Sniper issues

[Skreddy]

so, issue of vaporizing fuel solved (thanks Nolan for pointing me in a direction). I had a plethora of issues, small pinholes in the exhaust, leaking intake/exhaust gaskets and header heat affecting fuel delivery. I repaired the exhaust leaks, new intake/exhaust gasket, moved the power surge, ran new lines and insulated them and now its running. Issues resolved.....well sorta. Now I am running really warm in the engine bay, like i dont remember ever being so hot. Engine is 194-196 like always and now the MAT sensor is way above the normal 89-92 degrees. Its over a hundred and at about 110 (got up to 120) it wont idle up. Had to shut it down for a while and nurse it back in the garage.
Outside temp was about 88-90. I did some searching and all i can deduce is a bad MAT sensor.....face plant. Any one had a similar issue? I will call Holley tomorrow.

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Do you have an infrared thermometer? Checking temps with that may show it is just that hot.
If your fan has a clutch, is it working properly? If electric fans: do they move enough cfm?
I haven’t seen above 85 or so on my mat yet, but we haven’t been above 65 yet and mostly even in the low 50’s. So 20-30 difference between underhood air temp and ambient doesn’t seem that off base?

 

[Skreddy]

Pardon my ignorance, but is this EFI conversion different than others? I don’t remember seeing the cylindrical alum thing in other builds. The issues you are having make me wonder if all EFI conversions are this complicated. I thought EFI was supposed to lessen the problems.

You may have got this answered already but just in case or for others wondering. The aluminum cylinder mounted to the radiator in the first pics is the RobbMC Powersurge (ps). It is a little tank with a high pressure pump. The stock mechanical pump supplies this tank with low pressure fuel, then the high pressure pump feeds the sniper and provides a return option. Different reasons to use or not use this setup. Really just another flavor of fuel delivery depending on needs/wants.

 

[JKIII FJ40]

Skreddy, thanks for adding some items to check. I converted from the old four metal fan blade to the 6-plastic blade about two years ago. It bolted directly to the water pump and there isnt a fan clutch. Yes, its really hot so i believe the temp is right. Recently i removed the headers to install a new gasket and bolted everything up. It seems the header is throwing more heat than last year, I dont know if this is attributed to a rich setting or not. It no longer pops at an idle (fixed both the intake/exhaust gasket and exhaust leaks) like it used too and the garage doesnt smell like its running rich either.
Wondering if anyone is running a sniper with headers, how high is there MAT F reading. Just need to know if its normally hot. I may need to fashion a heat shield on the 1F intake.

 

[JKIII FJ40]

Posting an update, after many issues shortly after this post I removed the sniper and went back to the carb. After installing the carb it fired right up. Of course I couldnt let an old dog lie, I decided to do a post mortum of the issues.
The first issue that affected the high MAT reading was that I was too far advanced, that alone drove the temps. I also discovered the exhaust had a pin hole leak too. And the last issue that also contributed to my issues was the PCV grommet that was hard and cracked.
Recently I reinstalled the sniper and PS, luckily it was a matter of reconnecting everything back up as it was already pre-configured. It took longer to scrape the gasket off of the carb spacer (2x because I installed it incorrectly) than to hook everything back up. I also replaced the PCV with the fixed orifice one. It started right up to my surprise on the old config. I then ran the wizard just in case and have started the learning process all over again. Lots of learning to do (again), I need to add a return spring as the pedal moves real quickly and doesnt drop off as fast as it did with the carb. I had a good return spring on the carb so maybe I was used to that.
Only time will tell if my observations and corrections worked (or not). I may start another post on my second attempt at the Sniper with lessons learned (or add to this string). I know the PS may be a future issue with heat build up and hot fuel but for now it works to retest the water.

 

[cbmontgo]

Way more Sniper troubleshooting threads than carb problem threads these days. Makes one wonder if the juice is worth the squeeze.

 

[rlong]

Obviously people like different juices (I prefer fermented); you will find those that commonly change 5,000 - 8,000 feet in altitude get way more juice. I’m good with carbs but living at 5-6,000 ft with most trails at 7,000 to 12,000 feet I’m somewhat over carbs.

 

[SteveH]

Obviously people like different juices (I prefer fermented); you will find those that commonly change 5,000 - 8,000 feet in altitude get way more juice. I’m good with carbs but living at 5-6,000 ft with most trails at 7,000 to 12,000 feet I’m somewhat over carbs.

