Having issues after swap to Demon Carb on 86' 460ci
 

I spent the last week swapping to a new Weiand 8012 intake and BG Road Demon 4402020VFE on my 86' 460ci. After getting her started a couple times on different days I went ran it without issue for about 15 minutes today then 30 minutes later I went to start and she didn't want to turn over at normal speed. It acted as the starter rotation was slowing to a crawl on each cylinder. The starter is new and the battery was at full voltage.

A couple of friends guessed the new carb was somehow dumping fuel into the engine after the truck was shut off. The fuel was pooling on the valve or pistons and creating too much compression due to lack of space for the engine to turn over to start. Either by a plugged return line (fuel pressure is forced through the carb and empties into the intake) or a possibly a bad carburetor. This truck has the dual tank, "hot" fuel system with pumps in the tanks and return lines.

I haven't got a chance to check the return line (just got home from work and this happened today before work) and it has been below 32F here for the last couple of days and the truck has been sitting in the same spot for 2 weeks. Are there other things I should be checking or does the suspect seem to be the return fuel line? Also does anyone know what the stock Holley 4180 run at as in fuel pressure? To get the truck running, I cut the tube right after the splitter/return fitting and ran the fuel hose from there. Just want to make sure the pressures are close.

Sorry for the long winded post but I like to get the details out there.

I run my 86 F250 4x4 460 at 4-6 PSI after the return line. I have an oil filled fuel pressure gauge just before my filter. I run a 4160 600 CFM on an Edelbrock Performer manifold non EGR. I also run an external electric pump with regulator. Do you have the stock return valve? If so check it. But most new Holley's will take up to about 9 PSI before they force by the needle/seat valve. You could have your float level too high also. I had a lot of that type of trouble with a new Holley 4175. That carb was a nightmare until I completely tore it down & reset everything. Also secondary springs should be set to the vehicle.
PM me if you need help. I'm not the best Holley guy here but I have a fair amount of personal experience with them.
Craig

At this point I got the truck running but on a limited basis. On a cold start she will crank over and with 3-4 pumps of the gas she will start. I still have to figure out the idle and mixture tuning since the truck does something different every time I start her.

We think we figured out the sluggish start as advanced timing but I am unable to correct the issue. I retard the timing as much as 20 degrees and she will still do the same thing. If I rotate the distributer as far as she will go with the vacuum advance hitting the intake, a few slow cranks and a loud "woosh" is heard from the carb and she cranks normally but obviously won't start at that point. I have to let her cool down for up to 2 hours before normal cranking speed can be obtained on the starter. Someone suggested it was the starter and related cabling but this was dismissed as when the coil wire is unplugged, the truck starter turns over fine when it would otherwise crank slowly.

I found my timing marks after some sanding on the crank but now the truck is in its cool down phase and I won't be able to get back to her until tomorrow. The white mark someone made on the crank was actually around the 30 degree past TDC when I assumed it was TDC. Right now I have the timing set between the points where she stalls when rotating the distributer as I couldn't find the timing marks at the time. So the timing should be close enough not to do this IMHO.

So what can i do at this point? I feel I will have to retard the timing to the point the truck won't start to keep the cylinders from firing and fighting with the starter sequence. I'm past frustration at this point.

This is the truck being stopped while warm and then shut off and trying to start again:
YouTube - DSCF7403.AVI

This is after letting it sit for an hour:
YouTube - DSCF7404.AVI

One thing to do is the 460s in these years are famous for the outer harmonic balance to move around on the inner part. The rubber in between gets hard & breaks out. So bring the engine up on TDC #1 on power stroke. see where the TDC timing mark is. I almost bet the balancer has spun. I had to replace mine.
After that if by chance the marks are correct set the timing at 10 degrees with out vacuum advance connected. Total advance shouldn't be much more than 38 degrees.
I just listen to your second video. You have a timing issue. You need to do as I suggested in the beginning & make sure the distribute is correct. It could be off a tooth or two from the sound of your second video. Also check your wires for firing order & make sure they are correct also. PM me if you need further help many times I don't get back to a thread I respond to. I try but don't always make it.
Craig

At this point I've checked the wires for the proper firing order. As with the balancer spinning, I check the rubber when I was under the truck and it looked intact. I've never checked for TDC without using the balancer directly so someone will need to clue me in on doing that.

Also remember I can go out when the engine is cold and it will start as normal. The second video is only if the engine is warm or hot from just being turned off otherwise is spins over smoothly. As I said before, the current timing is gaged how the engine sounds with the position of the distributer so it should be close to normal now and the issue still persists. I'll check the other stuff tomorrow.

I explained how to check the timing mark & TDC. #1 Cylinder on power stroke. Pull the #1 plug. Stick you finger over the hole tap the starter & when you feel the compression pushing on you finger go slow & when it get to the top it will stop compressing. You can take a screw driver & stick it in the plug hole & turn the engine with the nut on the balancer back & forth until you get it on top of stroke. That should have your balancer & distributor on TDC & #1 cyl.. DO NOT TAP THE STARTER WITH A SCREW DRIVER IN THE PLUG HOLE. Use only your hand & socket & ratchet or break over bar to turn the engine.
I still think you have a timing issue, (IE: distributor off, balancer spun.)

Craig

I got it going. The balancer was spot on. I was one tooth off on the distributer and was surprised she ran. I got the suggestion from a friend to move one cog over on the distributer rotor until I found where she ran ok at.