Jump to content
CoastChief

First long drive in new to me MJ.

Recommended Posts

How’s everyone doing. I was driving my car for around 2 hours with no problems. The only issues I have noted are as follows.

 

speedometer cable.
-I here a rough clicking behind the cluster at 25-35MPH with bounce. Others have informed me that this is the speedometer cable. 

 

When going uphill the cabin vent fan stops working. Flat or downhill blows strong.

- haven’t diagnosed

 

 

lights in beams not working 

-looked on thread for light replacement. 
 

Bushings . Section at a time - $$$$


I have started all the ground wire refresh. Ordered new Bosch fuel injectors and haven’t decided on what spark plugs. Thinking of new radiator and headlight harness for preventive measure. 
 

Any thought appreciated.

 

 

8B0A1454-E837-4B9D-A29A-4B774401F46F.jpeg

Share this post


Link to post
Share on other sites
7 minutes ago, CoastChief said:

When going uphill the cabin vent fan stops working. Flat or downhill blows strong.

I'm sure the blower motor still works in that state, I've had this happen under hard acceleration where air will stop coming out of the vents. Check the vac lines, the motor should be running always. The vent doors are controlled by vac assisted motors. Unless you have a power surge when accelerating which can lead to future problems. 

 

Just do a thorough check of every service component and make sure everything is working and up to spec.

Share this post


Link to post
Share on other sites
2 minutes ago, eaglescout526 said:

I'm sure the blower motor still works in that state, I've had this happen under hard acceleration where air will stop coming out of the vents. Check the vac lines, the motor should be running always. The vent doors are controlled by vac assisted motors. Unless you have a power surge when accelerating which can lead to future problems. 

 

Just do a thorough check of every service component and make sure everything is working and up to spec.

Thank you so much Eagle, yes it shuts off sometimes randomly when I accelerate. I had to hit the switch a few times for it to even start. I’ll be sure to check the vacuum lines, and the vac assisted motors. I apologize I’m pretty green. The service components are the oil, filters etc? What causes power surges in the Comanche? c101 connector resistance. 

Share this post


Link to post
Share on other sites

^^^yeah that.

 

The HVAC fan is still working fine, it's just that you're losing vacuum to the actuators that direct the airflow.  When that happens it defaults to defrost.

 

There is a vacuum resivoir behind the front bumper on the passenger side to assist with low vacuum situations, and yours nay be bad, or one of the lines to it may be damaged/missing.  It will be either a small black plastic ball about the size of a softball, or a larger, more oval shaped canister.  Check the resivoir and all the lines to it, and follow the one line up into the engine bay/firewall to make sure it's still good.

Share this post


Link to post
Share on other sites
8 minutes ago, CoastChief said:

Thank you so much Eagle, yes it shuts off sometimes randomly when I accelerate. I had to hit the switch a few times for it to even start. I’ll be sure to check the vacuum lines, and the vac assisted motors. I apologize I’m pretty green. The service components are the oil, filters etc? What causes power surges in the Comanche? c101 connector resistance. 

No problem.

What Mjeff87 said about the blower. Wouldn't hurt to take it out and lube it up either. There is a ground mod you should do for it if you have AC. 

 

Service components do include those two and your suspension and steering pieces. Basically pieces that wear out with mileage and time.

 

Yes the C101 if your 88 has it(if it was made before the year 1988, went away with the late 88 and 89-90 model years) can be a huge source of resistance but not surge power.  Disregard my power surge comment, that was used in place of electrical resistance when I was lacking the better term.

Share this post


Link to post
Share on other sites
52 minutes ago, fiatslug87 said:

Plugs: I've been using Champion copper RC9YC for 30 years in my MJ, no problems.

 

40 minutes ago, mjeff87 said:

^^^yeah that.

 

The HVAC fan is still working fine, it's just that you're losing vacuum to the actuators that direct the airflow.  When that happens it defaults to defrost.

 

There is a vacuum resivoir behind the front bumper on the passenger side to assist with low vacuum situations, and yours nay be bad, or one of the lines to it may be damaged/missing.  It will be either a small black plastic ball about the size of a softball, or a larger, more oval shaped canister.  Check the resivoir and all the lines to it, and follow the one line up into the engine bay/firewall to make sure it's still good.

thank you all. I appreciate it

Share this post


Link to post
Share on other sites

Everyone else has made good points.

 

Speedo cable: if the cable is not physically damaged, remove it from the truck and remove the inner cable from the outer sheath. Clean it up and apply some white lithium grease and put it all back together. Make sure the cable is correctly routed. It should be clipped to the driver side upper control arm bolt on the frame side. If that clip is not there, it needs to be there.

 

Headlights: A headlight harness of some type should be considered mandatory at this point. It might make your headlights a little brighter, but the real advantage is safety - there's no longer full headlight current passing inside the truck. If your electrical system is in poor shape (and if you have any doubts, it is) the headlight switches have been known to catch fire. I strongly recommend some type of "not sealed beam" headlight as well. I'm partial to H4/9003 bulbs in Hella housings, but there are lots of good options out there.

 

HVAC vents not working: 99.95% chance this is actually a vacuum leak. Next time it happens, feel for air coming out of the top of the dash. If so, it's a vacuum leak. The leak could be anywhere in the HVAC vacuum circuit, but a good first place to check is the big plastic line running up the passenger side inner fender, as well as the connections at the reservoir.

 

While we're on the topic, I want to talk about another potential MJ fire hazard. The blower motor switch. Yet another sad tale of full accessory current being passed through a switch. Over time, the blower motor can develop friction in its bearings. Thanks to this resistance, the blower motor draws more current than designed, but not enough to blow the fuse. If it gets bad enough, this excessive current draw can cause the fan speed switch and the connector on the back of it to get hot enough to start melting. Let this go on for long enough and your truck burns down. I've seen this happen enough that I recommend preemptively replacing the blower motor and inspecting the fan speed switch connector for any signs of heat damage. Clean the contacts for the switch connector while you're in there. This is a high current circuit anyway, so it's very important to have low resistance at all of the connections.

Share this post


Link to post
Share on other sites
16 minutes ago, Minuit said:

Everyone else has made good points.

 

Speedo cable: if the cable is not physically damaged, remove it from the truck and remove the inner cable from the outer sheath. Clean it up and apply some white lithium grease and put it all back together. Make sure the cable is correctly routed. It should be clipped to the driver side upper control arm bolt on the frame side. If that clip is not there, it needs to be there.

 

Headlights: A headlight harness of some type should be considered mandatory at this point. It might make your headlights a little brighter, but the real advantage is safety - there's no longer full headlight current passing inside the truck. If your electrical system is in poor shape (and if you have any doubts, it is) the headlight switches have been known to catch fire. I strongly recommend some type of "not sealed beam" headlight as well. I'm partial to H4/9003 bulbs in Hella housings, but there are lots of good options out there.

 

HVAC vents not working: 99.95% chance this is actually a vacuum leak. Next time it happens, feel for air coming out of the top of the dash. If so, it's a vacuum leak. The leak could be anywhere in the HVAC vacuum circuit, but a good first place to check is the big plastic line running up the passenger side inner fender, as well as the connections at the reservoir.

 

While we're on the topic, I want to talk about another potential MJ fire hazard. The blower motor switch. Yet another sad tale of full accessory current being passed through a switch. Over time, the blower motor can develop friction in its bearings. Thanks to this resistance, the blower motor draws more current than designed, but not enough to blow the fuse. If it gets bad enough, this excessive current draw can cause the fan speed switch and the connector on the back of it to get hot enough to start melting. Let this go on for long enough and your truck burns down. I've seen this happen enough that I recommend preemptively replacing the blower motor and inspecting the fan speed switch connector for any signs of heat damage. Clean the contacts for the switch connector while you're in there. This is a high current circuit anyway, so it's very important to have low resistance at all of the connections.

