So I pulled the Wildcat out of hiding after 7 months today. It started right up and after warming up, idled nicely. Then it thanked me by blowing a heater hose! Bypassed the hose and drove it to Grumpy's for some parts for my 63 C10, then a short drive to a workplace. Total drive about 6 miles or so. Ran perfectly. It sat for about 20 minutes in the parking lot. After leaving the lot I noticed that upon acceleration it would hesitate and occasionaly backfire after about the first 1/8" or 1/4" of pedal travel. Almost felt like it was still trying to accelerate but was losing power. I was able to get it on the freeway and drive it home fine as long as I accelerated slowly and only used a small bit of travel with the pedal. It was not doing any of this for the out bound trip. Any thoughts as to what is going on? I checked the timing upon getting home. Tried both advancing and retarding but just changed the characteristics not the problem. Seems to be getting fuel. Was not too hot. Only in the high 60's today. No sign of detonation or poor idle. Not sure if this is part of the problem that I had with it in June where it completely died and then started up after an hour and ran fine. At the time it seemed like vapor lock as it was in the 90's that day returning from the car show about 2 miles away from home. No sign of water in the oil or oil in the coolant. Thought maybe after heating up a head gasket was expanding? The metal fuel filter is sitting next to a heater hose/metal mount. Could the fuel be heating inside the filter and causing issues after such a short drive? Thanks for any suggestions! Rick
Sounds like something is plugging the accelerator pump... When is the last time u had the carb apart?
Based on your earlier problems, vapor lock, possibly brought on by low fuel pressure is worth looking at. Check filter(s) and fuel pressure before you start ripping anything apart. Assuming there's fuel in the float bowl, you can check accelerator pump shot just by looking down the primary throttle bores with the air cleaner off and opening the throttle with the engine off. Devon
Sounds like something is plugging the accelerator pump... When is the last time u had the carb apart?
Carb is almost brand new. 800cfm Edelbrock. Less than 50 miles on it. Fuel filter is even newer. Going to let it cool over night and then try to simulate the problem again tomorrow afternoon. Only seems to happen after running it and then stopping for a while. Last time I checked the fuel pressure when it was cool and it was fine. I'll have to check it while it is acting up. Thanks for all fo the quick input!
Check the vents on the gas tank and the condition of any rubber lines. There is a chance the gas tank is original and it has debris in it so the pick up is being interrupted.
sorry about the double post... Don't know why that happened. I had a carter competition carb on my caprice, same carb... A 1/2" phenolic spacer works wonders for the warm running and vapor lock. This last weekend I put an edelbrock on a friends truck..it came off another truck that had an old rusty tank and the guy didn't use a fuel filter... After cleaning the bowls out I had to clean out idle ckt.. You can do this with car off, pull out idle screws and run a couple quick shots off compressed air in there. It should squirt out of vents by choke horn.. Did this a few times after some run time in between and he made a600 mile trip today . No problems..
Great info, thanks. It had a spacer/adaptor when I bought it and it was running a 600 holley on the stock manifold. Worth a try again for both performance and a help with the carb heat.
Check your heat-riser, it could be stuck closed, and that would cause the fuel to perculate out, and after a hot start, there would be a good chance that the fuel is still boiling off while you try and drive away. Happened to a buddy of mine and he almost burned down the car...unstuck the heat-riser and everything was fine.
Great suggestion 66. Going to check it out this weekend. That would be a simple fix! Crossing my fingers...
Heat Riser How would I know if it is stuck closed? With the Edelbrock carb on there the arm running up from the manifold is not attached to anything, but moves freely. It does have a 1" aluminum spacer so there is some space between carb and manifold, but it is metal so no real heat barrier. Off topic, but is there a replacement piece that I can install to sub for the piece that the heater hose attaches to top front of the manifold? The piece with the vaccum line coming off it... I'd like to clean up the engine bay and firewall and out here in AZ I don't think I've ever turned on the heat in any car, let alone a convertible that only gets use in nice weather. I'd like to eliminate the heater hoses to the firewall. Thanks!
