MAYDAY! MAYDAY Trying to get to Moab! Fuel system crisis!! HUGELY BUMMED OUT UPDATE

[Skigirl]

I need to know where I can get the part that just blocks off where the mechanical fuel pump botls on.

Here's the story if you want to read it:

Left for Moab about noon from Los Angeles. Long story short, I have an electric and mechanical fuel pump. Looks like the mechanical one is getting hot and starving the system for fuel (truck hardly moves once it's been in high heat bumper to bumper traffic, but runs just fine after it cools off. Fuel pump is new (both). New carb (Edelbrtock Performer 600 CFM), new fuel hose all around. New sock in gas tank. New inline fuel filter.

The air cleaner does NOT have a tube that connects to the cooler tube, so I thought maybe hot air was vaporizing the fuel in the carb before it could be fed thru. Am going to PAW to see if they have a cleaner that is more like stock.

But once I got thru all that stinkin hot traffic, the truck acted fuel starved - to the point where I had to get off the freeway and drive 45 minutes home (after taking 1.5 hours to go 30 miles). By the time I got back to my mechanic's shop the truck barely moved at all. They test drove it and said it was the fuel system no doubt. And that if it ran OK once it cooled off that it was probalvby that the mechanical fule pump just gets too hot to function.

So I want to just use the electric fuel pump and plate off the mechanical.

If I can get a plate tonight, I may still be able to get to Moab in time for Friday night - I could leave about 4 AM and get there by the BBQ. If I can't get this resolved tonight I'll probably just have to cancel.

 

[tRustyK5]

Just leave the mech pump in there and by-pass it...then hurry up and get there so I can live vicariously through you and everyone else!!


Rene

 

[Skigirl]

Ah, there's a bright thought! Thanks!

At this point I'll have to leave about 4 AM. Haven't had much sleep so don't want to drive during that early AM drowsy time. Traffic will be impossible for another few hours. Which will give me time to handle the pump, eat, and get a little sleep before I go.

Still sorry you won't be able to make it. So yes, vicarious trip via me is all you're gonna get. Providing of course that I actually make it to Moab...

 

[Skigirl]

OK, need some instruction. Once the hoses are removed, they get barbed together and clamped. Do the open ends of the fuel pump need to be connected together with hose?

Anybody know what the ID of the hose is so I can get the right sized barb?

 

[sweetk30]

no just fire up and go . sorry for to hear about your next installment of the road trip gone bad. goood luck

 

[Skigirl]

Thank you!

 

[Skigirl]

Anybody think that the air cleaner is a problem (just a round open cleaner, no tube to the big cooler hose... except that it's a big open thing? Will it create a too hot environment for the gas going into the carb and cause vapor lock or anything?

 

[83ZZ502_Jimmy]

My opinion is you are getting vapor lock. The fuel supply is too close to a heat source. This has happened to me before. You either need to re-route the current lines away from heat, or insulate them from the heat. I do not believe the air cleaner is the source of the problem.

John

 

[Skigirl]

Thanks John!

OK, took a look. Two hoses, each a different size. One looks like 1/4" and the other maybe 5/16 or 3/8??

 

[dontoe]

I had an electric fuel pump act similar. It was mounted to near the exhaust so it would get hot and vapor lock and the truck would stall. Cool off the fuel pump and it was fine. Moved the electric pump away from the exhaust and it was fine.

 

[dyeager535]

Vapor lock should NOT be a problem when cruising. The later setups (not sure what yours is) with a return line were even better about this, the fuel doesn't just "sit" and cook before the fuel pump, it's returned to the tank constantly. The stuff running up to the carb and the carb itself can, but the demands on the engine at speed require more fuel which means it doesn't have time to soak up as much heat. If it doesn't do it at idle, I say no way in heck is it vapor lock.

On a completely stock vehicle, it should be a problem in no situation.

Good source for the blockoff plates is the wrecking yard. I dislike chrome engine parts, and the only aftermarket blockoff plates I've seen are chrome. Went to the wrecking yard, found an older police (taxi) car, and used the black plate from it.

 

[HarryH3]

Ah, yet another episode of "Road Trips With Pam..."

Follow the fuel lines and make sure that they are never anywhere close to the headers, exhaust pipe, mufflers, etc. You want them to stay as cool as possible. While a cold air source would help keep the carb cooler, I think that it's most likely the fuel supply to the carb that is causing the issue.

 

[Skigirl]

Thanks guys. Ran crappy at anything but idle once things went downhill. But started at speed, then got worse.

Once the truck cooled off there was no problem, ran like a champ.

 

[3 on the tree]

Does your rig have the charcoal canister set up??? I have seen them clog up so that the gas tank does not vent, and the fuel pump tries to pull a vacuum on the gas tank. To check for this, just untwist the gas cap so it does not seal. Good luck.

 

[Skigirl]

Well, here's the latest.

Friend who works in a shop came over. He took the 2 lines off, we found a barb, re-attached, now no gas getting to the carb at all. Sit and stare at it a bit and realize that it indeed has 3 lines, not 2. Makes one now wonder if it's the mechanical pump at all. Maybe just fuel lines getting too hot...

So he's re-attaching the 2 lines back to the mechanical pump, but he cut one shorter to fit connecting them together and now it's too short to put back on the pump. So I'll have to either go get another hose and hook it up and drive it to the shop to have them figure out what the hell, or make use of my 2nd of 4 allowed AAA tows...

Guess I'm screwed for BB 05. I suppose that "road trips with Pam" are now better known as "anti-road trips with Pam". Too bad. The truck has some pretty cool stuff on it. If it only ran...

Thanks for all the help tho guys. I appreciate it.

 

[southernspeed]

Looking at this laterally, have you checked the float level on your new carb? Are all the vaccum take offs used/plugged?
Have you put the end of the hose (carb end) into a bucket and cranked the motor to see if you're getting a good flow of gas? Are the hoses new?(they can collapse internally).
Is the electrical coonection to your pump good (this isn't very lateral as you prob wouldn't have trouble with 2 pumps! But worth checking)

Good luck girl.

 

[poinzey]

Maybe I'm missing something here, but why are you trying to run 2 pumps? When you installed the electric one did you run it inline with the mechanical or parrallel? I would bypass the electric one temporarily and just use the mechanical for now. I'm assuming your talking about the 76? And before you hook up to the carb put the end in a can and check the flow like was mentioned earlier. You can always put a splice in right before the pump to extend the lines for now to get it running.

I had a similar problem on a 72 MGB I had, but in that case it was obvious where it was getting hot cause the line to the carbs was literally laying on the intake. It had the same symtoms yours does. Once I routed that hose differently it worked great.

The only other thing that comes to mind is you said you have a holley carb. Aren't they bad about blowing a check valve or power valve if they get a backfire through them. Maybe someone else can chime in who has more experience with Holley's.

Good Luck with the fix. Sounds like this is the part of the trip that mom would say "builds character"???(always hated that ).

 

[VikingWarlord]

Brilliant idea

Does your rig have the charcoal canister set up??? I have seen them clog up so that the gas tank does not vent, and the fuel pump tries to pull a vacuum on the gas tank. To check for this, just untwist the gas cap so it does not seal. Good luck.

I too had this exact problem. My 83 K5 was origionally from Cali and had the horrible over restrictive smog emmisions package including the charcoal canister. I had it buck and sputter and stall when it got hot. I ended up putting an electric fuel pump in as a bypass to the mechanical. No help to the problem. Grabbed a spare quadrajet my brother had and swaped that out too. Ran better but not right still. So I figured if I didn't need to pass emmisions here I may as well yank some of the smog stuff. I had far less places to hook crap up to on the "other" quadrajet so half of the vaccum line to the charcoal canister were plugged anyways. So after a pile of stuff yanked out in the driveway and finding some places where some of the solinoids to this smog stuff appeared seized, I fired her up. Runs amazing. I have since switched the carb again (the second quadrajet was off a 454 and I have a stock 350) to a Holley 4160 and it runs even better So that does seem 3 on the tree has a good thought process on this! Hope that helps.
Good luck and let me know if I can help at all.

 

[Skigirl]

On my last trip (just last month) this problem started. First shop I stopped at on the road (in Vegas) they put in a new mechanical pump. Next place they put in an electrical pump in line with the mechanical one. Didn't remove the mechanical. Don't know why but they didn't think it was necessary. Then had to go back there after the problem didn't resolve. They cleaned out the gas tank and replaced the sock, which was clogged and disgusting. They blew out the hard fuel lines. Replaced the fuel filters (inline and one in carb again - they were replaced the day before I left too). Replaced all the rubber fuel lines.

On the trip home,the problem came back and the last shop (all the shops were GM factory service shops except the first one) replaced the carb with an Edlebrock Performer. My old carb had sand in it. (I've since figured out why). When they put that carb in they did not hook the charcoal cannister back up and it still isn't hooked up.

finding some places where some of the solinoids to this smog stuff appeared seized

That's a thought. I'll also check vac lines, but I thought if it was a vac line problem that it'd run like crap all the time not just when hot. I like the idea of pulling all the smog stuff out, or disconnecting it all, if just to see if that makes a diff.

Anyway this is an entirely new fuel system. And until it got hot yesterday (extreme heat - I've never had the truck in bumper to bumper traffic in 100 degree heat for an hour or more) it ran great. And after it cooled off once I got home it ran just fine again.

When all is said and done I think it's probably the fuel lines are getting too hot. None of them were insulated and you all know how close they run to hot stuff. Of course it will be a challenge to re-create the environment again once I handle the fuel lines. It's cooled off here a lot now. Guess I'll have to go find a kick butt traffic jam. That could take a whole 10 seconds...

Since I'm not going to BB05 (waaaaaaah... somebody please call the Whambulance), I'll have all weekend to mess around with this. Waaaahhh.

 

[VikingWarlord]

That's a thought. I'll also check vac lines, but I thought if it was a vac line problem that it'd run like crap all the time not just when hot. I like the idea of pulling all the smog stuff out, or disconnecting it all, if just to see if that makes a diff.

Well I don't know why mine didn't run like crap all the time either ? Maybe one of the smog solinoids didn't work at a set (hot) temp ? I just know that like yours when it cooled it ran fine. Hot, didn't run at all. Now zero problems and zero smog equipment May not be your situation but I had a hard time guessing through it all since it was before I joined here. So I hope this or someone else helps you make sense of it all.
Good Luck and I am sorry you missed BB05. I too missed, and on Thur morning saw a few trailered AZ blazers and rockcrawlers that I think are from the PHX area on their way up, made me miss it even more......