Thank you so much Minuit, 

You are a lifesaver, Ill be sure to try to set some time aside tomorrow to check all areas mentioned above. I really want to get my Jeep as reliable & clean as ever. If there is any links or forum posts you really recommend please message them over. So far I'm following the - Recommendations for first owners, and everything Cruiser has written I printed out in a 3 ring so far. Just trying to take thing one step at a time, never worked on any cars in my life. 

Share this post


Link to post
Share on other sites

Just took some shots of the undercarriage, I found a hose that looks to lead to nowhere that troubles me ( 7th photo). I see no vacuum so I assume it was deleted? It’s a 1988 but thanks to eagle I know it was made in sept of 1987! ( thank you ) . I’m anxiously looking for indications of rust or failure. Testing it today it defiantly went into what sounded like a defrost setting. My hoses are quite old so it may be the cause. ( picture is old I cleaned the engine bay significantly). 

6 hours ago, cruiser54 said:

Get the Tips done first.

 

 

Vac ball routing.jpg

 

17 hours ago, eaglescout526 said:

No problem.

What Mjeff87 said about the blower. Wouldn't hurt to take it out and lube it up either. There is a ground mod you should do for it if you have AC. 

 

Service components do include those two and your suspension and steering pieces. Basically pieces that wear out with mileage and time.

 

Yes the C101 if your 88 has it(if it was made before the year 1988, went away with the late 88 and 89-90 model years) can be a huge source of resistance but not surge power.  Disregard my power surge comment, that was used in place of electrical resistance when I was lacking the better term.

 

17 hours ago, mjeff87 said:

^^^yeah that.

 

The HVAC fan is still working fine, it's just that you're losing vacuum to the actuators that direct the airflow.  When that happens it defaults to defrost.

 

There is a vacuum resivoir behind the front bumper on the passenger side to assist with low vacuum situations, and yours nay be bad, or one of the lines to it may be damaged/missing.  It will be either a small black plastic ball about the size of a softball, or a larger, more oval shaped canister.  Check the resivoir and all the lines to it, and follow the one line up into the engine bay/firewall to make sure it's still good.

 

145511C1-ED5F-4770-A4D8-538732315626.jpeg

21E1F7AC-3DE1-49FF-AE07-1893423BE03A.jpeg

E17D6D13-8B60-4872-9BD0-37B116B5BAC5.jpeg

28308317-9ECB-4D97-8CC2-A251AA3D689B.jpeg

82D1B76D-F04A-4F55-B473-7D6A4AE867B6.jpeg

590D0E12-AFB1-43BB-9846-4AB897E77E88.jpeg

C1820326-3BBC-4916-A78E-C1504B6EB1AD.jpeg

B9CE3D59-31CD-4591-9066-B1E73C2B53FD.jpeg

AF207AC8-2FE8-484C-80BF-43A806479F5E.jpeg

EC331E43-7A6E-4A42-B750-1237C9898C50.jpeg

6FA387C2-8571-48C7-A9DA-DF16B767D132.jpeg

C8417CE9-EC42-48B0-8211-11967E1622AD.jpeg

42024321-4641-4F89-8B5A-DF6A227065D0.jpeg

Share this post


Link to post
Share on other sites
23 minutes ago, CoastChief said:

Black and silver? 

 

Lol. That's your starter dork.

 

image.png.bd814d8f938fed289047483f61a03bcf.png

The hose circled is the evap canister and its run off.

Share this post


Link to post
Share on other sites

You have a VERY clean truck underneath! I’m jealous. 

 

Sounds like you’ve got lots to learn about the truck, thats what CC is for! :comanche:

Share this post


Link to post
Share on other sites
2 minutes ago, 500 MJ said:

You have a VERY clean truck underneath! I’m jealous. 

 

Sounds like you’ve got lots to learn about the truck, thats what CC is for! :comanche:

Yeah I’m a total scrub, I have only owned it for 20 days. 

 

9 minutes ago, eaglescout526 said:

Lol. That's your starter dork.

 

image.png.bd814d8f938fed289047483f61a03bcf.png

The hose circled is the evap canister and its run off.

Ah crap, I need to open up my manual and learn a bit more before asking! Thank you guys for your patience!!! 
 

 

 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...