[wrea3_98]

Hi guys I originally posted in the "Big Car" forum with an ignition question but I since found out another problem. Here what happened from the beginning. Fresh engine started for the first time to break in the cam. Fired right up and ran awesome for 20 seconds or so. It died like it was out of fuel. Cranked a few more time and couldn't get it to fire. Not even try to fire. Changed coil and points, still no start. Pulled plugs and they were all soaked. Cranked engine for 4-5 seconds to blow off any fuel from cylinders. I let plugs and cylinders dry overnight. This morning I reinstalled the plugs and cranked the engine for 4-5 seconds WITHOUT pumping the gas or adding any thru the top. Pulled #1 and #3 plug and they were soaked again. I shined a flashlght into both cylinders and could see puddles of raw fuel. Oil smells like fuel. Pulled center carb to check float level and other specs. All are fine per the manual. I am looking at excessive fuel pressure next as I have read 3-4 PSI max for tri-powers. BTW... the plugs get spark. I arc'd #1 to the block and got a blue spark when cranking. It has to be fuel related. The carbs were professionally restored, plated and asembled with all new parts. They look perfectly new as as far as I can see the center carb is set up just right. By biggest issue is that the cam has only 20 seconds on it and all this dead cranking cant be good for a new cam. Any thoughts? Thanks for any advice in advance.

[facn8me]

Hmmm I'd run a quick compression check and make sure you don't have a valve open when it's not supposed to be.

[tom s]

Sounds like flooding.Might try pulling the end carbs and making blockoff plates to get the cam broke in and than chace the problem.FYI,I NEVER use new carbs or dist to breakin a engine.Tom

[John Haley]

Check for rotted fuel lines between fuel pump and tank. Inspect the rubber line that connects the metal line to the fuel tank. You could be sucking air and then pumping a fuel / air bubble mixture to the carb.

[wrea3_98]

@ John The whole car has been restored and all parts front to back are new. No rotted lines.

@ Tom The car was restored and the ignition, carbs etc are all restored. Althoug your suggestions are valid, The parts on the car are all I have to use. I have no dyno and no extra distributors, carbs, intakes etc. I have built 15 Pontiac engines over the years and never had a single issue like this. I have always used the parts I am going to run and always do the exact same prodedures even when breaking in a cam.

@ facn8me I was going to try the compression check later but only to see if I gas washed the cylinders. but if a valve was sticking it would still try to fire somewhat or even run (with misfires of course). I have dealt with that in the past on Chevys I owned and they always run or at least fire.

[Radman]

What are you using for a fuel pump? If electric, get a bypass style fuel pressure regulator, and set it for nothing higher than 3.5LBS. A dead head style regulator can still allow the pressure to creep up higher than 4lbs at slow engine speeds. You will need to add a return line to the gas tank.

[geeteeohguy]

Look down the carb throats. Is there raw fuel on top of the butterflies? Is fule leaking out of the throttle shafts? It sounds to me like too much fule pressure or crud in the needle and seat of one or more carbs. If too much pressure, you will blow fuel right through the needle and seat and flood it. I only use stock spec mechanical pumps on my Pontiacs, and they work great. If you have gas contaminated oil already, that is a very bad thing with a new engine and cam. Drain it out and install fresh oil!!!

[wrea3_98]

Thanks Jeff I'm way ahead of you. Oil is drained and I just picked up more oil and zinc additive. Mike at PontiacTripower.com also thinks pressure. Its a Napa fuel pump. I had the Napa guy look it up and it states 6-7 lbs. I have a regulater and inline gauge on the way to check it out. Before it all gets here, I may just remove the fuel pump, drain the carbs and spray starting fluid down the center carb to see if it tries to start. That would point towards pressure or internal glitches. I know the float is good all the internals are set correctly. Could be the new needle/seat has some junk in it or isnt tight enough.

The outside of the carbs are all dry and I cant see much if any fuel on the butterflies. The intake under the carb is soaked. There was so much fuel going in while cranking that I saw the RH side choke tube (the one that connects to top of the center carb) sucking raw gas from the heat crossover on the intake, up thru the tube and dumping back into the carb. Never saw that before.

