Hesitates in 2nd gear and/or Sputters in 1st and 2nd

[greg92jeepxj]

X2 JPNinPA's post . Since the issue is mainly open loop , CTS readings ought to be monitored through warm up to see if gradual temp increase is read . Erratic readings will certainly conflict with open loop to close loop , fuel trim and O2 sensor switching lean/rich all trying to achieve correct air/fuel mixture but are dependent on accurate engine temperature as well as air inlet volume . If the vacuum is now strong , that's helpful . The O2 can better adjust fuel trim with the help of cam and crank sensors accurately reporting engine timing. Engine running well warm at closed loop should now mean intake volume is improved . CTS accuracy needs verification. Agreed.
Yes , battery voltage and connections must be good for PCM to get proper voltage for all sensors for reference and signal. Battery condition important yes but is the alternator putting out optimum ? Wondering if alternator is meeting demand . Alternators known to cause pcm glitch if output not optimum. Btw , voltage regulator controlled by pcm. More checking. Spark plug condition will be helpful , tan , white , carbonated , wet w/raw fuel . I'm guessing they're collecting deposits from idle quality poor . Based on progress made and no dtc's posted , I'm not betting alternator problem or more codes will be thrown but interested to know if output is good.

 

[JPNinPA]

Greg,
Wouldn't a faulty or erratic alternator be a constant and not just a open loop item?

 

[JPNinPA]

Update: Changed out the exhaust manifold gasket. Actually there wasn't a gasket there at all. Just a gasket on the intake manifold. Pulled the old gasket off and put the 1 piece gasket I got from Autozone. Bolted everything up tight and also changed out the O2 sensor since I already had it there. Fired up the jeep this morning and there was a slight "bucking" but it doesn't seem to be as bad as it was before. I'm going to run it all week and report back at week's end of any changes

also, ran some Seafoam through the vacuum lines. No leaks were in the lines but boy did that thing smoke out the neighborhood...lol

So.... fired the jeep up this morning and it did the same spit and sputter from take off. Cleared right up after I got 2 blocks from home and everything got warmed up. About at a loss at this point. Just seems like I'm chasing the rabbit down the hole

JPN: I'll pull the positive side tonight to do the reset and I'll report back tomorrow after the drive into work

Just wanted to take a min and thank everyone who has posted on here trying to help me figure this issue out

So after changing the gasket you ended with a "slight"bucking"", is it still a slight bucking or did it resort back to initial condition?
You might go back and check the intake and exhaust bolts for correct torq and be sure to tighten in he correct order. Recheck for leaks.
Question: Does your heater fan work only blow through your defrost?

If you could post up your O2 readings. Then unplug your upstream O2 sensors while off and try your cold start. Does the issue persist?

 

[Bond--007]

So after changing the gasket you ended with a "slight"bucking"", is it still a slight bucking or did it resort back to initial condition?
You might go back and check the intake and exhaust bolts for correct torq and be sure to tighten in he correct order. Recheck for leaks.
Question: Does your heater fan work only blow through your defrost?

If you could post up your O2 readings. Then unplug your upstream O2 sensors while off and try your cold start. Does the issue persist?

JPN, I'll go back over the bolts to ensure they are tight. I didn't realize there was an order of tightening for those. after the manifold gasket change, there wa sa slight bucking when I first started and ran the jeep. At this point, the full symptoms have returned just as they were prior to the gasket change. I guess I'll buy a couple cans of injector cleaner and spray all around the engine to see if there is a change in engine tone for vacuum leaks

Answer: No. I have all settings working except for the vent (the big plunger thing is broke, I looked under the dash when tracing that issue)

I did create an Excel doc to record the readings from the logging. It will be a couple of days to get a good consensus of readings to report back accurate numbers (trying to concentrate on open loop readings more). I will unplug the O2 before I leave work to see if the issue still occurs


Update: when writing down the readings available last night to create the doc, I noticed a pending DTC is back...AGAIN.

P0441 MOD$D1
Evap Emmission
Incorrect Purge FLow

I have already changed the pruge solenoid on this. Maybe a leaking vac line is causing it which in turn is causing the hesitation/bucking/etc

 

[Bond--007]

Update: I just unplugged the upstream O2 sensor and took the jeep for a spin around the parking lot. The jeep was still warm, but was hovering around 140*. The Fuel System data was showing as OPEN. When I fired up the Jeep, the CEL did not come on and it remained in the Open Loop. When I took off as I do from the house, everything shifted fine and the jeep DID NOT HESITATE or SPUTTER!!! Looking very hopeful right now but the drive home will tell once the engine has completely cooled. I'll post an update on this as soon as I get home from the drive from work (leaving here in about 2.5hrs). If it is related to the upstream, it will generate more questions than answers (1. if in open loop, why did unplugging it change the behavior since open does not read the O2; 2. this is a brand new O2 sensor and nothing changed when I changed it out, why; 3. can I just leave it unplugged or can it potentially cause damage). I know it's too early to ask or answer these questions, so we'll see what develops for the drive home

 

[greg92jeepxj]

Greg, Wouldn't a faulty or erratic alternator be a constant and not just a open loop item?

