dogkatcher

4.0 1993 xj base .. o2 sensor / cat/ exhaust 20k miles .. odomoeter reads 251k .. vacuum lines to map sensor look ok .. not sure where to locate cps .. which could have gone downhill quick .. not sure

engine rebuilt before bought with 230k .. dont know specifics .. ac removed .,. apparantly new plugs,coil, distrib when I bought it

engine light codes show nothing



colder fall air .. slight bucking on highway a cpl weeks ago, i figured new trans fluid .. trans slipping

but this week .. died after a turn / giving gas .. sitting at stoplight yesterday .. then fired right up .. no engine light codes

2day ,, died on a hill / stoplight .. giving it gas from idle

thus rolled backward into car .. no codes shown again

after leaving accident .. died at stop light on throttle again .. no engine light codes


any thoughts where to start?

hitch punched a nice hole in Impala bumper behind me .. didnt even know I was rolling


.. metal vs plastic .. i got good insurance thankfully

may pop

Bad or low battery will cause many idle/driveability issues. It causes the ECM to loose it memory.

dogkatcher

brand new battery .. interstate / green .. quite ok

cleaned all grounds too / new battery terminals .. alternator is a year old, fine

dogkatcher

took "paid sick day" today
1. new fuel filter .. engine seemed to like it .. a cpl stumbles by motor, but no stall
making me think fuel pump is going out .. in the past, they've just died ..... old fuel filter maybe was clogged up .. about 20k miles on it .. but stalling on upward hill / makin turn
2. changed spark plugs, nothing unusual on old ones .. looked evenly worn/residue
3. cleaned IAC & throttle body .. idles way better .. IAC was fairly black
4. rented fuel pressure tester .. constant 35 psi on fuel rail when running
5. checked exhaust o2 sensor (20k miles on it) fair amount of grey residue .. should that be cleaned / replaced ?
6. I unplugged vaccum to map sensor while running to check vaccum strength.. engine bogged down .. back to normal when hooked back up .. sprayed the hose inside too, t-body cleaner .. a bit of soot came out
now map sensor code showing up since I did that
tryin to find this gremlin .. we'll see if it dies randomly tomorrow

toasterknight

May not be a dying fuel sender, but the sock in the tank may be clogged as well.

dogkatcher

thought about that .. jeeps lifted / pump easy reach, but looks I need to drop tank to access safe in/out of pump .. maybe not? thoughts?

toasterknight

Either make an access hatch or drop the tank. Those are the option.

BlueRidgeMark

Not sure what the spec is on your year, but later ones are 49 psi. I know it was different in earlier years, just not sure what year it changed over. My 94 calls for 49.

dogkatcher

where to find this spec?

1993 4.0l High Output

constant 35 psi w/ motor running idle .. goes up to 37 briefly w/ throttle, then dips to 33 letting off throttle, then returns to 35 idle

40-42 psi when regulator vac unplugged

fuel pump prime w/ ignition .. goes up to approx 10 psi, then drops to zero after pump stops

psi drops to zero shutting engine off



figure pump is going bad .. changing whole unit

looking at the Bosch w/ new turbine motor .. thoughts?

cruiser54

Coupla things.

No mention of replacing dizzy cap, rotor and ignition wires.

Fuel pressure is good.

Bosch pump is good to use.

But, the loss of fuel rail pressure right away is troubling. This can be caused by one or more injectors not fully seating or a bad fuel pump check valve. A bad check valve will cause long crank times but no driveability issues.

dogkatcher

checked cap/rotor/wires .. all clean / still look new .. apparantly new parts when i bought it, coil was new also .. I put 20k miles on it since bought. spark plugs had typical grey residue .. none wet or oily

always have had long starts with this one, unless I prime w/ ignition

havn't had a stall yet, with said tuning .. changing pump out when weather warms up

looking at this mopar 4637192

http://www.wermopar.com/jeep/cheroke...name=fuel-pump

dogkatcher

removing the drain bolt a cpl weeks ago, it came out pretty wrecked ... threads trashed

emergency .. nearby parts stores not in stock .. rode bike to Ace hardware .. got same spec bolt .. but is twice as long .. it threaded in fine thankfully / holds fluid in

BUT .. is there anything inside that it could be hitting ?

just wondering, because my current .. bucking on highway .. random untimely stalls .. happened after this

I ordered / now have new bolt/crush washer .. havnt swapped it yet .. replacing it tomorrow

Just had engine scanned / diagnosed at a shop, they couldnt find the problem ... never died on test driver either .. go figure

but I did have a "buck" doing 55 afterward .. right about the point of trans down shifting

or ... maybe my tps .. is faulty, not very old though

rangermonroe

Swap your engine shutdown relay (I can't remember what it's called in the underhood relay box) with one of the other ones. IIRC mine uses the same one for the A/C. It was randomly dieing, and after a few minutes would crank like it was supposed to do. I was also suffering from massive "battery drain".

A couple weeks back I decided to chase this gremlin, and found that relay to be warm to the touch. I swapped them, and miraculously, the car now holds a charge and starts when I command it to do so.

Cheap, free, and easy to try. Probably not going to need a/c for a little while in Colorado, if my geography is correct.

dogkatcher

I will look into that .. thanks .. and NO AC in jeep / except 4 windows .. all AC components removed on rebuild before I bought it .. gonna be sub-freezing this week too


trouble is coming when throttle applied at stop / or on the verge of switching gears at high speed

stalls on throttle from stop .. or stutter on highway, felt like tranny slipping .. but its brief power loss .... Both are very random / never consistent / never know when / and not too often .. quite nail biting expecting a stall


today at lunch .. I swapped current BWD TPS (3 years old) .. with the one I bought it with, that tps had bad shifting issues

result ... died pretty quick, instant restart

left work .. on highway had 2 quick sputters on throttle .. got off highway & went to Napa

swapped IAC / TPS / MAT sensor with new Echlin

.. the old MAT was covered in black crap .. probably oil getting in there from CCV vent tube? .. I recently declogged the PCV .. no more oil shooting out of dipstick tube & no oil in airbox

hopin that was the issue .. very well could have been the combination of 3 crap parts on throttle body .. will find out tomorrow

dogkatcher

CPS .. go figure .. had that feeling .. random misfire gone, runs great
cps PN 56026921 0293

probing cps at connector .. weird ohm readings

my digital meter cross checking pins on cps connector pins

2000k setting for ohms

A-B = 238

A-C = 544

B-C = 200



when on 2000 -> setting

between all pins .. get a brief random number, then infinite


But.. running great with all above parts .. hope Im not back here on stall issue

thanks for all the help .. no cheap parts installed either