I am a new jeep owner. Just bought a 1990 jeep and have so far been towed twice and then off to a muffler shop. All is suppose to be perfect on it now except i am noticing i am inhaling lots of exhaust. Didn't seem to do that before. Muffler guy said he fixed holes and added a new muffler and that i am just picking up exhaust from it running with the top down. It has no ac so i plan on always having the top down. I googled and asked him about the o2 sensor? Maybe it went bad and i need to replace it. He says if so the check engine light would come on and i would hear it making noise. The more i google the more i am finding there is no check engine light on the 1990s. How hard is this job and can i change it myself? I like having a machanic that will help me keep this thing running but i am kinda interested in doing pthings if capable. Any suggestions on part to use? Looks like the one on there is a single wire with no heat? I will post some pics.... any help and advice is appreciated. Thanks
O2 sensor replacement questions
- Thread starter Amy lee
- Start date
That is the clutch slave cylinder bleeder valve. You're good.
As to the O2 sensor, I'm guessing it's throttle body FI as the sensor is in the manifold.
Mine is a '91 with MPI and I put my sensor where yours is (mines supposed to be in the head pipe about 4" from there).
The only reason I did this was the new exhaust had the bung but they didn't drill the pipe and I knew the manifold had a plug.
What difference could 4" make, well I've got similar issues to yours now and it's developed a random miss.
Maybe related, maybe not, dunno.
But, if I don't warm it up first, I'll get CE light and code 52 every time, O2 rich.
As for yours, I'm thinking the sensor is fouled.
Coolant from a leaking head gasket will do it, Oil will too.
As will a sticky injector or leaded fuel.
The fouling on the sensor will look different for each.
www.walkerproducts.com
As to the O2 sensor, I'm guessing it's throttle body FI as the sensor is in the manifold.
Mine is a '91 with MPI and I put my sensor where yours is (mines supposed to be in the head pipe about 4" from there).
The only reason I did this was the new exhaust had the bung but they didn't drill the pipe and I knew the manifold had a plug.
What difference could 4" make, well I've got similar issues to yours now and it's developed a random miss.
Maybe related, maybe not, dunno.
But, if I don't warm it up first, I'll get CE light and code 52 every time, O2 rich.
As for yours, I'm thinking the sensor is fouled.
Coolant from a leaking head gasket will do it, Oil will too.
As will a sticky injector or leaded fuel.
The fouling on the sensor will look different for each.
Troubleshooting Oxygen Sensors - Walker Products
www.walkerproducts.com
Wow... thank you! That link explains everything. I think i will give it a go. I don't think the 1990 jeep has a way to check codes so maybe i will just change it and see what happens.That is the clutch slave cylinder bleeder valve. You're good.
As to the O2 sensor, I'm guessing it's throttle body FI as the sensor is in the manifold.
Mine is a '91 with MPI and I put my sensor where yours is (mines supposed to be in the head pipe about 4" from there).
The only reason I did this was the new exhaust had the bung but they didn't drill the pipe and I knew the manifold had a plug.
What difference could 4" make, well I've got similar issues to yours now and it's developed a random miss.
Maybe related, maybe not, dunno.
But, if I don't warm it up first, I'll get CE light and code 52 every time, O2 rich.
As for yours, I'm thinking the sensor is fouled.
Coolant from a leaking head gasket will do it, Oil will too.
As will a sticky injector or leaded fuel.
The fouling on the sensor will look different for each.
Troubleshooting Oxygen Sensors - Walker Products
It should have OBD1.
You can check for codes as follows;
Without starting the engine, Ignition on, off, on, off, on, then the Check Engine Light will flash in a series, those are the codes.
This is if the CEL is actually working, it should come on when you first turn on the ignition before starting it.
How To Retrieve Your Jeep's Diagnostic Code
Torque Staff Report This method is used to retrieve OBD I and OBD II diagnostic trouble codes from your YJ, TJ, XJ, ZJ, and early WJ Jeep models.
