help needed asap

[dazza96]

posting this for a freind of mine he is stuck on frazer island with his 96 grand cherokee it is spewing out black smoke runing ruff as guts stalls then cpu has to be reset to get it to start again still fireing on all 6 when running and drinking fuel like i drink rum
can any body help
cheers daz

[rodxj]

Get him to do the old thee times with the key trick for any codes . Failing that, there's a dude at Rainbow, Rob Rye,s his name, that knows jeeps. Some swear by him, some swear at him , but he might be able to help.

[sturz_00]

posting this for a freind of mine he is stuck on frazer island with his 96 grand cherokee it is spewing out black smoke runing ruff as guts stalls then cpu has to be reset to get it to start again still fireing on all 6 when running and drinking fuel like i drink rum
can any body help
cheers daz

the 96 cherokee use to be able to do a diognostic check by swithing the key on and off 3 times and the leaving in the on position to read blinking fault light for this you could find the fault code without having to have a plug in unit. google fault codes to see what you come up with in regards to the grand? Good luck Has the engine fault light come on??

[dazza96]

no funny part is no check engine light is on

[rastus2571]

Dazza. Give the what, why, how ,and what was he doing when it happened.Was it running ok b4? What did he do to get it like this or what was he doing?

[rupicon]

I assume he has checked the air in take is not blocked?

[kj69]

tps ???????

[rastus2571]

very hard boys to diagnose when you dont have the full story.

[dazza96]

for you rastus2571 he was driveing along the rd to the barge to frazer then he drove on to the barge then he drove off the barge then he started to drive up the beach then i dont know what happened now it is spewing out black smoke
cheers dazza

i have all ready told you guy as much as i know

[dazza96]

after speaking to jj found out the way to fix all good now and grand is still burning around on frazer island

by diconecting both o2 sensors problem sorted till he get back home

[rastus2571]

Hows the fuel consumption going after doing this?

[Jonny Jeep]

Drinking fuel is typical of bad O2 or map sensors. With O2 sensors disconnected the Jeep will run slightly rough at around 12-13:1 in stead of the ideal 14.7:1. It programmed like that so it won't run lean which could cause engine damage.

If O2 sensors are bad, with the sensors connected it should run OK from a cold start for the first 30 seconds or so, It should also run OK at wide open throttle. Those are open loop modes where the O2 sensors aren't monitored.

[dazza96]

Hows the fuel consumption going after doing this?

i asked him for ya and answer i got was craploads better than before but he said he will trip it for me next time he fills up

[dazza96]

Drinking fuel is typical of bad O2 or map sensors. With O2 sensors disconnected the Jeep will run slightly rough at around 12-13:1 in stead of the ideal 14.7:1. It programmed like that so it won't run lean which could cause engine damage.

If O2 sensors are bad, with the sensors connected it should run OK from a cold start for the first 30 seconds or so, It should also run OK at wide open throttle. Those are open loop modes where the O2 sensors aren't monitored.

what i am trying to work out is the front o2 sensor controls the air fuel mix and the back or second 02 sensor tells you if ya cat goes bad it this right well this is how i have read it from goggleing the net

now i all so know the manifold has the normal crack in it could this also be the problem the grand was drowned when we got it we threw another motor in used all the sensors from drown motor as these where all we had to work with yes even grands have diferant plugs for sensors 96 to 97 we found out
(in fact what happened was it broke number 1 conrod and sent a peice out threw the sump)

back on topic any way i found out from a freind of a freinds freind that works for jeep he claims that when the jeep has a cracked manifold that is is better to disconect the front 02 and just leave the cat one pluged in and working other wise it causes the computer to have a fit and it just simpley makes the car run richer again eg no senor is better than a bad sensor and fause reading

but i am yet to try this so i i can only go by what i have heard but he is a good reliable freind and never given me the bum steer

[Jonny Jeep]

Front sensor is used for fuel mix, rear monitors cat condition. The way the computer monitors cat condition is by looking at the way the rear sensor switches in relation to the front. It should switch slower and as the waveform approaches that of the front sensor the computer knows the cat isn't doing it's job. From that, I'd say that if the front sensor is disconnected, it doesn't make any difference if the rear sensor is disconnected or not, as there is nothing to compare the rear sensor to.

A crack in the manifold ahead of the upstream sensor can allow air to be sucked in to the exhaust which would make the O2 reading from the sensor seem weak, which would result in the computer running a richer mix. Sometimes these cracks can create a ticking sound when the engine is cold which goes away as the exhaust heats up and closes the cracks. If that happens the fuel economy shouldn't really be affected.

[yetiboy01]

Most lilly the TPS ( throttle positioning sensor) when they fail they give a full voltage signal to the ECM telling the ECM you have pushed the pedal to the metal & will give the engine full fuel once you go over idle, no limp mode for this issue if it's the problem, only way around it is to replace the sensor, could be a bad connection at the ECM get him to unplug it, make sure there's no water or crap in the plug & reconnect it, do the same for the TPS, good luck


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[dazza96]

Most lilly the TPS ( throttle positioning sensor) when they fail they give a full voltage signal to the ECM telling the ECM you have pushed the pedal to the metal & will give the engine full fuel once you go over idle, no limp mode for this issue if it's the problem, only way around it is to replace the sensor, could be a bad connection at the ECM get him to unplug it, make sure there's no water or crap in the plug & reconnect it, do the same for the TPS, good luck


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this grand was over fueling at idle to but thanks guys got a lot to lok at when it gets back cheers daz

[dazza96]

Hows the fuel consumption going after doing this?
450 ks to the tank and this inc a bit of frazer island sand driving