Heat Riser in Intake Manifold on 1969 430? Have not gotten it to replicate the stalling sequence yet, but fuel pressure at idle (cold) is almost 10lbs. Accelorator pumps seem to be working fine as well. (cold) The arm that comes out of the intake manifold controls the heat riser valve? Correct? It seems to be free with a spring pushing it up. I've never seen it connected since the car came with a Holley 600, but it looks like it could attach to the carb on an arm that would keep it up warming up and down after the carb opens up the choke? IF the spring is keeping it up does that mean that it is "closed" and causing the heat problem under the carb? Looking at Jefferson Bryant's book on page 65 there is a picture of Greg Gessler's motor with the arm just laying on the manifold unattached to the choke arm" Looking at aftermarket intakes, they don't have these, correct?
Looking at it again it looks as though I have the arm position reversed for warm and cold? Up for choke off and down for warmup? I am going to try wiring it up all the way and see what happens. It seems to be just partially up with the spring pushing it up.
Bad plug wires? If it has accel wires, they are most likely the culprit. Spray them with a light mist of water, see if it gets worse, or open the hood when its dark outside, you will see the electricity leaking out.
Heat Riser in Intake Manifold on 1969 430? So I saw on another thread where the person was advised to check the coolant temp with similar issues. I checked it with an infrared at the radiator neck. Never exceeded 196, and between 160 and 180 while at higher rpms. The area near the carb by what I am assuming is the heat riser(?) was at or over 300 much of the time. Carb spacer went over 220 but carb did not. Of course I did not have it running as long as previously. The rest of the intake manifold was much cooler. So my next question is can that arm be on spring tension but possibly disconnected to the actual flap? Can that sheetmetal cover come off without damaging anything to loosen the flap/valve? I see one bolt and some tabs.
I might try that when it gets dark, but the problem does not happen until it has been driven for a couple miles and then has been sitting. Runs strong initially. Also the wires are a couple years old but have less than 30 miles on them. They are 8mm Accel "superstock" wires rated for 450 degrees... They are on looms all the way and pretty well separated except at the distributor.
I was able to get it to stumble again upon accerlation. It did it after only 1-2 miles of driving. The manifold is extremely hot around the base of the carb. Can I pull the cover off of the "lever" area and release the plate manually? I'd like to get a response before I go for it and mangle my intake manifold... Thanks!
The spring is actually a thermostatic coil. It should hold the heat riser shut when it's cold, and once it warms up the counterweight should move up and down freely. I can't remember which direction it should be in, but if you disconnect the spring it should just drop to the open position. However, you might have to drop the pipe and see if the butterfly has actually moved or if it isn't stuck (and come apart from) the shaft. If I remember right, (it's been a long time since I pulled a BBB apart) those heat risers were separate from the manifold and could be deleted. If this is the case you may want to consider this. From the sounds of it, it seems you've got a lot of heat happening around that carb; you might have to pull the intake off and plug off the riser ports. I'd only suggest this if you don't use the car in cooler weather; otherwise you'll get lousy mileage and the potential for carb icing will be higher. Another suggestion would be to get a spacer plate for the carb; - I've seen thin spacers used on them before and they then act like heat sinks and get the carb away from the most heat. That's what the previous owner had done to my buddy's Olds that almost burned down; he used about 3 or 4 gaskets as spacers. It worked until I set the carb back on the way it should be, and then it all heated up and boiled. We got the heat riser freed up, and the problem was gone.
Thanks 66electrafied. So I should be able to pull that little plate off and possibly see the coil or counterweight? Would be nice to be able to just pull out the "guts" and be done with it... I don't use it when the weather is cold, which it rarely is out here in AZ so maybe the block off option might be the final option. I hate to do it before I get an aftermarket manifold though. It has a spacer/adaptor now. Its metal though so it probably transmits most of the heat right up to the carb!
