i have a 1990 iroc z camaro. the person i bought it from was rebuilding it so it didnt have a motor. he told me he had converted for a carbed motor. i kno the factory fuel pump psi is too much so id need a return style pressure regulator but today i raised up the rear carpet and saw that he cut a whole and did something to the fuel pump, did he install a low pressure pump or something? thanks in advance. the pics show the pump in the back and the lines under the hood

 

Still has the feed line, the return line, and the vent line for the evap (charcoal) canister, so I'd say the stock in-tank pump is still in place and the PO was planning to use a return-style regulator. The only way to verify would be to pull the pump assembly out of the tank and see what's there.

Chances are, someone in the past has cut the access panel in the trunk to replace the fuel pump. Makes it easy for you - at this point you can do what you want - you could verify that there is a fuel pump in the tank that functions, get a return-style regulator, and go from there (if carbing your motor), you could yank out the in-tank pump and use/make a standard carb pickup that attaches to the feed line (the larger one), or you could go back to an EFI setup using an intank pump.

In the engine bay, the longest hardline is the one that ran to the charcoal canister (not the longest piece of hose, the longest hardline - the one in your pic with the bolt crammed into the fuel line). The larger of the other two is the feed line, and the other is the return line (feed line has a 3/8 inside diameter hose, return line has a 5/16 inside diameter hose).

 

well the last owner was the original owner. So what it looks like to you is the normal fuel pump? id still have to get a regulator right? and cant i get rid of the evap canister if i get a vented fuel cap?

 

yes, yes, and yes.

You'll need a return-style regulator like the Mallory 4309 to run a carb - they aren't cheap, about $90. If you see a regulator that's under $60 new, I guarantee that it's NOt a return-style.

But if you are going carbed, you could just make a carb pickup (since you tank has easy access) and use a mechanical pump on the block. Choice is yours.

Invest some time making a nice cover for that access hole in the trunk to cut down on road noise, reduce the chance that a mouse or bees or whatever will take up residency in your car, etc.

If it were me, I'd also get a new chunk of hose, much longer, and replace that one with the bolt in the end, routing it under the car to come out under the driver headlight area - I'd want the line to be able to vent if it needed (ie no bolt), but you don't want it ever leaking any fumes/gas into the engine bay where it could ignite.

 

i was planning on getting the mallory so id always have the option to just remove it to go back. Also if i get a vented fuel cap, what do i do with the line that suppose to go to the evap canister? and to use the mallory it should have an input from the tank, output to the carb, and a return back to the tank correct?

 

He either cut the hole to replace the in-tank electric fuel pump, or remove it. The only ways to tell would be to either put an ohm meter across the fuel pump wires, or pull the pick-up and look.

For the record, the line in the engine compartment with the bolt in it is the vapor line.

Obvious question: Why don't you ask the original owner what he did?

 

the original owner moved to another state for a job so he sold me the car for $300

 

That's what I was saying with the longer chunk of hose and running it under the car - just don't put the bolt in it

Yes - the largest line (3/8) is the feed line - run it to any port on THE SIDE of the Mallory. The other line (5/16) is the return, it gets connected to the BOTTOM of the Mallory. Then just run one more line out of the SIDE of the Mallory to the carb. There are 4 ports on the side of the mallory, the 2 left over just get plugged (or you can put a fuel pressure guage in one).

 

I would get a vented cap and remove the vapor line back to the tank, and cap it there.

 

yea that sounds like a good idea

 

I just got my vented Stant cap yesterday. It appears to let air in, but not out. That's the same thing the vent valve (the white thing back by the axle) does. So, not sure how well the system will work without the vapor canister.

 

What if i just run the canister line to the fuel door?

 

I've always wondered about my vented cap as well - there's been a few occasions that my tank builds pressure, and I didn't think it would with the vented cap. These occasions have been rare, really only this year I've noticed, but I have been driving the car this year. And it only seems to happen on the really hot days, when the air temps are over 92 or so (we've had some real scorchers for us this year).

But I would also think that pressure would get released on that 3rd (evap can) line. But I never looked real well at what's on the end of that evap can line in the tank - maybe it has a valve that doesn't open without the vacuum source on the evap can?

What if we just drill a very small hole through the cap? Yeah, fumes will leak out, but it would be no different than the old metal cap on your Bel Air, and will solve the pressure issues that we don't need on our carb setups.

 

i have another question, theres no engine in the car at the moment but when i turn the power on and turn the key, is the fuel pump suppose to make a noise?

 

If there's a battery hooked up, I would assume it would if the ECM is still getting power and the fuel pump relay is still connected. I guess it depends on what the ECM needs attached in order for it to be 'alive' and functioning - the ECM primes the fuel pump for about 2 seconds when key is first turned.

