P30 fuel tank electric pump works on bench but not in RV

Rover71 · August 15, 2015, 11:32 AM

Hi All, I'm a newbie to forums. We have an '89 Itasca P-30 ,454 with a single 60 gal.tank. I've just had it out, big job, to repair sending unit. Got it mostly back in and put about 10 gal. gas in to try it out.Gauge works and manual pump builds 6 PSI, but electric pump doesn't cut in. It worked OK on brief bench test , and I'm sure it was OK before removing tank. Normally the relay lets it run for a few seconds when key is turned on, not happening now.
Raining this AM, so thought I could possibly get some ideas before I dig into it? I believe it's the tan wire with white stripe that activates the pump, but have to be sure and not blow the gauge/sender.
If I'm in the wrong place,any instruction is appreciated---Harv

Rover71 · August 15, 2015, 01:29 PM

Re the '89 P-30 tank removal--On our Itasca, it's definitely not easy! They had to have put the floor on after the tank was in to make it that difficult. I had ours out 16 years ago to fix a fuel problem that had bugged us for a long time. It was the sock was quite clogged and had sucked up to the intake tube so that only a 5/16" area was letting fuel through, enough for level, but acted like vapor-lock on hills. The tank has to be dropped far enough on the left side to move over a little and allow filler tube and vent clamp loosening, then work the hoses off and lower more evenly. I had body jacked up enough to work behind wheel and access clamps there as well, remove mud flap.
This time, it was the sender itself that read full for a couple of years before I got ambition enough to go after it again.Managed to disassemble and clean up the sender to make it work OK so far. Now have to get pump figured out as per the last post.

circleD · August 15, 2015, 01:48 PM

There are several fuel pump posts on here. Use the search box. But my opinion about the electric pump is to check the connections and make sure the ground wire has a clean area. 90% of wiring issues on the old rigs is corrosion and rust issues. A little cleaning all is well.

Rover71 · August 15, 2015, 01:59 PM

I'm pretty careful about grounds, even soldered a new wire to the top of tank unit, which I haven't fixed to the frame yet, better do it.This old MH has several ground points and mostly grounded return wiring, better than some.

Oz · August 15, 2015, 11:28 PM

You did fine with your post. It was on the right board, just needed to be a new topic. I separated it and the replies and tweaked the title to fit your problem. Don't worry about getting your postings perfect, you'll catch on pretty quick.

circleD · August 16, 2015, 09:19 AM

If it worked on the bench it should work on RV. Unless its at a different position and the insides are messed up. Try tapping on it to see if that frees it up or makes a noise.
Check the voltage with a meter and use the same ground as the pump. Then get some scrap wire to try a different ground and see if that changes.

Rickf1985 · August 16, 2015, 09:22 AM

Quote from: Rover71 on August 15, 2015, 01:29 PM
Re the '89 P-30 tank removal--On our Itasca, it's definitely not easy! They had to have put the floor on after the tank was in to make it that difficult. I had ours out 16 years ago to fix a fuel problem that had bugged us for a long time. It was the sock was quite clogged and had sucked up to the intake tube so that only a 5/16" area was letting fuel through, enough for level, but acted like vapor-lock on hills. The tank has to be dropped far enough on the left side to move over a little and allow filler tube and vent clamp loosening, then work the hoses off and lower more evenly. I had body jacked up enough to work behind wheel and access clamps there as well, remove mud flap.
This time, it was the sender itself that read full for a couple of years before I got ambition enough to go after it again.Managed to disassemble and clean up the sender to make it work OK so far. Now have to get pump figured out as per the last post.

This information is what I have been looking for for a long time!!!! It sounds like you have the exact same setup as mine. Is yours an 80 gallon tank? I could never figure out how to get the fill and vent lines off.

DaveVA78Chieftain · August 16, 2015, 09:53 AM

Typical P30 Fuel Wiring Diagram

ClydesdaleKevin · August 31, 2015, 10:10 AM

Same thing kept happening with ours...and after changing the fuel pump 3 times and checking every connection, I determined that the fuel pump relay was bad. And its an obsolete part you can't get anymore. I rewired in a 30 amp standard relay, and its been hunky dory ever since! I have a thread on here somewhere explaining the process.

Kev

Rover71 · January 02, 2016, 10:05 AM

I think I owe some folks an apology, didn't get back to this post to check replies, partly from being new to forums.
In any case, I ended up pulling the tank again after checking wiring and no continuity.
Found that one of the tiny plug ends in fuel pump wiring had broken, beefed them up and all was OK until recently when the sock seems to be clogging again, about 2000 miles later.
Just finished making an access hole in the floor--pulling that 60 gallon tank is the pits!. I did another post about that, so I'll try to not repeat myself.Can't seem to get photos small enough to post? Hm?
Have a great day----Harv

Rickf1985 · January 02, 2016, 10:24 AM

Harv, What size is your Itasca? If it is a 31 I would be real interested in seeing where you made the hole. You could always e-mail me the pics.

Rick

Rover71 · January 02, 2016, 10:52 AM

Hi--The Itasca is a 23 footer , but there is another post on this forum from a 31' owner--I'll see if I can find the heading--Found it.
I got underneath and stuck a tape over the top of the tank until it hit what seemed to be the sender unit, then measured from there to top of wheel well. Got inside & measured back from that point, then halved the width for a start point. Cut a large enough flap in the carpet, had a tiny 6" drill bit which went thru floor & heat duct, protruding visibly underneath.
Under again with mirror & light,found I was pretty close, so I cut a 8" X 10" hole in floor, then a 1" hole saw in the drill hole to get a better look with a dentists mirror..
I was close enough to be able to measure and use a jigsaw with a shortened blade to cut the metal sub floor, being careful to not cut wires or tubing.
Took a while because of being extra careful, but sure beats pulling that tank!
I did take some pic's which I could email you, but the one in the other topic is pretty good. Good luck----Harv

1989 P30 fuel line configuration at tank?

shortbus · January 02, 2016, 03:28 PM

When did the p30s start getting in tank pumps? I'm pretty sure my 87 just has just the mechanical pump. I can see the advantage for an electric pump when I have to crank forever to get fuel up front after it has sit for quite some time, but otherwise the mechanical pump has seemed to work just fine for me.

Rickf1985 · January 02, 2016, 04:46 PM

Shortbus, Around 85, you should have one. I don't know if they used them on the shorter units though.

DaveVA78Chieftain · January 02, 2016, 06:08 PM

All 1985 1/2 P30 and later should have an in tank pump. Not sure if a P20 did or not.

They eliminated the mechanical fuel pump in 1990 when they replaced the carb with ECM controlled TBI.

shortbus · January 06, 2016, 12:29 PM

Quote from: Rickf1985 on January 02, 2016, 04:46 PM
Shortbus, Around 85, you should have one. I don't know if they used them on the shorter units though.

Ya, I'm thinking it maybe was left off because I'm so short. It seems Fleetwood still sets up the front electrical panel the same not matter what though. I have 3 relay locations and several other fuse and hookup locations that are not used but are all wired up. The relay location labeled fuel pump is empty and I have my trailer power source hooked up to the fuel pump fuse location so I'm quite sure I don't actually have an electric fuel pump.

DaveVA78Chieftain · January 07, 2016, 07:55 PM

P30 fuel relay location:

Circuit: