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KlassicBus79 Samba Member
Joined: January 10, 2010 Posts: 121 Location: Nova Scotia
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Posted: Fri Jul 25, 2014 6:36 am Post subject: |
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update: Drove the bus to work this morning outside air temp was 16C (61F), Bus ran fine very very slight bog at shift between 2nd and 3rd.
Had to go home for some paperwork outside air temp is now 20C (68F) and bogging was a little more severe.
What besides the fuel pump and Temp Sensor II could be affected by temperature? _________________ 79 Cal Transporter 2L |
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aopisa Samba Member
Joined: August 14, 2009 Posts: 605 Location: Vermont
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Posted: Fri Jul 25, 2014 7:20 am Post subject: |
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Diet Pepsi King wrote: |
update: Drove the bus to work this morning outside air temp was 16C (61F), Bus ran fine very very slight bog at shift between 2nd and 3rd.
Had to go home for some paperwork outside air temp is now 20C (68F) and bogging was a little more severe.
What besides the fuel pump and Temp Sensor II could be affected by temperature? |
Electrical resistance.
I had a bucking, hesitating issue that seemed to get worse as temperature increased. Turned out to be a poor negative battery to chassis contact. Not saying that you haven't been through a bunch of electrical stuff already, but that was what I found was my problem. _________________ 1977 Westy 2.0L FI
Leap into the boundless and make it your home! ---Chuang-Tzu
Please let me know if you do not receive this message... |
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KlassicBus79 Samba Member
Joined: January 10, 2010 Posts: 121 Location: Nova Scotia
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Posted: Fri Jul 25, 2014 12:42 pm Post subject: |
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so it's very warm out now. I wired up the fuel pump with it's own relay so it gets 12v right from the battery. I also put the original distributor back in with pertronix installed. It is still bogging and backfiring.
My helper was reading the fuel pressure when this was happening and when bogging fuel pressure goes to almost 0 when stopping 10 psi.
I'm thinking of draining the tank tonight and blowing compressed air through all the lines.
Any other thoughts? _________________ 79 Cal Transporter 2L |
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Randy in Maine Samba Member
Joined: August 03, 2003 Posts: 34890 Location: The Beach
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Posted: Fri Jul 25, 2014 12:47 pm Post subject: |
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Before you do that, can you rig the pump to draw from and return fuel to a 5 gallon tank? That would tell us if the tank or something in the tank is the problem.
Here is how the fuel line set up works.....
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KlassicBus79 Samba Member
Joined: January 10, 2010 Posts: 121 Location: Nova Scotia
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Posted: Fri Jul 25, 2014 12:49 pm Post subject: |
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Same diagram I used last year to replace the fuel lines. _________________ 79 Cal Transporter 2L |
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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KlassicBus79 Samba Member
Joined: January 10, 2010 Posts: 121 Location: Nova Scotia
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Posted: Fri Jul 25, 2014 4:04 pm Post subject: |
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Randy I ran the pump and I pumped lots of gas from my 5 gal jug to a 2.5 gal jug and it worked as it is supposed to. In fact all 3 of the pumps I have pumped fine.
So I decided to wire the pump directly up to the battery through a switch instead of the relay thus bypassing the double relay.
Got my son to toggle on the switch when I turned the key and then took it for a drive.
Same issues 0 PSI when bogging and 10 PSI when coming to a stop.
I have now drained the tank and will blow out the lines tomorrow. Will probably swap out the pressure regulator at the same time.
Do you think one of the short lines between the tank and the pump (B,C and F) could be collapsing under load? (I have metal lines as per the diagram) Hard to check for collapsed hoses while driving. All the hoses are FI rated hoses. _________________ 79 Cal Transporter 2L |
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Randy in Maine Samba Member
Joined: August 03, 2003 Posts: 34890 Location: The Beach
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KlassicBus79 Samba Member
Joined: January 10, 2010 Posts: 121 Location: Nova Scotia
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Posted: Fri Jul 25, 2014 4:41 pm Post subject: |
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I just did the vacuum line on and off part 29 PSI idling hose on 36 PSI hose off.
