• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Jeep went wacky.

SexJ1988 said:
I'll do a cold start video when I get home. I need to figure out how to adjust the distributor to make sure it's in time and not 180* out


Sent from my iPhone using Tapatalk
Click to expand...

NO NO NO!!!!! Do not mess with the distributor timing!!!!!

You have not already done so right????
 
90xj06 said:
unless you removed the distributor it would be fine. so long as it was running good.
Click to expand...

X2 X2 X2!!!!!!!!!!!!!!!!! If it ain't broke don't fix it LOL.:cheers:
 
Ecomike said:
What stuff did you put in that oil.

I have had that exact sound off an on for 70,000 miles on 289,000 mile 78 Wagoneer, 4.0

I fixed it finally by adding a quart of MMO, Marvel Mystery oil and running the warmed up engine for about 2 minutes at 4000 rpm. That forces the stuck lifters to rotate again and frees them up, and gets rid of the noise, except if the engine sits a while and you start it in very cold weather, then the noise will return till it warms up and you do the 4000 rpm for 1-2 minutes trick again.

Can you post photos of plug #1, #2 and say #4 for us to read them?

What exactly is it doing now? Have the symptoms changed any?

I think the ticking noise up front is a distraction, not the cause, but may be due to miss fires in cyl 1 and 2 and unburned gas in those cylinders killing the compression and spark. Are the 1 and 2 plugs oil fouled???

Fouled plugs, bad plug wires on those two, criss crossed plug wires or injector pig tails criss crossed, or stuck open injectors could be the issue.

Also check the vacuum line that goes from the lower side of the throttle body directly to the MAP sensor on the firewall. It is common for it come loose at the throttle body and cause the engine to run very rough.

Also, for the start sequence, try to switch the key to run for 5 seconds, then off, then on, then off, then try to start it.

Pull the vacuum line at the side of the FPR, Fuel pressure regulator on the front of the fuel rail that is attached to all the fuel injectors and see if there is any sign of wet fuel or fuel odor. If there is the FPR is leaking fuel into the vacuum and bypassing the injectors.

Keep in mind as you go that you may fix the original problem and later find you created a new problem in debugging process by criss crossing wires or bumping the wiring harness witch may have a loose connection inside in the harness....etc. And thus you may not realize you fixed the original problem. There are sensor grounds in the harness that are notorious for getting loose after all these years that cause the sensor grounds to come and go with vibration or movement as you work on it.

These year jeeps, Renix, 1987-90 are notorious for poor grounds that cause all sorts of starting and running issues.

There is a ballast resistor on the drivers side firewall that can cause fuel pump power issues. You should get a fuel pressure tester and test the fuel pressure while running, with the vacuum line attached and removed from the FPR (see the FSM instructions or old posts here, should get 29-39 psi depending on the vac line connection). Also watch the fuel pressure when you turn the engine off, Does it drop to zero or slowly bleed off to zero??? If yes you have a leaking injector or bad FPR.

Also check the fuel pressure before you crank the engine.

Post up all your results.
Click to expand...



I did cruiser54 C101 sensor refresh yesterday(ballast?)

I'm going to go check all the grounds but don't know where all are located, the only two injectors I've had apart at the same time is 1&2 so I'll try to make sure they arnt crossed, I'll pull the plugs and show all 6 labeled( granted they've only been in 3 days). Where can I get MMO? I changed plugs, wires, cap, rotor Monday so they SHOULD all be good. I'll see about borrowing a FPT to check that. Just nervous about the MMO trick because I don't want it to cause further damage. What's the key sequence supposed to do?


Sent from my iPhone using Tapatalk
 
Ecomike said:
What stuff did you put in that oil.

I have had that exact sound off an on for 70,000 miles on 289,000 mile 78 Wagoneer, 4.0

I fixed it finally by adding a quart of MMO, Marvel Mystery oil and running the warmed up engine for about 2 minutes at 4000 rpm. That forces the stuck lifters to rotate again and frees them up, and gets rid of the noise, except if the engine sits a while and you start it in very cold weather, then the noise will return till it warms up and you do the 4000 rpm for 1-2 minutes trick again.

Can you post photos of plug #1, #2 and say #4 for us to read them?

