Holley Sniper EFI install on my 258

[Belizeit]

Maybe good to keep Those jeep computers could get hard to find down the road. Who knows

 

[gr8dain]

Ouch, as in camshaft timing?

I have not pulled the cover off to see, but when the piston is at tdc, the timing mark on the harmonic balancer is way off (advanced). So I think the valves are not lined up with the pistons.

 

[gr8dain]

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

I am sure. I have already had people expressing interest, much like a shark in a kiddie pool. ?

 

[gr8dain]

Maybe good to keep Those jeep computers could get hard to find down the road. Who knows

Keep what? The motor? I do not have the original computer for the 258.

 

[JonathanJackson69]

I was working on my son's 1981 Scrambler's Holley Sniper EFI install yesterday, and for the life of me I could NOT find an existing port for the temp sensor that comes with the Holley package. What I believe was the sensor everyone has mentioned at the back, driver's side, of the head is WAY too small for the sensor that came from Holley. Can someone confirm (photo would be OUTSTANDING) the port location on the 4.2L straight 6?

I see a sensor next to a hose connection on the drivers side, at the rear of the head, but like I said, it is small - about half the size of the sensor provided by Holley. I have the engine on a stand, so I can see ALL around the thing and I'm stumped.

Thanks in advance.

 

[AJ2393]

Holley has a pretty extensive video online about the install on a CJ, maybe it weill help answer your questions.

 

[JonathanJackson69]

Holley has a pretty extensive video online about the install on a CJ, maybe it weill help answer your questions.

Not so much. Yeah, I watched that several times through trying to see where they mounted it, bu all that they do is mention the installation.

 

[Belizeit]

Have you called the tech line yet ? I haven't installed mine yet, but they have been pretty responsive so far, and I returned a couple of parts that I bought from them a year after purchasing and they returned my money.

 

[Mancunian]

Mine is a 258 manifold 84 vintage it should be in front of the carb location
There is a temp sensor there already attached to a bunch of wires you don't need.

Wondering if the 81 was pre-smog and may not have needed the sensor in the first place.

Also i found that the Loom is more like 2 looms - one for the original emissions wiring and one for the emissions wiring. You just need to split them near the bulkhead connector. The computer wires are the only things that needed separating on mine.

Finger pointing at sensor.

 

[JonathanJackson69]

Mine is a 258 manifold 84 vintage it should be in front of the carb location
There is a temp sensor there already attached to a bunch of wires you don't need.

Wondering if the 81 was pre-smog and may not have needed the sensor in the first place.

Also i found that the Loom is more like 2 looms - one for the original emissions wiring and one for the emissions wiring. You just need to split them near the bulkhead connector. The computer wires are the only things that needed separating on mine.

Finger pointing at sensor.


View attachment 77245

I do have a sensor in that location. I'll need to look at it again when I get home tonight. Size and thread type, it looks to be a match from what I remember, but I'll confirm later this evening.

Belizeit - I have not. I figured that these are meant for multiple configurations and they would not necessarily know every one of them. I may give them a call if I cannot get this figured out. As it was, I worked on getting the body mount bolts and shock nuts loosened in preparation for replacing them too.

I may need to start my own thread for this build, as I can see myself having a lot more questions that should all be together. Thanks all!

 

[walkerhoundvm]

The original sensor in that location is the coolant temperature override switch (CTO) which is in part what controls venting of your charcoal canister and your EGR, and should still be used in the case of an EFI install. There are likely vacuum hoses coming off of it. There are several other ports of equal size on the standard 4.2 intake, you may have to pull a plug to install your temp sensor. Alternatively, there are a couple ports of appropriate size in the block, about halfway down fore and aft on the driver side. If yours are too small (on the block) then I'd guess you might need a different sensor, but check for others on the intake.

 

[Mancunian]

The original sensor in that location is the coolant temperature override switch (CTO) which is in part what controls venting of your charcoal canister and your EGR, and should still be used in the case of an EFI install. There are likely vacuum hoses coming off of it. There are several other ports of equal size on the standard 4.2 intake, you may have to pull a plug to install your temp sensor. Alternatively, there are a couple ports of appropriate size in the block, about halfway down fore and aft on the driver side. If yours are too small (on the block) then I'd guess you might need a different sensor, but check for others on the intake.

On mine the CTO is where the arrow is pointing, you do still need it for the EGR

 

[JonathanJackson69]

This sensor here is what I was thinking would be the temperature sensor/switch. As you can see here, it is an electrical connection only. The sensor to the right looks to be a vacuum connection. Would THAT one be the CTO, if vacuum hoses connect to it? Would the sensor I am pointing to be the location for the new temperature sensor that Holley provides?

Thanks guys for all of the time!

 

[walkerhoundvm]

View attachment 77304
This sensor here is what I was thinking would be the temperature sensor/switch. As you can see here, it is an electrical connection only. The sensor to the right looks to be a vacuum connection. Would THAT one be the CTO, if vacuum hoses connect to it? Would the sensor I am pointing to be the location for the new temperature sensor that Holley provides?

Thanks guys for all of the time!

Yep, right on all accounts!

 

[JonathanJackson69]

SWEET! Can I swap this sensor out for the new one or is it still needed for other systems?

 

[walkerhoundvm]

I believe you can just pull it and replace with your sensor, yes, just as @Mancunian suggested

 

[JonathanJackson69]

I believe you can just pull it and replace with your sensor, yes.

COOL! That was my hope! Now, I know exactly how to move this forward. Thanks very much!

 

[Mancunian]

That's the location i used!

Do you have an automatic or manual transmission?

Is this a CA spec engine? the CTO looks to have more vac ports than my Postal.

I put my O2 sensor where the pulse pipe branched off the exhaust, just welded a O2 bung at that location.

 

[JonathanJackson69]

This is a manual transmission. Not sure about the CA thing. My son got it from a women out of Seattle. How can you tell?
I installed the O2 sensor in the existing port just after where all of the exhaust comes together but just before the connection from the manifold to the exhaust pipe.

 

[tower210]

This is a manual transmission. Not sure about the CA thing. My son got it from a women out of Seattle. How can you tell?
I installed the O2 sensor in the existing port just after where all of the exhaust comes together but just before the connection from the manifold to the exhaust pipe.

You can tell by the belts... CA got serpentine... rest didn’t .