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Unread 11-03-2013, 02:36 PM   #31
ZeeJay1997
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Quote:
Originally Posted by xrunndonex View Post
I stole the idea from another thread about a similar problem lol
Ratmonkey advised taping on gauges regularly. I taped a vacuum gauge to my windshield to help diagnose a clogged cat.

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Unread 11-03-2013, 02:38 PM   #32
coralman
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Sorry for the devilery Joe, we get bored sometimes.
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Unread 11-03-2013, 02:48 PM   #33
JoeZedJ
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Haha no big, actually kind of entertaining.

So yea I am going to start looking at the PCM. I just read a couple posts about the solder joints going bad, plus the 12 steps deal showing the use of a couple zip ties. I gots me plenty of zip ties so I'll start by zipping that bugger up. I have a good pick-a-part by me so hopefully I'll be able to snag a PCM or at least one I can monkey with before I destroy my own. Also going to snag a few injectors if I can. I am handy with the soldering iron (did some electronics works while i was in the military).

...beer thirty.

Thanks again, I'll post back up tomorrow and let you all know whats what.

joe
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Unread 11-03-2013, 09:31 PM   #34
Oldfrog
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After seeing that video, I can tell you that my gauge does that too and I spent $60+ on it brand new. I dont think you have a fuel delivery problem. I think you have an electrical problem.

You said the grounds are all clean and tight. If you've had some electronic training, then you already know that merely looking at the connections wont tell you if they are good....especially when they are on the side of the engine block with the constant heating and cooling of the connection. If you havent yet removed the grounds and made them sparkle, I suggest you do so, if for no other reason, just to eliminate that as a cause.

Does it stall, misfire or hesitate mainly after the engine temp warms up a bit? Does it do it when it's stone cold ?

In one post, you mentioned keeping it running via the throttle...or something like that as I recall. As in... giving it gas made it stall or kept it running?

Then you recently mentioned Zeejay's 12 step list . Are you saying that you havent gone through the list, step by step, yet?

Have you wiggled the PCM connectors while it's running?
( zip ties are only a bandaid, btw...and junkyard PCMs are hit or miss...providing you get the right one in the first place. But feel free to waste more time and money.)

How about checking the voltage across the outer pins if the TPS connector next time it dies while leaving the key on and the connector unplugged. Tell us what the voltage is. It needs to be +5VDC. That 5 volt supply voltage is constant throughout several sensors...including the CPS.

Go through Zeejay's list and find some joy.
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Unread 11-04-2013, 03:17 AM   #35
Uniblurb
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Ahh, here it is in the middle of night, can't sleep thinking of those 2 little 11mm bolts, so you know what that means? Lol, and glad some of you enjoyed the subliminal message.

The only reason I brought testing the new crank sensor back up is I remember helping some gal on here. She was so adamant about getting a CKP which showed absolutely no resistance she took her meter to the dealer. Ended up bench-testing 4-5 of them right on their parts counter before she finally found/bought one which was perfectly clear. Just a thought and some good info Oldfrog about testing voltage to all the sensors.

As I've posted many times before bad grounds, particularly the PCM ground on one of the coil studs, took out my PCM along with the crank sensor. Vicious circle when the PCM grounds all the sensors. Not until these grounds were clean did I stop going through 3 PCM's and 4-5 crank sensors. Thanks to Zee for helping me through this!

Noticed in your fuel test video Joe you have a fairly loud exhaust. Is your cat fairly new and you don't happen to have the infamous cracked manifold/header where the tubes are welded together at the bottom do you? Our 4.0's are notorious for this and many of us have had to replace the header. This can cause a rich fuel mixture clogging the cat which some of us have found out.

Yeah, I'd like to see your fuel test under a load. When the pump starts going out they can give some quirky symptoms. On mine the engine seemed to hesitate/almost stall when making left turns after warm-up and go figure.

You'll eventually get through this and good luck!

