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map sensor vacuum location

Posted: June 17th, 2015, 6:27 pm
by rammit11
I was inquiring to see if anyone has tried going to a port directly on the intake manifold vs. the throttle body for the map sensor('98 xj 4.6 stroker ) and if there was any difference as to how the engine runs. I have a slight ping under load at around 1200 rpms when driving up slight grades ,changing the throttle slightly lighter seems to help make it disappear and was wondering if the map sensor is seeing to low of vacuum and causing this to happen . Please correct me if I am thinking backwards on this, lower vacuum = lower voltage leaning things out and higher vacuum = higher voltage making things richer. I would be running some tests on this myself but I am short on time right now. Thanks for any insight on this.

Re: map sensor vacuum location

Posted: June 17th, 2015, 6:37 pm
by IH 392
You want a nice smooth signal for the map sensor, putting it on a port will see it fluctuate with that cylinder and the might run fairly poorly?

Re: map sensor vacuum location

Posted: June 22nd, 2015, 10:45 pm
by cruiser54
I switch all my Renix Jeeps from throttle body vacuum source to intake manifold vacuum source.

Re: map sensor vacuum location

Posted: June 23rd, 2015, 4:50 am
by jeepxj3
cruiser54 wrote:I switch all my Renix Jeeps from throttle body vacuum source to intake manifold vacuum source.
To the intake manifold plenum and not to just 1 intake runner, right?

Re: map sensor vacuum location

Posted: June 23rd, 2015, 12:18 pm
by cruiser54
jeepxj3 wrote:
cruiser54 wrote:I switch all my Renix Jeeps from throttle body vacuum source to intake manifold vacuum source.
To the intake manifold plenum and not to just 1 intake runner, right?
I move the IAT sensor to the air cleaner and put a vacuum fitting in it's place.

Re: map sensor vacuum location

Posted: July 14th, 2015, 5:05 pm
by rammit11
Thanks for the suggestion to move iat. I did move mine and after about a week the computer has adapted to the change and pinging is all but gone and is running like a different vehicle.

Re: map sensor vacuum location

Posted: July 14th, 2015, 5:17 pm
by cruiser54
Seriously? That's one to store in the old memory banks.......

Re: map sensor vacuum location

Posted: February 8th, 2016, 6:59 am
by cruiser54
I haven't done a write-up on it yet, but I do have some photos.

all my Tips can now be found in one location:
www.cruiser54.com