Birty Dastards Jeep Club
Tech Forum => Workshop => Topic started by: Nosebolt on December 06, 2012, 11:45:06 AM
-
this is ongoing from the TPS issue, have fitted a new Mopar TPS and seemed to be fine for about 10 miles, now I have a similar problem but its not exactly the same where as before the engine would limit at 20 mph it will now get to 40mph but the revs fluctuate when under load I did manage to get it to do the same with the bonnet up and it sounded like it was back firing into the air box.
what could be causing this?
HELP!!!!
-
Just a thought... did you try pulling codes.......... :icon_winkle:
-
Possibly either the CPS or the distributor switch plate if it has one, or a faulty coil pack if they are fitted, I say this as im not sure what one you have.
edit, ah just seen :icon_rolleyes: I would suspect either the CPS or the switch plate in the distributor.
-
been doing some research and the symptoms seem to match a MAP sensor failure, a quick search on eBay and found a used low milage gen part for £18 so have ordered it and will see if it helps.
Have also taken off and cleaned the air idle motor which was heavily sooted.
14 mile drive home should be interesting
-
If it's rich could be lambda. it would run ok for a few miles then start running lumpy, then start missing and back firing....... i know i changed mine earlier this year, :icon_winkle:
-
positive side of all this is when you're all fixed the mods will have to make this a stickie......
Cos its gonna happen to us all over the next few months years.......... Ad this information all in one place is gold :icon_super:
-
back home now, as I said I had the air idle motor off and cleaned it also took off the MAP and made sure air ways were clear and rubber not cracked, refitted it all and engine would not idle :banghead: 2 footed it to drive home and was rough as fuck for about 6 miles with the engine check light on, the all of a sudden EC light went off and engine started to run sweet all the way home :017:
the replacement Manifold Air Pressure Sensor is ordered and will be here early next week but the more I read the more I recon it is the MAP at fault, just read this (http://www.jeepsunlimited.com/forums/showpost.php?s=b741c8852d0874f44cc8d7d97120e264&p=322205&postcount=4) hope this is the problem as will be a cheap fix at £18
-
Does sound like your symptoms,interesting how it started running well again after rough start.
Be tempted to keep the gear to swap MAP in the Jeep and see how long it runs Ok before swapping out.
-
Is the cat breaking up?
-
Is the cat breaking up?
my TJ cat collapsed causing backfiring through my airbox/ snorkel :icon_winkle:
but i did get downstream oxygen sensor fault
-
cat is about 6 months old, fitted new when I had the stainless exhaust made
-
From your previous thread, how much carb cleaner did you put down it's throat?
Too much can interfere with proper combustion and dislodge carbon and crap, either of which can affect the cats and lambda sensors.
-
had the problem before the carb cleaner was used, there was a slight improvement after it was used
-
Check the fuel pressure on the fuel rail. should be about 45 psi.
-
just tried to go out and it wouldn't start, did the key thing again and got a fault code 12 which makes sense as I disconnected the battery when I did the TPS, had a look at the dissy and the points and cap are well fucked so of on a walk to try and get replacements now, will report back later
-
ok new dizzy cap and rotor fitted and it wouldn't start, took off the IAC (53007562) and fired up but idled at 3000 rpm seems the piston on the idle air control has come loose, don't think this is my rough running problem but could def be the starting problem.
trying a quick fix to keep the ZJ on the road and will order a replacement today.
more to come when new parts fitted
-
FFS. I would've had a Basil Fawlty moment with the F'er by now.
Can't be much left to change,hope you sort it.
-
AAAAAARRRRRRGGGGGG :banghead: :banghead: :die:
so new air idle control motor fitted and used, tested MAP sensor fitted, it idles fine at start up but when warm the same old problem comes back,
I asume the fuel system is next to check but how do I do that? or do I just take it to a garage and bit the bullet?
-
Have you tried to eliminate a CPS problem ?? its possible for the cps to break down when warm/hot and a simple way of finding out, is when the engine is hot get a hosepipe and run cold water over the cps for a short while, then go drive it and see if the problem has or hasnt gone away, if it has then as the cps dries and warms back up the problem will return but if the problem hasnt gone away then this should eliminate the cps of the cause of trouble, I had a similar problem a few years ago (not a jeep but the same setup) and this was how I diagnosed the cps fault.
-
now I'm even more confused, just tried the engine again after letting it cool down and as soon as it got warm it started again, so went through the process of checking all plugs were seated properly by unplugging and pushing home firmly and have just run it for a good 10 mins with hint of the problem, so next as soon as the misses gets back (she has gone out without a key as usual) I will take it down the bypass and see how it performs
if it does show the symptoms again I'll try that check on the CPS
-
first test drive and seems ok,
need to go out of town tomorrow so that will be a proper test, fingers crossed
-
what do I do now?
test drive yesterday was fine so wife used the ZJ for work today and it happened to her twice on the 14 mile journey.
:100:
-
is it worth checking the upstream O2 sensor? the old sensor was reused when new cat/exhaust was fitted
-
NB I maybe missing something and I can only apologise if you've already done it but have you plugged a fault scanner in?
-
dont have a fault scanner only done the key thing to get codes
-
Maybe worth buying a £30 one off eBay it may save your wallet and sanity
-
Up stream lambda/ o2 sensor, controls mixture.......... :icon_winkle:
-
OBDII ordered
-
Up stream lambda/ o2 sensor, controls mixture.......... :icon_winkle:
TBh I dont know enough about these electrical cars, so would a bad O2 sensor cause intermittent rough running?