[Rapdron]

I had the identical problem 2-3 years ago.
65 GTO Tri power, used the original carbs on the motor that was just rebuilt
Ran for 2-3 minutes & died out, center carb looked like it was flooding.
Tried it a few more times & changed out the center carb. Re-checked float-OK
Still flooded & died. Drained the oil a second time & checked fuel pressure
Long story short, it wound up being the pump.
Brand new pump put out more pressure than the seats could handle.
Changed the pump after yelling at my local NAPA dealer (said it couldn't be!)
Ran perfect after that. Finished breaking in the motor.
A little over 10,000 miles later, no obvious side effects from washing down the cylinders with raw gas. Motor still runs & sounds great.
Hope this helps
Ron

[pfilean]

Yeah it does sound like the main prpoblem may be fuel pressure. But the gas coming back in the choke air suply tube would worry me. It shouldn't have any point where it could pick up gas. It is only supposed to pick up air from some point (I don't know what year you have) warm it and deliver it to the choke stat. If it is picking up raw gas then it sounds like something else is amiss.

[shaker455]

Originally Posted by wrea3_98

Hi guys I originally posted in the "Big Car" forum with an ignition question but I since found out another problem. Here what happened from the beginning. Fresh engine started for the first time to break in the cam. Fired right up and ran awesome for 20 seconds or so. It died like it was out of fuel. Cranked a few more time and couldn't get it to fire. Not even try to fire. Changed coil and points, still no start. Pulled plugs and they were all soaked. Cranked engine for 4-5 seconds to blow off any fuel from cylinders. I let plugs and cylinders dry overnight. This morning I reinstalled the plugs and cranked the engine for 4-5 seconds WITHOUT pumping the gas or adding any thru the top. Pulled #1 and #3 plug and they were soaked again. I shined a flashlght into both cylinders and could see puddles of raw fuel. Oil smells like fuel. Pulled center carb to check float level and other specs. All are fine per the manual. I am looking at excessive fuel pressure next as I have read 3-4 PSI max for tri-powers. BTW... the plugs get spark. I arc'd #1 to the block and got a blue spark when cranking. It has to be fuel related. The carbs were professionally restored, plated and asembled with all new parts. They look perfectly new as as far as I can see the center carb is set up just right. By biggest issue is that the cam has only 20 seconds on it and all this dead cranking cant be good for a new cam. Any thoughts? Thanks for any advice in advance.

I hope it's simply your pump.

Did your carb guy run these units on a live Pontiac before he shipped them to you?

This is a good example why we live test here.
Jeff

[MikeR64]

At the risk of dissing our host, I recently bought the whole Tri-Power setup for my 64 GTO. I installed an original intake and all the repro stuff – carbs, fuel lines, linkage – all that. I fired it up. It decided not to idle. Nothing below 1,500 RPM. After a few e-mails back and forth to Paul, who gave me a lot of good troubleshooting tips, I had to tell him that this was a perfectly running car and the only changes were a cast iron intake and all the repro carbs, so it wasn't anything to do with the distributor or cam or whatever.
I decided to take the center carb apart and while inspecting it, found a bunch of stuff (blasting media?) jammed in the idle pickup tubes. After clearing those out, I put it back on and it fired and ran perfectly, even though I had not yet adjusted the idle mixture screws. The next day I went to start it and it started and died, much like your car. That is when I saw the nice fountain coming out of the center carb. WTF?? I took it off carefully thinking I had gotten something in the needle seat and I did not want to dislodge it. It turned out the fuel inlet needle was cocked in the seat part because the float drop was too much, allowing it to come too far out of the seat and jam sideways in the brass seat/inlet tube thing.
I fixed that. Right now, the rear carb is on it’s way back to the vendor because after it sits for an hour or so, the throttle plates jam shut so tight that you cannot open them using the gas pedal. You have to use pliers on the arm, then it will work okay – until next time you drive it.
I am just saying that the quality of rebuilds seems to be a bit less than what it should be, so even though your fuel pump may be putting out a pound or two more than the theoretical max, your issue may be due to faulty or sloppy methods of rebuilding. On their behalf, Paul at PY has done a great job working with me to try and get all this B.S. resolved.

