63_Engine dies after warm up Part III_all is revealed

[Steve D.]

This one ends with a whimper. Duke was on the right track with a post re: checking the fuel line strapped to the frame near the exhaust manifold. I split some rubber hose and used that as insulation on that section of fuel line, but to no avail. Today, a friend noticed that the line from the fuel pump outlet passes very near the block. I gave it a slight tweak to widen the air gap with the block, slipped a split piece of tubing over it for insulation where it passes the block, and "voila!", no more stumble and die.

Thanks everyone for helping troubleshoot this nagging problem.

Steve

[Ralph E.]

Re: 63_Engine dies after warm up Part III_all is revealed

Congrats … you've been chasing this gremlin for over a month.
Hope you found it this time.

[John D.]

Re: 63_Engine dies after warm up Part III_all is revealed

Make sure you go to local auto store and ask for a hose that is good for todays wonderful ethanol. Don't worry about losing a point. You can catch the car on fire for a buck hose. JD

[Ed S.]

Re: 63_Engine dies after warm up Part III_all is revealed

Steve
So you are saying that the stumble problem was caused by a vapor lock? That was it?

[Duke W.]

Re: 63_Engine dies after warm up Part III_all is revealed

Currently available "low pressure" fuel hose should be stamped SAE 30R7. The maximum working pressure is 50 psi.

Fuel hose from reputable manufacturers has been formulated for E10 since at least the early 80s when E10 (commonly called "gasohol" back then) became available in some parts of the USA. I recall trying some in Connecticut circa early 80s in a rent-a-car while on a business trip. There was no difference in operating characteristics that I could detect.

Don't trust the counter clerk - most are clueless. Verify that the hose is stamped for SAE 30R7.

The frame pipe to fuel pump inlet nipple hose should be replaced anytime the fuel pump is removed because this location is hot and elastomeric materials degrade at exponentially higher rate with higher operating temperature. The hose from the tank outlet to the frame pipe degrades more slowly due to a cooler location, but if you don't know how old it is, swapping it out should be good for another 20-30 years.

...glad you found the problem, Steve. Others have considerably mitigated vapor lock/percolation problems by insulating the fuel supply lines from the frame pipe to the carburetor/fuel meter fuel inlet.

Duke

[Richard M.]

Re: 63_Engine dies after warm up Part III_all is revealed

Coincidental issue......

Yesterday we discovered and remedied the identical problem on a '67 L71 BB. After fixing a high RPM TI module failure, we still had continual stalling problems after 10 to 20 mile high speed, high airflow rides. Perfect running, no bogs, no detonation, or any other anomalies. Slowing down to 25 MPH on country roads and slower, or stopping at lights....it would stall. Last time it did this the other day, we removed the Air Cleaner lid, pumped the throttle, no fuel out of the squirters. When it stalled, it would have that pungent "LEAN BURN" smell. Tank cap was fine when removed, no hiss, so the vent was fine.

We concurred that the fuel system was Vapor Locked, or a possible fuel pump oddity. But failed pumps usually don't react that way. The fuel must have been bubbling in the hard line near the exhaust manifold. After about 20-30 minutes, it'd start and run fine, until the next slow drive after a hard run. Case in point, running E10 93 Octane pump gas.

We insulated the fuel line from the battery tray to the pump. Problem solved.

[Leif A.]

Re: 63_Engine dies after warm up Part III_all is revealed

Rich,
What did you use for insulation?

[Richard M.]

Re: 63_Engine dies after warm up Part III_all is revealed

Rich,
What did you use for insulation?

Leif, We couldn't find the NASA approved right stuff locally, need to order. Jegs has it HERE.


So we experimented.....

We slit some heavy wall Trident Marine approved fuel hose and clamped it onto the hard line. Certainly not the preferred method, but we had to try it until we get the good stuff.

Here's the Bubba action for now.....Right next to that nice original sharp edged hose clamp on the fuel pump fitting. We've been fighting a stalling problem for quite a while, along with some other ghosts. We lost much hair on this one. Sometimes you just have to wing it.

[Leif A.]

Re: 63_Engine dies after warm up Part III_all is revealed

thank you, Rich

[Frank D.]

Re: 63_Engine dies after warm up Part III_all is revealed

Interesting, my lil ole '63 250hp mill started stalling out on super hot days. It was a stumble at a steady state cruising speed and the car just died and I had to pull over. It immediately restarted which I thought was asymptomatic of vapor lock (I worked through the bulkhead connectors and they're fine). I'll get some of the insulation to see if that helps... (I do run non-ethanol Wa-Wa gas).

[Steve D.]

Re: 63_Engine dies after warm up Part III_all is revealed

Thanks for the kind thoughts

[Steve D.]

Re: 63_Engine dies after warm up Part III_all is revealed

I replaced the 30R6 hose from frame to pump with 30R7 and wrapped most of it with Thermo-Tec tape. I also wrapped all of the steel line from the pump outlet to the filter. The "eureka" test on Friday was done with the carburetor spacer in place. But I noticed that hood would not completely close with the spacer in place, so I removed it. Today I started it and after 20 minutes it was still idling well. I took it around the block a couple of times, pulled in and left it idling for another 5-10 minutes, then drove it again. All seems well, but I still have my fingers crossed.

Steve

[Steve D.]

Re: 63_Engine dies after warm up Part III_all is revealed

Apparently so, since insulating the fuel line seems to have stopped the problem. There were a lot of conflicting signals on this one.