Please help with stalling issue... Here are the details.

I have a '79 with a crate 350 that the previous owner installed. It has an Edelbrock performer Intake with the Performer 600cfm carb. When I got the motor it ran 'okay'. The previous installation did not include the wiring for the electric choke, so it ran at a VERY fast idle at all times. I fixed that issue and drove the car around for some months without any complaints. Then I had an ufortunate fire in the engine bay due to a leaking glass fuel filter. Needless to say, I have repaired all the damage (and then some) and have it running again. The engine has a slight "slapping" sound from the left side... but runs well enough at idle now. I can apply throttle quickly or slowly and the engine revs up smoothly. However, when I put the car in gear it idles WAAAY down to around 700RPM (before it idles at 1100RPM) and when I apply throttle it dies. If I apply it smoothly and VERY slowly it will accelerate slowly, but lacks any type of power. It looks like the issue is when the engine is under load it has no power. I can't even drive it right now because of this. Any ideas on how to proceed with diagnosing this issue? I am suspecting it is vacuum related or timing or a combination, but I do not have the experience to know if this is true or what to do.

Here are some other points of interest:
1) After the fire was put out by me (using an ABC Fire extinguisher) all the carb linkages were frozen. I took the carb off and cleaned it up with WD-40 and all linkages now work. I can see the choke/primary/secondaries all doing their job. I can see fuel being sprayed at the appropriate times (I think)

2) Here is the list of things that were replaced after the fire:
a) Replaced ACCEL HEI with a Flamethrower HEI (new springs, bushings, etc) rebuild kit
b) Replaced all plugs with new plug wires
c) All new Spark Plugs (NGK Platinum)
d) New engine bay wiring harnesses (from Ecklers)
e) New Vacuum advance unit (came with Distro rebuild kit)
f) Disconnected all vacuum lines except PB, Headlights, Vacuum Advance, and some steel line that goes behind the engine
past the vacuum advance and toward the tranny?
g) New Radiator (DeWitt) + SPAL fans: Weren't damaged but I removed the radiator to fix the other stuff and figured what the heck
h) New Fuel Pump - I had to install a Holly pump in order to get my new Fuel filter/line to work (Edelbrock)

One last note:
*I replaced the HEI components but did NOT move the cap at all.
*I do not know how to "time" an engine so I have not adjusted any timing.
*When I got the ignition back together (according to Haynes manual) the car would not start. It was missing and backfiring like mad. So I moved all spark plug wires counter-clockwise and it started right away.

Anyone can view pics of my car by pointing their browsers to this URL: http://photo.thewhelans.info/index.p...der=/Corvette/
Pictures are mixed but you can see the before/during/after pictures and my particular setup.

 

recheck the firing order 18436572

make sure the #1 plug wire position on the cap is the same as you had it before the rewire. Looking at the picts it appears to be the same, but double-check.

is the accelerator pump squirting fuel?

Did you take the carb totally apart and clean it all up? or just clean the exterior. Could have baking soda in there.

 

I would look to the carb as well.

 

I just freed up the obvious, exposed linkages... I did not take apart the carb. I was debating purchasing one of the edelbrock rebuild kits ($40) do you think that would help?

Turtlevette, how do I confirm the accelerator pump is squirting fuel? With the air cleaner off, when I add throttle quickly, I do see a spray of fuel in the front two ports... when I go WOT, I see fuel squirt into the back two as well.

 

are you doing this with the engine running or not? if the engine is running then the fuel you see might not be from the accelerator pump if it is not running then that is the pump working.

 

That sounds good. Maybe we need to focus on timing. Check out my edited post. Is number 1 plug in the same place it was before the rewire.

is the vacuum advance getting vacuum at idle?

 

With the engine off, if I add throttle, I see fuel squirt into the carb.

As far as timing... wires were melted so I removed all of them at the same time. When I reinstalled, I plugged them in according to the Haynes repair manual, which listed the firing order. (I'm not near it now so I can't confirm what is listed). When it was all back together, it would not start. I moved all plugs exactly one spot counter-clockwise and it started right up.

It runs well at idle, very stable, and when it isn't in gear it seems to rev up nicely.

As far as vacuum advance... it IS hooked up, and when I disconnect it while running the engine quits. I'm assuming this is supposed to happen?

 

Any other input? Or is this thread going to quit like my engine?

 

It sound to me like you are going to learn a little bit more about your engine and statically re-time it.
All you are looking to do is to get the engine at TDC on #1 cylinder then ensure that the rotor on the dist. is pointing at the #wire on the cap. That's really the best way to ensure you are at a good starting point with the timing. The Haynes manual has a decent description of how to do this, but if you need more help I'm sure someone will chime in.

 

Probably timing at this point, it would cause the symtoms you describe. Since you havn't put a timing light on it (right?), go ahead and just turn the distributor a slight amount. I'm guessing it's retarded (the timing) and as you advance it it will smooth out and the idle will increase. A good rule of thumb is to advance it, then back off slowly 'till the enginge starts to "labor" or slow down, the back up a tick. This will be "close" to correct, and will give you a better feel for actual performance.

It would be WAY better to use a timing light, but you get the idea. Also, I would definitely go through the carb. I've done a number of burn jobs, and the hard foam floats are almost always damaged, even if they still work at first. The fact that you see a 'squirt' in the secondaries (shouldn't happen!) also tells me it's goofed up.

Do stuff one step at a time so you don't lose your way!
Good luck and keep us posted.

Hans

PS The metal pipe to the trans is for the vacuum modulator (smooth shifting) if it's an automatic, and it hooks up to the intake manifold behind the carb.

 

Make sure the timming is correct, no vacuum leaks and disassemble the carb and CLEAN it completely. If all other things are correct and working properly, it sounds like you have a stuck rod in the carb. Should be very easy to fix. Also, you might want to re-think that purple stuff in the engine bay. That alone could cause some major issues in the way the car performs

 

Check out the sticky thread at the top of the Tech/Performance section on timing. You need to get a timing light.

 

Sorry, but I don't think the ptoblem is timing!

Is the engine isn't producing power..... should be very very retared.... and an engine very retarded will be not able to rev!!!!

If you try to retard a lot your timing, the net result will be an engine doing a lot of backfire with flames from the barrels when you try to rev it !!!!!

Otherwise, if is retarded but didn't backfire..... will produce some power.... not much, but maybe 30% less than normal.

As for my esperience, when an engine run smooth without any load but you can't apply throttle under load..... is a typical syntome of a very lean condition!

Did you open the carburetor?
Did you check the level in the float bowls?

One more equestion..... are you sure about vacuum leaks from the intake or so.... ?

Keep us informed!