..

But if that dry air leak is supplemented by the choke-blade also being somewhat closed then you have the stage set for a runaway rpm, immediately.

my best guess

 

[brandon marsh]

It HAS to be air leaking somewhere. Since this is a new? install? of an intake, did you pull the little pins out of the valley crossover? These will "jack up" the intake and prevent it sealing. And it might be some other related sealing issue. Check that the carb is not "jacked" on the flange, AKA interfering with the EGR/ choke well, whatever.

LOLOL This is about the third or fourth thread on this same problem in the last 2-3 weeks

The pins were removed so idk

 

[brandon marsh]

The pins were removed so idk

 

[AJ/FormS]

Where is the PCV plumbed to?

 

[brandon marsh]

if you are talking about the valve that sat on the head covers when i bought this truck from a guy last year it didnt have one it was running ok but not the best the guy suggested a new carb and intake

 

[AJ/FormS]

OK Brandon
first off,
if this is a streeter, you need to install and plumb a PCV to the underside of the primary blades. You see that big capped nipple there? That is what you hook to with the proper PCV-rated thick-wall hose.
2) see that vacuum line going to the booster? For diagnostic purpose clamp it off. Later you will replace that, what looks like fuel line, with the proper thick wall tubing and prove the check-valve in the booster is working.
3) remove the vacuum line from the Vacuum advance can and PLUG it.
4) remove your air cleaner retaining nut off that air-horn stud! before you start the engine.
5) loosen the screws on the choke housing and rotate the black housing until the choke blade is hanging vertical. With the engine off, whack the throttle one time to disengage the fast-idle cam.Make sure the fast-idle cam rotated to "off". Now, go find your mixture screws and screw them in until lightly seated, them back them out 2.5 turns. Finally, find your speed screw, and crank it in until it hits the throttle arm, then add 2 turns.
6) make sure the secondaries are closed and that the weighted secondary valve is properly seated.
7) loosen your distributor just enough so it moves then push the Vcan towards the firewall about one-half inch, and snug it just a tad.
8) now climb in and grab the key. Do not let go. Then kick the gas pedal twice and with a fully charged battery, Crank it! If the engine still revs up, be prepared to shut it off. Be prepared to slap the gas pedal and/or babysit the engine until it warms up.

If it fails to start, it may be flooded, or it may not be getting any air at all.
So press the gas pedal down about halfway and hold it there while cranking. If it springs to life, be prepared to slightly lift off the pedal as the speed comes up. But it may not have enough rpm to stay running now, so don't lift all the way.
If you get it this far and it's not reving but won't idle either, shut it off. Go find the speed screw and turn it in three more turns then start it up again.
Ok now, just pull the Vcan timing in until the engine is happy, and let it warm up.
After it's warmed up, install your timing light and set the timing; 8 to 10 for a stock engine; 12 to 14 for a warmed up one; 16 to 18 for a hot street automatic.
Then bring the idle into line.
But if you think it's flooded, pull a couple of plugs out and look. If they are wet, pull them all out and dry them. Also; disable the coil, and pump the gas out by cranking it, in short bursts; remember, this air-bound mixture is now ready to explode, so don't do it inside a building and have your fire extinguisher nearby.
If you found gas in the cylinders, you will have to oil the cylinders up a lil. then put it all together and try again.
But if you found no gas in the cylinders, since the plugs are out, I'd put a lil oil in the cylinders to help seal the rings. Let it sit for 10 minutes, rotate the engine 1 turn, then another lil squirt and wait another 10 minutes. Then pump it all out, clean up the mess, put the plugs back in and try again.