What exactly is it doing now? Have the symptoms changed any?

I think the ticking noise up front is a distraction, not the cause, but may be due to miss fires in cyl 1 and 2 and unburned gas in those cylinders killing the compression and spark. Are the 1 and 2 plugs oil fouled???

Fouled plugs, bad plug wires on those two, criss crossed plug wires or injector pig tails criss crossed, or stuck open injectors could be the issue.

Also check the vacuum line that goes from the lower side of the throttle body directly to the MAP sensor on the firewall. It is common for it come loose at the throttle body and cause the engine to run very rough.

Also, for the start sequence, try to switch the key to run for 5 seconds, then off, then on, then off, then try to start it.

Pull the vacuum line at the side of the FPR, Fuel pressure regulator on the front of the fuel rail that is attached to all the fuel injectors and see if there is any sign of wet fuel or fuel odor. If there is the FPR is leaking fuel into the vacuum and bypassing the injectors.

Keep in mind as you go that you may fix the original problem and later find you created a new problem in debugging process by criss crossing wires or bumping the wiring harness witch may have a loose connection inside in the harness....etc. And thus you may not realize you fixed the original problem. There are sensor grounds in the harness that are notorious for getting loose after all these years that cause the sensor grounds to come and go with vibration or movement as you work on it.

These year jeeps, Renix, 1987-90 are notorious for poor grounds that cause all sorts of starting and running issues.

There is a ballast resistor on the drivers side firewall that can cause fuel pump power issues. You should get a fuel pressure tester and test the fuel pressure while running, with the vacuum line attached and removed from the FPR (see the FSM instructions or old posts here, should get 29-39 psi depending on the vac line connection). Also watch the fuel pressure when you turn the engine off, Does it drop to zero or slowly bleed off to zero??? If yes you have a leaking injector or bad FPR.

Also check the fuel pressure before you crank the engine.

Post up all your results.
Click to expand...



I just changed the oil to 15-40 5.5qts to run it and flush any gunk. I'll be changing again soon once I find the issue.


Sent from my iPhone using Tapatalk
 
Every one stocks MMO, Walmart, parts stores...Marvel Mystery Oil. It is a light weight cleaning oil that will disolve carbon and varnish that make the lifters stick. Also good for piston rings....etc. Don't forget to drain a quart of oil first. Once again, what thick additive did you add? It may be too thick if the PO already used a bunch of it??

The critical grounds are at the oil dip stick area on the side of the engine block, right with the starter motor ground. There are two rings with I think two small wires each attached usually under the large starter motor ground wire. Also clean the battery post and clamps and the wire ends if they a loose clamp design (aftermarket clamps) like mine. See Cruiser54 's site and posts and links here and his ground refresh how to papers on his site for the location and method of fixing hidden in the harness crimped grounds that come loose over the decades. I have not had to mess with my C-101 or the harnesses yet, but I did run direct ground lines from the battery to some of critical sensors like my TPS and I rerouted the sensor grounds from the oil dip stick area directly to the battery negative post on one 89.

But I used an ohm meter to find the weak grounds and either fixed then or ran new ones.

MMO will not hurt the engine.

The engine at 4000 rpm trick has always worked for many of us for years. Only way it would not work is if something is already damaged. But your ticking sound is EXACTLY like mine was and many others here. The 4.0 is notorious for that ticking sound from a stuck lifter that stops rotaing. The high RPM forces the stuck lifters to start rotating again. 4000 rpm is not red line. Ask Cruier54 and 8MUD and 5-90

You can try it at 3000 rpm a few times, then 3500 rpm a few times and work up to 4000 rpm gradually like I did. I was nervous the first time I tried it too.

Key sequence primes the fuel rail. In run, pre crank, the pump only runs a few seconds and shuts off. Sometimes they will start right up if you prime 2-3 times, if the fuel rail drained due to a bad injector leaking or a bad FPR. Also if the battery is weak or the wires from the battery to the starter are corroded, the Renix engine will not crank at the high enough RPMs to get the ECU to see a good enough CPU signal. One more reason to love clean battery posts and clamps and grounds on the Renix rigs!!!

