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

[jbee]

Thanks @GA Architect for pointing this out to me.

The stalling pre 160 is a mystery as only a handful of the 20+ trucks Ive built will do this.

It 200% feels like a vacuum leak the way the AFR surges and wont keep up.

I grabbed one today at lunch because the only truck I have doing this is my current build. I’ve got less than 100 miles of test driving on it and was hoping it would learn its way out before the new owner took delivery.

This was worth a shot.

Took it out and did as many stop and go’s from speed as i could before it hit 160.

It died the first stop then 4 more times it did not. It wanted to the second time and recovered at 200 rpm

The other two times it only dipped to 500 rpm and came back to 850 idle (ive been running my sniper idles higher recently)

4 more stops after 160. No issues.

Im going to let it cool off and try again. Promising lead. Totally makes sense. The only 3/4” hose I had.

View attachment 3286595

View attachment 3286596

Peek-a-boo PCV.

 

[WildernessRimFab]

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

I installed an Innovate Motorsports 3729 Heat-Sink Bung Extender HBX-1 in October (Post #88 on this thread).
I have 6>1 headers and the O2 is as far back as I can get before first gasket/flange.

I'll now be very careful about turning on the key without starting the truck, and also trying to start the truck more often without waiting for the full fuel prime.

 

[wngrog]

I installed an Innovate Motorsports 3729 Heat-Sink Bung Extender HBX-1 in October (Post #88 on this thread).
I have 6>1 headers and the O2 is as far back as I can get before first gasket/flange.

I'll now be very careful about turning on the key without starting the truck, and also trying to start the truck more often without waiting for the full fuel prime.

I think that spot is too close. I’ve started going 6-8” further back and have had little issue with any unless the key was turned a lot

 

[WildernessRimFab]

Holley Sniper 02 install instructions above. They clearly dont want the sensor that far back.

So you are installing after your first exhaust gasket/flange? (Not counting the exhaust mani gasket of course)?

 

[wngrog]

View attachment 3591161

Holley Sniper 02 install instructions above. They clearly dont want the sensor that far back.

So you are installing after your first exhaust gasket/flange? (Not counting the exhaust mani gasket of course)?

You are mounting yours in front of the collector if you are on the header itself which would be 1-2” before the collector.

You need to be downstream of the flange. About here.

 

[WildernessRimFab]

I assumed that it was not desirable to be downstream of the header flange.
I suppose I could weld in another bung, plug the 1st, and verify that the readings are consistent between the 2 locations.
Thanks everyone.

 

[brian az]

I’m running stock exhaust, here’s where mine is:
Holley Sniper 2300 install with PowerSurge - https://forum.ih8mud.com/threads/holley-sniper-2300-install-with-powersurge.1248419/post-13972231

I’ve not had any problems with the sensor. It’s been there for 3 years, although I don’t drive it much, less than 5000 miles I’d guess.

 

[WildernessRimFab]

I’m running stock exhaust, here’s where mine is:
Holley Sniper 2300 install with PowerSurge - https://forum.ih8mud.com/threads/holley-sniper-2300-install-with-powersurge.1248419/post-13972231

I’ve not had any problems with the sensor. It’s been there for 3 years, although I don’t drive it much, less than 5000 miles I’d guess.

Thanks @brian az

I think you have a little more pipe real estate with the stock manifold. The "collector" so to speak is much further upstream. I'll order another bung and put the 02 farther back one of these days. My truck runs awesome right now so I do not want to mess with it