Holley Sniper EFI install on my 258

[Mancunian]

How did you wire the Sniper to the HEI? i see a yellow wire - so i think you are not controlling timing.

What does the log say? The manual seems to say it's possible to trigger a log on certain events.

Check out this link maybe relevant (I have not used these guys but they seem to know what they are doing)

https://www.efisystempro.com/efi-pro-hangout/solving-sniper-rfi-problems

I am in midst of fitting my Sniper - be a while before i can try it though
for reference here's mine - i have the standard intake and the coolant sensor is on the left

Good luck

 

[walkerhoundvm]

It's been a while, but I think there's another plug you can put it in about 12" fore of that rear plug?

 

[bigwalton]

Glad to see it's on and running. Hope the stalling issues work themselves out.

 

[Mancunian]

Are you, or can you run vacuum advance.?

 

[tower210]

Could you mount the temp sensor in the heater hose line? It should flow all the time regardless of t-stat position; might have to build a creative mount....

 

[gr8dain]

Could you mount the temp sensor in the heater hose line? It should flow all the time regardless of t-stat position; might have to build a creative mount....

I did run the temp sensor in the heater hose. It seems to be working for now.

 

[gr8dain]

How did you wire the Sniper to the HEI? i see a yellow wire - so i think you are not controlling timing.

What does the log say? The manual seems to say it's possible to trigger a log on certain events.

Check out this link maybe relevant (I have not used these guys but they seem to know what they are doing)

https://www.efisystempro.com/efi-pro-hangout/solving-sniper-rfi-problems

I am in midst of fitting my Sniper - be a while before i can try it though
for reference here's mine - i have the standard intake and the coolant sensor is on the left

Good luck

Correct. I am not having the sniper control timing at this point. Holley suggests letting te system do its learning first before having it control the timing.

I will check out that link. Thanks. There is a lot to learn about this system and all it can do.

 

[gr8dain]

Glad to see it's on and running. Hope the stalling issues work themselves out.

Thanks. I think they will. I need to adjust the idle screw a littl clockwise I think. I will get to that later today.

 

[gr8dain]

It's been a while, but I think there's another plug you can put it in about 12" fore of that rear plug?

Not sure. I will look. But if it is the same size as the one on the rear, the Holley sensor is too wide for it anyway. The Holley temp sensor is a 3/8”.

 

[spankrjs]

Shouldn't the IAC be controlling the idle? Maybe look at what feedback that sensor is giving to the computer before adjusting the hard idle set screw? On the GM TBI stuff, you can see how many "steps" it is at, see if falls within an acceptable range?

Sometimes, if you adjust the idle screw, the IAC will compensate for what you did, and put the idle back where it was before

 

[spankrjs]

Shouldn't the IAC be controlling the idle? Maybe look at what feedback that sensor is giving to the computer before adjusting the hard idle set screw? On the GM TBI stuff, you can see how many "steps" it is at, see if falls within an acceptable range?

Sometimes, if you adjust the idle screw, the IAC will compensate for what you did, and put the idle back where it was before

I was wrong on this set up. I looked at the instructions under Tuning, Throttle Blade Adjustment, allows you to set the idle where you want it. After a re-start, the TPS/IAC re-set. IIRC with the GM TBI, you have to unplug the TPS/IAC, jump two pins at the diagnostic connector, adjust the idle stop screw, then shut down engine, reconnect everything, re-start, to reset the base idle speed. This is much simpler

 

[Belizeit]

Where did you get the fitting for the hose that the sensor screwed into ? Looks like I will need to get one for mine.

 

[gr8dain]

Where did you get the fitting for the hose that the sensor screwed into ? Looks like I will need to get one for mine.

A friend gave it to me. So I have no clue where he got it. It was probably on his CJ when he got it.

 

[gr8dain]

I was wrong on this set up. I looked at the instructions under Tuning, Throttle Blade Adjustment, allows you to set the idle where you want it. After a re-start, the TPS/IAC re-set. IIRC with the GM TBI, you have to unplug the TPS/IAC, jump two pins at the diagnostic connector, adjust the idle stop screw, then shut down engine, reconnect everything, re-start, to reset the base idle speed. This is much simpler

Yep. Set via the blade setting on thr display.

I did adjust the physical screw. It worked. But maybe too far. So I set it higher a little today.

 

[tower210]

Update after a Month of Driving?

 

[gr8dain]

Update after a Month of Driving?

I am happy with it. I had to “trick it” by covering the air inlet for the IAC sensor when serting the idle screw. I found that trick online. It worked. Now I have a normal idle. I alao had to increase the fuel inflow percentage when the temp was between 130 and 160 to reduce the pre warming stalling.

But i think I have it at a good setting now and am very happy that I can hop in and go regardless of outside temp.

 

[gr8dain]

So I have tinkered with the Sniper a little. I reset the IAC sensor by covering the air inlet for that sensor, setting the idle 50 rpm lower than my desired setting. Then pulled the tape off of the i let and starting the Jeep. Whamo, idle fixed and settled nicely. No more stalling.

But I had a throttle tip in issue that was not apparent with the high idle. It would act like the pedal was tough to press smoothly. It would provide reaistance, then all of a sudden, I was at 1300 rpm and wanting to spin the tires from a stop.

After researching, i found two solutions. One was to swap the lonk between the primaries and secondaries so that they all did not open at the same time. The issue is the vacuum providing resistance to opening the secondaries.

I chose the other solution which is to extend the point where the throttle cable attaches to the link. I added a flat piece of metal allowing me to put a new hole for attaching the throttle cable about 1/2” higher. This was enough added leverage to allow the cable to open both the primaries and the secondaries smoothly.

I took it on a test drive and it was so much smoother. So happy I did the efi and so happy I did this mod. I just wish that Holly would provide this piece with the kit to start sonce so many people experience it. They sell a piece for the extension for about $13 if I remember. I fabbed my own for free.

 

[gr8dain]

So after getting it running smoothly and loving it, my motor jumps timing and dies. I get it running, but the timing is off, and the starter destructed and chewed teeth off of the flywheel.

Instead of rebuilding the 4.2 (it has other issues like blow by), I picked up a 4.0. I won't be needing the Sniper. Crap. Like I spent $1200 and only got 8 months use out of it. Stuff never seems to work out for me. Oh well.

 

[Mancunian]

Ouch, as in camshaft timing?

 

[tower210]

I’m sure someone here will help you get some salvage value