Flagler XJ

Hello all i have been reading/searching this forum a while and found alot of help on here...But I have 3 issuses troubling me on my xj.
First off its a 1988 2.5 ltr, 5 spd 4x4. stock and simple with new Exh

1: Whats the best plugs for me? NGK or Champ's??? I see to many thoughts on this, but all for the 6 cyl models.

2: I start up the jeep, it idles like crap, then idle goes up to normal, then back down to crap. i unplug the TPS and nothing happens, idles fine, plug it back in and idles like crap and dies? (doesnt sound normal to me) While driving, out of no where the jeep will feel like it just has a dead short and wants to die (spits/sputters) give it some throttle and it clears up a tiny bit, sometimes it does it at stoplights and wants to die. It just had the following done from previous owner, Plugs (Bosch Platinum 4's) Wires, cap, rotor, fuel filter, new fuel pump relay, strainer on pump, and feed line coming from the pump to the sender. They thought the pump was bad, took it all apart and it was good, so they freshened it up a bit.......any ideas? Only does it maybee once, twice a week or so? And has crap for throttle response as well. I checked all connections and vacum lines, all good. It feels like a elcetrical issue, not fuel...feels like it hits a brick wall LOL....

3: I read all the threads on the vacum Dana 30 that I have, when I bought it 2 out of the 3 vacum lines (white,yellow) were not hooked up. I hooked them up with some pieces of vacum line and the "part time" light is on, only when you are NOT on the throttle, give it gas and it goes off. Now weird part, With the jeep in 2wd and the vacum lines hooked up, the front driveshaft spins. with the vacum lines off, it still spins in 2wd. Leave lines off put it in 4 hi and low, jack up the front and I can free spin each wheel like its not engaged? (normal?) I put it in 4 low and drove on some dirt trail and it drives fine front driveshaft spinning and all no noises or clunks, but I dont think Im in 4x4?????? any ideas????


Thank you in advance for all the help i can get, love the site and helpful info

mike37

well number 3 is just friction
you have one wheel that is still turning the diff so it makes the drive line turn even with the disco disconnected

mike37

number 2
you my need a new TPS
or it my need to be adjusted

Flagler XJ

You said friction for the front diff question? So why would the part time light only come on when I am not giving it throttle? Maybee I crossed the lines? and so with the lines off I put it in 4 low, Im not actually in 4 low? I thought the drive shaft didnt spin while it was in 2wd? still confused on this one. As far as the Idle issuse it sounds like TPS to me as well, I just want to make sure that there is no little "secret tip" im missing

mike37

the drive shaft can still turn in 2wd

the light and throttle deal sounds like you don't have a vacuum reservoir
you should have a elongated ball looking thing under the front right bumper

Flagler XJ

Yah its there.....

mike37

check for vacuum leaks
I cant find the vac diagram right now

Flagler XJ

k...will do tomorrow with some TB cleaner the old School way hahaha thanx man....Let me know if you find any info on the Plugs as well...I have searched and searched

mike37

just use the stock plugs

9XJSPORT7

Yeah on the plugs use the stockers. I don't like the bosch plugs never have had good luck with them, escpecially the +2's and +4's, but thats just me.

c-loss

x3 on the plugs. The simple 4.0 doesnt like all that fancy crap in there just give it a basic plug and it will be alot happier

BigCountry96

x4 on the plugs, bosch platinums do not have a good track record with just about any vehicle, good 'ol copper Autolites are the way to go

Flagler XJ

Cool, but I have the 2.5 4 Cyl, not the 4.0.......And I have no idea what the stock plugs are?????? thats what I was trying to figure out above

Howler_GT

Idle issue:
Check everywhere for vacuum leaks, DO NOT forget the vacuum canister.
Most XJ's have them inside the front bumper, but the earlier models had the "soup-can" style under the hood. Yours being an 88 2.5L, they are probably in the engine compartment.
MAP sensor can also drastically effect idle. One of the vacuum lines will run to it, often on firewall.

PLUGS: What is often meant by "stock plugs" is nothing fancy, no $6 a pop plugs.
NGK's are decent. Champions USED to be, but tend to fail fast.
I have never had a problem with the "cheapie" Bosch plugs
Despite the fact that our 91 Laredo runs the Bosch +2's and Lil Red seems content with the Bosch Iridium.

Flagler XJ

Yah I put some Champion RC12Yc's in today, gapped them to 35 and sea foamed the motor. I also changed the Intake/Exh manifold gasket B/C I thought it had a leak, but i found out that the manifold was cracked....So I found one on Ebay new for 54.00 shipped. I think its the TPS to be honest, It has crap for throttle response, and when I un-plug it it runs better.... go figure, i am gonna go to the local pull n save and pull one off out there and try it before i invest 40.00 dollars for nothing, I will also pull a map sensor as well.


Whats the deal with shimming the coupler over on my front axle to get the 4x4 to work right? Do i have to pull the front axle out to do it?