Question about 1990 Jeep Wrangler

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1990 jeep wrangler

Runs rich won't stay running replaced map and temp sensor

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Cadaver is right on -- except he missed one question that needs to be asked first. You say you replaced the temperature SENSOR.

Which one? If it was a 1 wire sensor, installed in the head at the back corner of the valve cover, on the drivers side, that one is for the gauge only..... And it is call the temperature SENDER.
You likely need to replace the one for the ECU, which is usually in the side of the block behind the exhaust manifold (lay under the vehicle and look up on the driver side -- you will see two sensors in the side of the block. The one way down by the oil pan is the knock sensor, the one higher up is the coolant temperature sensor. DO NOT remove the coolant temp sensor on a hot engine -- antifreeze is going to come out when you remove it and you could be scalded!

I ask the question above because the temp sensor is the usual cause for running rich -- but as you can see from Cadavers post, its not the only possibility. The other most common cause (also associated with lack of power) is a plugged air filter. Have you checked yours lately?

If you have the I-6, any OBDI scanner set up for chrysler should be able to read the codes from it (assuming you have the orginal 1990 engine in the vehicle AND you have the HO version.) If you have the non HO version, then Cadaver is correct. No reasonably available scan tool for the Renix Jeeps...
Easy to tell which version you have : Do you have a check engine light? Yes = HO, No = Renix.
Note, the AMC symbol on the dash in the renix version is NOT a check engine light -- in fact its actually a low fuel light...

Hope this helps!

Posted on Feb 15, 2015

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    _-__-___-_ Feb 15, 2015

    x2 , all that, there can be up to 4 temp sensors, or more, Dash gauge, overheat for A/C , transmission, and ECT for engine. yes,Renix does stink that way, zero support. (0ver the counter tools) OP< this is a very old car, why not do the compression, ? first, then vacuum, then the tuneup, (full) , we then can test the sensors, all can bet tested easy, no need to guess( replace the 02 at tuneup, they are 100k mile part) and while there see if the exh, manifold is cracked, this year car loves to crack there. the vacuum test, 19" of vacuum at idle (till it stalls) and vacuum not bounching like made (bad that) and if running you never said how how long right foot can keep it running, and if can or can not.? but if Can, the vacuum must drop fast, as you gun the throttle or the cat is melted or broken up, (as all mine did x3)

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    _-__-___-_ Feb 15, 2015

    got tools? if not get it serviced, with tools this is easy, ask. we can show how to do each step if you want.

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    _-__-___-_ Feb 15, 2015

    never seen an HO. high output, but all this changed for better in 1993. with real ECU.

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    _-__-___-_ Feb 15, 2015

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    _-__-___-_ Feb 15, 2015

    my guess is 93+ HO swap to 90?

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    _-__-___-_ Feb 15, 2015

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    _-__-___-_ Feb 15, 2015

    tuned up, new cap,rotor ,wires-set, sparkplug ,air filter , and fuel filter? need the 60K list?

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    _-__-___-_ Feb 15, 2015

    if engine has full power ,does it? when running? the ISC (iAC) loves to stick and if closed stuck, will stall. ever clean it, i hand to every 10 to20k miles for 500k miles on 3 of my jeeps. ask how and best way ? i

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    _-__-___-_ Feb 15, 2015

    all i have are questions, can rigth foot save the stall? yes/no? easy or hard.? if yes. a key test, costs zero. stalls hot and cold or is car drivable at all, with wild right foot? all this is input and engine, its a 4.0L renix right? stock, engine, no hacks?


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Which engine, 2.5L , 4L, or?

no scan tool for 93

is CEL lamp glowing running.

lots of things can cause rich, we do tests to find which, lots of tests.


BAD IAT , air temp sensor. reads too cold

oxy sensor would be first. not map, map would be last and can be tested easy the map. just a voltmeter test,

ECT sure, if way off.

water temp not 180F or more. holding, if low, ECT sees and and ECU

never leaves cold start. and sucks fuel for ever .

way too high fuel pressure.

EGR stuck open ,but that causes hot stalls.

bad spark for any reason, ever tune it up?

got black spark tips?

not reading the scan codes and CEL glowing, the ECU

could be in limphone mode. and will run rich and retarded spark.

use the jumper wire and read out the DTC codes. first.

using the diagnostic jumper , shown in the FSM.

Posted on Feb 07, 2014


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SOURCE: 97 jeep wrangler 2.5 running lean

check fuel pressure and check exhaust for leaks. exhaust leaks caqn play with the o2 sensor readings

Posted on Sep 25, 2008

  • 3 Answers

SOURCE: 92 Jeep Wrangler MAP sensor bad?

This may not be your MAP but your Catlettic Converter. I also own a 92 Wrangler and had some of the same issues. My issue was actually a couple of things but they all came from a crack in my exhaust headder.

You may want to check your exhaust headder for cracks. If there is even a small one, (which are VERY common w/ YJ's) than your O2 sensor is thinking that the engine is running too lean. Therefor telling the fuel pump and injectors to dump more fuel into the engine. Well, truth is your not running too lean, in fact, you begin running too ritch.

The unburned fuel that is now comming out through your exhaust collects on the porslen screen inside your catalettic converter where it burns off, causing the screen to melt together. Resulting in a clogged cat.

The only way to fix this is to replace the ehaust headder (welding the crack will not work) and replacing the cat. This would explane your loss in gas mileage and power, due to over back pressure. The ticking sounds like the back pressure working on your valves.

Hopefully I'm wrong and this is not your issue because it is a very expencive repare. You're looking at around 350.00 to 500.00 just for a good headder and atleast 250.00 for the cat. However, an easy way to test this is to take a flash light and have a good look at your headder anywhere there are joints where pipes come together. Look for black, ashy spots above and around the joint. If you see this anywhere then I hate to tell you but this mite just be your problem.

