• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Found my "no bus" ,still crank and no start

well you've either got a short in the 5v bus that's putting the PCM into protect mode, or the PCM be going bad.

PCM shutting off is definitely your no bus issue if you've not got 5v at the CPS.
 
87manche said:
well you've either got a short in the 5v bus that's putting the PCM into protect mode, or the PCM be going bad.

PCM shutting off is definitely your no bus issue if you've not got 5v at the CPS.
Click to expand...
I can agree with that. :) its honestly a lot of me not knowing what I don't know, ya know? Ill let everyone know what gets discovered tomorrow. ..hopefully.
 
Sometimes it pays to pay. So the electrical super guru came by Wednesday and spent several hours going through the heep. Almost 50 years of experience and some cool tricks and tools and he eventually came to the decision that the coil pack was bad. He tested it several ways and said by everything he knows it SHOULD be working but wasnt. So I sent a buddy for a late evening run to the store for one while we continued checking stuff. Put the new one in and blamO. It has fire. Timing was super off so it wouldn't actually run but It finally has life.
After work yesterday I went and started from scratch. Set It to tdc and verified by pulling the valve cover and checking the rockers so I KNEW I was at tdc on compression. Managed to give myself a heart attack by dropping a valve cover bolt down the oil pump drive hole and into the oil pan. :eek:
After much cursing and freaking out I grabbed my magnet on a stick and was able to fish it out. Phew!
So after putting everything back together (again!) I dropped in the oil pump/cam sensor assembly. Everything I've read states that at tdc you have to align the sensor by using a toothpick type device (I used a straw off a can of brake cleaner) which goes through corosponding holes. Ok, that was easy enough as I've done it about 2 dozen time so far to this motor...
Turn the key and blurp! Still way out of time. Wtf!?!
Now granted the Internet is ALWAYS to be taken with a massive dose of salt but I was stumped. Great Google states this is how it's done. It also says that unlike a real distributor, the cps doesn't really work the same and adjusting it with the clamp loosened does nothing.
Well... maybe, maybe not. But all I know is in frustration I started playing with it, intentionally misaligning the holes and what do you know...
VAAAAROOOOM!!!

I can't express how excited and relieved I am! This has been such a butt kicker that I was beginning to think I really should through gas on it and walk away.

Now, it wouldn't be a jeep if it didn't keep some challenges to drive me at least a little nuts. It doesn't run "right". It idles great though maybe a fuzz to high, but it idles. The problem comes when you give it fuel. Crack the throttle body and it stumbles and misses. Go way wide on it and it roars like it should (kinda) but when I let off it coughs then dies.
I am guessing the two major causes are the computer trying to relearn a base line. It has been cleared and sat with no battery a long (months) time.
The other thing is likely gas. There was about 1/8-1/4 tank which has been in it for over a year. I added some acetone and 5 gallons of fresh, hi test and I'm smelling less of that old gas smell. I think it will work through that issue well enough.
Not seeing any leaks from the motor which makes me very happy. I did see a drop of either trans or P/s fluid which I'll need to track down. Not a gush but I hate leaks.
I'm hoping today after work I can get in some more time with it. So ready to be back in a jeep!
Thanks for all that offered advice and ideas...not to mention encouragement! Thanks a bunch!!
 
Good start!
Sounds like you're doing the cam sensor backwards. The pin is placed in the hole before you stab it. The connector should face rearward and its centerline should end up essentially parallel with the block
 
Digger87xj said:
Good start!
Sounds like you're doing the cam sensor backwards. The pin is placed in the hole before you stab it. The connector should face rearward and its centerline should end up essentially parallel with the block
Click to expand...
I hear ya but can't for the life of me figure out how I'm doing it wrong.?? I've probably done it 20 times since this all began and followed this proceedure:
Set #1to TDC on compression stroke.
Align timing marks by rotating harmonic balancer clockwise (direction of run) and set to 0 degrees.
Use screwdriver to rotate oil drive to 11 o'clock position.
Insert straw from spray cleaner (perfect size) into hole on oil drive housing and into corosponding hole in cam sensor rotating thingy.
Drop drive assembly into block and allow it to rotate clockwise as it meshes with cam gear. Only once have I been able to get it to point directly to the rear, parallel to the block. And that went from an able to idle motor to no start/misfire again.
Pulled it all apart and reset tdc etc all over again, dropped in the drive again and this time it's about at 10 30-almost 11 o'clock, nearly touching the block. Turn key and it fires right up. Idles smooth. But crack the throttle and it sputters like out of time and generally sounds odd.
I'm stumped. Seems like if those holes are not aligned then my motor idles fine. If I follow the procedure to align them I get nothing. Anyone have a lot of experience with this that wants to come tell me what I'm doing wrong?? Help. ;)
 
