Sniper Conversion - 72 FJ40 - F155 Engine

[Skreddy]

I verified that my Idle Speed Curve Settings are correct.
I ramped up my fuel prime from 100% to 140%.
Now it idles at 850 on cold startup and ramps down to 750 when warm.

I'm done messing with any more settings until I reinstall the seats and get some driving/self learning.

I actually found I had to reduce my fuel prime because increasing it made hot starts worse.
When mine idles low at cold start my AFR is rich: 8-9. It’s almost like the iac isn’t opening enough, though it shows 100%. You’ll have lots of opportunities for tuning though…. Get those seats in!

 

[Skreddy]

Agree - I'm just starting to think about this also. And therefore, maybe this dumb question.

Aren't there external (out of tank) high pressure fuel pumps available that wouldn't require the level of modification you've done to your tank? What's the advantage of the in-tank pump?

2 popular options for non in-tank are the corvette pump with return and the RobbMC Powersurge tank.
If doing in tank, I don’t feel a recess is needed, but will depend on install. Lots of ways to accomplish the end goal I not one is “right”.

I think determining in tank or not has a lot to do with other factors like year, seats, accessories under the hood, mechanical fuel pump condition (RobbMC), intended use, etc.

 

[WildernessRimFab]

If doing in tank, I don’t feel a recess is needed,

I am 6'3" tall so a recess was needed for me!! I wanted to keep my seats as low as possible.

Get those seats in!

You are 1000% correct! I got this thing running 3 days ago and haven't had more than 20 minutes at a time to mess with it since then.

Glad that others are finding this useful for their own planning purposes.
I only started this thread because my Sniper conversion was slightly different in several areas.
There are lots of ways to get this done, everyone's rigs/goals/preferences are different as @Skreddy points out above.

 

[EricG]

@EricG there are absolutely external high pressure pumps. Not a dumb question at all.
There are pros and and cons to both, in my opinion:

External Pump Pros: Easier installation and replacement, lower cost
External Pump Cons: More noise, accelerated wear from heat (not surrounded in fuel), potential fuel starvation when cornering/off-camber due to the limited baffling of the OEM tank.

Internal Pump Pros: lower noise, constant pump cooling due to fuel submersion, less starvation issues due to the in tank reservoir tray (constantly fed by fuel return), one hole in the tank which covers supply/return/vent lines.
Internal Pump Cons: lots of extra installation work, welding on a gas tank, additional cost of pump assembly and recess plate.

Nearly every modern factory vehicle has an in tank pump, so surely there is some reasoning behind that.
(Since this is ih8mud, this is where someone posts up an odd modern production vehicle with an external EFI pump...)

Thanks! My other motivation is that I have an 80 series subtank, but none of the rest of the bits. So I've been thinking about ways to make that work (in my 80), and that pump recess might end up being useful there.

 

[WildernessRimFab]

I am happy to report that I got the seats reinstalled last night and went on a drive around town. A couple issues to sort out (besides tuning).
- I need to get a new fuel level sender. The CCOT sender that came with my CCOT tank is not correct for my cluster.
- My stock alternator is not providing enough amps at idle with the headlights/heater fan/wipers/sniper. I can watch my battery voltage drop to below 12.5 at stoplights.
I was aware that this may be an issue but wanted to keep the stock unit for starters to "minimize variables" with the Sniper stop.
I'll likely end up with a GM style Delco CS-144 3 wire alternator.

The truck stalled a few times when coasting to a stop, but the Sniper seems to be learning its way out of this behavior.
I haven't messed with the IAC settings (Ramp Down/Hold) so that may be another possible solution.

Very happy to be driving the truck around with temps in the mid 30s. Not a single sputter/hiccup on accelerlating from a stop which was standard behavior with the Weber 38 in cold temps.

 

[Skreddy]

The iac settings will help that coming to a stop issue. This is more of an issue with manual transmissions than auto because of the sudden loss of load when you can put it neutral. Work around is to engine brake more. But changing iac settings drastically helps (tune it fully warm though). I have completely tuned my stall out and now just get a brief lean spike to 18 or so afr, but it’s so brief I can’t even hear the change in engine sound when it happens.

Is your voltage regulator stock or aftermarket? You can adjust the VR to increase charging but it can be finicky, meaning you may make idle bolts better but then get 16+ volts while cruising. I had the same issue but with an aftermarket VR and ultimately swapped in the Toyota 80 amp internally regulated alternator.

 

[WildernessRimFab]

I have the stock alternator and voltage regulator. I'd rather not mess with "overclocking" the voltage regulator.

Do you have a part number available for the Toyota 80 amp internally regulated alternator? Or which vehicle this originally came out of?

 

[WildernessRimFab]

I did a couple basic engine tune up items that I probably should have done earlier: timing and plugs (it had been a couple years).
New plugs installed (NGK BPR5EY gapped at 0.035")
Timing adjusted (timing had migrated to ~4 or 5 bTDC, now its at ~10 bTDC, the bb is about halfway between the needle and the bottom of the window).

The truck ran so much better, and so different that I restarted with a new baseline setup tune.
Air temps are single digit highs right now and below zero at night so more driving will have to wait.

Pending sniper related items include:
- adjust valves
- tuning/driving/learning
- upgraded alternator (REMY 14958 looks like it will work. This is a double groove pulley so I may need to swap the pulley off my stock alt)

On other related items:
1. my 9/72 level sender doesn't fit the new tank and the new sender that came with it isn't compatible with the dash gauge)
2. the stock 30 amp gauge on the cluster wont work with the new alt
3. my speedometer/odometer grenaded last fall for the 2nd time in 2 years. I don't want to keep replacing this with old parts

Moral of the story is that a Dakota Digital VHX w/GPS speedo may be in my future. This will solve all three issues above.

 

[WildernessRimFab]

I have had some communication with Holley support regarding the intermittent stalling on deceleration/coasting issue that many of us have reported.
They suggested investigating the PVC valve as the OEM poppet style PCV can behave as an intermittent vacuum leak that throws AFRs into spikes.
A fixed orifice style PVC is recommended by Holley as the solution:
Help With PCV Setup - Holley Performance Products Forums - https://forums.holley.com/forum/holley-efi/sniper-efi/36560-help-with-pcv-setup

@brian az had a breif thread on this question but there was no resolution.
Sniper install: Fixed orifice PCV valve? - https://forum.ih8mud.com/threads/sniper-install-fixed-orifice-pcv-valve.1245865/

I bought a Duralast PCV1009DL from Autozone for $1.37 and gave it a try. The base of this PCV is about the same size as the breather tube on the F155 so I initially connected the new PCV to the breather tube with electrical tape as a test. This worked well and seemed to minimize the stalling issue on a couple neighborhood test drives.

The orifice flows less than the poppet style but it is always open under all throttle conditions.

The fixed orifice PVC can be easily connected to the breather tube with 3/4" ID hose and a couple clamps (OEM crowd cringes).
Note that this will effect your tune and you may have to readjust your throttle blades to achieve the correct IAC at idle.

I'll report back when one of the following occurs:
1. I start having oil leaks or blow out a main seal
2. Backfire propagates into the crankcase through the PCV
3. This solves the stalling issue for a total cost of less than $5 with no ill effects.

 

[aztoyman]

Thanks for following up with all this.

 

[brian az]

@brian az had a breif thread on this question but there was no resolution.
Sniper install: Fixed orifice PCV valve? - https://forum.ih8mud.com/threads/sniper-install-fixed-orifice-pcv-valve.1245865/

Oh yeah, I forgot all about that. I ended up installing a brand new OEM PCV. And I still get the stalling below 160°, usually only on cold days. Maybe I'll try the fixed orifice PCV after all.

 

[WildernessRimFab]

Oh yeah, I forgot all about that. I ended up installing a brand new OEM PCV. And I still get the stalling below 160°, usually only on cold days. Maybe I'll try the fixed orifice PCV after all.

@brian az Its worth a shot! Its 2 bucks, 10 minutes, and 100% reversible.
The fixed orifice PCV is used on many modern vehicles with EFI for this exact reason.
Once I started thinking about the fixed PCV it made sense how the poppet style could throw the O2 sensor and AFRs out of whack.