Yes , it would . Since we do not know the condition of the charging system at this time even though no error code was displayed I am suggesting the charging system be check. This driveability problem is not going away without a fight so I believe that no stone should go unturned and be ruled out if good. It's coming down to the problem is not obvious and it's time to check all the possibilities . At this point , it might not be a bad idea to go over the evap system to be sure that a rich mixture isn't being introduced to a cold engine causing a miss. Again , if no DTC is being displayed , should we just assume there is no problem since it's possible an intermittant problem with a vacuum solenoid isn't open at the wrong time long enough to set a code ? For,all,we know , the ground from the PCM to the evap,solenoid could be grounding on the harness due to a short . Not knowing if the '97 TJ even has an electronic solinoid , I'm suggesting items such as this be checked as a possibility. If not electronic and vacuum and controlled by a vacuum switch , it is sure to not set a error code. This is,perplexing I admit , open loop versus closed but we need to know what is causing the miss cold / open loop and so,far even the scan tool hasn't revealed the obvious. Nothing is being found in closed loop with the scanner to be faulty so it seems we need to find what is happening during warm up that shouldn't . Not saying the alternator is bad or voltage regulator ( pcm ) either but it's better to know if is or isn't. We seem to hit dead ends but there's still,a miss and I think,the basics need a going over to be sure. I guess a check list / update of what was done , I.e. Grounds and battery terminals cleaned for example be posted so,we,know " well , it's not that ". But I will,respect that it's less likely to be the charging system if not a problem warm engine. As long as the alternator is "exciting " and supply to pcm is good even in open loop then we should be able to cross,that off , I'd say. I am still,open to,suggestions but I just believe nothing that could affect the PCM voltage wise or,the engine vacuum , spark,or fuel / air should be left to chance.

 

[greg92jeepxj]

Yes , it would . Since we do not know the condition of the charging system at this time even though no error code was displayed I am suggesting the charging system be check. This driveability problem is not going away without a fight so I believe that no stone should go unturned and be ruled out if good. It's coming down to the problem is not obvious and it's time to check all the possibilities . At this point , it might not be a bad idea to go over the evap system to be sure that a rich mixture isn't being introduced to a cold engine causing a miss. Again , if no DTC is being displayed , should we just assume there is no problem since it's possible an intermittant problem with a vacuum solenoid isn't open at the wrong time long enough to set a code ? For,all,we know , the ground from the PCM to the evap,solenoid could be grounding on the harness due to a short . Not knowing if the '97 TJ even has an electronic solinoid , I'm suggesting items such as this be checked as a possibility. If not electronic and vacuum and controlled by a vacuum switch , it is sure to not set a error code. This is,perplexing I admit , open loop versus closed but we need to know what is causing the miss cold / open loop and so,far even the scan tool hasn't revealed the obvious. Nothing is being found in closed loop with the scanner to be faulty so it seems we need to find what is happening during warm up that shouldn't . Not saying the alternator is bad or voltage regulator ( pcm ) either but it's better to know if is or isn't. We seem to hit dead ends but there's still,a miss and I think,the basics need a going over to be sure. I guess a check list / update of what was done , I.e. Grounds and battery terminals cleaned for example be posted so,we,know " well , it's not that ". But I will,respect that it's less likely to be the charging system if not a problem warm engine. As long as the alternator is "exciting " and supply to pcm is good even in open loop then we should be able to cross,that off , I'd say. I am still,open to,suggestions but I just believe nothing that could affect the PCM voltage wise or,the engine vacuum , spark,or fuel / air should be left to chance.

I posted before I read Bonds reply. An evap,code has reared its ugly head again and yes there is a module so that just raises more questions with regards to trust of after market parts . More to check as well,as vacuum lines.

 

[Bond--007]

getting ready to head out of work. I'll post an update regarding the drive home

 

[greg92jeepxj]

Update: I just unplugged the upstream O2 sensor and took the jeep for a spin around the parking lot. The jeep was still warm, but was hovering around 140*. The Fuel System data was showing as OPEN. When I fired up the Jeep, the CEL did not come on and it remained in the Open Loop. When I took off as I do from the house, everything shifted fine and the jeep DID NOT HESITATE or SPUTTER!!! Looking very hopeful right now but the drive home will tell once the engine has completely cooled. I'll post an update on this as soon as I get home from the drive from work (leaving here in about 2.5hrs). If it is related to the upstream, it will generate more questions than answers (1. if in open loop, why did unplugging it change the behavior since open does not read the O2; 2. this is a brand new O2 sensor and nothing changed when I changed it out, why; 3. can I just leave it unplugged or can it potentially cause damage). I know it's too early to ask or answer these questions, so we'll see what develops for the drive home

