yea.. v8 has been a plan now for... i... dunnknow... 8 years... i guess too lazy and too cheap. i actually bught a rust free 62, as the 60 is just too far gone now, for my taste, so im gonna move the drivtrain and tons other parts and run the 3fe for a while and see if i like it.
Build 1985 FJ60 Gets a Holley Sniper EFI Setup
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keep in mid there's a setting in there, that affects the reaction rate of the unit to changes sensed by the O2. 1-5, 1 being the fastest. Its there to compensate for O2's that are far awya from the intake, and comes factory on 3. if youre that close to "good" with the rpm at 680, try moving that to setting 1, and see what happens, before bumping the idle.
once i put a bunch of miles on mine, and had the idle good, i also cranked the lean "learn" down to 0% at idle rpms to help lock it in. Basically, i'm not letting it lean out. I'm trying to replicate a carb.
Mine still does it. Tried various VE table values to lean and rich out high vacuum operation. No luck!
Before 160* or after? I don’t know the fix but most I’ve seen do it are before 160*
Mine is before 160. Does it through warmup and will even do it at temp if it just got there. If I let the car sit a little then it’s all good. I have headers and my theory is that the cold intake manifold (no exhaust heat like the oe manifold) is creating the issue for me.
Do you guys have the issue with a stock exhaust manifold? That would thicken the plot for me.
Do you guys have the issue with a stock exhaust manifold? That would thicken the plot for me.
Mine started doing it shortly after install. It worsened as time went on and I kept killing O2 sensors. It got so bad I couldn’t keep the truck running. I pulled the engine and found massive carbon build up. This thing ran very rich. I also had a large exhaust leak at the number 2-3 ports in my headers. I did find that rev matching on the downshift helped to keep it from stalling, but eventually it wouldn’t even idle in neutral.
I had massive blow by too. My guess is that we’re shooting ourselves in the foot trying to put EFI on an intake design based off of 1930’s technology and worn out engines. These snipers do not like to have any blow by and if there is a pinhole exhaust leak or vacuum leak they start to freak out.
There is something to be said about the temperature component of this problem. I’m rebuilding my engine currently and have been thinking about installing a fluid heat riser with an in-line coolant heater to keep things warm up here in Montana. I haven’t totally given up on the sniper set up, but this issue really makes me wary of sticking it back on my fresh engine. I would be so frustrated if this problem persists.
The carb can be tuned to work with a vacuum leak or exhaust leak. You can run it rich or lean depending on circumstances or fuel type. The carb is very forgiving and is designed to work with this intake setup.
The #1 and #6 cylinders are further away from the fuel source than 2 and 5. And 3-4 are closer still. The carburetor is designed to work with a pulse so as the exhaust is forced out the intake is sucking in. This happened in rhythm with the engine timing. EFI does not require this to function. I’m not smart enough to know if this pulse is effecting the snipers function or not. I think that would be a question for the engineers at Holley.
I will say that I drove across the country twice with my truck completely overloaded with stuff and then putted around town for 6 months before winter set in. That’s when my engine finally took a dump on me. So, this set up does have promise, but I’m not sure what exactly is the cause of this issue.
I had massive blow by too. My guess is that we’re shooting ourselves in the foot trying to put EFI on an intake design based off of 1930’s technology and worn out engines. These snipers do not like to have any blow by and if there is a pinhole exhaust leak or vacuum leak they start to freak out.
There is something to be said about the temperature component of this problem. I’m rebuilding my engine currently and have been thinking about installing a fluid heat riser with an in-line coolant heater to keep things warm up here in Montana. I haven’t totally given up on the sniper set up, but this issue really makes me wary of sticking it back on my fresh engine. I would be so frustrated if this problem persists.
The carb can be tuned to work with a vacuum leak or exhaust leak. You can run it rich or lean depending on circumstances or fuel type. The carb is very forgiving and is designed to work with this intake setup.
The #1 and #6 cylinders are further away from the fuel source than 2 and 5. And 3-4 are closer still. The carburetor is designed to work with a pulse so as the exhaust is forced out the intake is sucking in. This happened in rhythm with the engine timing. EFI does not require this to function. I’m not smart enough to know if this pulse is effecting the snipers function or not. I think that would be a question for the engineers at Holley.
I will say that I drove across the country twice with my truck completely overloaded with stuff and then putted around town for 6 months before winter set in. That’s when my engine finally took a dump on me. So, this set up does have promise, but I’m not sure what exactly is the cause of this issue.
Skreddy
SILVER Star
On my 40 I was able to tune out that stall coming to a stop, now I get just a real quick lean spike to about 18 afr. I achieved it using the IAC tuning functions. I think I ended up with a longer decay time and hold?
Tune hot starts and functions first, then work on cold settings. (Easier to repeat hot start/running).
Tune hot starts and functions first, then work on cold settings. (Easier to repeat hot start/running).
I have the issue. It's always when the temp is below 160. And I'm running the stock exhaust manifold.
Mine acts moody like that too. I think it may be weather related or maybe it's just me driving a little sloppy
My stop stall issue went away after adjusting the valves, 2 were tight. Headers.
what all have you tried?
Youre supposed to have a healthy motor to start with. The unit LEARNS. Watch some of the videos they have online. Assuming your engine is healthy, once it learns and you tweek the unit for you peculiarities, transfer the learn to the table, smooth it once or twice, and lower the learn %. If the engine is healthy.. that wont seem necessary, but...