BTW, if you do try to use zip-ties to lock-in the connectors on the PCM I found the 1/4" ones work just fine when doubled-up and fit in the connector slots perfect. Saw where you already have some and here's a photo of mine. Only found out later you shouldn't do this on a new reman unit and meant for one with the bad solder joints. Just a temp fix, wiggle the connectors first, if that's your problem.
jeep-pcm-resized-down-wire-ties-new-one-3-16-2012.jpg

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-Stalling ZJ? 12 things to check before replacing a sensor; the Dirty Dozen
-Crankshaft position sensor multimeter test. & video of testing.
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Unread 11-04-2013, 04:06 AM   #36
coralman
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I'm not an electrical whiz by any means but I have often wondered but never really explored the idea of moving the grounds closer to the pcm with larger gauge wire. Or leave them where they are at and use larger wire. Just a thought.
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Unread 11-04-2013, 04:22 AM   #37
Uniblurb
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To me you can never have enough engine grounds. I ran an extra one from either a coil stud or the dip stick bracket to the firewall. Also ran a larger one from the front coil stud to the bottom of the alternator stud. This one was mainly because when I removed the alternator bracket from the block I couldn't believe the coating/glaze on the aluminum which doesn't like steel/iron.

Have read where the PCM metal case is not supposed to be grounded. I've removed my multiple PCM's so many times I try to keep an eye on the bottom right nylon insert in the firewall since it's really starting to collapse with the bolt/screw/case close to the metal. Not sure how much of a problem it would cause if touching metal or not?
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-Stalling ZJ? 12 things to check before replacing a sensor; the Dirty Dozen
-Crankshaft position sensor multimeter test. & video of testing.
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Unread 11-04-2013, 05:24 AM   #38
ZeeJay1997
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Anytime i have a persistent driveability problem, step 1 is to wiggle the PCM connectors. I dont clean the connectors right away because I dont want to wear the sockets out. By persistent, I mean something the standard tune up, TB, cable and ground cleaning will not heal.

In regards to the dirty dozen, I have noticed very few posters that actually do these things. It's always "I read the 12 things" because by the time they get to the point of asking for help, they're already suffering from post gremlin stress disorder. Then when they do post, a drive-by sensor changer tosses them a bad idea to further feed the beast.

OP, if the fuel pressure load check is good, keep pecking away at the dirty dozen. It may not fix anything, but you've eliminated some things as a cause, and when you do hit the jackpot, the Jeep will run sweet.
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Unread 11-04-2013, 05:26 AM   #39
ZeeJay1997
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Quote:
Originally Posted by coralman View Post
I'm not an electrical whiz by any means but I have often wondered but never really explored the idea of moving the grounds closer to the pcm with larger gauge wire. Or leave them where they are at and use larger wire. Just a thought.
All I can figure is that the engineers decided that the coil and the PCM need to be at the same potential.
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Unread 11-07-2013, 10:16 AM   #40
Uniblurb
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I didn't like the fact that on the link I posted earlier for the "New Bosch 67646 Fuel Pump Module for Jeep Vehicles 1996" from e-herko there wasn't a photo of the module in the ad and stated "NOT FOR 4WD VEHICLES" in the specs which is wrong.

So I contacted e-herko CS through email and after about 4 back/forth responses they finally have a photo of the pump module while correcting the text in their ad. Even had them spell "Vehicles" correctly instead of "Vehilces". LOL.

http://www.ebay.com/itm/160700802361...S:1123&vxp=mtr

At least they didn't change the price which is still $90 w/free shipping. Don't know what's going on with Amazon and when I posted this link earlier this same pump module was $150, went up to $175, and now it's $240 which is close to what I paid for it a year ago from them ($228). It's only $395 at Advance and throw your discount code at that price!
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-Stalling ZJ? 12 things to check before replacing a sensor; the Dirty Dozen
-Crankshaft position sensor multimeter test. & video of testing.
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Unread 11-30-2013, 03:28 PM   #41
JoeZedJ
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Ok guys back at this one...

