Stock Grand Cherokee Tech. All ZJ/WJ/WK Non-modified/stock questions go here! ZJ (93-98), WJ (99-04), WK (05+)
All ZJ/WJ/WK specific tech questions asked here!

Difficulty cold starting V8

Thread Tools
 
Search this Thread
 
Old 12-14-2012, 12:52 PM
  #1  
Junior Member
Thread Starter
 
Artful Owl's Avatar
 
Join Date: Jul 2010
Location: Scotland, Ayrshire coast
Posts: 84
Likes: 0
Received 0 Likes on 0 Posts
Year: 1999
Model: Grand Cherokee
Engine: 4.7 V8
Default Difficulty cold starting V8

My 99 V8 takes a bit of winding before it will start on the recent cold mornings. I fitted a brand new Bosch battery a couple of weeks ago, and had new spark plugs fitted last week.
It seems to be an engine dampness problem as it fires up after I spray the visible electrical terminals with damp start / WD40 type spray

Is this a common problem, is there a fix ?.
Old 12-16-2012, 06:33 PM
  #2  
Former Sponsor
 
go-part's Avatar
 
Join Date: Nov 2012
Posts: 99
Likes: 0
Received 0 Likes on 0 Posts
Model: Cherokee
Default

This is usually caused by a leaking fuel pump check valve or fuel injectors.


The fuel pump contains a check valve so the fuel doesn't drain back after you shut the engine off. When this valve leaks, you will have a long crank time before it starts. Usually if it's the fuel pump check valve it will have a long crank time after sitting overnight.


If it isn't that, then it may be your coolant temp sensor going bad..

http://autorepair.about.com/library/faqs/bl226i.htm
Old 12-16-2012, 06:55 PM
  #3  
Old fart with a wrench
 
dave1123's Avatar
 
Join Date: Nov 2010
Location: Manlius, east of Syracuse, NY
Posts: 14,398
Received 723 Likes on 628 Posts
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
Default

The dampness on the Scotish coast is legendary! It's like living in a swamp! I think you may have to pull and clean ALL your electrical plugs and connectors and apply dielectric grease. DO NOT grease the 02 sensor plug because the signal levels are so low, grease might interfere. I don't know if your overseas model still has spark plug wires or coil packs, but if it has wires, replace them.

You can install an in-line check valve for the fuel system before you drop the tank and replace the pump. If you have an external fuel filter with three hoses, the check valve is in the filter. Your 99 is the change-over year from the ZJ to the WJ and lots of things are different, as well as being an overseas model.
Old 12-19-2012, 12:19 PM
  #4  
Junior Member
Thread Starter
 
Artful Owl's Avatar
 
Join Date: Jul 2010
Location: Scotland, Ayrshire coast
Posts: 84
Likes: 0
Received 0 Likes on 0 Posts
Year: 1999
Model: Grand Cherokee
Engine: 4.7 V8
Default

Cheers guys the problem seems to be the terrible dampness we have here as it starts okay on dry mornings, a spray of damp start or WD40 type spray helps. I've never heard of the grease but I will remove the contacts and spray them with electric contact cleaner at the weekend.

The coils over the plugs are another possible source, I've owned several Jaguars fitted with the dammed things and they always caused problems
Old 12-20-2012, 07:11 AM
  #5  
Old fart with a wrench
 
dave1123's Avatar
 
Join Date: Nov 2010
Location: Manlius, east of Syracuse, NY
Posts: 14,398
Received 723 Likes on 628 Posts
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
Default

The grease will help especialy where the coils fit over the plugs. Your high voltage may be shorting over.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
rc3797
Jeep Builds
3
05-06-2016 08:53 PM
DWStiles
Modified XJ Cherokee Tech
25
10-02-2015 01:15 PM
Rotorhead
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
10
08-31-2015 12:41 PM
Jethro4days
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
18
08-25-2015 08:42 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 


Quick Reply: Difficulty cold starting V8



All times are GMT -5. The time now is 06:28 PM.