-
Yes if the sensor is failing , or bad wiring to the sensor intermittent, as i posted it will run OK until the engine gets up to temp at this point the ecu reads the o2 to adjust mixture if it gets no signal or a bad signal it will stay rich or lean if it stays rich it chokes up the engine, lack of power missing and back firing till eventually it stops. if you let it cool down it will run OK again..
i had this problem...........
if you order a code scanner make sure it shows real time sensor readings, you can look at all the sensors working or not with the engine running..... hope this helps you :icon_winkle:
-
As tag said and also when your engine is started every time it will run open loop which basically means that the ecu ignores the o2 sensor and injects a default amount of fuel, it takes somewhere between 30 to 60 seconds for the o2 sensor to wake up, once its operating correctly the ecu will switch to closed loop taking readings from the o2 sensor which if working correctly will constantly vary in voltage from 0v to 1v (lean/rich lean/rich etc etc) o2 sensors usually fail over a period of time and they usually fail giving a lean reading so the ecu will richen up the fuel/air ratio.
Symptoms of a failing oxygen sensor includes:
Sensor Light on dash indicates problem
Increased exhaust emissions
Increased fuel consumption
Hesitation on acceleration
Stalling
Rough idling
If your handy enough to find the correct wire going to the sensor you can connect a volt meter (set to a low range above at least 1v dc) and monitor the sensor yourself, using your obdII scanner you can set it to watch the o2 sensors and see that they are varying between 0 and 1v and drive around and keep an eye on them, also handy is your fuel trims, long term and short term, ideally they need to be around 0 which is ideal, a negative % reading is lean and a positive % reading is rich, the most they will go to is 25% which is when a check engine light will illuminate, but either way you do it, your scanner will be very usefull in finding this intermittent fault.
-
The O2 is live once the engine achieves operating temperature and not before, so when normal temperature is achieved 80ish no matter how long this takes the O2 is ignored by the PCM.
-
wish I could just fit a carb :banghead: :banghead:
-
But you can, the cost would be the APEX on this.
-
The O2 is live once the engine achieves operating temperature and not before, so when normal temperature is achieved 80ish no matter how long this takes the O2 is ignored by the PCM.
No it doesnt ... when you start the car it is in open loop (default injection and no o2 sensor) for closed loop to occur the o2 needs to be up to operating temperature, around 600F, it takes around 30 to 60 seconds for this to happen and an ecu to change from OL to CL in around 90 seconds which is when the ecu adds in the o2 sensor.
the car also enters open loop at WOT and ignores the o2 sensor input, if it didnt the car would lean out as a result of the o2 sensor switching voltage and your car would fall flat on its face, not a good thing. WOT is usually considered 80% throttle or more.
-
OBDII arrived and used, got codes
P0201 Injector Circuit Open Cylinder 1 - ? injector or wiring?
P0505 Engine Idle Air Control Fault - TPS and MAP changed should be fixed
P0127 Intake Air Temperature Too High - ? have fitted new air filter
have reset the codes as recon two are now fixed so will drive and wait for it to happen again and get new codes, if injector will try swapping 1 and 3 and see if fault moves if not could it be a wiring fault/short?
-
is it worth checking the upstream O2 sensor? the old sensor was reused when new cat/exhaust was fitted
Yes
-
See how easy it is to fault find with electronics and OBD.
You still want to return to hit and miss dizzy timing and carbs?
BTW, high intake air won't be down to a blocked filter.
-
with hind sight all those faults were down to me, at various times I run the engine with out various sensors, with No1 injector unplugged and with no airbox fitted
anyway after reseting the error codes the problem has not returned (just been driving on and off for 3 hrs), it does not seem right to me that just reseting the codes would stop the fault so recon it is still there just waiting to fuck me when least expected. :011:
and yes give me carbs and a dizzy anytime
-
You confuse me Bruce (not hard I know) one minute you embrace technology and the next your want a dizzy lol
-
:lol_hitting: the difference is the tech I use does what I tell it
with this fucking car it goes wrong, hides the fault then lies about whats wrong, spends my money on new bits it don't need then asks for more.... bit like being married I suppose :banghead:
-
:lol_hitting: the difference is the tech I use does what I tell it
with this fucking car it goes wrong, hides the fault then lies about whats wrong, spends my money on new bits it don't need then asks for more.... bit like being married I suppose :banghead:
It could be worse, you cold end up like Bulldog lol
-
I cant imagine at his stage of life good old NB will ever become ruggedly handsome, charismatic, and generally Fonz like :greggmo:
I am willing to take some shekels off him in exchange for some life coaching tho :icon_super:
-
I cant imagine at his stage of life good old NB will ever become ruggedly handsome, charismatic, and generally Fonz like :greggmo:
I am willing to take some shekels off him in exchange for some life coaching tho :icon_super:
:lol_hitting: :lol_hitting: :icon_super: :icon_super: :lol_hitting: :lol_hitting:
-
Think you'll find if you disconnect a injector then reconnect, it will throw a code.
try disconnecting the front o2 sensor it just plugs into the loom and check the plug socket for a good connection, then go for a run unplugged see if you get your symptoms. cant hurt............ :icon_winkle:
-
2 days use and no fault.............yet :017: