1985xjlaredo

I have an 88 XJ Chief. 4.0 5 speed. The other night coming home it started to lose power and surge and miss I made it too the drive way then shut it off. How it will not start. I have spark it is blue and strong. I can start it on starting fluid, and I dont smell fuel in the cylinders while Im cranking. The plugs dont get wet either. I don't think that all six of the injectors could have gone bad at the same time. So what sensor could be bad that wouldn't tell the ECM to fire the injectors?

Abovetimberline

Is the fuel pump working?do you have fuel at the rail? What causes injectors not to open is the cps,but you have spark so it would be the pcm.

jeepjeep90

i have been having the same issue with my renix 4.0 and alot of people have give sooo much help so i will pass it along check to see if you have pressure at the rail when the key is in the on position but not running if you dont check to see if the fuel pump turns on and for how long normal is around 4 seconds change your fuel filter there is two on on the pump one by the passeger frame rail by the tank check vacuum to your FPR

1985xjlaredo

ok good pressure at the rail with the key on. I can hear the pump turn on when I turn the key. I have good vacuum at the regulator. You said that the "cps" would cause the injectors not to open. Are you talking about the camshaft position sensor in the distributor?

jd4x426

the cps is the crank position sensor its on the bellhousing and this is a very common problem with these xjs do a search and you will find hundreds of threads on it first try disconnectiong and cleaning the terminals

XJ Stryker

OMG use Punctuation dude.

1985xjlaredo

I thought that the crank sensor controlled spark? I have had one go out before and I had no spark.

jeepjeep90

WOW, i didn't realize punctuation was a rule in a forum. I'm here trying to help and your going to pick on me because i didn't use punctuation. Really?

1985xjlaredo

So would the camshaft position sensor going out cause the injectors to not fire? And when the crank sensor goes out you have no spark, right?

1985xjlaredo

Anyone?

JeepCoMJ

if it's injectors won't open...then your jeep isn't aroused enough to fire it's cylinders.

jeepsterokc

i had the same issue on my 87 cherokee. and i tried the cps and replacing the pump and filter. ended up needing a new computer. apparently the computer tells the injectors when to open. but i messed with some terminal wires earlier because they were loose. and i think i friend my computer because theyre not firing again now

jeepsterokc

im telling you dude. go to a junk yard. and get another computer. mine sits right under the lowest part of my dash on the drivers side far right. a giant grey box with two plugs. or if you have a buddy with another jeep the around the same year. swap em out. i guarentee thats your issue

944.0

Do you people not look at dates?

Hunter Bostic

I got a 1988 jeep xj 4.0 motor 5 speed. I went to go riding Saturday morning and it fired right up but died after about 5 seconds. Fuel pump aint coming on and the injectors are not getting fire to any of them. I am getting fire to the plugs. I know this is from like 2009 or so but i could really use the help! Thanks!