My 94 XJ stalling thread (round two)

[weaselguys]

The first time I had the stalling issue was about a yr and a half ago ,it backfired ,spitted & sputtered on the hwy and died , I was able to retart it a few times and drive short distances only. It turned out to be the fuel pump (low volume) the fuel pressure would spike downward and it would die.

Now round two.

First it has some known problems , high idle and a little rough .Also the NSS switch it wont restart w/o moving the shifter if you only go for a very short distance in the morning and it has no backup lights.

The first stalling problems:
Stalled at three stop lights ,started right back up and hesitated , jumped ,bumped several times in 44 mile trip.

Replaced fuel filter
hesitated once in 16 mile trip .Next day it was cutting out in 2 miles and cutting out twice on coners.

Replaced dist cap & rotor
,checked and replaced plugs as needed.

Fuel pressure
at idle 31 psi , 39psi with vacuum line disconnected
Fuel leak down test within spec
Fuel volume looked good pumping into mason jar.

TPS
checked with volt meter readings are within spec.

MAP
AB terminals,switch on engine off 5 volts
AC terminals ,switch on ,engine off 5 volts
AB terminals engine running 1.49 volts ?

CPS
BC terminals showed no continuity

Drove 16 mile trip no problems ,went 10 miles further no problems, turned around and it cut out once and then it shut down twice on corners . Started right back up.

Checked CPS still showed no continuity on BC terminals

Replaced MAP sensor with junk yard sensor and it shutdown 4 times in 5 blocks and was harder to start back up.

Pulled fuel rail tested each injector , they do fire , sprayed cleaner threw fuel rail ,looks clean.

put original MAP sensor back on.

Checked for codes none

Cleaned throttle body and checked the IAC the pintle was not moving.

Replaced the IAC now no more high idle. Still shuts down.

Got dist pickup code

Replaced the 91-93 53006150 dist that was in it with a 94-99 56027028 dist with removable CMPS . Still shuts down.

Tested temp switch and retested the Map Sensor .Tested ok

NSS continuity tested , no cont in neutral or 1-2

Replaced the CKPS . Still shuts down

Checked the voltage at each sensor , readings are all over the place. These are ll on a 5 volt circuit and the the only wire they have in common is the black/lt blue wire from the ECU

I traced the black/lt blue wire back to the ECU there is not 5 volts in this wire , should there be ? Maybe its the ECU

[4.3LXJ]

5 volts is the right voltage

[Mudderoy]

I don't know if this issue extended to the 2001, but for the 1998 there is a problem with the wiring harness resting on the fuel rail, after a while it rubs the insulation off a wire and it grounds out. I still find it hard to believe that in that big bundle of wires it rubs the specific one that causes this issue.

I was CERTAIN I had a TPS issue because it acted just like it did when the TPS was bad. I spent $65 for a new TPS and it didn't fix the problem. After searching a while I found this obscure known issue. I used a tie wrap to raise the wiring harness off the fuel rail and it solved the problem! I'm still amazed.

I know this doesn't fit your problem exactly, but there are several wires in that harness. It's a simple fix, you might give it a try.

[weaselguys]

It's something for me to look at I'm running out of sensors to replace , if not that then I have to look at the oxygen sensor and the ECU.

[4.3LXJ]

Does your check engine light work?

[weaselguys]

I'm not sure I will have to look ,I'm not getting codes. Also I'm unsure if the black/lt blue wire from the ECU to the sensors is supposed to carry 5 volts or if the is the wire the sensors respond to the ECU on . And I'm not sure about the low volt reading form the MAP sensor with the engine running I have 1.49 Volts the haynes manual says it sould be 2 volts and I found another reference for 1.5 volts .I have over 200,000 miles and I wanted to keep it going to 300,000 but I'm not going to keep throwing money at this issue.