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Renix Dead Spot And Idiling Low


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This is a very informative topic and I've been following it with interest because I just bought an 88 but I don't know all of the acronyms that are being used.  Is there somewhere on the site that lists the acronyms or could someone give a quick rundown of them.....I know TPS but I'm not sure of the TCU and ECU.   Thanks.

 

Hope this helps! http://comancheclub.com/topic/12163-acronyms/

 

(July 2014 MJOM)

 

Wow, just what I need, thanks for the link!

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This is a very informative topic and I've been following it with interest because I just bought an 88 but I don't know all of the acronyms that are being used.  Is there somewhere on the site that lists the acronyms or could someone give a quick rundown of them.....I know TPS but I'm not sure of the TCU and ECU.   Thanks.

This should help. 

 

Click on the link in my signature and read/perform items 1 through 5. You will become more familiar with acronyms and your Jeep in general....

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This is a very informative topic and I've been following it with interest because I just bought an 88 but I don't know all of the acronyms that are being used.  Is there somewhere on the site that lists the acronyms or could someone give a quick rundown of them.....I know TPS but I'm not sure of the TCU and ECU.   Thanks.

This should help. 

 

Click on the link in my signature and read/perform items 1 through 5. You will become more familiar with acronyms and your Jeep in general....

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This is a very informative topic and I've been following it with interest because I just bought an 88 but I don't know all of the acronyms that are being used.  Is there somewhere on the site that lists the acronyms or could someone give a quick rundown of them.....I know TPS but I'm not sure of the TCU and ECU.   Thanks.

This should help. 

 

Click on the link in my signature and read/perform items 1 through 5. You will become more familiar with acronyms and your Jeep in general....

 

Will do, thanks.

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Well.... Bad news. New egr is on and I fixed the tps ground issue on the TCU side and still no improvement.

 

I did the egr test again. When i unplug the solenoid connector and all the vacuum hoses are connected the truck makes no change in rom. When i hook up the hose coming from the solenoid directly to the egr valve the truck stalls. Which is good. Idk what to do next!

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Its brand new from autozone and I was getting correct readings (from what you said). You can look back from what the readings actually were i forgot.

 

I also said the heater was working but I am going to double check that. I went back through my manual and it seems that the fuel pump relay has four orange wires going to 87. The o2 sensor has two orange going to 87a and one orange going to 87. I will double check later today.

 

And just to double check my knowledge, 87a and 30 should have 12 V. 87, 85, 86 should have no voltage. Correct?

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Can't look that up right now, but if the O2 sensor heater doesn't get heated, your O2 sensor doesn't work. I was too lazy to re-read the thread. Sorry. 

 

If you click on the link below and scroll through, you'll see not only some nifty Jeep technical photos, but a diagram of the REnix relay center.

 

http://www.cherokeeforum.com/members/cruiser54-42565/albums/jeep-technical-photos/

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I'm following this thread, too. I have a low idle when cold and it hovers quite a bit, nearly stalls everytime I depress the clutch and then picks itself up. its mysterious for sure.

Do the ground refreshing. Post 1 in my Tips.

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Okay and here are the results...

 

with pictures!  :brows:

 

with the relay out of the connector:

30, 87a, and 85 all have conductivity

2.1 ohms for resistance of pin 85

 

85 goes to solenoid (dark blue with white stripe)

30 goes to o2 sensor (orange)

87a goes to connector which goes to sync? (black)

87 goes to another connector which runs somewhere (light green)

86 goes to solenoid with fuseable link 

 

with truck running:

30,87, and 87a all had 14 V

I had the ground of the multimeter on pin 85 while testing for these voltages

 

I also switched relays from the a/c relay

 

IMG_3480%255B1%255D.JPG

 

light green wire is 87

 

IMG_3481%255B1%255D.JPG

 

black one on the very right is 87a

 

IMG_3484%255B1%255D.JPG

 

solenoid:

bottom left with white stripe wire is 85

top left orange wire is 86

 

IMG_3482%255B1%255D.JPG

 

IMG_3483%255B1%255D.JPG

 

 

 

 

So from my thinking in the picture above......

30 should always have the 12V power source

when 85 and 86 get power from the solenoid then pin 87 will have the 12V power

when 85 and 86 are not energized 87a should have the 12V source

 

IMG_3487%255B1%255D.JPG

 

plus.... it shows that there is a yellow wire and three oranges. which looks like the relay on the opposite end.

 

I used this diagram in your picture cruiser to chose the o2 sensor relay on the very right but it seems like the wrong one to me.  :dunno:

 

 

 

 

:doh:  :???:  :hmm:  But when i tested for voltage 87 and 87a both had 12V. Something isnt right.

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I'm following this thread, too. I have a low idle when cold and it hovers quite a bit, nearly stalls everytime I depress the clutch and then picks itself up. its mysterious for sure.

Do the ground refreshing. Post 1 in my Tips.

 

 

 

Just did this while replacing my rotor, cap and leads. It helped significantly. I also did the contact points on my coil. I should've gone through your list ages ago, but there were so many mechanical issues to tackle first. It still has a low idle, but it doesn't waver nearly as much as it did.. Thanks Cruiser!

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There's a good possibility that my diagram is correct and the FSM is wrong. You could do a continuity check to verify. I'd appreciate it.

 

You could also unplug the O2 sensor, start the Jeep and check for power between the red and black wires. 

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Okay so today I did a lot of wire testing to check for high resistances and for power where there needs to be.

 

The O2 has power going to it.

 

My manual FSM is CORRECT for the 02 heater relay. If standing by the passenger side wheel and looking down at the relay towers, the 02 heater relay is the one on the very left. 

So cruiser... the picture you have is wrong in my case.

 

I also took the connectors off the ECU and tested various wires/sensors to make sure there is a good connection. To do this a made a simple jumper wire from the target sensor/wire to my driver side door area. This gave me enough length to probe my jumper wire to the ECU connectors. 

 

Doing this I tested:

TPS wires

all grounds

air temp input

coolant temp input

wires coming from relays

map sensor

B+ Latch relay wires

 

I seem to have good connections everywhere. My thought now is that since connections are good there is a driver/device issue. Sensor or ECU...

My O2 and TPS are new and adjusted to be working correctly

My MAP values seem to be within spec. voltage drop of 2.2V

My air and coolant sensors are close in values 1760 and 1988 respectively

The only thing I cannot test is the IAC

 

So I might just replace that and see what happens.

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