Did you replace the CPS sensor???? If so you need to pull it and do the Eco-Cruiser-5-90 CPS modification to it to boost the cranking voltage from the CPS to the ECU. Aftermarket Renix CPS sensors do not put out enough voltage stock......
Try one pig tail on each injector #1 and #2 one at a time and see if performance improves with one and not the other, then you know which injector it should be connected to.



SexJ1988 said:
I did cruiser54 C101 sensor refresh yesterday(ballast?)

I'm going to go check all the grounds but don't know where all are located, the only two injectors I've had apart at the same time is 1&2 so I'll try to make sure they arnt crossed, I'll pull the plugs and show all 6 labeled( granted they've only been in 3 days). Where can I get MMO? I changed plugs, wires, cap, rotor Monday so they SHOULD all be good. I'll see about borrowing a FPT to check that. Just nervous about the MMO trick because I don't want it to cause further damage. What's the key sequence supposed to do?


Sent from my iPhone using Tapatalk
Click to expand...
 
SexJ1988 said:
It ran great before all these issues started so I didn't know if maybe it jumped or something.


Sent from my iPhone using Tapatalk
Click to expand...

From the sound of the video the timing is fine, you just have stuck noisy lifters up front that desperately need MMO for a good 20 minute warm up then a hard run at 3500 to 4000 rpm. I think I started at 3000 rpm 8 years ago, and the years got more comfortable doing it faster, in seconds instead of 1-2 minutes, at 4000 rpm instead 3000-3500.

Never had one blow up yet. Only had one fail to work, but it did no damage. Damage was done when the clown ran it dry with no oil first. It still ran but was too damaged by running with an empty oil pan for too long.
 
What is a CAS you say you replaced?

Last time had your cyl 1 and 2 problem, mine was cyl 3 and 4 on a new buy. Compression test showed the head gasket failed between the 2 cyls. Idled rough but smoothed out at higher rpms. No oil or coolant head gasket leak issues at all, just air passing back and forth from one cyl to the other. But it had no lifter noise.

All it needed was ahead gasket.

SexJ1988 said:
Bought a 1988 Cherokee 4.0L 4wd Sunday. Drove great when I test drove it.

Drove about an hour home started misfiring, then died. Restarted it and now it runs super rough, also started making noise kinda like piston slap or lifter tick.

I've replaced plugs, wires, cap, rotor, CAS, oil, thermostat.

Still nothing.

It literally was like a sewing machine when I test drove it.


I was tinkering and noticed that I can unplug cyl 1&2 injectors at the same time and nothing changes, but if I unplug any of the others it stalls.

Help.
Click to expand...
 
Did the old oil you drained smell like gasoline????

Does the new oil smell like gasoline now?

That would be a sign of no spark or a leaking injector or criss crossed wires on one or more cyls.
 
Ecomike said:
Every one stocks MMO, Walmart, parts stores...Marvel Mystery Oil. It is a light weight cleaning oil that will disolve carbon and varnish that make the lifters stick. Also good for piston rings....etc. Don't forget to drain a quart of oil first. Once again, what thick additive did you add? It may be too thick if the PO already used a bunch of it??

The critical grounds are at the oil dip stick area on the side of the engine block, right with the starter motor ground. There are two rings with I think two small wires each attached usually under the large starter motor ground wire. Also clean the battery post and clamps and the wire ends if they a loose clamp design (aftermarket clamps) like mine. See Cruiser54 's site and posts and links here and his ground refresh how to papers on his site for the location and method of fixing hidden in the harness crimped grounds that come loose over the decades. I have not had to mess with my C-101 or the harnesses yet, but I did run direct ground lines from the battery to some of critical sensors like my TPS and I rerouted the sensor grounds from the oil dip stick area directly to the battery negative post on one 89.

But I used an ohm meter to find the weak grounds and either fixed then or ran new ones.

MMO will not hurt the engine.

The engine at 4000 rpm trick has always worked for many of us for years. Only way it would not work is if something is already damaged. But your ticking sound is EXACTLY like mine was and many others here. The 4.0 is notorious for that ticking sound from a stuck lifter that stops rotaing. The high RPM forces the stuck lifters to start rotating again. 4000 rpm is not red line. Ask Cruier54 and 8MUD and 5-90

You can try it at 3000 rpm a few times, then 3500 rpm a few times and work up to 4000 rpm gradually like I did. I was nervous the first time I tried it too.

Key sequence primes the fuel rail. In run, pre crank, the pump only runs a few seconds and shuts off. Sometimes they will start right up if you prime 2-3 times, if the fuel rail drained due to a bad injector leaking or a bad FPR. Also if the battery is weak or the wires from the battery to the starter are corroded, the Renix engine will not crank at the high enough RPMs to get the ECU to see a good enough CPU signal. One more reason to love clean battery posts and clamps and grounds on the Renix rigs!!!

Did you replace the CPS sensor???? If so you need to pull it and do the Eco-Cruiser-5-90 CPS modification to it to boost the cranking voltage from the CPS to the ECU. Aftermarket Renix CPS sensors do not put out enough voltage stock......
Try one pig tail on each injector #1 and #2 one at a time and see if performance improves with one and not the other, then you know which injector it should be connected to.
Click to expand...



No additive. Just drained oil, poured extra oil through it till it ran gold from drain, put in new oil (5.5qts 15-40) was going to run it in the engine till I get everything solved and then change again.

I did change the cps(that was a bitch to do)
Link to his mod?

I replaced the battery clamps.
Going to replace fuel filter tonight as a precaution.
Going to try to clean/reroute grounds to better them.


Sent from my iPhone using Tapatalk
 
Ecomike said:
What is a CAS you say you replaced?

Last time had your cyl 1 and 2 problem, mine was cyl 3 and 4 on a new buy. Compression test showed the head gasket failed between the 2 cyls. Idled rough but smoothed out at higher rpms. No oil or coolant head gasket leak issues at all, just air passing back and forth from one cyl to the other. But it had no lifter noise.

All it needed was ahead gasket.
Click to expand...



Crank angle sensor/ crank position sensor
It's the same thing.

The sensor at the top of bell housing that takes 3ft of extensions and patience as not to lose the bolts lol.

I'll drain some oil tonight to smell and add MMO.


Sent from my iPhone using Tapatalk
 
Will be doing compression test Monday when my tester arrives. As for now I can't find a Fuel pressure tester local so I'm screwed on that one.


Sent from my iPhone using Tapatalk
 
Here is a link of links to Cruiser's great write ups on the CPS modification and the ground fixes, locations etc. He is a good friend of mine here on Naxja. He was a jeep dealer service manager years ago and was involved in the Dealer fixes for the issues like CPS starting problems that persist today with 87-90 jeeps.

The CPS fix is easy. Just use the next size drill bit in a drill bit kit to enlarge the bolt holes on the CPS, then when mounting push the CPS down from the top as you tighten the bolts. That moves the CPS a wee bit closer to the flex plate and nearly doubles the cranking voltage. It WORKS like a dream!!!! Best mod I ever did to my Renix fleet. Use to take 9 seconds of cranking to start my 87. Or 2-3 tries.

https://www.google.com/search?q=cru...la:en-US:official&client=firefox-a&channel=sb
 
Did you ever confirm the firing order? Reversing 1+2 will definite cause them to act as dead cylinders!
 
RCP Phx said:
Did you ever confirm the firing order? Reversing 1+2 will definite cause them to act as dead cylinders!
Click to expand...



I followed the Cherokee forum had a picture(app won't let me upload for some reason) but going to switch the injector plugs and see this evening


Sent from my iPhone using Tapatalk
 
SexJ1988 said:
I followed the Cherokee forum had a picture(app won't let me upload for some reason) but going to switch the injector plugs and see this evening
Click to expand...

I was referring to the spark plug firing order!
 
You must log in or register to reply here.

Similar threads

G
98 XJ tick tick ticking!
2
Replies
29
Views
5K
straws
S
A
Very odd idling issues
2
Replies
38
Views
4K
Rob Mayercik
R
C
New Jeep...new problems!
Replies
0
Views
297
CheapJerokee
C
C
New Jeep...new problems!
2 3
Replies
44
Views
3K
CheapJerokee
C
B
Jeeper needs Help !!
2
Replies
22
Views
3K
denverd1
denverd1
Back
Top