alignment of the holes is for initial setting. Once in correctly, a 'set sync' function is performed with the scan tool to sync the cam and crank sensors. This is done by watching the sync PID and turning the oil pump drive housing so the sync reads 0*. +/- 1* at about 2000 to 2500 rpm.
The only reason that the cam sensor/ oil pump drive housing isn't settling in correctly is if the mechanical timing of the crank and cam are off.
 
And it would idle just fine if it was off?
I've tried hooking the shop scanner (snap on solus) to the obd port but it doesn't communicate. The scan tool is a pos that does that with a lot of vehicles. Maybe I need to find one that works and do the sync you mentioned? That's above my level. :(
 
Digger87xj said:
A tooth off on the crank is 1/2 tooth on the cam .. Yes it would idle just fine.
Click to expand...
Fml... I swear when I set it it was dead to nuts. I'll try the scan tool thing once I find a good one. I've never done that sync so maybe (crosses fingers) that's the issue. I really, REALLY don't want to pull the front of the motor apart AGAIN! :(
 
Still haven't found a good scan tool and the jeep is still having issues. Starts and idles just fine. As it warms up and reaches around 190-210 (closed loop?) It has a few idle burps and then stalls. Restarts easily and idles fine for a few until it burps and dies.
If, at any point, you get in the throttle it is R O U G H!.Stumbles and shakes like it's misfiring or way out of time.
Anyone with any ideas (or great skill and in the N Virginia area) I'd greatly appreciate some help.
 
Interesting. Guru hooked up the scan tool and everything checks out fine. He said it sure sounds/acts like the exhaust is clogged. Put a vacuum gage on it and as soon as we cracked the throttle the needle dives. He says clogged exhaust can cause that.
Now the cat and muffler are brand new. Spun hi flow and a single chamber Flowmaster knock off. For kicks I disconnected everything from the collector and nothing changed.
Sooo....
That leaves the possibility of a/both precats being bad? They are not new and while they worked before the swap... who knows?
So how does one check the precats? How do I replace them?
 
Yup. Everything reads good to go, no codes thrown either. Gonna try and fnagle the precats out tomorrow and see what I see. Stupid things... always what I haven't replaced. Haha
 
Maybe in post 43 timing was so off that when it fired, unburnt gas was in the exhaust and melted the precats, but I still think it's something else.
 
gradon said:
Maybe in post 43 timing was so off that when it fired, unburnt gas was in the exhaust and melted the precats, but I still think it's something else.
Click to expand...
That's possible even though I did pull the plugs and let it vent the gas when I got the new coil rail.
My main guess is those are probably the original precats. Working in a military auto craft shop means your stuff is often "bothered" by folks when you're not there to keep an eye on it. It wouldn't surprise me if at some point some klutz knocked the exhaust manifold on the ground and I never noticed. I'll get em pulled tomorrow and give em a look and shake. I know the rear cat I replaced was pretty heavy and looked to be the original. I'll know more tomorrow and will post up what I find.
On a related note... is there anything special about the precats? Where can I find replacement ones without breaking the bank? I got the rear one from performance curve but I don't see any specific precats on their site...
Thoughts?
 
You must log in or register to reply here.

Similar threads

D
1996 4.0 No Crank, Starter Works When Jumped
2
Replies
24
Views
399
Saudade
Saudade
S
No Start No Bus
Replies
16
Views
3K
Rob Mayercik
R
S
another No Bus and faulty instrument cluster thread...
Replies
0
Views
42
stuckinthemidwest
S
jeeperguy21
I can't believe my battery still works
Replies
4
Views
146
Phil
Phil
Ecomike
87 Renix XJ No fuel, No brake lights, cranks fine
2
Replies
27
Views
897
Anak
Anak
Back
Top