Some of my carb issues were self-inflicted due to air leaks from a 2 way fuel valve, but the AFI TBI system I installed on my truck has resulted in perfect hot-weather running and no issues at 12,000' elevation. I live at 7000' elevation and I used to have endless hot-soak and vapor lock issues that created dangerous driving situations.

The seat-of-the-pants throttle response is much improved. Gas mileage blows (10 mpg), but I only put a few tanks of gas in it every year. I have had zero issues in ~6 years of this setup. Most of AFI's parts are GM-truck bits with their programmed computer and in my case, a modified FJ62 distributor.

 

[cbmontgo]

All good points. I'm at 9,100' and am a die-hard carb guy.

 

[zerotreedelta]

Both have their place, no bones about it. If your carb is running nicely, there's likely not a big lift to get from a swap.

I've had zero issues with my Sniper+Hyperspark since it went together, but it was indeed much easier to do a very tidy/reliable install of the Sniper as part of a frame-off job while everything is out in the open. It was definitely a "if going to do it, now is the time". Wiring, fuel lines, gaskets/manifolds are all 10x easier without the body in the way.

I can see how a retrofit job would be a bit more fiddly, so easier to have issues as a result.

 

[JKIII FJ40]

Some pics of the re-install of the sniper. I made a bracket for the PS when I first installed it, so that made for a quick install along with the hoses already at the right length. This time around I added the fixed orifice PCV, however I didnt have any 3/4 hose so i stretched some 5/8 hose and not only does it hold the PCV, it also holds it on the shaft as well. I didnt see a need for any clamps as it is good and tight. I also added a throttle return spring as i wanted a little resistance matching what I had on the carb. Yes, it looks like a hot mess at the moment. After some run time I may make some more permanent improvements. As configured, everything can be uninstalled in about an hour and a half and three beers.

 

[JKIII FJ40]

Obviously people like different juices (I prefer fermented); you will find those that commonly change 5,000 - 8,000 feet in altitude get way more juice. I’m good with carbs but living at 5-6,000 ft with most trails at 7,000 to 12,000 feet I’m somewhat over carbs.

Some of my carb issues were self-inflicted due to air leaks from a 2 way fuel valve, but the AFI TBI system I installed on my truck has resulted in perfect hot-weather running and no issues at 12,000' elevation. I live at 7000' elevation and I used to have endless hot-soak and vapor lock issues that created dangerous driving situations.

The seat-of-the-pants throttle response is much improved. Gas mileage blows (10 mpg), but I only put a few tanks of gas in it every year. I have had zero issues in ~6 years of this setup. Most of AFI's parts are GM-truck bits with their programmed computer and in my case, a modified FJ62 distributor.

Steve H., my back up plan is the AFI kit I picked up several months ago. I was half temped to put it on but went with the sniper as everything was already configured and installed under two hours. Glad to hear your set up has been running so well over time. I have read a few of the threads on AFI installs but havent read anything long term. The fuel mileage is a concern, have you thought about sending the chip in to someone to check the parameters?

 

[mrboatman]

I have been running a sniper set up for over 5+ years. First on a F engine then reset it and on a 2 f engine. I just had to get a smog on the 2 F engine and it passed with old air cleaner and old oil and 1 year old gas. Th sniper is the way to go

 

[SteveH]

@JKIII FJ40

Long term AFI stuff - see my Reply #143 here and further replies: Affordable Fuel Injection - https://forum.ih8mud.com/threads/affordable-fuel-injection.1058154/page-8

If I found a REAL TBI expert with a chip burner or something, I'd let the check out the AFI fuel programming. I suspect AFI runs the system a bit rich to ensure no damage from running lean (burned valves, etc.). Just a hunch on my part. I truly don't care about the fuel mileage, except if I take longer trips I have to fill up more often. I think I may have gotten 12 mpg on a highway drive last year.

 

[JKIII FJ40]

thanks for the info.

 

[JKIII FJ40]

Update to the thread. I've managed to take it for a couple of small trips, its still wanting to stall on approaching the first stop after starting. Although its nothing like it was on the first install, the ECU seems to catch it just in time. I firmly believe the fixed orifice PCV was one of my issues. After parking it when its hot and trying to restart a min or two later the MAT goes high, the heat from the headers maybe the issue here. Once going down the road it drops. I also had a back fire on a decel once too. But all in all it is no better than a carb when its hot. Overall it is running better and still has a lot to learn.

 

[JKIII FJ40]

Some pics from today, gauge seems to be operating where everyone says it should be. No issues with the power surge either. I do plan on adding some hard lines and maybe an in-line pump.