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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
Guys I'm having an issue with my 89 Laredo. It takes forever to get the thing cranked and when I do I have to keep giving it gas to keep it running, as soon as I let off it dies. I've looked over cruisers renix posts and am planning on doing some work with the throttle body tomorrow along with new plugs wires cap and rotor. Does anyone else have any ideas on things I can try?
Replaced all the spark plugs, wires, cap and rotor. It will stay cranked but is still having some idle problems. Revs up to about 1200RPM then drops down to just barely above 0. The IAC was pitch black when I pulled it out of the throttle body, cleaned it up as best I could but from the looks of it, its never been cleaned. Probably just going to pick up a new IAC and TPS from NAPA on Monday to see how it goes.
Really those grounds matter, you could chase your own tail all day and get nowhere if they are not good. My IAC trouble was more the plug, than the iac it's self. Also, cleaning the ground gang on the dipstick stud, as well as checking sensor ground resistance is a really supper place to start.
It's free to borrow a fuel pressure tester btw. 39lbs with the vac line off the regulator, (located at the front of the fuel rail), about 10 less with it on.
Being that it's so crucial and only takes two minutes, I'd check the AC output from the unplugged CPS, first, always. (plus that will help some get familiar with the meter to use to check ground resistance).
Here's another "no brainier" >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>.There is a brittle little tube. It comes out of a rubber plug, low on the engine side of the throttle body. It runs back to the firewall, then up to your MAP sensor sort of high up there near center on the firewall. CRUCIAL!! The MAP will tell the ECU to dump fuel with less/no vacuum. Any crack or blockage and it will be pig-rich. (black smoke, fouled black plugs). You can pull the line off the MAP and feel for vacuum with your finger. If it runs!
Last edited by DFlintstone; 03-07-2015 at 06:13 PM.
I will definitely check the grounds tomorrow. And if I can get it cranked up to check the vacuums I will do that as well. I found that line that comes off the bottom of the throttle body when I cleaned it today (guy I bought it from rigged up an intake and put a bunch of glue around the gasket, leaked down into the TB and was holding the butterfly valve closed). The piece that sits inside the throttle body that the line hooks up to wasn't in real good shape, so that may be a big problem.... If I can get it uploaded I have a video of it idling...Tomorrow should be loads of fun...
Yesterday I spent about an hour under the hood and didn't get as much done as I had hoped, but I still got some things done.
1. Cleaned the ground gang at dipstick stud. I noticed that there was a place for a bolt just forward of the ground is anything really important supposed to be attached there?
2. Checked the fuel pressure at the rail. Gauge was jerky between 38 and 41. Hit the gas, drops to 30 then comes back up. Just had a guy look at all of the fuel injectors 2 weeks ago, he replaced all the O-rings and had to replace 3 of the injectors.. he determined that the other three had been replaced recently. I didn't do the 746 upgrade on this round, but am planning to upgrade them all to 746s in the near future.
3. Started on Cruiser's Renix Tips got #1 done and got halfway through #3 (finished the right side of the engine bay, still have to do the left side). As I was doing tip #3 I noticed that a ton of things had T-taps and crimped couplers... the electrical system is a total mess and I have a feeling I will be replacing a lot of wires depending on what I find this afternoon...
This afternoon I'm going to get the voltage meter out and check the TPS and CPS as well as ground resistance and vacuum.
On a side note, I'm pretty sure the timing is off, I am definitely am going to have to replace the valve cover gasket (not cork!) as well as the thermostat housing. Long story short I had to have everything re-tapped because they stripped a lot of stuff out... power steering and alternator were flopping around and causing lots of issues... they took the thermostat housing off and stripped out those bolts and put everything back together with electrical tape to keep it from leaking.... I'm not sure they had a good understanding that tape melts when it comes into contact with heat ................ it looks like they may have backed out some of the valve cover bolts too so, I'm going to leave it alone and take it to the guy who re-tapped everything to do out of fear that they screwed up those threads too. This may be a big part of the problem, but I'm trying to knock out everything I can to save having a big mechanic bill... plus all the stuff I'm doing has to be done anyway...
here is a link to a video of the current condition...
Good work, nice post and wowa! Sheez...I might suggest a compression test to get a better idea how much work I'd want to put into that. Granted it might not be as bad as it sounds, but it sounds pretty bad. Having a set of wet/dry compression numbers might come in handy down the road one way or the other.
Good work, nice post and wowa! Sheez...I might suggest a compression test to get a better idea how much work I'd want to put into that. Granted it might not be as bad as it sounds, but it sounds pretty bad. Having a set of wet/dry compression numbers might come in handy down the road one way or the other.
Okay, I did a compression test myself this afternoon. Compression as a whole is not great, and cylinder 4 would not turn over or read at all, so I'm going to assume a 0 compression. Here are the numbers I got, but I will probably have the shop do it again just to double check:
Dry: 70 80 75 0 80 90
Wet: 70 70 80 0 80 90
Cranked 5 revolutions on each stop... I have other findings as well, but I will post those in the morning when I can pull photos off my phone, found some kind of sensor that I need help identifying... still working on tip#3 but I have finished 1 4 and 5.
Okay, I did a compression test myself this afternoon. Compression as a whole is not great, and cylinder 4 would not turn over or read at all, so I'm going to assume a 0 compression. Here are the numbers I got, but I will probably have the shop do it again just to double check:
Dry: 70 80 75 0 80 90
Wet: 70 70 80 0 80 90
Cranked 5 revolutions on each stop... I have other findings as well, but I will post those in the morning when I can pull photos off my phone, found some kind of sensor that I need help identifying... still working on tip#3 but I have finished 1 4 and 5.
Nope, the particular guide I found didn't have opening the throttle in the instructions. I still have the compression tool so I could retest if need be
Nope, the particular guide I found didn't have opening the throttle in the instructions. I still have the compression tool so I could retest if need be
Unplug the CPS and have the throttle wide open and see what you get.
Pull the valve cover, see if the push-rods are on the rockers. I mean that's what I'd do. There is no sensor, ground, or throttle position that gives a goose egg for cylinder compression. Actually with both push-rods in the pan it should read something. Maybe they market a larger can of that Restore stuff?.....Seriously though..a rebuildable block is more valuable than a trashed one. Something to consider as you run it.
If you drain the oil, is some of #4 piston in the tray?
Last edited by DFlintstone; 03-10-2015 at 01:07 AM.
talked with my mechanic this morning, and he is gonna set me up with fixing the dead cylinder problem, so I'll point him to this thread to read everything that we have talked about/done so far.
However, when I was working through Tip #3 I found a sensor that definitely needs to be replaced. My brother and I had the jeep cranking really well (after cleaning the ICU/Coil), but when I pulled this particular sensor, the jeep quit cranking at all. It came off into a few pieces and was corroded really bad. I have no idea what this thing is, and haven't had any luck with google searches, so if you guys could provide some assistance I would greatly appreciate it.
03-06-2015, 10:39 PM
89 4x4 idle/run problems
Also, cleaning the ground gang on the dipstick stud, as well as checking sensor ground resistance is a really supper place to start. 
................ it looks like they may have backed out some of the valve cover bolts too so, I'm going to leave it alone and take it to the guy who re-tapped everything to do out of fear that they screwed up those threads too. This may be a big part of the problem, but I'm trying to knock out everything I can to save having a big mechanic bill... plus all the stuff I'm doing has to be done anyway...
