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A few questions, and one problem.

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Old 08-15-2012 | 01:12 AM
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matt0106's Avatar
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From: Little Elm, TX
Year: 1987
Model: Cherokee
Engine: Inline 6 cylinder
Question A few questions, and one problem.

The problem is my 87' Cherokee Laredo takes forever to start. It cranks like 6 times, every single time I start it up. It cranks, starts, then runs perfectly fine. I already replaced the CPS, but that didn't help. It still cranks more than it should. I searched the forums and found someone that has a similar problem, in that thread someone said to "refresh connections before replacing parts." Should I check all the grounds like he said?

The questions are:
1) should the gap between my bumper and grille be .4 of an inch?
2) the 4WD indicator light doesn't come on, is there a specific reason?
3) is it safe to drive my jeep with the "inspection plate" off of the bell housing?
Old 08-15-2012 | 01:33 AM
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Aimless Rambler's Avatar
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From: Northern Utah
Year: 1992
Model: Cherokee
Engine: 4.0
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Originally Posted by matt0106
The problem is my 87' Cherokee Laredo takes forever to start. It cranks like 6 times, every single time I start it up. It cranks, starts, then runs perfectly fine. I already replaced the CPS, but that didn't help. It still cranks more than it should. I searched the forums and found someone that has a similar problem, in that thread someone said to "refresh connections before replacing parts." Should I check all the grounds like he said?

The questions are:
1) should the gap between my bumper and grille be .4 of an inch?
2) the 4WD indicator light doesn't come on, is there a specific reason?
3) is it safe to drive my jeep with the "inspection plate" off of the bell housing?
Forgive me if this sounds silly but bare with me.

6 times? Do you mean 6 revolutions before the engine starts? Or 6 times trying ... such as ... stick key in, turn it and you get ... grr rrr rrr rrr rrr rrrr (sound effects) ... nothing 5 times until the 6th try? Why I ask ... I've owned my Cherokee 2 years and it has always taken about 6 - 10 revolutions before it cranks. Someone once mentioned the battery amperage but it hasn't really concerned me too much.

As for the other questions
1) Sounds reasonable probably depends on use and if it's stock or after market bumper.
2) Light don't work haha ... if it physically goes into 4WD could be light or connection.
3) Probably not a good idea ... dirt, water, dead critter parts ... get inside.

I'm sure others will be more helpful ... but I doubt they're awake right now. Ha. Good luck with everything.
Old 08-15-2012 | 01:33 AM
  #3  
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From: Santa Rosa, California
Year: 1987 Comanche,1990
Model: Cherokee
Engine: 4.0L Renix
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I might be able to answer the long start up. Usually the renix era jeeps take longer to start. To start try doing some ground refreshing. Then if that fails it might be your fuel pump.
Old 08-15-2012 | 02:02 AM
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Mine takes a while as well.

Hold the key down till she purrs. Once it is on it has no problems.
Old 08-15-2012 | 02:11 AM
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From: Santa Rosa, California
Year: 1987 Comanche,1990
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Engine: 4.0L Renix
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Originally Posted by 90CherokeeLaredo
Mine takes a while as well.

Hold the key down till she purrs. Once it is on it has no problems.
Think he wants to save his starter, but yes it I too have to hold my key down.
Old 08-15-2012 | 05:30 AM
  #6  
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From: FL
Year: 2001
Model: Cherokee
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Originally Posted by matt0106
The problem is my 87' Cherokee Laredo takes forever to start. It cranks like 6 times, every single time I start it up. It cranks, starts, then runs perfectly fine. I already replaced the CPS, but that didn't help. It still cranks more than it should. I searched the forums and found someone that has a similar problem, in that thread someone said to "refresh connections before replacing parts." Should I check all the grounds like he said?

The questions are:
1) should the gap between my bumper and grille be .4 of an inch?
2) the 4WD indicator light doesn't come on, is there a specific reason?
3) is it safe to drive my jeep with the "inspection plate" off of the bell housing?
1.Bumpers are not adjusted well on brand new Cherokees
2.Transfer case switch is most likely problem, I just replaced mine.
Old 08-15-2012 | 05:47 AM
  #7  
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From: Smiths Station, Al
Year: 87
Model: Wagoneer
Engine: 4.0 I6
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Originally Posted by car5car
1.Bumpers are not adjusted well on brand new Cherokees
.
How did u get a brand new cherokee to see this.

Never had bumper issues on my 87. Till i was coming off a ledge and beat on the rear now it dont sit good.
Old 08-15-2012 | 07:06 AM
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Year: 1990
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Engine: 4.0
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Start with this:

