Sniper Conversion - 72 FJ40 - F155 Engine (2 Viewers)

[CarcaineProblems]

@WildernessRimFab … makes sense, thx

So what are the ramifications of plugging both ends?

 

[wngrog]

@WildernessRimFab … makes sense, thx

So what are the ramifications of plugging both ends?

Your engine will fill up with old oil residue.

Now just use your old PCV and pretend its not there. Figure out how to add an “adapter” to the 3/8” top of the old PCV into the 3/4” hose size need for the new PCV valve.

 

[CarcaineProblems]

Thanks Nolan, I see what that means on the engine side - what about blocking that end of the riser under the Sniper? Just for my own education, what are the consequences of doing that?


I’ll take your advice and put the new pcv on top of the threaded (and hollow) old pcv

 

[wngrog]

Thanks Nolan, I see what that means on the engine side - what about blocking that end of the riser under the Sniper? Just for my own education, what are the consequences of doing that?


I’ll take your advice and put the new pcv on top of the threaded (and hollow) old pcv

Where are you running your PCV hose on the intake? Its supposed to go in the intake manifold. Dead center under the carb base plate.

 

[CarcaineProblems]

Let me go check. I will see if I can spot how you have it setup in some of your posts as well

 

[CarcaineProblems]

@wngrog Like this? The brass barb runs to the pcv valve into the crankcase. Other 2 are blocked

 

[WildernessRimFab]

That's the correct location to hook up the PCV.

 

[WildernessRimFab]

The tired 40 amp alternator wasn't up to task following the Sniper install.
With the headlights on I could watch the voltage drop below 12.5 on the Sniper LCD screen when idling at stoplights.

Ordered up a 90 amp internally regulated FJ80 alternator and dropped it in last night (Thanks @ToyotaMatt)
Mounting was pretty simple on the 72F155 with the alt on the lower drivers side. My tensioner worked without mods, I had to file off about 1/2 mm from the inside of one of the mounting ears to get over the bracket. I did have to remove the double groove pulley and install the single groove that was on my old alt, as this would have interfered with my PS belt mounted on the passenger side uptop.

Steps as follows:
- Remove the instrument cluster, remove B and W ammeter connections and connect those wires to themselves (add lots of electrical tape/insulating tape)
- remove external voltage regulator on the firewall, keep the White wire with red stripe for the connection to the new alternator.
- connect the W/R wire to the IG and S terminals on the alt (I didnt use the L terminal on the alt for a dash light)
- install alternator, I did a "test run" without all of the wiring hooked up temporarily before I buttoned everything up.

With the new alt, I can have all accessories turned on at idle (headlights, heater, radio, wipers) and the voltage is steady at 13.6 volts.

Old vs new:

New alternator installed

All in all this swap was easier than I expected based on some of the reading that I did.
I'll clean up the wiring this evening and get back to driving.

 

[WildernessRimFab]

Happy to report that I drove to work this AM in the cruiser with multiple accessories on (headlights+heater) and the voltage never dropped below 13.7.
I feel spoiled now...

Last item related to the Sniper rabbit hole is a Dakota Digital RTX cluster so I can have a speedometer and a gas gauge.

Are there any Mud vendors who sell these? Or have folks just purchased direct from Dakota Digital?

 

[WildernessRimFab]

Last call for Mud vendors selling Dakota Digital RTX clusters... Thanks

 

[WildernessRimFab]

Well my 02 sensor grenaded a few weeks back. Replaced with a Bosch 17025 and just installed an Innovate Motorsports 3729 Heat-Sink Bung Extender HBX-1 tonight.

The white dot on the extender needs to face upstream. The extender only came with a single copper washer 1.6mm thick. Couldn't get the dot lined up. I tried heating it and also sanding it but I still had about 90 degrees to go. Seems like these extenders should come with a couple different thicknesses of washers!

I dug around and found a steel crush washer of appropriate size that was 1.3mm thick. Bingo.
Truck seems to run the same which is good.

Before and After

 

[aztoyman]

What made you decide to put the heat sink bung extender on?

 

[WildernessRimFab]

What made you decide to put the heat sink bung extender on?

My O2 sensor that came with the sniper lasted only 8 months! That's what made me decide. The heat sink bung supposedly extends the life of the sensor.

 

[WildernessRimFab]

Checking back in since I replaced the 02 sensor in November 2023...the replacement Bosch 17025 02 sensor started misbehaving yesterday. It was intermittently pegging at 35.6 AFR on startup. I turned off closed loop and drove around town just fine. The sensor is welded in and mounted per Holleys specs. Very frustrating because I didnt drive the truck much at all over the past 5 months...

I did a firmware update on the Sniper ECU and that didnt seem to fix the issue.

Im going to drive it around in limp mode to see if the problem persists.
If it persists I will try and clean the sensor.

Im also going to call Holley and see if they can send me a new sensor.

Has anyone else found a substitute 02 sensor that is more durable?

 

[wngrog]

Any chance you have turned the key on a bunch of times without starting it? I’ve seen people that were doing wiring turn to switched 12 multiple times and it kept priming and sent a lot of raw gas down when they finally start the truck fouling the O2

 

[WildernessRimFab]

Any chance you have turned the key on a bunch of times without starting it? I’ve seen people that were doing wiring turn to switched 12 multiple times and it kept priming and sent a lot of raw gas down when they finally start the truck fouling the O2

I didnt turn on the igniton repeatedly without starting but this is something good to think about for the future.
I am goinng to try turning down the fuel prime in the sniper map. Currently I am at a 5 out of 10.

Has anyone tried turning off the fuel prime entirely? I wouldnt mind cranking for a couple seconds if this increases 02 sensor longevity.

 

[WildernessRimFab]

I remembered that I bought the Bosch 02 sensor at O'Reilly's, so they happily exchanged it within the 1 yr warranty period.

Installed new sensor, reduced fuel prime to 60 percent (was at 100%), reduced fuel prime multiplier to 3 (was 5). Started right up and ran perfectly.

I'll report back when this sensor grenades, and keep reducing the fuel prime parameters until I have starting issues.

I would imagine that the default settings on the Sniper are based on easy starts and not 02 sensor longevity?

 

[wngrog]

I remembered that I bought the Bosch 02 sensor at O'Reilly's, so they happily exchanged it within the 1 yr warranty period.

Installed new sensor, reduced fuel prime to 60 percent (was at 100%), reduced fuel prime multiplier to 3 (was 5). Started right up and ran perfectly.

I'll report back when this sensor grenades, and keep reducing the fuel prime parameters until I have starting issues.

I would imagine that the default settings on the Sniper are based on easy starts and not 02 sensor longevity?

Had you messed with the prime or was it stock?

 

[WildernessRimFab]

Had you messed with the prime or was it stock?

I had a saved version of the baseline setup map, 100% fuel prime and 5 fuel prime multipler was indeed stock. I did not mess with that previously.

The truck took a couple seconds to start yesterday at 60%, 3 multiplier, so Ill inch back up towards the stock settings and find a happy medium where I dont nuke o2 sensors twice per year.

 

[wngrog]

I have a truck that I put the O2 sensor too close to the engine And it liked to eat O2s. I added a spacer and it’s never happened since that was about 20,000 miles ago

It was not this one but this is what my search turned up