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Discussion Starter #1
I've been tweaking away at my carb for a while to try and find that sweet spot. After a few close misses, I'm finally coming to the gurus for a little help.

Car:
1979 El Camino
231 V6 w/ Dualjet Carb (Car was once an ECM car but all the electronics have been removed.)

I originally had started messing with the carb to try and pass emissions. After a bit of tweaking, I finally found that it was failing miserably due to the jets that I was running. Pulled out the size 75 jets and dropped down to 73s. Emissions passed just fine, but there was still something that was a little off.

The problem that I've been having is that I can't get the car to a point where it will start up without also having it running very high when in park or neutral. Either I can tune it down to the point where it's unable to start when cold and it has a normal sounding idle speed in park, or it starts up well and will rev very high when shifted out of gear. (This also makes it jump when shifted into gear.) Right now I'm set in the middle. I have to baby it just a bit to get her started in the morning and the off gear idle is a sounds a bit high. Forgive me but I don't have a tach, so I'm just going by how it sounds.

Right now I'm running size 71 jets and the idle mix screws are about 1.5 turns out. I'm thinking that it still might be running rich because I get a little bit of dieseling when I shut the car off.

I'm starting to think that this is really due to having all the electronics removed so it can't calibrate the fuel mixture differently between hot and cold. But I'm hoping that there might just be some magic silver bullet to tuning this in. Any help would be appreciated.

Thanks in advance.
 

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probably be better off finding an older model dualjet to work with,or hooking back up the electronics, the electronic ones can be pretty finicky after having the controls removed, not to mention if you havent changed the distributer the ecm cant properly adjust the timing without knowing what the fuel is doing
 

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If the Dualjet you are working on had electric connections on the passenger right front, and on the driver's side front, then it is a CCC carb, and nothing you do with the jets will make it work. It will basically run with the jets wide open all the time. You might find a sweet spot at some combination that will idle OK, or run OK at 35, or run OK at 55, but everything else will be way off.

Scandolis has a good suggestion on finding a non CCC dualjet and work from there. MountainMan carbs might be a good place to look. His advise about the distributor is also correct- you need a non ECM distributor if the ECM is removed You may have already done this when you removed the ECM stuff).
 

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X2 on the non-comp carb. If your using an e carb with no computer, your adjustments are meaningless
 

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Discussion Starter #5
I'm sorry, I should have clarified. The car was originally equipped with the computer, but the PO had removed all the electronic components and replaced everything with the mechanical. It's a non CCC carb and distributor. The reason that I brought up that it was computer controlled at one point is that it feels like the problem is due to the rpm change when the engine warms up. I cant find a happy medium between cold and warm. Either it wont start when cold or revs real high when warmed.

I'm wondering if this could be something with the EGR valve opening up and throwing off the mix or something like that.
 

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So, you have a noncomputer carb and distro, right??? Is your carb a q-jet, or what?? You do have vacuum advance on the distro, right??
 

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Discussion Starter #7
It's a dualjet (q-jet less the secondaries) and it does have the vacuum advance on the distributor.
 

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Check that the choke is operating properly, does it open all the way after warm up if not that is causing it to stay on fast idle. Let it warm up and then look at the choke plate and open it manually then crack the throttle it should fall off fast idle or the linkage is binding.
 

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Discussion Starter #9
I actually checked the choke with a wire jumped off the battery to verify that it is working right. I was thinking it could be the other way. Maybe it's not staying closed long enough for the engine to warm up and I possibly have the idle speed up too high.
 

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Mike if you are looking at the carb from the front on the lower passenger side, I mean really low and about in the center front to rear, is the fast idle adjustment screw. Maybe someone set it too high so that when your choke is closed the rpm is too high. With a cold engine it should take the choke at least 2 - 3 minutes to fully open. I see you checked it with a hot wire but is it getting power from the harness when running?
 

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Discussion Starter #11
Hmmmm. Well, I'm pretty sure that it is still getting power from the harness to open up the choke because i can check it after I take it out and it is wide open. I haven't ever checked the fast idle adjustment screw though. I'll check that tomorrow on my day off. How would I adjust this? Or figure out if it's off from where it should be?
 

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Looking at the choke bell housing their will be a lever just behind it on the right side if your facing the choke that looks like it could be weighted, if it is up when warm it won't come of fast idle. If you can touch it and it falls down it is binding. You can clean it with carb cleaner and then spray lube.
That adjustment screw will be very hard to see on the bottom carb plate.
Try that
 

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To adjust it - Engine off, give it a little throttle opening and at the same time close the choke completely and hold it while you let go of the throttle. Now without touching the gas pedal or linkage start the engine. It should be running at about 1500 - 1600 RPM. Adjust the almost impossible to see screw to the desired RPM.
 

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Discussion Starter #14
Well, It looks like that did it. Pulled up a video on how to adjust it and that fixed everything up. I turned up the fast idle and turned down the base idle. Now she starts up and runs without revving uncontrollably. Thank you guys for all of the help.
 

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Glad you got it. If you think that one is hard to see you should look for it on a holley.
 
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