So here is what I have done thus far. I have tested the TPS pretty thoroughly. That does not seem to be the issue. Voltages increase/decrease as I open the throttle, I even used an analog meter one time to look for weird spikes/losses in voltages, no dice.

I continued to drive my rig as is for a while (its my daily driver anyways...) I got a wild thought about O2 sensors, so i checked those out and I have the 4 wire type. All seem to be functioning just fine.

To add further I did check my grounds and wire brushed them up, even though they didn't really need it. I even went so far as to add a second ground (using ground strap material instead of an thick battery wire) I am a ham nerd too so I am aware of RF signal/grounds. My Jeep is very clean. So I am doubting any issues with my grounds.

HERE IS THE KICKER!

I was sitting on the crapper one day and I happened to be reading my Haynes Manual, I noticed a line in there when it came to the CPS installation "Be sure to install the paper spacer otherwise damage to the sensor could occur". When I installed the MOPAR sensor, there was not a paper spacer on the end of the CPS. I did a little research on this bugger and it sounds like I could have just tossed away 90 bones on this because of a dang piece of cardboard. My question to the 4.0 gods, could that be an issue? What is the purpose of the spacer? I don't remember a spacer or cardboard on the old sensor so is it possible that there is a piece of trash in my bellhousing somewhere? Does the sensor hang out in space by the flex plate or does it actually butt up on something? I am trying to envision what this looks like, so if anyone has a rebuild photo that shows the sensor location minus motor or vise-versa I can better understand whats going on.

My research is going to continue into the whole CPS/PCM reading sequence now.
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Unread 11-30-2013, 04:41 PM   #42
ZeeJay1997
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the tip of the crank sensor should be app. .030 from the outer diameter of the flywheel. the fly wheel has notches in it so the PCM can determine position and rpm of the crank. when the notches pass the tip of the sensor, the magnetic field in the sensor collapses.

the mopar sensor comes with a felt spacer. the idea is to press the tip with spacer into the flywhhel with one finger and tighten the bolt. When the flywheel moves, it throws the spacer off. I found the spacer when i opened the inspection panel on bottom

the top of a cereal box with a little dab of grease on it works good if your sensor doesnt have a spacer.
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Unread 12-01-2013, 10:46 AM   #43
LynF
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I have a 93 ZJ, 5.2 engine Laredo i have been fighting with it to run for a couple weeks now, bought the crank sensor ( havent changed that yet) i had bought it a accel coil thinking the one in it was oem - it was- I had this nagging voice saying to change the coil so i finally did it - no easy feat since i am disabled and cant stand for long- i got it changed anyway and got in and she fired right up and ran 100% better- no skipping, proper idle and more balls than it has had in a long time. the test was this morning when i started it for the first time again she fired right up! everything pointed to the cps, but it was wrong - thankfully this time everything it was doing stopped when i changed the coil. It was assumed the previous owner had tested it and she said she had- or rather her mechanic had-- this was definitely BS as i had found out other things she said had been done and were not completed like he replaced the pads on the front braked ( which should have worked when i got it even thought he rear lines were gone) it had no brakes at all because there was air in them and he hadnt taken the time to bleed them- put in new bleeder screws but didnt bleed it- not a mechanic i would go to. Some things are just common sense ... my first jeep was a 67 wagoneer that my dad had- straight 6 and 3 on the tree... we put a 283 v8 in it with 3/4 cam , holley 4bbl, hi rise manifold... man could she go!!! that was the beginning of my love affair with jeeps- there have been a few since then and now i finally have another. Oh the old owner also did something to the hi/low for the fwd and it is caked in rust and frozen in high and it has hoses off but I cant figure out where they go but that will be a spring project since it is full time 4x anyhow. the registry was fun, they value my jeep at 3800.00 I dont know how anything 20 years old could be valued at that !
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