[geeteeohguy]

"FULE"??? I swear, guys, it has to be the cold medication!!! Yikes. Seriously, I think 6-7 psi fuel pressure is most likely the problem. You only should be running 3-4 psi with these set ups. It's about volume, not pressure. This ain't fuel injection. X2 on reproduction anything, pretty much. Thank goodness the repro stuff is out there: without it we'd have nothing. But it's impossible to beat the quality of good old USA made OEM anything.

[wrea3_98]

I have no idea if they were run.

Originally Posted by shaker455

I hope it's simply your pump.

Did your carb guy run these units on a live Pontiac before he shipped them to you?

This is a good example why we live test here.
Jeff

[wrea3_98]

Thanks for all your input guys. As of now I have decided to rule a few things out. I will pull the fuel pump off the timing cover to keep it from pumping. Then I will drain the center carb and disconnect the front to rear carb linkage so only the center carb will work. Instead of fuel I will add starting fluid only to the center carb and crank it to see if it tries to fire. This way I can keep from flooding. If this works, I will bypass the F&R carbs with fuel and go direct from the filter to the center carb with a fuel pressure regulator and a temporary pressure gauge inline. I do believe I will be pulling the intake since I am getting a little fuel into the heat crossover area and its bubbling out of the vent tube at the intake and the carb. Most likely a bad gasket seal around the crossover. I will post my updates.

[wrea3_98]

Using a mechanical fuel pump. Napa brand rated at 6-7 lbs per thier book.
How should ad a return line? The only pump I see offered most places is without AC and without a retun line. Also I had to have my fuel sender restored since they dont make the catalina sender anywhere. My sender is without a return line. This car is restored and I would hate to have to drop the tank and ad a return to the one I have. Mabey if I use a vented cap I can return thru the vent tube???

Originally Posted by Radman

What are you using for a fuel pump? If electric, get a bypass style fuel pressure regulator, and set it for nothing higher than 3.5LBS. A dead head style regulator can still allow the pressure to creep up higher than 4lbs at slow engine speeds. You will need to add a return line to the gas tank.

[wrea3_98]

OK guys I am being told by most everyone to drop fuel pressure to 3.5 PSI for a tripower. I have the GM service manual and they say and I quote: "If the pump is operating properly the pressure will be 5 1/4 to 6 3/4 pounds. If the pressure is too high or too low it should be removed and repaired". With that said, what were factory tripowers/fuel pumps doing to new cars? My condition cant be something that new cars had to deal with in 1965 or they would have all been in trouble. Mabey the carbs were built with parts to withstand the higher pressure and todays kits give cheaper replacement parts that cant handle the pressure? I'm still going to regulate mine to see it if works.

[geeteeohguy]

Forget the return line if the vehicle never had one. Get the fuel pressure under control with a reulator. It needs to be 5 psi or less. 6-7 is too high.

[wrea3_98]

Got it running today until I burned a resistor wire in the dash harness. Its always something.

[gtorich]

Originally Posted by wrea3_98

OK guys I am being told by most everyone to drop fuel pressure to 3.5 PSI for a tripower. I have the GM service manual and they say and I quote: "If the pump is operating properly the pressure will be 5 1/4 to 6 3/4 pounds. If the pressure is too high or too low it should be removed and repaired". With that said, what were factory tripowers/fuel pumps doing to new cars? My condition cant be something that new cars had to deal with in 1965 or they would have all been in trouble. Mabey the carbs were built with parts to withstand the higher pressure and todays kits give cheaper replacement parts that cant handle the pressure? I'm still going to regulate mine to see it if works.

Ive always wondered about this myself over the years, no body seems to give an answer to why it needs under 5lbs.........you only hear thats what they need.

Try finding a fuel pump that has a 3-5 lb limit, i haven"t been able to find one.

Odd that the manual says 5 1/4 to 6 3/4 lbs..........i know they didn"t come with regulators new in 65-66.

Would be interesting to get a straight answer on this.

Rich