Topic: mods done so far to a mj....

[cz777]

i know this is a MJ which i own but  its still a jeep in heart .... here are some of the mods i have done to the jeep so far without a trouble yet .... the rear shocks are for a S-10 ,a coil over shock -mod of cutting top cross bar off and install .for some power -rocker arms from a ford 300 cid -mod by cutting off some of the upper part of arm for clearance of the PVC baffle ....now the latest mod for the a  better intake for the TBI fuel system since i dont know of any after market made one ! so i pick up a MPI manifold from a junkyard ..at looking at this thing and seen ,yes work again ! i got the injector holes weld up ..1'' mod plate for the 2 different bolt patterns .the lower i used allen bolts with studs on top with a 1 3/4 hole with side wall 3/4'' down notched at 22* angle 1/8 deep grooves for swirling air flow ..upper power steering mount bolt boss was removed ... i also had to make an cold air system too because of manifold angle and height to air box ......the log style manifold is a pile of crap! it's working great-testing over time will tell !    

[FourbangerYJ]

[chardrc]

so i pick up a MPI manifold from a junkyard ..at looking at this thing and seen ,yes work again !  

sounds sweet. can you go into some more detail about what you did for the IAt and coolant temp sensors with the mpfi manifold? how is the idel? others have had problems with the tbi and not running coolant through the manifold (with having the coolant sensor relocated to the thermostat housing form a mpfi 2.5l) where their jeeps wont idle worth a damn... get some pictures if you can...

[Quite Happy]

Too bad there's not a "Like" button for Fourbanger YJ's post.  LOL!

[cz777]

sounds sweet. can you go into some more detail about what you did for the IAt and coolant temp sensors with the mpfi manifold? how is the idel? others have had problems with the tbi and not running coolant through the manifold (with having the coolant sensor relocated to the thermostat housing form a mpfi 2.5l) where their jeeps wont idle worth a damn... get some pictures if you can...

thermostat housing is from XJ-7 and made new wire harness to extend to the sensor  ....it runs great ! air filter housing was a pain so a made cold air system because the center of the TBI injector housing was moved 4 '' over to the fender so out goes the air box . 45* angle 3'' exhaust pipe app 15 '' long mated with a 10'' cone air filter to a flex tube to the injector top cap .....sorry no camera yet --will post pics next ! 

[chardrc]

so did the intake air sensor just screw right into the mpfi manifold?

[cz777]

so did the intake air sensor just screw right into the mpfi manifold?

THAT IS A BIG YES! there are 4 holes on a flat area on the MPI manifold .i used an intake air sensor for 6 ''4 liter '' with a extended wiring harness and its in the center lower hole - rest are closed up with threaded plugs with teflon thread sealer ....now its running with H.A. CPS sensor -now its better because the advance of 10* it fires the injection system sooner as well ,with the rocker arms i am using it reshapes the profile of the cam timing etc sooner opening .......

[chardrc]

hmm i wonder what the output voltage for a given temp difference the 4liter ait sensor gives compared to the tbi one. wonder if that could be part of why your setup works where others haven't had luck with a none heated intake manifold. or i wonder if the tbi manifold gets extra hot around the egr valve without water in it causing problems, which was eliminated by the mpfi manifold not having an egr valve.

[cz777]

hmm i wonder what the output voltage for a given temp difference the 4liter ait sensor gives compared to the tbi one. wonder if that could be part of why your setup works where others haven't had luck with a none heated intake manifold. or i wonder if the tbi manifold gets extra hot around the egr valve without water in it causing problems, which was eliminated by the mpfi manifold not having an egr valve.

the ohm's on both 2.5 vs. 4 are the same as the book goes for the temp sensor ... i used a lazer temp gun to test out the temp difference ...yes the egr tube does raise temp of the manifold near the mounting point of the TBI like a anti-freeze up devise as well...i no longer have a egr system working ... ''where others haven't had luck with a none heated intake manifold '' why this is true because of the manifold design itself a twin ''v'' with log -log in the center to two ''V'' feeder tubes which is very old school aka 1930's design !

[cz777]

hmm i wonder what the output voltage for a given temp difference the 4liter ait sensor gives compared to the tbi one. wonder if that could be part of why your setup works where others haven't had luck with a none heated intake manifold. or i wonder if the tbi manifold gets extra hot around the egr valve without water in it causing problems, which was eliminated by the mpfi manifold not having an egr valve.

also the water heated manifold works because Coolent sensor is about 18'' from the  thermostat  /water neck so the  sensor is slowly heated . i am using a GM [1/4 '' tip] Coolent sensor [homemade wiring harness] which works very well and TPS is set at .850 volts ......

[sharpxmen]

anyone cares to comment about carb icing?

EDIT: not sure if or how it applies here since we're talking TBI but just asking

[chardrc]

get a chance to take any pics yet?