Renix Ground Refreshing
The Renix era XJs and MJs were built with an under-engineered grounding system for the engine/transmission electronics. One problem in particular involves the multiple ground connection at the engine dipstick tube stud. A poor ground here can cause a multitude of driveabililty issues, wasted time, and wasted money replacing unnecessary components.
The components grounding at the dipstick tube stud are:
Distributor Sync Sensor, TCU main ground, TCU "Shift Point Logic", Ignition control Module, Injectors, ECU main ground which other engine sensors ground through, Oxygen sensor, Knock Sensor, Cruise Control, and Transmission Sync signal. All extremely important stuff.
The factory was aware of the issues with this ground point and addressed it by suggesting the following:
Remove the nut holding the wire terminals to the stud. Verify that the stud is indeed tightened securely into the block. Scrape any and all paint from the stud’s mounting surface where the wires will attach. Must be clean, shiny and free of any oil, grease, or paint.
Inspect the wire terminals. Check to see that none of the terminals are crimped over wire insulation instead of bare wire. Be sure the crimps are tight. It wouldn’t hurt to re-crimp them just as a matter of course. Sand and polish the wire terminals until clean and shiny on both sides. Reinstall all the wires to the stud and tighten the nut down securely.
While you’re in that general area, locate the battery negative cable which is fastened to the engine block just forward of the dipstick stud. Remove the bolt, scrape the block to bare metal, clean and polish the cable terminal, and reattach securely.
Another area where the grounding system on Renix era Jeeps was lacking is the engine to chassis ground. There is a braided cable from the back of the cylinder head that also attaches to the driver’s side of the firewall. This cable is undersized for it’s intended use and subject to corrosion and poor connections at each end.
First off, remove the cable end from the firewall using a 15mm wrench or socket. Scrape the paint off down to bare metal and clean the wire terminal. Reattach securely.
Remove the other end of the cable from the rear of the head using a 3’4" socket. Clean all the oil, paint and crud from the stud. Clean the wire terminal of the cable and reattach securely.
A suggestion regarding the braided cable:
I prefer to add a #4 Gauge cable from the firewall to a bolt on the rear of the intake manifold, either to a heat shield bolt or fuel rail bolt. A cable about 18" long with a 3/8" lug on each end works great and you can get one at any parts store already made up. Napa has them as part number 781116.
A further improvement to the grounding system can be made using a #4 cable, about 10" long with 3/8" terminals at each end. Attach one end of this cable to the negative battery bolt and the other end under the closest 10mm headed bolt on the radiator support just forward of the battery. Napa part number 781115.
 
 
If you want to upgrade your grounds and battery cables in general, contact Jon at
www.kelleyswip.com. He makes an incredible cable upgrade for a very reasonable price.
 
Revised 11-28-2011
Old 08-15-2012 | 07:06 AM
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Then check your CPS output:

Renix CPS Testing and Adjusting
 
 
Renix CPSs have to put out a strong enough signal to the ECU so that it will provide spark.
Most tests for the CPS suggest checking it for an ohms value. This is unreliable and can cause some wasted time and aggravation in your diagnosis of a no-start issue as the CPS will test good when in fact it is bad.
The problem with the ohms test is you can have the correct amount of resistance through the CPS but it isn’t generating enough voltage to trigger the ECU to provide spark.
Unplug the harness connector from the CPS. Using your voltmeter set on AC volts and probing both wires in the connector going to the CPS, crank the engine over. It won’t start with the CPS disconnected.
You should get a reading of .5 AC volts.
If you are down in the .35 AC volts range or lower on your meter reading, you can have intermittent crank/no-start conditions from your Renix Jeep. Some NEW CPSs (from the big box parts stores) have registered only .2 AC volts while reading the proper resistance!! That’s a definite no-start condition. Best to buy your CPS from Napa or the dealer.
Sometimes on a manual transmission equipped Renix Jeep there is an accumulation of debris on the tip of the CPS. It’s worn off clutch material and since the CPS is a magnet, the metal sticks to the tip of the CPS causing a reduced voltage signal. You MAY get by with cleaning the tip of the CPS off.
A little trick for increasing the output of your CPS is to drill out the upper mounting hole, or slot it so the CPS bracket rests on the bell housing when pushed down. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.

 
 
Revised 07-30-2012
Old 08-15-2012 | 07:07 AM
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And do this for sure:

Renix Jeep C101 Connector Refreshing
 
The C101 connector on 1987 and 1988 Renix Jeeps was a source of electrical resistance when the vehicles were new. So much so that the factory eliminated this connector in the 1989 and 1990 models. The factory recommended cleaning this connector to insure the proper voltage and ground signals between the ECU and the fuel injection sensors. We can only imagine how this connector has become a larger source of voltage loss and increased resistance over a period of almost 25 years. The C101 connector needs to be cleaned at least once in the lifetime of your vehicle. Chances are it’s never been done before.

Almost every critical signal between the engine sensors, injectors, ECU, and some to the TCU, travel this path through the C101 connector.
The C101 connector is located on the driver’s side firewall above and behind the brake booster. It is held together with a single bolt in it’s center. To get the connectors apart, simply remove the bolt and pull the halves apart. You will find the connector is packed with a black tar like substance which has hardened over time.
Take a pocket screwdriver or the like and scrape out all the tar crap you can. Follow up by spraying out both connector halves with brake cleaner and then swabbing out the remainder of the tar. Repeat this procedure until the tar is totally removed. This may require 3 or more repetitions. Wipe out the connectors after spraying with a soft cloth.
If you have a small pick or dental tool, tweak the female connectors on the one side so they grab the pins on the opposite side a bit tighter before bolting both halves back together.
 
Revised 07-17-2012
Old 08-15-2012 | 11:53 AM
  #11  
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Year: 1990
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Originally Posted by NorCalJeep
Think he wants to save his starter, but yes it I too have to hold my key down.
I am too lazy to find out how to fix it, as long it starts.

Someday I will fix it.
Old 08-15-2012 | 08:01 PM
  #12  
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From: Little Elm, TX
Year: 1987
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Like six revolutions. I replaced the "old" CPS with one from AutoZone. I guess on my next day off, I'll try all the things Cruiser54 mentioned. But for now, I'll leave it.
Old 08-15-2012 | 08:07 PM
  #13  
matt0106's Avatar
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Year: 1987
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Engine: Inline 6 cylinder
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Originally Posted by NorCalJeep
I might be able to answer the long start up. Usually the renix era jeeps take longer to start. To start try doing some ground refreshing. Then if that fails it might be your fuel pump.
It can't possibly be the fuel pump, it's a whole new assembly.
Old 08-15-2012 | 09:26 PM
  #14  
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Originally Posted by matt0106
Like six revolutions. I replaced the "old" CPS with one from AutoZone. I guess on my next day off, I'll try all the things Cruiser54 mentioned. But for now, I'll leave it.
Excellent plan.
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