'98 ZJ 4.0 Cranks but will not start - Lots of parts replaced - Please Help! - Page 2 - JeepForum.com
Reply
 
LinkBack Thread Tools
post #16 of 27 Old 01-07-2017, 12:50 PM Thread Starter
TheGrimJeeper
Registered User
1998 ZJ 
 
Join Date: May 2009
Location: Chicago
Posts: 20
Garage
Quote:
Originally Posted by ZeeJay1997 View Post
it takes two minutes to swap a relay.
Sorry, forgot to mention I did that. There was no difference. I tried swapping it with the horn, the a/c and the wiper relays.

TheGrimJeeper is offline  
Sponsored Links
Advertisement
 
post #17 of 27 Old 01-07-2017, 12:56 PM
ZeeJay1997
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Posts: 9,044
Quote:
Originally Posted by ihbinder View Post
I installed the new NTK 02 sensors. The "older" relays worked for the short time that I ran the engine where they did not work at all when the Bosch 02 sensors were in place.
This tells me that the relay has weak contacts. did you try swapping it with another relay as well?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
ZeeJay1997 is offline  
post #18 of 27 Old 01-07-2017, 01:27 PM Thread Starter
TheGrimJeeper
Registered User
1998 ZJ 
 
Join Date: May 2009
Location: Chicago
Posts: 20
Garage
Video of the problem

Alright, I'm not sure if JF allows for embedded videos but here is the Youtube link of what happens with a full battery charge:

https://youtu.be/bfm4jGRcQPQ

I just shot that maybe 20 minutes ago and the weather was decent enough to where it shouldn't affect anything.
TheGrimJeeper is offline  
 
post #19 of 27 Old 01-07-2017, 02:32 PM
ZeeJay1997
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Posts: 9,044
You've got a lot of variables working against you. As you said, cold weather is not your friend.

It difficult to tell from the video, but here's my theory...

When it fired, it back fired and smoke came out in the engine bay. maybe a sign of a plugged cat. the symptoms you described in your first post are indicative of this condition. But the bad fuel pump would also cause those symptoms.

If it is totally plugged, it cannot create enough vacuum in the intake to fire. The back pressure from the exhaust goes around the valve seats and pressurizes the intake causing the fuel to be pushed around a failing injector oring.

You have a couple of options to explore this theory. You can pull the O2 sensors and try it. The nuclear option is to drill some holes in front of the cat. I dont recommend this unless you can weld.

You really need a compression tester, a vacuum gauge, and a fuel pressure tester right now.

And dont discount the earlier suggestion that the fuel lines may have ice in them. Maybe try some HEET.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
ZeeJay1997 is offline  
post #20 of 27 Old 01-08-2017, 05:20 PM Thread Starter
TheGrimJeeper
Registered User
1998 ZJ 
 
Join Date: May 2009
Location: Chicago
Posts: 20
Garage
Quote:
Originally Posted by ZeeJay1997 View Post
You've got a lot of variables working against you. As you said, cold weather is not your friend.

It difficult to tell from the video, but here's my theory...

When it fired, it back fired and smoke came out in the engine bay. maybe a sign of a plugged cat. the symptoms you described in your first post are indicative of this condition. But the bad fuel pump would also cause those symptoms.

If it is totally plugged, it cannot create enough vacuum in the intake to fire. The back pressure from the exhaust goes around the valve seats and pressurizes the intake causing the fuel to be pushed around a failing injector oring.

You have a couple of options to explore this theory. You can pull the O2 sensors and try it. The nuclear option is to drill some holes in front of the cat. I dont recommend this unless you can weld.

You really need a compression tester, a vacuum gauge, and a fuel pressure tester right now.

And dont discount the earlier suggestion that the fuel lines may have ice in them. Maybe try some HEET.
Well, thank you so much. I appreciate your suggestions a LOT. It's really hard to get anyone to come over to physically LOOK at the car because winters are so crumby here,
Since I consider myself a novice mechanic still....I don't own any of those tools, and I can't weld very well. But I know a few people who do so I will start making some phone calls tomorrow. In the meantime I may try some HEET, but it should be getting significantly warmer in the next couple days.

If the cat is the issue...that was a concern of mine from the beginning but I sort of forgot about it since the thought of it makes my wallet very sad. But after some research I realized I could do this myself and I know a few people that would either be willing to let me borrow a welder or possibly come weld it for me for a small fee. Before I decide to weld it, I may try your hole-drilling suggestion just because it interests me.

If anyone else has any suggestions, feel free to let me know but ZeeJay1997 has brought up some points that address my initial concern, so I will definitely follow their suggestion for now...I'll let you know how the pressure, vacuum and compression testing goes.
TheGrimJeeper is offline  
post #21 of 27 Old 01-08-2017, 08:16 PM
Uniblurb
Web Wheeler
 
Uniblurb's Avatar
2004 WJ 
 
Join Date: Jan 2012
Location: Central
Posts: 10,213
Many parts stores, like Advance & Autozone, have loaner tools like Zee mentioned. Not sure about the Chicago area but they do here. Normally you pay full price, can keep for up to 30 days, then return for a full refund. All 3 of those tools together are probably $100 online but a parts store may charge more.

Good suggestion by Zee in dumping a bottle of "HEET" in the fuel tank. Even if you have ice forming in the line/filter now it will help dissipate the water once it warms up in outside temps. May also melt the ice itself in the lines.