Posted on Mar 18, 2009

  • 6982 Answers

SOURCE: caster adjustment for 1990 jeep yj wrangler

caster is adjusted at the rear of the lower control arms. Camber is fixed and cannot be adjusted by normal means (though special off-set ball joints are available to do that) Toe in is adjusted by turning the sleeves in or out on the tie rod ends. None of this should be done at home though crude adjustments can be made in order to get the front end reasonably straight. Adjustments are made on an alignment machine that allows precise adjustments to all you mentioned as well as front/rear tracking.

Posted on Mar 12, 2010

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3 Answers

Have 97 jeep wrangler 2.5 running rich

double posted, now adds rich but not the actual DTC number
why not post real numbers.
we work best with hard facts not interpretations. ...

case in pont
mike uses ford book to look up jeep DTCs.
he fails.

May 25, 2014 | 1997 Jeep Wrangler

1 Answer

Runs rich wont stay running replaced map and temp sensor

double posted but now with engine stated.
see previous post for answer.

Feb 05, 2014 | 1990 Jeep Wrangler

1 Answer

1990 jeep wrangler runs rih won't stay running replaced map sensor and temp sensor

which engine,? the have up to 3 choices.
what are the full symptoms,
did you do the full listed 60k mile tune up on car?
sparkplugs,wire, cap rotor/filters? no engine runs right with bad spark
unless it's a diesel.
starts good
runs good or bad hot or cold engine
idle at 800 RPM hot?
stalls> when hot and cold engine
lost of power

only stalls , but runs perfect even up hills, at wide open throttle.
fresh gas, or 1 year old?fuel.
can your fast right foot , save the stall, and easily?

ok stalls 101.
1; lost 12vdc to EFI system.
2: lost engine compression.
3: lost spark.
4: lost fueling or floods
there is a simple test for each.
do you want more guesses, or how to do tests.
can do both, but my guessing fails 99 /100 times.

tune it up
do the right foot test. those are always first. on stalls.

Feb 05, 2014 | Jeep Wrangler Cars & Trucks

1 Answer

1990 Jeep Wrangler 2.5l idles rough/ black smoke/ fuel odor

You could pay a garage to diagnose the problem cheaper than throwing more parts at it.
The problems may be connected or they may be different issues.
Yes I would change the oil and filter, but first I would make sure the fuel system is not dumping too much fuel into the cylinders.
The O2 sensor helps the computer decide on how much fuel the engine needs, along with the other sensors. And you said you have already replaced the O2 sensor.
A mechanic would take a scanner and "read" the sensors and look for something out of normal range.
The fuel pump and fuel filter are off the list as far as causing a rich mixture goes.
I would start with the rich mixture and then see if fixing that issue takes care of the no start when hot issue.
Change the oil and filter first, and see if the injector is on too much.
You can watch the spray and tell - at idle it should be very light.
Also look at the engine temp - is it warming up to normal 195 degrees? Can you tell if the fuel pressure regulator is blown and pouring fuel into the throttle body ?
Without a scanner its going to be more difficult, but not impossible to diagnose.
Let me know what you find out.

Jul 23, 2012 | 1990 Jeep Wrangler

1 Answer

92 jeep wrangler 5 spd 4 cyl skipping and bogging down replaced timing chain distributor plugs wires injector o rings cleaned out fuel tank new map sensor and new crank sensor sometimes it runs fine but...

Replace the catalyst convertor. When a convertor goes bad, the guts of it break apart and end up clogging the exit port. One of its functions is to remove toxins from the air. Helps the emission system to run rich or lean gas exhaust.

May 06, 2012 | 1992 Jeep Wrangler

1 Answer

1990 wrangler with a 4cyl was dying at idle found the vac line to the map sensor had a crack replaced it and reset the computer. Still dies at idle and now cuts out at higher rpm. Have to fan clutch th...

It could be a combination of 2 things. A faulty MAP sensor itself or a bad TPS (throttle position sensor). It's not uncommon for a bad TPS to idle when the motor is cold but once warm, not idle fast enough to keep the vehicle running.

Jul 18, 2011 | 1990 Jeep Wrangler

2 Answers

I have a 97 wrangler 2.5. Check engine light is on, running lean, loss of power and high fuel consumption. I have replaced the o2 sensors, reset check engine code. light stays off and engine runs great for...

Something odd about what you posted. An engine that is running lean shouldn't be using a lot of fuel. Lean is when there isn't enough fuel going into the engine. Two other sensors that regulate fuel flow are the map sensor and throttle position sensor. Temp sensor generally would cause a rich condition but I'd test that too. Be sure to check for vacuum leaks at the manifold and lines as well as fittings... A vacuum leak will give the O2 sensor a lean reading...seeing that, the computer will try to compensate by adding fuel. Clearing codes can change the way it's running but as soon as the computer runs through it's internal diagnostics it will turn the light back on if there is a problem.

Mar 24, 2011 | 1997 Jeep Wrangler

1 Answer

I Have a 2000 Jeep wrangler V 6 4.0 liter. ITs running rich.

4.0 is an L 6 . Not having the luxury of being there and doing the necessary testing myself, you will need to do that. You will need to get either a chilton or haynes basic manual and a decent digital volt/ohmeter. things I'd immediately check are the map sensor, manifold temperature sensor and finally, remove and visually inspect the fuel injectors (can test good electrically but be fouled on ends, causing a poor spray pattern). These are suggestions only...I would not replace any of these without testing.
Any questions about specific items, just ask!!
Good luck

Jun 22, 2009 | 2000 Jeep Wrangler

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