But you could also test the fuel pump by just applying 12v to the fuel pump relay (I think on the green/white wire) which will activate the relay and should make the pump run if there's a battery in place.

 

i dont think i have an ecm

 

sorry - forgot about that

You can also just get 12 volt to the connector - up under the car right where the rear seats are there is a connector where the fuel pump/sender wires run from inside the body to outside (they run under the carpet) - get the right color wires from the wiring diags and put 12v and a ground to the right wires on the fuel pump side of the connector, and put you ear against the tank and listen for the pump whining - do it for just a second or two, since you have unconnected fuel lines up front, or you'll be spraying gas everywhere.

 

theres no gas in the tank anyway, can i just wire it to a 12v power sourse and to a toggle switch?

 

Yeah - you could just get a good ground connection and bump the + wire to 12v for just a sec while your ear is against the tank just to hear if it whines. You don't want to run it long, cause it needs to have gas run through it to keep it cool and not burn up.

 

You have that hole already cut out - and looks like the wires have been cut and recrimped - that makes it easy!

 

good! so i see i have 3 wires, im assuming they are ground, positive, and negative. but what color is what?

 

No! One is for the fuel guage sender, one is ground, one is pos for the fuel pump.

Ground is neg (on everything except German cars).

Here's wiring diags: http://www.austinthirdgen.org/index.php?pid=19

 

Looks like a pink wire runs to the fuel guage sender, a grey wire is + to fuel pump, a black wire for ground.

I can't tell colors that well, but in your pic above looks like the 2 fuel pump wires are the ones that were cut and crimped - looks like the fuel guage wire they left untouched.

 

ok thanks, so id just run a switch to the black and grey one to turn on my fuel pump

 

The black will ground when the battery is connected properly and the ground starps are connected properly, then you can put a switch on the grey to turn on/off the power to the pump.

For testing it now (before motor), you can just run a wire from black to battery neg, and run a wire from grey to bat pos.

When you get ready to do final wiring, let me know - I'll explain how to wire the fuel pump up using your existing fuel pump relay - that way the fuel pump will always come on with the key, and you won't have to mess with a toggle for the fuel pump.

 

i want it on a toggle. i have a thing for the toggles lol. all my lights are wired to toggles too. lol and im going with push button start

 

The tank vent allows air in to replace the volume of the fuel pumped out. Excess pressure is vented through the Fuel Tank Pressure Control valve. When the engine is stopped, the valve is closed and venting to the canister takes place only through a tiny orifice, to keep most of the vapour where it can be condensed back into the tank instead of saturating the canister. When the engine is running, manifold vacuum opens the valve and vapour is vented freely into the charcoal. There isn't ever any vacuum directly applied to the vent line on the tank.

 

OK, I'll buy that.

Since we carb swap guys now have vented caps, no ECM, and removed the charcoal canister, would drilling a very small hole in the cap to help release the pressure be a good idea or not?

 

Just put a filter on the end of the canister line after you remove it, if you want.

 

It's already open - just an open end to a rubber fuel hose leading out below the car away from the engine bay - been that way for 4 years now. But I just had a thought - maybe a mud-dawber or something nested in the hose end, and that's why I had the pressure issue so bad a few days ago when it was so hot. I'll have to take a look! A small filter is a good idea.

 

i see 4 tubes from my pump but only 3 under the hood. why?

 

The tank vent isn't under the hood, it's above the axle.

 

i looked in my Haynes book about the fuel pump and the one in the picture only has 3 lines

 

Your Haynes book has a picture of a different car.

 

ohh ok. is there a pump from another gm vehicle like a carbed truck that would have a lower pressured electic fuel pump? because my friends 1990 chevy truck doesnt have a mechanical pump and its carbed, and stock

 

if it is a 1990, then your bud's truck should have a tbi, not a carb. someone correct me if i'm wrong.

 

its definatly a carb. its a 2 barrel

 

does it look anything like this?

 

Nah thats not it.

 

hmmm... i was just pretty sure gm stopped with the carbs in late 80's. guess i was wrong.

 

I removed my cansister and heres a crude drawing of how I replummed it. I needed the space for a vacuum canister for the power brakes.

Auggie

 

Then it's not stock.

 

Your friends truck is 20 years old - at this point it could have had anything swapped into it.

You don't have to run a mechanical fuel pump, you can use an electric pump. You can:

1) use the intank electric pump which makes way too much pressure - you just have to use a return-style fuel pressure regulator like the Mallory 4309

2) use or make a carb pickup and use an external electric fuel pump designed for a carb - needs to be mounted close to the tank (stock fuel filter area is where most attach them) and they are loud (always hear them running)

3) use or make a carb pickup and use a mechanical pump on the block

 

well my friends dad gave him the truck, they are the original owner and nothing has been done to it. but my mallory came in today and im gonna hook it up in the morning!

 

Then it's not carb, it's TBI.