While a little pricey the catalytic converter for your 98 4.0 may be cheaper than you think. While a little louder than OE the Walker 15820 cat is $110 on Rockauto or $117 on Amazon with prime.

http://www.rockauto.com/en/moreinfo....sn=374&jsn=374

RA probably charges $10 for shipping but you can cover part of that cost by entering in discount code 5387936748131651 in the "How did you hear about us?" box at checkout for 5% off.

It's kind of tricky getting the cat out of the middle of the front pipe and muffler, especially with no power tools/grinder. I've done it before with lots of heat from a propane torch but you don't want to destroy/dent the muffler inlet or front pipe outlet. I've used a hacksaw and chisel/hammer but lots of heat and rust cutter. Then you could just clamp in the cat w/o having to use a welder.

It would be much better to do some testing first. At least when it's just cranking over doing nothing shut it off. Then remove the cap on the drivers side fuel rail and push in on the shrader (air type) valve pin with a small screwdriver with a rag over it to see if fuel pressure comes out. Best to wear safety glasses and good luck.

2004 4.7L WJ Limited, 96 4.0 ZJ


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Uniblurb is offline  
post #22 of 27 Old 01-10-2017, 08:22 PM Thread Starter
TheGrimJeeper
Registered User
1998 ZJ 
 
Join Date: May 2009
Location: Chicago
Posts: 20
Garage
Quote:
Originally Posted by Uniblurb View Post
Good suggestion by Zee in dumping a bottle of "HEET" in the fuel tank. Even if you have ice forming in the line/filter now it will help dissipate the water once it warms up in outside temps. May also melt the ice itself in the lines.
I tried this....It got up to almost 40 degrees today so I figured it would be a good day. No start still...although it does try a lot hard TO start.

Quote:
Originally Posted by Uniblurb View Post
It's kind of tricky getting the cat out of the middle of the front pipe and muffler, especially with no power tools/grinder. I've done it before with lots of heat from a propane torch but you don't want to destroy/dent the muffler inlet or front pipe outlet. I've used a hacksaw and chisel/hammer but lots of heat and rust cutter. Then you could just clamp in the cat w/o having to use a welder.
This is actually a really good idea, thank you. I will do this at LEAST until I can get to my welder, even.

Quote:
Originally Posted by Uniblurb View Post
It would be much better to do some testing first. At least when it's just cranking over doing nothing shut it off. Then remove the cap on the drivers side fuel rail and push in on the shrader (air type) valve pin with a small screwdriver with a rag over it to see if fuel pressure comes out. Best to wear safety glasses and good luck.
I have someone bringing a guage over this weekend but I have pressed on the fuel pressure valve with a screwdriver and it HAS pressure when primed...Fuel sprays out pretty far, for about a half-second.
TheGrimJeeper is offline  
post #23 of 27 Old 01-10-2017, 10:23 PM
trol1374
Registered User
1995 ZJ 
 
Join Date: Dec 2016
Location: San Antonio
Posts: 62
Sounds like what my 95 limited did. First the starts were difficult. Then sluggish. Changed fuel filter, helped some. Changed TPS, IAC, still no. Then it was harder and harder to start of that first start when it got cold. I changed the PCM and all the problems went away. So did you check your ECM? Or try finding one at junk yard.
trol1374 is offline  
post #24 of 27 Old 01-10-2017, 11:43 PM
ZJ35
Registered User
 
Join Date: Jan 2016
Location: SFV
Posts: 94
i replaced the capacitors in the PCM and mine started right up… not sure if this was discussed already.
ZJ35 is offline  
post #25 of 27 Old 01-15-2017, 02:56 PM Thread Starter
TheGrimJeeper
Registered User
1998 ZJ 
 
Join Date: May 2009
Location: Chicago
Posts: 20
Garage
It's allliiiivvveeeee!!!

Holy hell....Today was nice so I decided to take my o2 sensors out and try and start it.
The front sensor came off very easily with an adjustable wrench and the rear sensor needed a little Blaster fluid (similar to WD-40) but wasn't too big of an issue.
It started right up! It's just very loud and I don't have much room to move, but it seemed as if none of my gears were working, which is odd. I've never had a problem with my transmission. So I'll have to go back and check everything...check my relays and such...But I am BEYOND excited right now...
I want to thank everyone for easing my Jeep stress...
Next step: New Cat....I have a friend who will weld one on for me...I just have to buy it.
I will update with any new developments.
TheGrimJeeper is offline  
post #26 of 27 Old 01-15-2017, 03:00 PM Thread Starter
TheGrimJeeper
Registered User
1998 ZJ 
 
Join Date: May 2009
Location: Chicago
Posts: 20
Garage
Quote:
Originally Posted by trol1374 View Post
Sounds like what my 95 limited did. First the starts were difficult. Then sluggish. Changed fuel filter, helped some. Changed TPS, IAC, still no. Then it was harder and harder to start of that first start when it got cold. I changed the PCM and all the problems went away. So did you check your ECM? Or try finding one at junk yard.
Would a diagnostics computer tell me if the ECM is bad? I'm asking for future reference because I've tested it with two different units and haven't gotten codes for that.
TheGrimJeeper is offline  
post #27 of 27 Old 01-15-2017, 05:51 PM
ZeeJay1997
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Posts: 9,044
When you disconnect the battery the cat monitor goes to not ready state and will not turn on the CEL. And it will not set a cat code unless it's been through the drive cycle that sets the monitor to ready.

And you may need to replace those O2 sensors since you didn't get a code when it was running.

About the transmission, be sure the connector on the top on the transmission is seated good and swap the transmission relay with a known good relay.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
ZeeJay1997 is offline  
Reply

Tags
cps , fuel pump , iac , tps

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome