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What is average idle for 89 4.0L laredo
- Thread starter DenT
- Start date
RaiderXJ
NAXJA Forum User
- Location
- Middletown, PA
I'm not 100% on this, but i think its around 600RPM. Let me guess, you're having a high idle problem?
- Location
- Terra Firma
650 to 800 RPM
martin
NAXJA Forum User
- Location
- Huntsville, AL
When I had my XJ into the dealer to have the throttle body cleaned he went over all the engine sensors to make sure everything was working.
He found I had a high idle, I don't have a tach in my XJ. I read the read out as he adjusted the idle speed. With the XJ in park he set the idle speed to 900 rpm. If you have it in gear then the idle will be something less.
He found I had a high idle, I don't have a tach in my XJ. I read the read out as he adjusted the idle speed. With the XJ in park he set the idle speed to 900 rpm. If you have it in gear then the idle will be something less.
Just as Eagle said........the rpm on the Renix is very unstable,it will fluctuate somewhat around 200 rpm,,,,,,,,Eagle and alot of us old timers know the Renix system,dont hesitate to ask any questions about this system,I have lost alot of my edge on this system since I have mainly been trin to keep up on the newer Chrysler Speed density stuff,OBD and what not..............shoot away........I need to start workin my old school memory on the Renix,I need to get the edge back.................
Rags
Rags
Rags, what tricks
I have the 88' RENIX set up. What are the tricks to get this thing running right. I have had a few problems over the years, seems to be working fine now. But anything will help. Do have a stalling problem on hills, auto. Think it's the fuel pump, replacing this week. Just clean the throttle body, I mean really cleaned it. So some advice would be great.
I have the 88' RENIX set up. What are the tricks to get this thing running right. I have had a few problems over the years, seems to be working fine now. But anything will help. Do have a stalling problem on hills, auto. Think it's the fuel pump, replacing this week. Just clean the throttle body, I mean really cleaned it. So some advice would be great.
RaiderXJ
NAXJA Forum User
- Location
- Middletown, PA
Hey Rags, i got one for ya
This is on a 88 4.0 Auto. Not all the time but sometimes, when I first start it, mainly when the engine is cold, the rpm will jump up to 2000 and slowly rise to almost 3000 before kicking down to normal. One time it was at 3500 and wouldn't come down. Sometimes it doesn't go as high, but it will increase before it goes down. I've cleaned the TB, including the IAC passage, and replaced the IAC motor. One thing I thought it might be was the butterfly valve in the TB. Is it supposed to be totally closed, or a little gap, because mine is gapped a little (IS this just a matter of loosening the 2 set screws on the shaft and adjusting the valve or what?) Thanks for any help u can give.
TIA
RaiderXJ
This is on a 88 4.0 Auto. Not all the time but sometimes, when I first start it, mainly when the engine is cold, the rpm will jump up to 2000 and slowly rise to almost 3000 before kicking down to normal. One time it was at 3500 and wouldn't come down. Sometimes it doesn't go as high, but it will increase before it goes down. I've cleaned the TB, including the IAC passage, and replaced the IAC motor. One thing I thought it might be was the butterfly valve in the TB. Is it supposed to be totally closed, or a little gap, because mine is gapped a little (IS this just a matter of loosening the 2 set screws on the shaft and adjusting the valve or what?) Thanks for any help u can give.
TIA
RaiderXJ
All right here goes...............not in order.off the top of my head
87 to early 88,need to bypass the bulk head connecter for the TPS wires,and wire around this connecter,take that connecter out of the loop,all the TPS wires,for the PCM side and the trans,second.......add ground to TPS ground right at TPS,needs to be 5 ohms or less to ground good,GM weather pack connecters just plain suck,you can get teminal repair kits to freshin these connecters up at the TPs etc.where ever the GM style connectors are used........Third....,need to use a GM style IAC actuation tool to close the IAC motor,unplug the IAC when fully shut,start engine and warm up,set min airflow to around 650 rpm or a tad higher if engine worn,I just bend the stop on the TB instead of trin to adjust the stop screw,also you need to remove the welch plug on the lower half of the TB to gain access to a torx screw that is your secondary idle air bypass,you need to pop out this screw and clean this passage and reinstall screw,make sure the screw is lightly seated all the way before you set min airflow(butterfly adustment),you use this secondary air air bypass screw for fine adjustmant after the base idle is set,next after the min airflow is set and secondary airflow,you need to adjust the TPS to 12%,that is a DRB value.......I have been told you can do this without a DRB buy probing the TPS signal wire for the engine side and sweeping the TPS to full throttle and then back idle and calculate 12% of the min to Max voltage you observed on the DVOM( example idle= 1.00 volt WOT= 5.00 volt difference of 4 volts,so 12% of 4 volts, idle value would be 1.48 of a volt.....jump in someone if my math is screwey .I think you get the idea...........also another tip is to use the CPS patch kit that wires the CPS directly into the PCM,I use these on all the years of renix,also need to set the CPS AC cranking voltage to at least .75 AC volt,if you get up near a volt or over the CPS usally rubs the interupter ring on the flywheel,also you need to sync the dist manually to compensate for Timing chain stretch,...That will be in another post when I get all my facts and memory straight........................hope this helps.............remember.do one thing at a time to observe the changes,not all at once ,if you did one thing wrong,then you will have a reference point to look where you screwed up........A best tool fot he Renix is a DRB 2 and the Renix adaptor harness and super card..........I see these floatin around Ebay once in awhile,and will seriously help get your Renix running its best............also on the idle flash(jump in rpm),the Renix PCM has been updted numerous times to address different issues,all the Mopar PCM remans they offer now are the latest and greatest...........Mopar does offer a hot rod PCM for the Renix(offroad only),and an addition of a High altitude CPS helps also.....................Thier is more.....I will return
Rags
87 to early 88,need to bypass the bulk head connecter for the TPS wires,and wire around this connecter,take that connecter out of the loop,all the TPS wires,for the PCM side and the trans,second.......add ground to TPS ground right at TPS,needs to be 5 ohms or less to ground good,GM weather pack connecters just plain suck,you can get teminal repair kits to freshin these connecters up at the TPs etc.where ever the GM style connectors are used........Third....,need to use a GM style IAC actuation tool to close the IAC motor,unplug the IAC when fully shut,start engine and warm up,set min airflow to around 650 rpm or a tad higher if engine worn,I just bend the stop on the TB instead of trin to adjust the stop screw,also you need to remove the welch plug on the lower half of the TB to gain access to a torx screw that is your secondary idle air bypass,you need to pop out this screw and clean this passage and reinstall screw,make sure the screw is lightly seated all the way before you set min airflow(butterfly adustment),you use this secondary air air bypass screw for fine adjustmant after the base idle is set,next after the min airflow is set and secondary airflow,you need to adjust the TPS to 12%,that is a DRB value.......I have been told you can do this without a DRB buy probing the TPS signal wire for the engine side and sweeping the TPS to full throttle and then back idle and calculate 12% of the min to Max voltage you observed on the DVOM( example idle= 1.00 volt WOT= 5.00 volt difference of 4 volts,so 12% of 4 volts, idle value would be 1.48 of a volt.....jump in someone if my math is screwey
.I think you get the idea...........also another tip is to use the CPS patch kit that wires the CPS directly into the PCM,I use these on all the years of renix,also need to set the CPS AC cranking voltage to at least .75 AC volt,if you get up near a volt or over the CPS usally rubs the interupter ring on the flywheel,also you need to sync the dist manually to compensate for Timing chain stretch,...That will be in another post when I get all my facts and memory straight........................hope this helps.............remember.do one thing at a time to observe the changes,not all at once ,if you did one thing wrong,then you will have a reference point to look where you screwed up........A best tool fot he Renix is a DRB 2 and the Renix adaptor harness and super card..........I see these floatin around Ebay once in awhile,and will seriously help get your Renix running its best............also on the idle flash(jump in rpm),the Renix PCM has been updted numerous times to address different issues,all the Mopar PCM remans they offer now are the latest and greatest...........Mopar does offer a hot rod PCM for the Renix(offroad only),and an addition of a High altitude CPS helps also.....................Thier is more.....I will returnRags
PaulJ
NAXJA Forum User
- Location
- Lynnwood, WA
Rags, What do you mean by a CPS patch kit? Does it just do away with the connector? Do you set the CPS cranking voltage by shimming it?
- Location
- Terra Firma
PaulJ said:
When you buy a replacement CPS for a Renix XJ, you can buy just the CPS, or you can buy it with a replacement connector that bypasses the main harness and goes directly into the ECU. This is supposed to send a stronger signal to the ECU.
In typical DaimlerChrysler fashion, the kit with CPS and replacement harness costs less than the bare CPS.
Jeep came out with a kit years ago for 87 to early 88 xjs that includes a new CPS and a wire harness that you wire right into the PCM,the kit is actually cheaper then just buying a CPS,go figure......................this kit works on all the Renix equipped XJs
CPS adjustment..........unplug CPS,connect DVOM leads to sensor side plug of CPS,set DVOM to milla volts AC,polarity does not matter,crank engine and observe meter,you want at least .75 volts AC while cranking,if you need to adjust,here goes..........I have done a million of these and it takes great care and finesse as not to ruin the sensor,I use a long pry bar/screwdriver,I position the tip right above the sensor plastic center on the mounting ear and tap lightly with a medium hammer,tap,check.if still low,tap again....untill you get the .75 volt......you need to be careful as not to drive the sensor to close to the flywheel ,it will rub and ruin the sensor.................this adjustment here helps the cold weather starting blues and the abnormal long crank time................it will never start like Corporate Speed density.but it sure helps .................................Rags
CPS adjustment..........unplug CPS,connect DVOM leads to sensor side plug of CPS,set DVOM to milla volts AC,polarity does not matter,crank engine and observe meter,you want at least .75 volts AC while cranking,if you need to adjust,here goes..........I have done a million of these and it takes great care and finesse as not to ruin the sensor,I use a long pry bar/screwdriver,I position the tip right above the sensor plastic center on the mounting ear and tap lightly with a medium hammer,tap,check.if still low,tap again....untill you get the .75 volt......you need to be careful as not to drive the sensor to close to the flywheel ,it will rub and ruin the sensor.................this adjustment here helps the cold weather starting blues and the abnormal long crank time................it will never start like Corporate Speed density.but it sure helps
.................................RagsCPS patch kit ......auto trans ..87 to 91 Renix injection,#83100066.........
CPS patch kit....manual trans.....87 to 91 Renix injection....#83100063
High altitude CPS for Renix fuel injection........#53005421...........
I found my pages and stuff on the web I had from years ago!!!
egroups.................arizona xj
CPS patch kit....manual trans.....87 to 91 Renix injection....#83100063
High altitude CPS for Renix fuel injection........#53005421...........
I found my pages and stuff on the web I had from years ago!!!
egroups.................arizona xj
