88' 4.0 cherokee timing ?
01-21-2012, 08:03 PM
#1
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88' 4.0 cherokee timing ?
okay...the notch on the damperner is pointing at zero, i made a mark on the distributor housing on #1.. but the rotor is pointing past the mark on the dist. housing.
currently the engine is turning over with spark and fuel but no fire..has it jumped time and can it be adjusted? or is time to replace the chain.
regards,
Brian
currently the engine is turning over with spark and fuel but no fire..has it jumped time and can it be adjusted? or is time to replace the chain.
regards,
Brian
01-22-2012, 12:23 AM
#3
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Year: 90,84
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Engine: 4.0,2.5
I haven't had mine out in years, been looking here allot though. I think the trailing edge of the rotor should be lined up with the center of #1. (there at 5:00), facing in from the side. It's a little ahead so when the ecm advances the timing it's still "in the hood". That"s why the dizzy is held with a pin, it has a sensor that tells the ecm weather say, #1 or #6 is coming up to fire, and that's all. Do you have a digital meter? The $5 one from harbor freight actually does work! You really need to talk with Cruiser. Have you had the dist out? Every diagram I've seen seems to be wrong..... Oh, and freedgr is a veritable wizard as well!
Last edited by DFlintstone; 01-22-2012 at 12:26 AM.
01-22-2012, 07:17 AM
#4
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
The rotor is supposed to be .020" past the cap terminal at #1 TDC. So you're probably fine. If the dizzy's never been out that you know of, I would be looking somewhere else.
How good is the spark? Is it blue and snapping or orange and lazy?
Ever done this? Takes 5 minutes and very well could be your problem. It would be nice to eliminate this as a possibility.
Renix Jeep ICU/Coil contact refreshing
The contacts between the coil and the ICU on your Renix Jeep can become corroded and loose causing a complete or intermittent no-start condition. I recommend the following procedure as a maintenance precaution to insure this is eliminated as a possible cause now and in the future.
The coil is attached to the ICU by two T20 Torx bolts. Remove these two bolts and lift the coil up off the ICU. You will see 2 pins and 2 sets of contacts. Clean both the pins and springy contact pieces with a good electronics cleaner.
Squeeze the springy contacts closer together with some needlenose pliers. Apply some dielectric grease to the contacts and bolt the coil back on to the ICU.
While you’re right there unplug the connectors from the ICU and inspect the pins in the harness connector. Make sure the pins are not retracted into the connector. Spray out the connector and the receptacle of the ICU with the same good electronics cleaner you used earlier. Apply dielectric grease to the connectors and plug them back in.
I feel this procedure should be performed at least once in the lifetime of a Renix Jeep.
Revised 11-29-2011
How good is the spark? Is it blue and snapping or orange and lazy?
Ever done this? Takes 5 minutes and very well could be your problem. It would be nice to eliminate this as a possibility.
Renix Jeep ICU/Coil contact refreshing
The contacts between the coil and the ICU on your Renix Jeep can become corroded and loose causing a complete or intermittent no-start condition. I recommend the following procedure as a maintenance precaution to insure this is eliminated as a possible cause now and in the future.
The coil is attached to the ICU by two T20 Torx bolts. Remove these two bolts and lift the coil up off the ICU. You will see 2 pins and 2 sets of contacts. Clean both the pins and springy contact pieces with a good electronics cleaner.
Squeeze the springy contacts closer together with some needlenose pliers. Apply some dielectric grease to the contacts and bolt the coil back on to the ICU.
While you’re right there unplug the connectors from the ICU and inspect the pins in the harness connector. Make sure the pins are not retracted into the connector. Spray out the connector and the receptacle of the ICU with the same good electronics cleaner you used earlier. Apply dielectric grease to the connectors and plug them back in.
I feel this procedure should be performed at least once in the lifetime of a Renix Jeep.
Revised 11-29-2011
01-22-2012, 10:05 AM
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the dist was replaced about 5 yrs ago...the spark seems a little lazy, matter of fact it got me in the hand when i was doin the spark test when i initially broke down and it wasn't the type that shoots to your elbow. when i got it in the shop at home the spark is not a blue, heck i just went through one of the kids dirtbike that wouldn't fire and that spark is a big crackin blue now.
i haven't checked injector pulse yet
i haven't checked injector pulse yet
01-22-2012, 10:19 AM
#6
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
the dist was replaced about 5 yrs ago...the spark seems a little lazy, matter of fact it got me in the hand when i was doin the spark test when i initially broke down and it wasn't the type that shoots to your elbow. when i got it in the shop at home the spark is not a blue, heck i just went through one of the kids dirtbike that wouldn't fire and that spark is a big crackin blue now.
i haven't checked injector pulse yet
i haven't checked injector pulse yet
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01-22-2012, 04:47 PM
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okay i cleaned up icu as you suggested..everything looked clean to begin with but i gave it a shot of cleaner and then greased it.
i pulled a plug out and did the spark check.. definately orange and lazy.. not sure where to go from here.
i pulled a plug out and did the spark check.. definately orange and lazy.. not sure where to go from here.
01-22-2012, 08:34 PM
#11
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Year: Several
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Engine: 4.0
Orange, yellow - anything other than crisp blue is defective. That won't affect injectors!
Replace coil wire first - if still orange, replace coil.
Jeep Coils are famous for going bad. Aftermarket coils are worse, get OEM.
Replace coil wire first - if still orange, replace coil.
Jeep Coils are famous for going bad. Aftermarket coils are worse, get OEM.
01-22-2012, 09:07 PM
#12
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Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Courtesy or Cruiser
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 it’s mounting holes with the first drill bit that just won’t fit through the original holes. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.
Revised 11-29-2011
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 it’s mounting holes with the first drill bit that just won’t fit through the original holes. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.
Revised 11-29-2011
01-23-2012, 09:29 AM
#14
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Year: 90,84
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I once pushed the button on my kitchen timer, went out, opened the hood, hooked up my meter, read .3 on the CPS, put things back and came back in. Under 3 minutes. Not saying you don't have not have an issue with the grounds or the coil, but it's nice to actually know. Allot of people go OEM, (or I bought Napa "premium"), because of problems with some others.
Your signal commonly has a problem getting through your C101 connector. So much so that Jeep put out a deal on how to run a separate new wire through the firewall to the ECM.
It might be a good thing to do this, (Below, C/O Cruiser again), if for no other reason to avoid future problems, and it might save you now!
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, and the ECU travel the path through the C101.
The C101 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. Apply a true dielectric grease, not the stuff that came with your brake pads, to the connection and bolt it back together.
Revised 11-29-2011
Your signal commonly has a problem getting through your C101 connector. So much so that Jeep put out a deal on how to run a separate new wire through the firewall to the ECM.
It might be a good thing to do this, (Below, C/O Cruiser again), if for no other reason to avoid future problems, and it might save you now!
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, and the ECU travel the path through the C101.
The C101 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. Apply a true dielectric grease, not the stuff that came with your brake pads, to the connection and bolt it back together.
Revised 11-29-2011
