Renix Running PaiNs!!
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cruiser54 (04-27-2020)
#34
Okay I’m a D**k, I did fix anything yet! Unlike about 99% of all the other 100’s of post I’ve read, I really would post the solution. Nothing has really changed. Still won’t idle, runs FAT! About every 8-10 starts I’m pulling and cleaning the plugs!
Question about the MaP sensor. I back probe the plug with key ON engine off. Got 5+ Vdc input, 4.6 Vdc output to ECU, and 0.0 ohms for the ground. However, testing at the ECU plug, C6, I get no voltage. I probe C6 at the ECU plug and the output side of the MaP sensor plug and get .3 ohms resistance. Not sure if I’m testing it right. But, seems to make sense input and out out can be there all day but if it’s not making it to the ECU, well how could it communicate. Right? When I apply vacuum manually to the MAP, it’s changes the idle but very little.
Just trying to nail down the sensors that would have it running so rich at a cold start. Correct me if I’m wrong, but I’m thinking in order of something like MAP, O2, Then maybe IAT?
Spend the day trying to get the vacuum UP. Had about 10” at idle. Torqued the manifold (newish motor had a few gear cycles ), Found a couple little leaks etc got it up to 13” at a LOW idle.
The amount of frustration on this thing is bar none the most of any vehicle I’ve ever owned
Question about the MaP sensor. I back probe the plug with key ON engine off. Got 5+ Vdc input, 4.6 Vdc output to ECU, and 0.0 ohms for the ground. However, testing at the ECU plug, C6, I get no voltage. I probe C6 at the ECU plug and the output side of the MaP sensor plug and get .3 ohms resistance. Not sure if I’m testing it right. But, seems to make sense input and out out can be there all day but if it’s not making it to the ECU, well how could it communicate. Right? When I apply vacuum manually to the MAP, it’s changes the idle but very little.
Just trying to nail down the sensors that would have it running so rich at a cold start. Correct me if I’m wrong, but I’m thinking in order of something like MAP, O2, Then maybe IAT?
Spend the day trying to get the vacuum UP. Had about 10” at idle. Torqued the manifold (newish motor had a few gear cycles ), Found a couple little leaks etc got it up to 13” at a LOW idle.
The amount of frustration on this thing is bar none the most of any vehicle I’ve ever owned
#35
Oh yeah, While on the hunt for vacuum leaks I pulled the TB to clean all the gasket maker off the mating surface. Also found the rubber insert for the MAP sensor wasn’t as good as I thought. Come on Cruiser mod #31 then. TB was spotless other wise.
I’ll eventually get the whole Cruiser list done IF the truck sticks around and ever runs right!
Cruiser mod #23 ready when I get the OP fixed up
I
I’d like to move forward to other sTuFF!
Just for why nots, my other Cherokee! I’d like to take a picture with both of them someday, if I can ever drive more that 10 miles! Help me FiX this heap, I’ll take someone for a $100 hamburger!
I’ll eventually get the whole Cruiser list done IF the truck sticks around and ever runs right!
Cruiser mod #23 ready when I get the OP fixed up
I
I’d like to move forward to other sTuFF!
Just for why nots, my other Cherokee! I’d like to take a picture with both of them someday, if I can ever drive more that 10 miles! Help me FiX this heap, I’ll take someone for a $100 hamburger!
#36
Junior Member
Joined: Oct 2012
Posts: 41
Likes: 5
From: Garnet Valley, Pa
Year: 1990
Model: Cherokee
Engine: 4.0
Renix Running PaiNs!!
Stick with it, we are here to help. If you can take some more pictures of the engine compartment from all sides maybe we can see something you are missing.
#37
I have the same issue, including dashlights. But the car won't die, even if idling at very low rpms.
I have to change the alternator who proved to be delivery far too high voltage.
"Maybe" it will help.....
#38
Once it gets running right I’ll Tidy everything up nice so don’t judge!
What do you think about the power issue from the MAP output to ECU?
Thanks for the reply and the help!
Standard 57’
Cable upgrades , the fender ground is actually a stud welded to the inside of the fender. Good an clean.
Soldered, cleaned and used “ox-gard”, all my sensor grounds show 0.0 ohms.
Ignore the brake booster, it’s plugged till I replace the check valve and grommet that’s cracked.
