Vapor Lock? Help!
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FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Thanks to all for the responses, suggestions, experience, etc. I'll take them into account when I get to the truck later this week.
However, my brother called last evening and thinks he may have solved the problem. He tried to start the truck a day after it stalled on me and it would not pump gas. So, he started looking back from the pump toward the tank and found that I didn't put hose clamps on the hose going into the fuel pump. And, I remember why - I put that hose on while the engine was HOT and I was at the side of the road, and I didn't want my hands/arms beside the exhaust manifold for some reason.
Anyway, he put clamps on and got it to start and it seems to run well. However, it was 70 degrees at the time, so we'll have to see what happens when it gets hot again.
Thanks again! I'll let you know how it goes.
However, my brother called last evening and thinks he may have solved the problem. He tried to start the truck a day after it stalled on me and it would not pump gas. So, he started looking back from the pump toward the tank and found that I didn't put hose clamps on the hose going into the fuel pump. And, I remember why - I put that hose on while the engine was HOT and I was at the side of the road, and I didn't want my hands/arms beside the exhaust manifold for some reason.
Anyway, he put clamps on and got it to start and it seems to run well. However, it was 70 degrees at the time, so we'll have to see what happens when it gets hot again.
Thanks again! I'll let you know how it goes.
Methanoholic
Joined: Mar 2009
Posts: 6,442
Likes: 8
From: Maine (NorCal Native)
Bull crap ... Suction side or Pressure side doesn't matter ... Vapor locks can and do happen on either side!
-Enjoy
fh : )_~
Moderator
Joined: Jan 2001
Posts: 57,005
Likes: 2,750
From: Virginia
You can make water boil at room temperature by putting a vacuum on it.
People use pressure cookers because they can cook at a higher temperature than 212F because the water is under pressure.
The suction side will have a tendency to vapor lock quicker because it's at a lower pressure than the pressure side.
I guess the word I used ("only") was too strong.
People use pressure cookers because they can cook at a higher temperature than 212F because the water is under pressure.
The suction side will have a tendency to vapor lock quicker because it's at a lower pressure than the pressure side.
I guess the word I used ("only") was too strong.
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FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
My bother called again this evening. Has been playing with the truck some more and thought he'd made more progress. Said the hose that connects the steel line to the pump was on at an angle such that is was probably sucking air. When he put the clamps on he pushed the hose on further, first.
Also, he found some vacuum leaks, which isn't surprising since the "mechanic" the PO hired disconnected lotsa lines when he installed the non-stock carb. Apparently the idle is getting less bad. (It idled poorly but ran well after that - as long as I got gas to it.)
He also thought the RF tire was suspect as the wear was odd and we'd both detected a shimmy. But, he was gonna take it out for a test run and take it thru the car wash as well. What he didn't say was that he took everything out of the bed in order to wash it out. Sure enough, the truck is running much better. And, the RF tire was bad. In fact, it blew! Fortunately it went across the road from a Ford enthusiast, so he took my brother in his '62 truck to get the spare. The spare not only solved the vibration and shimmy, but the tracking problem we'd been having.
Looks like I may get to drive the truck all the way home on Friday.
Also, he found some vacuum leaks, which isn't surprising since the "mechanic" the PO hired disconnected lotsa lines when he installed the non-stock carb. Apparently the idle is getting less bad. (It idled poorly but ran well after that - as long as I got gas to it.)
He also thought the RF tire was suspect as the wear was odd and we'd both detected a shimmy. But, he was gonna take it out for a test run and take it thru the car wash as well. What he didn't say was that he took everything out of the bed in order to wash it out. Sure enough, the truck is running much better. And, the RF tire was bad. In fact, it blew! Fortunately it went across the road from a Ford enthusiast, so he took my brother in his '62 truck to get the spare. The spare not only solved the vibration and shimmy, but the tracking problem we'd been having.
Looks like I may get to drive the truck all the way home on Friday.
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
I fought a vapor lock condition on my truck the first summer I owned it. Turned out, the PO had put one of those universal inline fuel filters on it just ahead of the carb. Being a I-6, that put the filter directly above the exhaust manifold. I moved that filter, and the problem went away. Fuel was visibly boiling inside that filter as well.
That said, I feel your pain, but I think you're on the right track to getting the issue resolved.
That said, I feel your pain, but I think you're on the right track to getting the issue resolved.
Motorcraft number: FG-44-B
On an inline six this filter would be right above the exaust manifold, as per factory specs. The factory FG-44-B filter is metal. If it was replaced with a see through plastic one, in the same place, then there is your problem on why its vapor locking. The metal the factory filter is made of is a poor conductor of heat, and it is also smaller and does not hold as much fuel as the aftermarket filter. The plastic aftermarket filter is larger, it will let the fuel pool in the filter, staying at the heat source longer, and it will also let the heat right in to the fuel and boil it.
Replace the see through universal aftermarket filter with the factory type filter and your vapor locking (boiling at the filter) should go away.
Post Fiend
Joined: Dec 2007
Posts: 8,521
Likes: 16
From: Lost
Actually, on my truck, the factory filter threaded into the carb. I put that style back on, and relocated the inline type to the pump inlet, and haven't had any issues in the 12 years since doing so. Heck, I've never replaced the filter at the carb, and only replaced the inline once, a few months ago, just because it was so old. I use the see-thru kind to keep tabs on how much crud is in there, and the old filter had very little. Rather impressive, for 30 year old fuel tank/lines.........
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FTE Legend
Joined: Jul 2010
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Likes: 48
From: Northeast, OK
Made it!
Just one last post in this thread - the pickup made it! Yesterday afternoon I successfully drove it the 110 miles to my shop, with no problems whatsoever.
Having said that, there's been a lot of prep to get to that point. Most of that you've probably read before. But, yesterday I put 2 used tires my father took off of his '01 Buick on the front to replace the very suspect one there awa the one that blew when my brother was test driving the truck.
And, I put on an alternator belt. Note that I didn't say that I replaced the existing belt, 'cause there wasn't one to replace. Apparently the previous one broke while my brother was driving it as it should have been between the other two belts, and they were still on.
Today I've started getting the thing into shape where it can be used. First was the compression test, with a cold-engine spread from 112 to 137 psi, which is acceptable. And, now that I know the engine is ok I'm removing the smog stuff with expectation of getting a reasonable idle out of it when done.
So, if you have suggestions on how to remove the smog kit (not if) then please chime in. But, I'll probably open a new discussion thread on that topic soon.
Tnx
Having said that, there's been a lot of prep to get to that point. Most of that you've probably read before. But, yesterday I put 2 used tires my father took off of his '01 Buick on the front to replace the very suspect one there awa the one that blew when my brother was test driving the truck.
And, I put on an alternator belt. Note that I didn't say that I replaced the existing belt, 'cause there wasn't one to replace. Apparently the previous one broke while my brother was driving it as it should have been between the other two belts, and they were still on.
Today I've started getting the thing into shape where it can be used. First was the compression test, with a cold-engine spread from 112 to 137 psi, which is acceptable. And, now that I know the engine is ok I'm removing the smog stuff with expectation of getting a reasonable idle out of it when done.
So, if you have suggestions on how to remove the smog kit (not if) then please chime in. But, I'll probably open a new discussion thread on that topic soon.
Tnx
Thread Starter
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FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Panman65 - Thanks, but it wasn't vapor lock as it turns out. I didn't have a clamp on the hose just ahead of the fuel pump and it appears to have been sucking air at that point. With that fixed I've now moved on to resolving a miss I have at idle - see my recent post on that topic. Tnx again.
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