Technical 292 Dies at Acceleration

The 292 in my 59 Edsel is doing one thing thats keeping my from driving it more often. From a dead stop, if I try to accelerate too quickly, the engine will hit a spot where it just dies out. It happens pretty early on too, before I even get any speed. BUT, if I accelerate really slowly past that spot, everything is fine. Once I'm going, there is no stopping that engine. It's coupled to a 2 speed Mile-O-Matic transmission, not sure if that means anything. The carburetor was rebuilt about two years ago. I visually tested the accelerator pump and it is shooting a nice stream into the carburetor on each side. So that seems ok. After some testing, I found I was only getting 7 inches of mercury. I replaced the pvc, which got me 17 inches, but this did not improve my situation. Here is a video showing acceleration and stalling with and without a vacuum gauge installed:





Heres the update from the other day, I show the problem after my question about the exhaust:



miker, from another forum, told me and which I am starting to believe that I have a little crap in the carb, and it's a lean bog the accelerator pump can't cover. Not an obvious blockage, but just a little here and there till it's too lean. Maybe even blocking part of the power valve circuit, so it only shows up on transition.

 

I would clean the idle circuit really well. It has a lot of small orifices in the emulsion tube and the idle jet. The engine runs on the idle circuit from idle to about mid throttle. As you accelerate, that circuit must work. The well where the idle jet picks up fluid probably has some crap in it. Once you clean it, install a fuel filter to prevent recurrence.

 

have you checked the simple things?,,fuel filter? HRP

 

Yeah, it's new.

 

It could be a bad accelerator pump . The old style leather cups don't do well with todays alcohol content in the fuel.

 

Vacuum advance ? Points ?

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Never mind i just noticed that you checked the pump

 

I'd check possible vacuum leaks. No problem until the engine is under load? Maybe the line to the vacuum modulator on the trans?

 

These are checking out ok.

I have a two speed Mile-O-Matic transmission original to the car, I don't believe there are any vacuum lines going to it.

 

Power valve is leaking or not working.

 

I guess a rebuild is in order.

 

Could be the power valve. I lubed all the linkages with TriFlow and that helped a bit.

 

If the carb is somehow not the issue, I was told that bumping up my timing to 10 degrees before tdc instead of the 6 degrees I have it at now could help. Any thoughts?

 

I personally did that very thing to my 41 buick . I installed custom headers , custom intake , 3 holley 94's - I also took my timing from 2 degrees to 6 degrees because of a lazy acceleration . I also have vacuum advance that is enough to help with letting the clutch out and initial load . Goodluck

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You have not talked about the distributor. Inside is a little wire that goes to the points. The plate the points are mounted on moves, and the wire must move with it. When you punch the thottle, the plate moves because the vacuum drops. On my 312, (same dizzy), the wire had broken but the plastic insulation held it together. A real head scratcher. Any Y block responds very well to more advance, it will really wake up.

 

I'd thought about maybe a flakey ground somewhere on the engine or chassis but I like this diagnosis even better. The way it just shuts off sure has me leaning more toward an ignition rather than a fuel issue. Now get out there with an ohmeter and start jiggling some wires around!

 

What do you have your initial advance set at? 6*? Bring it up to about 14* and throttle the engine with the timing light on the marks, you should have around 34-36* total by 3000 rpm. No vacuum advance.

 

Agree with power valve. Might be the wrong one installed.

 

The fact that you can accelerate through the dead spot slowly makes me think it's not a timing issue and more related to fuel delivery. The power valve and/or accelerator pump would make sense. I'd start there. Not to mention a real good deep cleaning for the carb.

 

I was going to repeat the issue of a crook accelerator pump but you say it is squirting two good streams of fuel. Are the accelerator linkages working in unison or is there slop in the worn joints that is making the mixture too lean early on and the accelerator pump "squirt" is too late to overcome the leanness created by opening the throttle plate?
Also I have seen a blown intake manifold gasket give a lean mixture regardless of how good the carburettor is. Is the car stumbling on a light throttle opening and then going good under load? This indicates vacuum leak(s) somewhere and will need to be fixed before anything else is attempted

 

Timing didn't seem to achieve anything

I checked the wire and it was perfectly good.

Yeah I was sat 6, but now I'm at 10. Distributor's weights and vacuum advance seem to be working just fine. I'll try your method soon.

Linkages all work well with no slop, intake has new gaskets and checks fine /no leaks, and as far as overall vacuum leaks, I can't find any anywhere.

Here's a video: (I had the pcv valve disabled / plugged during this video)

 

bad motor mounts torque the engine it moves and acts like taking the foot off the accelerator,

 

See post number 2.

 

I think the signs all point the same direction now, rebuild. Looks like this is what I'll be doing next. This will be its second rebuild since I've had the car. (6 years)

 

Who is rebuilding the carburetor? I assume that if it was done 2 years ago the components are ethanol compatible but if you are running fuel containing ethanol, you might have to go to slightly larger jets and power valve. Getting all of the passages clean is very important but the most important part of rebuilding a carburetor is getting all of the adjustments correct by following the instructions with the carb kit. Too many people think they don't have to do the adjustments. The accelerator pump covers the initial throttle motion until the power valve can react to the vacuum change.

 

I think I'll have it professionally done by gottafishcarburetors.com

 

Took the carb off today, gonna let it dry out a few days before I send it out.

 

Silly question - but - do you have a "dash pot" on your carb? Its a little device that arrests deceleration. That may be why your engine stalls. Either it is failing or you don't have one.

 

Oh, sorry for the late reply. Yes, I do, and it was not working right. But in addition, this is what my float bowl looked like:

 

check vacuum advance operation distance w a suction pump w guage -- at rest, & w the engine running to see how far it moves at rest and then how far the timing advances when running -- also, w the same device, check the ported advance suction from the carb nipple to make shure yer gittin some --

thisun's the one I use --
http://www.amazon.com/Actron-CP7830-Hand-Vacuum-Pump/dp/B0009XQUK2

also, take the accel pump diaphram *off* and feel of it -- if it's hard, replace it -- could be it's workin but not as well as it should -- seen *this* a LOT over the years