Ha, for us hard learners ;0 the code patterns can be a bugger to get right of you have several. The 02 sensor is a piece of cake to replace and cost around $35 or so. Lots of guys say do NOT use Bosch ones but NKT which is NGK's line or a another common brand. far as the fumes, my 91 has a clean bill of health but it is a bit stinky with the back window off or rolled up. Thus I never run like that anymore. I run the top with no doors or sides and have added a 90 out the side or rear corner instead of straight out the back. It did help some with the fumes.
disaster06
New Member
I have been searching but have had mixed results, does an 89 YJ only have the upstream O2 sensor? I looked downstream and dont see one after the CAT, nor do I see a wiring harness.
(all I have come across, is that my 89 is an OBD1 and should only have 1 o2 Sensor, I have a 2.5L by the way if that makes a difference).
Thanks!
(all I have come across, is that my 89 is an OBD1 and should only have 1 o2 Sensor, I have a 2.5L by the way if that makes a difference).
Thanks!
I believe OBD1 only uses 1 sensor, I cannot find a downstream listing. Matter of fact my 99 F250 V10 only uses one upstream sensor but is OBDII.
down stream started in 1996 USA or 1998 in canada, is down stream is only OBD2, CAT testing, (called OBD2 monitors)
the coax clutch slave is 100% normal. (not seen on 95s 94+)
the engine is probably running rich. or the CAT burned up 20 years ago, all cars with dead cat stink, ALL DO.
The O2 sensor there is easy to change, and allows closed loop at idle and easy cruise. if it shorts out the engine goes rich
and the cat glows red hot. and burns up then stinks, all cat cars made from 1979 same answer. (gas , otto cycle engines ,ICE)
high fuel pressure , FPR bad.
got DTC blink codes?
post photos of top left rear of engine called the throttle body so we can go ,gee that is wrong, etc. photos are like magic , no?
map sensor or hose to it a wreck. or clogged
injector leaks. at idle. and exh stinks, rich. air fuel mix, is going to stink,
EGR bad. makes stink of NOX. fumes.
yes the CEL lamp works, in the dash !! "check engine lamp or SES or MIL" has 3 names sorry.
key on it GLOWs if not the CEL lamp burned out 20 years ago? or some derp removed it to hide the errors it reports to get higher sales price. <evil
there are 2 ways to get the DTC CODES (DIAGNOSTIC TROUBLE CODES) THE KEY ON 3 TIMEs TRICK TOLD IN THE FREE SERVICE MANUAL.
OR a jumper at the DLC< means next to ECU is diag logic connector.
There is no OBD1 scan tools sold now. (rare or crazy expensive scalping)
your exh tail pipe tip looks super rich to me.
make sure all vacuum hose match page 25-4 in the SM.
This car was 2.5L TBI day1 new, throttle body injected not MPI like mine.
make sure fuel pressure is good spec, and regulates, correctly
make sure map works
make sure 02 sensor is good, BOSCH is great gee they invented it , it's GERMAN quality, folks that install wrong O2 and then blame bosch is silly and endless. Internet rumors. or they had 2x normal fuel pressure and now the poor 02 is packed deep in carbon,. gee not BOSCH's problem it is the techs problem. end full stop,BOSCH rumors.
The ECU may be over injecting or fuel pressures are too high
The ECU inputs must be correct or it sure can over inject, MAP readings wrong sure. O2 sensor, stuck at 0volts for ever it will runs rich as a pig.
ECT reading wrong and shows readings for Alaska not Key west FL. dig? it must read correctly or gets stuck in cold ECU fueling for ever rich.
bad injector, leaks.
the coax clutch slave is 100% normal. (not seen on 95s 94+)
the engine is probably running rich. or the CAT burned up 20 years ago, all cars with dead cat stink, ALL DO.
The O2 sensor there is easy to change, and allows closed loop at idle and easy cruise. if it shorts out the engine goes rich
and the cat glows red hot. and burns up then stinks, all cat cars made from 1979 same answer. (gas , otto cycle engines ,ICE)
high fuel pressure , FPR bad.
got DTC blink codes?
post photos of top left rear of engine called the throttle body so we can go ,gee that is wrong, etc. photos are like magic , no?
map sensor or hose to it a wreck. or clogged
injector leaks. at idle. and exh stinks, rich. air fuel mix, is going to stink,
EGR bad. makes stink of NOX. fumes.
yes the CEL lamp works, in the dash !! "check engine lamp or SES or MIL" has 3 names sorry.
key on it GLOWs if not the CEL lamp burned out 20 years ago? or some derp removed it to hide the errors it reports to get higher sales price. <evil
there are 2 ways to get the DTC CODES (DIAGNOSTIC TROUBLE CODES) THE KEY ON 3 TIMEs TRICK TOLD IN THE FREE SERVICE MANUAL.