... Say your engine is running great, and then something tragic happens, like the O2 s***s the bed, or you bang your exhaust off a rock and you start leaking on a gasket, or some other bull****... If its always learning and nothing has been locked in, not only is trying to correct for the sudden ****ed up reading, but it thinks they are normal, and now your map is all screwed up.
I have a feeling no one here really wants to read or watch all the videos, as I know I sure didn't, and what you'all want is a plug and play computer that will decide "hey, I think the extra O2 is a vacuum leak, and me not providing enough fuel, so I'm going to back off the fuel untill he fixes it next month"... and that ain't gonna' happen. Its a fuel map, not AI. its stupid. it's gonna see o2, run rich, see thats not fixing it, and add more. SO, what I would do, is do what I did for a crash course, and that is ... go thru the software and for each parameter, google it to see what it does. you'll get the specific vids, and youll also bring up the Holley forum site where its possible someone that actually knows Holley FI (not me, or anyone else here) suggests a parameter change for a particular issue that someone asked, and that issue may match yours... that exact suggestion likely wont fix your particular issue the same way, but you can start to tinker and see the changes.
That being said, you can tune this engine leaner than the stock settings, but with this being essentially a tractor motor incapable of repeatable precise burns, I've found you gotta do it with a broad brush that mimics a carb. Once you get the fuel delivery adjusted for air and engine temp i've found the engine is great in open loop before 160, and and lowering the negative closed loop compensation limits down to 5% below 39MAP and below 1750rpm, and setting the idle to 800-850 drastically cuts down stalls when slowly drifting to halt in gear with closed plates. that seems to stop the starvation and hunting that caused the lean stall, by making sure theres enough fuel (rich) and not letting the computer back off the fuel while in a low enough rpm to stall.... I may be completely wrong but at least thats how I interpreted the issue, how I went about solving the issue, and the result is 90% satisfactory. Keep in mind the caveats, two different issues can cause the same result, my engine likely has poopy vacuum at low rpms due to a cam and valve job, your engine is not the same as my engine, my base fuel map is not stock, and... I'm and idiot that likes to tinker and i very well may come to the wrong conclusion for the right reason and visa versa. so theres that to contend with
if you are having an issue before 160F , is that when the truck is in open loop. Maybe there is some issue with the default settings in open loop. I know (different setup) I had a problem with random stalls before I had a good speed sensor. Not saying thats your issue, but might be related. I'm referring to a different fuel injection setup, but might be worth looking at on the sniper....
with the sniper is there a speed sensor input......
with the sniper is there a speed sensor input......
Well, that’s one of the best explanations I’ve read. I will look further into this. I know you need a healthy engine… now… perhaps I will put the sniper back on after I finish rebuilding my engine and see if I can learn it how to work.
What’s amazing is that it didn’t stall with a carb which doesn’t have the advantage of an idle valve. No reason that a carb can keep it running and a sniper can’t. Good overview above. Open loop is a good idea. I do think this is caused by it making a correction in the wrong direction. Seems to me that it leans way out when it shouldn’t.
It does not, but it does have the venturi effect sucking fuel off the bowl if air crosses it, wheres the FI ONLY gives fuel when the computer tells it to. I think when youre drifting to a halt in gear, those flaps are closed, its in open loop, its going lean, you come close to a stop, you push in the clutch, the rpms drop, it goes closed loop, with no vacuum and no fuel and it cant see the rpm plummet to add fuel until its too late.
so you see what i thought was a solution?
I raise rpm a tad over stock to buy time..
I quicked the setting that tells the computer how often (fast) to react so it jumps in quicker..
I limited the computers ability to negative learn fuel (a little lean stalls, a little rich doesnt)
I also have a sit ton of other parameters adjusted that likely affect the solution, i don't know though.
I did notice one hot rodder with a manual transmission and heavy cam had an issue similar to mine (ours?) and his solution was to add a baseline of air, by drilling a small hole in the butterfly... He wrote it solved his issue.. I think that worked because the idle air % will go to zero in open loop. I actually think if i could figure out how to stop that, it would work the same as drilling the hole. his solution is too bold for me considering it may not work for me, and i tried other things like adjusting the idle air %, which had some minor effect, but didnt solve it so i abandon that route.
just so you know youre not crazy, one of the things i noticed, was a fresh program took time to get screwy. thats why i think something like a vacuum leak, has a compounding effect. over time the computers attempts to eliminate what it sees, layers up as it continues to fail, because it cant patch a mechanical issue with an electronic solution. so, say an issue free engine needs x fuel, but leaks make it think it needs x+1... it adds fuel.. next time out, it's x+1+1.. ,then x+1+1+1... but the effect of the leaky headder stays the same.
Time again for my Caveat. Maybe my assumption is wrong, but it lead me down the right path.
50% of what you read on the holley forum will be ideas for solutions, and the other 50% will be someone telling you to upload your files for examination. I never did the latter. I just lurked, tried possible solutions, and repeated.
Keep in mind, unless you somehow get this thing to run way lean under load and youre dumb enough to do that, you cant break it. run your new program, and have a spare sd card to download the original file if its way wonkey and youre 10 miles from home. have fun, **** around with it, thats what i did. (I have 8 cars and AAA platinum, so, im not relying on an 80's LC as a DD)