Cherokee cold start, chocking problem

[deesweet]

My 98 Cherokee is having trouble with cold starts. At first it was just a little hesitation but now it takes a while to start if it hasn't been driven with-in an hour. Warm starts are no problem. I checked my altenator, starter, battery (they are all less than a year old and in good shape), my air filter is clean, my spark plugs are new. I know I have no external fuel filter (in-tank assembly) so I checked how my fuel pump is working and it is ok. I also have NO codes. I had a pickup with this problem and it was the cold start censor but my local parts place says there is no cold start censor for my jeep. Could it be the map censor? Does anyone else have any other ideas?? Your help is greatly appricated.

 

[guysmiley]

Most cherokee's of that year, body have problems with the fuel pump assy. Its not a weak pump. I'm sure you checked pressure, and the pressure is there. Its a problem with the check valve that lets fuel depressurize and drain back to the tank. Connect a pressure gauge and leave it overnight. Check the gauge first thing in the morning, if it is low, have someone crank and watch the gauge. It will finally start when pressure builds. If you don't have any problems with the fuel system, check for spark on cold start and clean out throttle body. Throttle body gummed up will give you problems. Good luck, post back with the fix, interested in finding out what it is. Map sensor will give you all around driveability problems and most likely trigger the CEL. The map sensor converts pressure/vacuum into electrical signals for the ecm to use to set fuel and ignition timing.
Guysmiley

 

[deesweet]

Thank you, I will try that.

 

[90Xjay]

Thank you, I will try that.

any luck with the problem yet?
Keep us posted

 

[deesweet]

My husband thought that adding rubbing alchol to my tank would clean it out (it has worked for him in his truck) however it only worked for about a week and know I am having trouble again. He put the gauge on it tonight so we'll see in the morning if its the throttle body.

 

[droopey]

My wife has a 99 sport. Does your husband think there is water in the fuel, or
is he using the alcohol for some other reason?

 

[deesweet]

there was no problem with the pressure come morning.

My wife has a 99 sport. Does your husband think there is water in the fuel, or is he using the alcohol for some other reason?

Yes he thought thier could be water in it. He also thought I may have gotten some low quality gas when we were forced to buy from a no-name station on a road trip. Adding alchol or fuel treatments have helped a little but the problem keeps coming back.

 

[90Xjay]

Isopropyl alcohol can help disapate small amounts of water. It is the main ingrediant in gas line antifreeze products usually

 

[deesweet]

I just failed my state inspection. As the tech hands me the report he says I don't know why your check engine light is on but you failed for emmisions. And as I pull away my check engine light goes on, ugh! The report he gave me listed a group of possible causes. I'm thinking its the O2 censor any chance my starting problem could be related to this?

 

[guysmiley]

An O2 sensor generally will not cause starting problems. An O2 sensor needs to be hot to operate properly. Its a chemical reaction that is transferred to electrical signals that the ecm can use. Anyway...newer vehicles on the road have heated sensors, meaning that current flows through the sensor to heat it up on initial startup. But even then, it takes a little time to warm up. Significantly faster than the single wire versions. An O2 sensor only moniters the oxygen content in the exhaust and has the ecm regulate the fuel through injection pulse. It is possible you might have a bad coolant temp sensor. If you can give me the codes on your inspection report, I might be able to help you out.
Guysmiley

 

[90Xjay]

I just failed my state inspection. As the tech hands me the report he says I don't know why your check engine light is on but you failed for emmisions. And as I pull away my check engine light goes on, ugh! The report he gave me listed a group of possible causes. I'm thinking its the O2 censor any chance my starting problem could be related to this?

If the O2 sensor has been bad it will make the engine burn rich.

deesweet, run your finger(or husbands finger) around on the inside of the end of the tail pipe.

See if there is thick black soot built up there.
If so, that is un-burned fuel in the form of carbon.
That is an indication of a bad O2 sensor.
That can foul plugs and make a hard to start situation

 

[deesweet]

Re: Cherokee cold start, choking problem

OBD System Code: P036 (only had one code)

(i do not have any codes on my dash when i check myself)

 

[deesweet]

If the O2 sensor has been bad it will make the engine burn rich.

deesweet, run your finger(or husbands finger) around on the inside of the end of the tail pipe.