ECU pin C6, black is grounded to battery, key ON. ?
#39
In the mean time. I think we can be reasonably sure that all the grounds have been delt with. Uncertain still if I am testing the ECU signal from the MAP correctly. I assume if there is the “4.6V” going from the MAP to the ECU and nothing in between that KEY on , engine off should yield the same voltage at the ECU plug. Or does the motor need to be running?
Crusier!?!
in the mean time, I am continuing to split the loom toward the ECU / firewall ...
For once, I actually have the time and money to throw at a project thankfully, but I’ve been d**king with this HeeP for 4+ weeks now
Crusier!?!
in the mean time, I am continuing to split the loom toward the ECU / firewall ...
For once, I actually have the time and money to throw at a project thankfully, but I’ve been d**king with this HeeP for 4+ weeks now
Last edited by Base2Final; 04-29-2020 at 04:49 PM.
#40
Seasoned Member
Joined: Jul 2013
Posts: 259
Likes: 15
From: Southern California
Year: 1988
Model: Cherokee
Engine: 4.0L
I've been working on a new oil pan gasket and RMS the past few days, but I'm getting back into the top end at the end of the week (new injectors, valve cover gasket).
Only thing I saw that could possibly be amiss is the bottom of the vacuum canister has an inlet/outlet without a cap or hose. Maybe this is the way it's supposed to be, but just looking for someone to confirm.
#41
Anyone have any experience/ luck repairing the flat three pin plugs by chance? One of the pins for the CPS is whack and keeps giving me no start fits. I found that stabbing a piece of paper clip in the pin snugs it up enough to temporarily fix that but would like a more permanent solution.
Ordered a NTK 23553, I have a strong suspicion this whole F**kN mess is revolving around either the MAP or the O2, or both
Ordered a NTK 23553, I have a strong suspicion this whole F**kN mess is revolving around either the MAP or the O2, or both
Last edited by Base2Final; 04-29-2020 at 10:55 PM.
#42
Seasoned Member
Joined: Jul 2013
Posts: 259
Likes: 15
From: Southern California
Year: 1988
Model: Cherokee
Engine: 4.0L
#43
Junior Member
Joined: Oct 2012
Posts: 41
Likes: 5
From: Garnet Valley, Pa
Year: 1990
Model: Cherokee
Engine: 4.0
Renix Running PaiNs!! PROGRESS!
Looked at your pictures then went outside to look at my engine compartment, my vacuum canister has a short hose off the bottom that does not connect to anything looks like a drain hose don't know if that is the way it should be, our XJ's are 30 years old so who knows what might had fallen off. I could not see anything wrong in your pictures maybe someone else will take a look. I know when I changed my injectors to the 4 hole ones it idled and ran a lot better. I know my injectors were bad as it was running rich and my oil smelled like gasoline. When my XJ was acting up a few years ago it took me a month or two to fix (a bad new part I installed, I assumed it was good) it was driving me crazy during that time. If I think of anything else I will let to know.
#44
Seasoned Member
Joined: Jul 2013
Posts: 259
Likes: 15
From: Southern California
Year: 1988
Model: Cherokee
Engine: 4.0L
I noticed a smell of gasoline in my oil when I just changed it. This issue started when I installed the Bosch 746 injectors. I even emailed the guy at the time but it wasn't too bad then so I brushed it off. This time I got the Bosch 703's with a lifetime warranty. We'll see how it goes.
#45
Looked at your pictures then went outside to look at my engine compartment, my vacuum canister has a short hose off the bottom that does not connect to anything looks like a drain hose don't know if that is the way it should be, our XJ's are 30 years old so who knows what might had fallen off. I could not see anything wrong in your pictures maybe someone else will take a look. I know when I changed my injectors to the 4 hole ones it idled and ran a lot better. I know my injectors were bad as it was running rich and my oil smelled like gasoline. When my XJ was acting up a few years ago it took me a month or two to fix (a bad new part I installed, I assumed it was good) it was driving me crazy during that time. If I think of anything else I will let to know.
Roger ThaT! I smelt my oil and it does have a little gas smell to it. I have NO idea what injectors I have in there now but, The C54 man says the 746’s as it were are good. Stupid I have to wait a week for a NTK O2 sensor. Might as well find me some injectors as long as I’m throw parts at it.