Fuel Delivery: TPI to Carb Conversion - Page 5 - NJFBOA - Home of New Jersey's Camaros and Firebirds

WildBillyT · 02-27-2012, 02:22 PM

If you are looking for a reference book, this is a decent one:

http://www.summitracing.com/parts/HPB-HP1052/

Some of the stuff is certainly dated but it's great for things like pump cam selection, idle adjusting, choke settings, etc that don't change over time.

88WS-6 · 03-06-2012, 03:14 PM

Plans to re-do my fuel system:

- Edelbrock 17933 performance in-tank pump (255lph)

- All new lines and fittings (suggestions, 6 -AN?)

- Mallory 4309 FPR (for the current carb)

- Vacuum gauge

- Fuel pressure gauge

- Fuel filter just before the carb

That should get the car running correctly as-is with my carb. Down the road if I feel like going back to TPI or to HSR or some other EFI, I can just take the FPR out of the equation. Seem legit?

I need to take my tank down one of these days and see what's left inside as far as the pick-up and strainer go. He said he removed the pump but who knows what else could be missing... I'm concerned right now with how it is running because he took out the charcoal canister and the mechanical pump on the block has no return lines. Could this cause vapor lock or excess pressure in the lines/tank?

BonzoHansen · 03-06-2012, 03:30 PM

Quote:

Originally Posted by 88WS-6

Seem legit?

Seems expensive and complicated for a carb on a mild engine. You really need to get under that car, see what you really have, do some testing and go from there.

Tank has to be vented somewhere or it will collapse on itself. BBC Camaros ran with no return line, I think yours can too.

I still think your supposed vapor lock is an ignition problem.

WildBillyT · 03-06-2012, 03:42 PM

Quote:

Originally Posted by BonzoHansen

Seems expensive and complicated for a carb on a mild engine. You really need to get under that car, see what you really have, do some testing and go from there.

Tank has to be vented somewhere or it will collapse on itself. BBC Camaros ran with no return line, I think your scan too.

I still think your supposed vapor lock is an ignition problem.

Back then they had a gas cap that vented to the atmosphere.

BonzoHansen · 03-06-2012, 03:56 PM

Quote:

Originally Posted by WildBillyT

Back then they had a gas cap that vented to the atmosphere.

A 3rd gen? I don't think so. I could be wrong. It had an EVAP system. but I am saying the PO did something to vent it.

WildBillyT · 03-06-2012, 04:10 PM

Quote:

Originally Posted by BonzoHansen

A 3rd gen? I don't think so. I could be wrong. It had an EVAP system. but I am saying the PO did something to vent it.

I was commenting on the mentioning of BBC/60's cars running with no return line. The gas cap was vented to allow air to displace the fuel being used. Without a vented gas cap an older car won't run right.

I have not seen his car but if all of the original fuel stuff is ripped out and it's a single line to the tank and there's no venting going on that could be an issue.

Pure speculation though, since I haven't seen it firsthand. I think we are staying the same thing with different words.

BonzoHansen · 03-06-2012, 04:24 PM

Oh, ok. Probably so.

The pump return line is not related to venting. GM used it on some apps to stave off vapor lock. My point is many cars did not have it and had no issues. I still think there are a number of answers being thrown around that have no question yet.

The OE tank has a vent line, so he likely did something to that line. Or it might also have a one way check vent that allows air in, been a while, I forget. Or he put the wrong (unvented) cap on. If it were totally unvented the tank would collapse, and it would be difficult to fill up.

OP, I hope the tank is low when you try to pull it out. Full tanks are heavy! Also be careful not to bend the filler neck. GM banged that up in 3rd gens, all 1 piece.

//<86TA>\\ · 03-06-2012, 07:28 PM

the 3rd gen tank has no direct vent line, it has a vacuum break line that goes to the back of the rear seat area.

pulling the tank is not too bad, just need a second set of hands and be DAMN SURE you get the car up as high as possible and the axle as low as possible. then there will be no issue with the tank clearing anything or the fuel neck getting caught up. doing this on a lift would be even better.
With no return line, i had vapor lock issues in my car. Usually only when trying to start the car hot, after sitting for a little while. If the lines are insulated where they enter the engine bay, this will probably be a non issue.

I still say remove the electric pump, splice the lines (temporary, should be replaced) and see how the car runs with just the mechanical pump thats already there. Could be a simple fix.

If you run lines, 6an is fine. Factory hard line might be better.

88WS-6 · 03-07-2012, 05:29 AM

Quote:

Originally Posted by //<86TA>\\

Usually only when trying to start the car hot, after sitting for a little while. If the lines are insulated where they enter the engine bay, this will probably be a non issue.

The last time I had issues was after it ran for a bit and then I let it sit for 15 minutes. Car would barely start and then die if I was off the throttle. I'll need to take a trip out in the car and bring it back home, let it sit and then try to start it up after 15 minutes again. I doubt adjusting three screws on the carb fixed that issue.

The only other time I had a problem was when I was driving it home the day I bought it. It would cut out cruising at 65mph on the parkway (which Bonzo thinks is ignition related).

88WS-6 · 07-10-2012, 06:56 AM

*Update*

Phil and I got under the car this past Saturday and removed the Holley blue pump. He can chime in with the details, but it was just getting in the way. We hooked up a fuel pressure gauge after removing it and I'm getting 8-9 psi at the carb (right out of the mech pump on the block) so I'll be getting a regulator to knock that down.

88WS-6 · 07-20-2012, 05:46 AM

Regulator is installed. PO put the banjo fitting to the carb on wrong so we couldn't re-use it. I'm picking up a new one after work today and then hopefully we'll see correct pressure to the carb. After that we are going to bump the timing a little and then Duke Island tomorrow.

Phil you are the man!

88WS-6 · 07-23-2012, 01:09 PM

Well it didn't make it to the meet. The regulator is in and the carb is getting a steady 5 psi, but we couldn't get the motor to run long enough to time it. Seems like it's only running off the accelerator pump because it would only stay running with constant throttle application. Time for a carb rebuild... yay.