| Vapor Lock [message #185429] |
Sat, 22 September 2012 18:40  |
captjack
Messages: 271
Registered: February 2010
Location: Sebastopol, California
Karma: 1
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Senior Member |
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Last week I gave my GMC a vapor lock test and it did reasonably well. Normally, even with a electric fuel pump outside the tank, but inside the frame rails, I'd have problems on hot days during climbs. I dropped the tanks and put pumps in the tanks and moved the fuel filter and steel fuel lines to the outside of the frame rails.
So, the test was towing my Honda CRV from Medford, OR up over the pass to CA, something like a 3000 foot climb in 24 miles with almost 90 degree temps. I made it almost to the top before I noticed some hesitation about every 10 seconds, but she kept on going. With my previous setup I would have been on the side of the road for at least 30 minutes. I'm guessing that without the extra 3000 lbs, there would have been no problem.
I'm going to boost the pump pressure from the current 2 1/2 lbs which may help. I'm wondering if plugging the intake manifold crossover might also help, but don't want to take that on until I have enough time in case of broken bolt problems.
Any other suggestions?
Jack Christensen - K6ROW,
'76 Glenbrook/Clasco - "The Silver Bullet",
Sebastopol, CA
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| Re: Vapor Lock [message #185432 is a reply to message #185429] |
Sat, 22 September 2012 19:04  |
armandminnie
Messages: 864
Registered: May 2009
Location: Marana, AZ
Karma: 2
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Senior Member |
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| captjack wrote on Sat, 22 September 2012 16:40 |
I'm wondering if plugging the intake manifold crossover might also help, but don't want to take that on until I have enough time in case of broken bolt problems.
Any other suggestions?
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Blocking the crossovers is the best thing of all the things that I have done for vapor lock. Since I (with help) did that I have had almost zero problems with a lot of miles in high temperatures - up to 110 degrees climbing hills.
Armand Minnie
Marana, AZ
'76 Eleganza II TZE166V103202
visit my gmc blog
click here to visit gmcws.org
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| Re: Vapor Lock [message #185435 is a reply to message #185429] |
Sat, 22 September 2012 19:25 |
gbarrow2
Messages: 765
Registered: February 2004
Location: Lake Almanor, Ca./ Red Bl...
Karma: 3
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Senior Member |
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Jack,
Broken bolt problem is far more likely to occur with exhaust manifold bolts than intake.
Not saying it can't happen, but don't recall any one on this forum discussing a broken intake bolt in past ten years.
You could try loosening and re-tightening each bolt a bit without removing any. If they are all easy you could continue with removal and blocking.
If any are stuck enough to ba a concern then delay the job till you have plenty of time.
It'd be nice to get the job completed while you still have some warm weather for testing and see if your problem is solved.
Gene Barrow
Lake Almanor, Ca.
1976 Palm Beach
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