OR a jumper at the DLC< means next to ECU is diag logic connector.
There is no OBD1 scan tools sold now. (rare or crazy expensive scalping)
your exh tail pipe tip looks super rich to me.
make sure all vacuum hose match page 25-4 in the SM.
This car was 2.5L TBI day1 new, throttle body injected not MPI like mine.
make sure fuel pressure is good spec, and regulates, correctly
make sure map works
make sure 02 sensor is good, BOSCH is great gee they invented it , it's GERMAN quality, folks that install wrong O2 and then blame bosch is silly and endless. Internet rumors. or they had 2x normal fuel pressure and now the poor 02 is packed deep in carbon,. gee not BOSCH's problem it is the techs problem. end full stop,BOSCH rumors.
The ECU may be over injecting or fuel pressures are too high
The ECU inputs must be correct or it sure can over inject, MAP readings wrong sure. O2 sensor, stuck at 0volts for ever it will runs rich as a pig.
ECT reading wrong and shows readings for Alaska not Key west FL. dig? it must read correctly or gets stuck in cold ECU fueling for ever rich.
bad injector, leaks.
and that header End gasket not leaking if it leaks the exhaust sucks in air, just after each putt, (have hard proof)
and this air is 20% oxygen and makes the o2 read 100% lean{0v} (air is lean max) so to compensate the ECU goes max rich ! OOPS FAILS.
and now the stink. this is called fuel trim on OBD1 and OBD2 both .
the fuel trim goes 100% rich. in this failing mode a simple exhaust leak.
i uses rubber tube to my ear, duct taped to end of round 20" dowel rod. (no burns) and wave it too engine all over that side of engine , exh ports to front
of muffler. if I hear putt putt to my ears that is an exhaust leak. fix it.
case in point,
my 1988 the SST factory headers loved to crack, and there is a simple cure then, the clamp at the rear busted on 2 of my 88 jeeps. (a factory flaw)
and the O2 went totally mad and MPG sucked fuel like a pig.
I designed my own grilla clamp (weld up by me) and drove 250,000 miles not one problem (beyond normal service) 4liter engines.
and this air is 20% oxygen and makes the o2 read 100% lean{0v} (air is lean max) so to compensate the ECU goes max rich ! OOPS FAILS.
and now the stink. this is called fuel trim on OBD1 and OBD2 both .
the fuel trim goes 100% rich. in this failing mode a simple exhaust leak.
i uses rubber tube to my ear, duct taped to end of round 20" dowel rod. (no burns) and wave it too engine all over that side of engine , exh ports to front
of muffler. if I hear putt putt to my ears that is an exhaust leak. fix it.
case in point,
my 1988 the SST factory headers loved to crack, and there is a simple cure then, the clamp at the rear busted on 2 of my 88 jeeps. (a factory flaw)
and the O2 went totally mad and MPG sucked fuel like a pig.
I designed my own grilla clamp (weld up by me) and drove 250,000 miles not one problem (beyond normal service) 4liter engines.
Ozark mike
New Member
My cat was removed by po and I have replace all sensors mine doesn’t have a smell with top off. O2 sensor can be hard to get off from heating and cooling of pipe. I broke mine and ended up using impact to get it off.
his car is not your car,
his is running rich and yours is not, thus the smell...
a good cat eats up all that rich burning fuel and catalysis it so it does not stink of fuel raw. ( 1 of 3 things it does)
if he gets the 02 sensor working and it goes to closed loop the nasty smell ends.
using the correct tool the o2 comes off, or do it hot. (using leather gloves,)
we fix these in order. or the 2nd new 02 is wrecked again, see how that works?\
good luck guessing.
his is running rich and yours is not, thus the smell...
a good cat eats up all that rich burning fuel and catalysis it so it does not stink of fuel raw. ( 1 of 3 things it does)
if he gets the 02 sensor working and it goes to closed loop the nasty smell ends.
using the correct tool the o2 comes off, or do it hot. (using leather gloves,)
we fix these in order. or the 2nd new 02 is wrecked again, see how that works?\
good luck guessing.