fuel pump replacement alternatives?

[John_D.]

My son's 1992 RS (305 TBI) is not getting fuel. We haven't determined if the pump is not getting any electricity, or if the pump is just shot.

Went the easy route first, put a new filter on it. Checked all the fuses.

If it is the pump, it seems like it would be a lot easier to put a new inline pump on it, instead of dropping the tank or cutting a hole in the trunk...

Anybody done this? I believe I need a 13 psi pump, anybody got a recommended part # and source?

[3.4 slow to go]

TBI didn't have that much of a psi requirement.You could go the external pump route, but remember to get a puller pump. There is also a fuel strainer that can get all clogged up. It's basically a pre-filter, located before the inlet side of the stock fuel pump. Check the fuel pump relay or the oil pressure switches. some fuelpumps are switched to oil pressure.

[John_D.]

Thanks for the info. I've been trying to do some diagnosis on it. Unfortunately the Haynes manual does not have the tbi wiring diagram. It has the carb and the tpi. Also they say run 12v to terminal G on the ALDL connector, but this is an empty slot on the ALDL, so I think this is probably for tpi cars too.

There are 3 wires going to the tank. Any ideas on which one is supposed to be hot for the pump? Also any ideas on location of the relay?

[jeff-87z]

are you getting any ses codes ????

[John_D.]

There's no check engine light turned on.

The car sat for 6 months and the battery completely died, so any stored codes would be long gone. Replaced the battery. Can get it to run for a couple of seconds if I pour a little gas in the top of the tbi. Not sure if this is enough for it to set a new code.

[3.4 slow to go]

fuel line might be clogged. Get a fuel, pressure tester for TBI & make sure.

[John_D.]

Already did that. No pressure at the tbi at all.

That's why I'm trying to diagnose either no electricity to the pump, or a pump failure.

Gas will gravity feed all the way down the line, so it's not blocked anywhere. Just no pump action going on.

I need to figure out which one of the 3 wires going to the pump should be hot when the key is on. So I can tell if it is hot or not, and then go from there...

May need to try to find a Chilton's, since Hayne's doesn't have it in their book.

[3.4 slow to go]

get the Digital Multi meter & have at it. IF you don't have 1, RadioShack has a nice autoranging one for about $30. a very good deal.

[John_D.]

Have a nice digital meter already. But with three wires, if one is hot, then is it a wiring problem or a bad fuel pump? Since the pump and gauge sending unit are all-in-one...

Which wire should be hot when the key is on, for what is it, like 5-10 seconds, then if no oil pressure, it shuts off...

Where is the relay, in case that is the problem?

When I can isolate the parts, then I can test them... Running blind right now. So if anyone knows the wiring scheme, please share.

[3.4 slow to go]

I'm gonna have too refer you to the peeps over @ www.thirdgen.org . I recommend the V6 section. they're always ready to help people in need. [img]graemlins/thumbsup.gif[/img]

[John_D.]

Sounds good. Thanks for the info! [img]smile.gif[/img]

[3.4 slow to go]

Tell em " 'Project sent ya"

[John_D.]

This is what I got from the guys at thirdgen.org

"You should have power on the tan/white wire at the tank flange/fitting. There should also be a pink wire (gauge) and black wire (ground). You may measure voltage at the pink wire, but it should be lower than 12V."

So I'm going to try it this weekend.

Also the relay is on the firewall next to the brake booster, and the oil pressure switch is above the oil filter.