Hose back on revving to 3000 RPM reads 29 PSI and when going back to idle it reads 25 PSI then back up to 29.
This was with very little fuel in the tank. _________________ 79 Cal Transporter 2L |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51117 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Fri Jul 25, 2014 5:12 pm Post subject: |
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Home Depot and other tool rental stores will rent you or let you demo one of those snake inspection cameras, 2 minutes down the filler neck will answer many questions. _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
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KlassicBus79 Samba Member
Joined: January 10, 2010 Posts: 121 Location: Nova Scotia
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Posted: Fri Jul 25, 2014 5:18 pm Post subject: |
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I have been looking in the fuel gauge sender hole. Haven't seen much in the way of sediment or rust.
Just drained the tank through there with a hand pump. _________________ 79 Cal Transporter 2L |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51117 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Fri Jul 25, 2014 6:12 pm Post subject: |
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Never mind, you are way ahead of me. Shove a wire through the outlet while you are in there incase anything is lodged in the tube. _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
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KlassicBus79 Samba Member
Joined: January 10, 2010 Posts: 121 Location: Nova Scotia
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Posted: Fri Jul 25, 2014 6:38 pm Post subject: |
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The PSI numbers I got with revving at idle to 3000 and back are lower that what the test said to expect. I will be checking the lines and swapping out the fuel pressure regulator tomorrow.
Just priced that thing out and I sure hope my spare regulator is good _________________ 79 Cal Transporter 2L |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51117 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Fri Jul 25, 2014 6:48 pm Post subject: |
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Try the pinched return line test first to rule out the fuel pump. _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
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KlassicBus79 Samba Member
Joined: January 10, 2010 Posts: 121 Location: Nova Scotia
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Posted: Sat Jul 26, 2014 11:15 am Post subject: |
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Hi all been working all morning trying different things and finally found the issue.
Tried all the things everyone suggested. Did the fuel pressure regulator test and it passed with flying colors.
So then onto the fuel tank inlet and outlet. I blew 100 PSI air up the return outlet and heard something that didn't sound like air. Didn't see anything when looking in the tank so went and got an inspection camera. Still saw nothing lying in the tank but did manage to see something sticking out of the supply inlet. Pushed from below with a wire and it took a lot of force to push whatever it was out of the hole. Still couldn't see what it was with the camera but put the shop vac hose in the baffle tank and vacuumed around in there.
Put all the hoses back on and took it for a drive. Pressure never went below 29 PSI no hiccups at all.
Looks like it is going to be a great summer after all
Thanks for all the suggestions guys it sure helped me get to the right spot. _________________ 79 Cal Transporter 2L |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Sat Jul 26, 2014 11:58 am Post subject: |
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Gary (Aeromech) found a rag or old sock in one tank. The most common item on the late bays is the end of the bird's beak breaks off, and the ring inside falls out when they split. Those pieces can sit in the tank for 20 years doing nothing and then just the right bump, turn and fuel slosh puts them into the baffle where they sit into or on the outlet. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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KlassicBus79 Samba Member
Joined: January 10, 2010 Posts: 121 Location: Nova Scotia
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Posted: Sat Jul 26, 2014 1:22 pm Post subject: |
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Not sure what it was but it was white and looked a bit like plastic. Would never have seen it without the camera. Wouldn't have thought anything would need that much force to dislodge. _________________ 79 Cal Transporter 2L |
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51117 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Sat Jul 26, 2014 3:46 pm Post subject: |
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Diet Pepsi King wrote: |
Still couldn't see what it was with the camera but put the shop vac hose in the baffle tank and vacuumed around in there. |
Did you clean out the vacuum first and go through it after to locate the chunk of whatever?, I don't declare jobs like that done until I have the offending bit of crap in my hand.
Good to hear you are getting close! _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
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