 

[WildernessRimFab]

I still get the stalling below 160°, usually only on cold days

This is good to hear, considering that I just got my Sniper running a month ago and have not driven it above 40 degrees air temp.
I usually don't drive my cruiser much during the winter, but I wanted to get the Sniper troubleshooting out of the way before the nice weather is here.

 

[WildernessRimFab]

Adjusted the valves and installed a 2F valve cover (1979 model supposedly). A couple valves were slightly out of adjustment and the truck idles noticeably smoother.
The valve cover was installed with a new OEM gasket and what I thought were the correct valve nuts/seals from @ToyotaMatt (my fault not his).
The valve cover studs on the F155 are way too long for the 1979 2F valve cover, also the threads on the upper portion of the stud don't go deep enough.
Trimming/threading my studs shorter wont work because the threads are rolled and there isn't enough material present below the existing threads.
I've got it band-aided together with a stack of washers (it doesnt leak somehow?) but I'll need to fix this.

From the looks of it, I need shorter valve cover studs like these. Note the shorter non threaded area at the top compared to mine.
Anyone got four of these in their stash???

Looks like this ebay ad has 4 of the shorter studs that I need along with 3 *bonus* long studs.

FJ40 Valve Cover OEM Stud F 2F Toyota Land Cruiser 1968-7/80 | eBay - https://www.ebay.com/itm/255451160213

 

[WildernessRimFab]

I got some total length measurements from the EBay seller, the short studs are 15mm shorter than the long studs.
This lines up well with my measurement when I considered chopping the studs, I came up with 14mm.
I'll report back with the results.

 

[WildernessRimFab]

Reporting back on the sub 2 dollar PCV valve (Duralast PCV1009DL) to combat the stalling on deceleration issue....

IT WORKS GREAT

The improvement wasn't immediate as the ECU has to learn around this new part, but I have had this PCV installed for 2 weeks now with no ill effects.
It hasn't stalled out in at least half a dozen drives, where with the old PCV it would stall out at least once per drive around town.

 

[CarcaineProblems]

Quick question on removing the old PCV valve - does it just pop off or do I take a wrench to the nut on the bottom of it?

Thanks!

 

[WildernessRimFab]

Quick question on removing the old PCV valve - does it just pop off or do I take a wrench to the nut on the bottom of it?

Thanks!

The old PCV just pops off. Not sure of the year of your cruiser but there is no nut on the PCV on my 72 F155 engine.
There is a rubber grommet on the engine side that also needs to be removed.
The 3/4" ID hose is slighty undersized for the PCV tube on the engine but you can squeeze it on there.

 

[CarcaineProblems]

Thanks. I see something that a wrench could get on, under the PCV, but doesn't look like its part of the PCV.

Mine is a July 1969

Much appreciated!

 

[wngrog]

I have had some communication with Holley support regarding the intermittent stalling on deceleration/coasting issue that many of us have reported.
They suggested investigating the PVC valve as the OEM poppet style PCV can behave as an intermittent vacuum leak that throws AFRs into spikes.
A fixed orifice style PVC is recommended by Holley as the solution:
Help With PCV Setup - Holley Performance Products Forums - https://forums.holley.com/forum/holley-efi/sniper-efi/36560-help-with-pcv-setup

@brian az had a breif thread on this question but there was no resolution.
Sniper install: Fixed orifice PCV valve? - https://forum.ih8mud.com/threads/sniper-install-fixed-orifice-pcv-valve.1245865/

I bought a Duralast PCV1009DL from Autozone for $1.37 and gave it a try. The base of this PCV is about the same size as the breather tube on the F155 so I initially connected the new PCV to the breather tube with electrical tape as a test. This worked well and seemed to minimize the stalling issue on a couple neighborhood test drives.

The orifice flows less than the poppet style but it is always open under all throttle conditions.

The fixed orifice PVC can be easily connected to the breather tube with 3/4" ID hose and a couple clamps (OEM crowd cringes).
Note that this will effect your tune and you may have to readjust your throttle blades to achieve the correct IAC at idle.

I'll report back when one of the following occurs:
1. I start having oil leaks or blow out a main seal
2. Backfire propagates into the crankcase through the PCV
3. This solves the stalling issue for a total cost of less than $5 with no ill effects.

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.