With upstream O2 unplugged the PCM will,remain in open loop and follow a programmed map as,it's called to,run the fuel system and ignition for rich mixture mode and bypass engine sensors . The O2 is necessary however during open loop to monitor oxygen / fuel and rich/lean cross counts until engine warm and pcm enters closed loop. The PCM runs on a default with the O2 disconnected . JPNinPA most likely asked this to,be done to isolate the upstream O2 for,it's part in this problem and apparently has an effect. As I've stated , I,respect his diagnostic literate experience and enjoy his input . Even with. My experience , I'd still,hand him the wrench.
You cannot on a permanent basis run the engine with the O2 unplugged as,it will run in open loop constantly and cook,the catalytic converter and run rich constantly to name a few.
May we ask what brand the upstream O2 was ?
This is encouraging , won't take that from you and certainly hope for your sanity that you've found the gremlin even if it means changing a brand new O2 sensor for a good part if the one in place now is jacked up . Hate for that to happen but I know you want/need this jeep to run and be dependable. Let us not overlook the evap error code that popped up !

 

[JPNinPA]

Yes I asked to unplug the O2 as a diagnostic.

You found the beast. Verify with full cold startup.

Swap the O2 with an OEM and fix the evap issue.(first see it isn't a bad or loose gas cap)
A failing O2 sensor can give erratic readings like it is warm when it isn't or cant self heat. Once your exhaust is up to temp the O2 is hot enough the system will function at a constant.

 

[greg92jeepxj]

Yes I asked to unplug the O2 as a diagnostic. You found the beast. Verify with full cold startup. Swap the O2 with an OEM and fix the evap issue.(first see it isn't a bad or loose gas cap) A failing O2 sensor can give erratic readings like it is warm when it isn't or cant self heat. Once your exhaust is up to temp the O2 is hot enough the system will function at a constant.

You the man JP , you the man ! I'll fetch the tools and run to the parts store for you anytime !

 

[Bond--007]

update: ran the jeep on the interstate. It did not buck, hesitate, or sputter out of the parking lot, pulling on to the main road or merging onto the interstate. It is running rich as I can smell it when I let off the throttle and when stopped the RPM is around 1100. The O2 sensor i put in in the pic below. The other pic is the original i pulled out

 

[Bond--007]

http://i256.photobucket.com/albums/hh190/leonbond/IMG_0627_zpse41a1f3f.jpg

http://i256.photobucket.com/albums/hh190/leonbond/IMG_0626_zps576f3dda.jpg

Revised

 

[JPNinPA]

update: ran the jeep on the interstate. It did not buck, hesitate, or sputter out of the parking lot, pulling on to the main road or merging onto the interstate. It is running rich as I can smell it when I let off the throttle and when stopped the RPM is around 1100. The O2 sensor i put in in the pic below. The other pic is the original i pulled out

When you swap in the new IEM O2 reset the PCM again and then report back the condition and rpm of the idle. High idle is a vac leak most of the time. Though reset may correct it.

Is it just me or are all the pics the same?

 

[JPNinPA]

You the man JP , you the man ! I'll fetch the tools and run to the parts store for you anytime !

Parts run!!

http://www.rockauto.com/catalog/moreinfo.php?pk=1643906&cc=1185296

http://www.rockauto.com/catalog/moreinfo.php?pk=1643324&cc=1185296

 

[Dragon5126]

what BRAND O2 sensor is it? this actually may be the answer you seek... Bosh sensors are notorious for creating issues... and they are the mfg of most if not all "house brand" sensors. Stick with NGK/NTK for reliability

 

[JPNinPA]

Dragon,

If you look back a few posts he shows an image. I believe he stated he got them off ebay.

Oh I looked back it was Az.

 

[Bond--007]

UPDATE: Ran the Jeep to work this morning. The CEL was on due to the O2 being unhooked. The jeep was running at high RMPs (1500-2000) just at idle in Neutral. I stopped the jeep and reset the DTC just to clear the CEL. Started the jeep back up (O2 still unhooked) and the jeep ran fine until the CEL lit up again. It looks like the PCM runs a "normal" open loop until it expects the O2 sensor to be operating. Once it doesn't provide data to the PCM, the PCM will go into a default open loop (the scanner showed the system was in OPEN2 mode vs the OPEN mode during regular warm-up). It appears the issue is the O2 sensor. Now I'm trying to determine if the issue lies in the wire harness or the sensor itself

 

[Bond--007]

BTW, the brand of O2 sensor I purchased is a SMP

 

[Bond--007]

I contacted the seller on EBay and advised them the SMP sensor does not work with the Wrangler. They said due to the issue with the sensor, they will ship me a NTK sensor to replace the SMP (plus a mailing label to return the SMP)......... update to come