76 FJ40 Holley Sniper issues and a resolution

[South Texas 97]

Covered elsewhere is my sniper install with a return and in tank fuel pump.
I followed the original routing of the fuel line from the mechanical pump up and around the valve cover and then to the sniper.
It all worked very very well started right up and learned as it should. Several 100 miles without problems.
However, as I was driving from Houston to Ouray, Co., on the second day in the early afternoon the AFR went to 35 and the engine died. Air Fuel ratio s normally between 12 and 15.
Rolled to the side of the road and tried a restart, turned over fine, but would not start. Took a deep breath and decided to let it cool down a bit. The coolant temp was around 187, with the MAF around 120. It gets hot in West Texas. After 30 minutes or so, it started right up, and I went on my way.
This happened about 20-25 times over the next three days.
When I turned the key to the run position the fuel pump ran for three seconds or so, and then there was a gurgling sound. After some thinking, it seemed like old school vapor lock, the fuel was getting very hot. Once I arrived at Ouray, went on to Montrose and picked up some additional 3/8 fuel line and re routed the pressure line to in front of the radiator. And ended up doing the same to the return line. The issue did not reoccur.

Fuel line routing is something to think about if you are installing a Sniper.

Up from the ex mechanical pump location

My replacement routing was like this, I am waiting on a 120 degree fitting to loop the return back away from the engine. Directly under the return are two cut outs on the heat shield and when the engine is running, hot air blasts up through those cutouts, directly on the return fitting.

In the end drove 1300 miles to Ouray staying off the freeways and doing about 50mph, about 500 miles in and around Ouray, Silverton and Montrose, and then drove back to Houston.
Very happy with the sniper after resolving the fuel heating issue.
With all those stops along the road waiting for it to cool down, around 15 people stopped to check if everything was ok.
While not official part of Solid Axle Summit 8, being on the wait list, I did make some good friends along the way.

 

[mrboatman]

I followed the same as the old fuel lines along frame and up around valve cover and had no issues even in the Vegas heat. I have the inline fuel pump.

 

[StinkyPig]

First and foremost...thats an impressive drive in an FJ40!
Did you have the hose shielding installed on the lines from the start? It seems to me that the amount of fuel circulating through the system would negate any possibility of vapor lock. Hell, the stock steel lines attached to a carb would be more of a factor wouldnt it? Obviously you fixed it.
I ran a short section of aircraft fire sleeve as seen in the image below. I also now have a souped up 2F which does run a wee bit warmer but no issues so far this summer. I am also not in the heat and elevation like you were.
That must have been very frustrating.

 

[South Texas 97]

@StinkyPig i notice you have a returnless system, which in hindsight would have been a better way to do it. I had shielding on both the fuel feed and the return. I have since added the header wrap, and will be adding more.
@mrboatman all i can say is that it was a fairly long trip that it eventually shut down on me. And with the re route of the lines, the issue has not reoccurred, and I hear no gurgling from the tank.

 

[GA Architect]

@South Texas 97 - Interesting you had Sniper issues going to SAS....Here is a post in my thread about my Sniper and an issue, similar to yours, and what was diagnosed. < Click here >

Although it might not be your issue, but it was mine. Once I changed the filters, it ran just fine. I've since changed my filters about ever two years or so....Interesting that I had fuel filter issues; while wheeling at SAS 4, one of the 40's in our group had to change it's fuel filter along the trail. Maybe there was a local fuel station that served up some bad petrol?

 

[zerotreedelta]

I always found the factory routing a little interesting, as it goes right past the thermostat. That said - it's hard lines, and it looks like yours was rubber, so perhaps something there. (I have mine on the factory routing, but using hardlines, and also in WI.) I wonder if running headers also added to some of the underhood heat, enough to push it over the line.

Could you have cleared the vapor lock by cycling or jumping the fuel pump relay for a few minutes, given the Holley is a return system?

 

[South Texas 97]

@GA Architect good point on the filter, it was new when I installed the sniper, but now has 2500 miles or so, on a tank that was cleaned out with vinegar, so perhaps some loose stuff. It is a cheap replacement so will add that to the list.
@zerotreedelta , I was uncomfortable leaving the pump cycling for too long, being out in the middle of nowhere in 120 degree heat. I did pick up a spare relay, as it was too hot to the touch when I first opened the hood, so thought that might be failing, but it did not make a difference, the pump would run, then gurgle, gurgle.
Until I go on my next long trip, won’t really know if the problem is truly solved, but the rerouting of the lines,( added a 150 degree AN6 elbow to the return line to get it away from the engine), additional heat wrap on the lines, and some heat wrap installed on the headers should be a good start.

Header wrap as well. Although waiting on more wrap to finish the job.

 

[Skreddy]

Keeping heat away from the lines is never a bad thing.
When you changed the line routing did you also top off the gas tank or anything? My curiosity is: do you maybe have a fuel pickup problem in the tank? If I run my fuel low enough I can hear the return fuel splash back in the tank (if idling at a stop and being quiet otherwise). Not sure your exact setup in regards to return line but that could be the gurgling if you run a return. Or a corroded/too short/kinked/etc pickup tube for the pump could lead to gurgling. Like my kids sucking a staw long after their chocolate milk is gone….