See if there is thick black soot built up there.
If so, that is un-burned fuel in the form of carbon.
That is an indication of a bad O2 sensor.
That can foul plugs and make a hard to start situation

Ok, tried that and its clean and my brother (have him here helping me) says its not running rich it is running lean.

AND thank you everyone for your help so far

 

[mud4feet]

P0036
02 Sensor Heater Control Circuit (Bank 1 Sensor 2)
Shorted condition detected in the oxygen sensor heater element control feedback sense circuit.

From:
http://www.wjjeeps.com/faultcodes.htm#0010

From personal experience, when the O2 sensors go bad, it causes severe loss of power and some really, really bad mileage........heck, might cause hard starting too. New sensors are in the neighborhood of $50.

my $.02,
mud

 

[90Xjay]

P0036
02 Sensor Heater Control Circuit (Bank 1 Sensor 2)
Shorted condition detected in the oxygen sensor heater element control feedback sense circuit.

From:
http://www.wjjeeps.com/faultcodes.htm#0010

From personal experience, when the O2 sensors go bad, it causes severe loss of power and some really, really bad mileage........heck, might cause hard starting too. New sensors are in the neighborhood of $50.

my $.02,
mud

good find Mud!

 

[deesweet]

P0036
02 Sensor Heater Control Circuit (Bank 1 Sensor 2)
Shorted condition detected in the oxygen sensor heater element control feedback sense circuit.

From:
http://www.wjjeeps.com/faultcodes.htm#0010

From personal experience, when the O2 sensors go bad, it causes severe loss of power and some really, really bad mileage........heck, might cause hard starting too. New sensors are in the neighborhood of $50.

my $.02,
mud

When my O2 sensor went bad in my Dodge Dakota it caused stalling and choking problems. $50 would be great for that part I was thinking it would be about three times that (it was $160 for the dodge). And yes I'm getting crappy gas mileage. Thank you!

 

[guysmiley]

Not to disagree with anybody, but is it possible its a code p0360? Are you reading the code right. p0360 is an ignition fault which sounds like what you have. Like I said, I could be wrong, but never had an O2 sensor cause a no start. The original complaint was a hot soak, after vehicle has sat a few minutes after running. The computer will be in a default stage, fixed running condition until it warms up, then the O2 will start operating. If the sensor was that bad, the vehicle will run very rough and stall out. You should have received a CEL light a long time ago. P0036 states bank 1 sensor 2 which is the sensor after the cat. That sensor has no effect on engine operation. Sensor 2 is only used to check condition of the catalyst. Just a thought.
Guysmiley

 

[Wrangl3r93]

The o2 sensor i bought for my gf's jeep was 58 dollars after tax and it was a straight unplug/plug back up install(15 minutes at most). But judging by your description and by personal experience of a bad o2 sensor i think guysmiley is right. The o2 sensor will make it run very very bad but i've never heard of it making a vehicle not start. Good luck though.

 

[deesweet]

the new 02 censor did not fix the problem but according to the inspection tech i needed to show the reciept for it to get it re-inspected anyway (nj sucks). I guess i will now have to check out the ingnition - or have my husband do it. thats something i don't have any experience with.

 

[johnnstace]

Hi there - new here but i wanted to comment on the problem you are having.

I have a 97 Cherokee Country that is having the same issue. 155k miles on mine.

When cold you need to crank about 30-40 seconds and it will start and idle a bit rough for a bit. If you crank for about 10 secs and stop wait a couple secs and then retry it wil pop right off.
If the vehicle is warm - say you run into Starbucks for a latte and restart it starts right away.

The issue is a check valve at the fuel pump in the gas tank that is leaking. This causes the liquid fuel that was in the line to the rail to drain back into the tank.

Normally when the check valve works the fuel cools but remains in the line and becomes repressurized instanly. When the fuel runs out it is like it ran out of gas and takes awhile to fill the line. Doing this is tough on the starter and battery.

Of course the geniuses at Chrysler put the whole fuel pump assy in the gas tank making it a great revenue program for the service department at the dealer to repair them.

I have not fixed mine yet and I am getting an estimate on the fix this week. I am having the entire thing replaced while they are in there so I don't have to mess with it again.

I may do it myself but dropping the tank and all the rest almost seems to be more than I want to take on. If anyone has done this repair and can comment on it I would be interested in hearing your experiance.

john