vn missfiring

[skeeta1]

Hi all
I am having problems with my vn missfiring
the long story
Coming out of winter i had to replace the battery in the vn (looked like the original one )so got it going again ,was good for about two weeks and i get a call from the cook ,"car wont start ,flat battery",so i put in another and jumped in for the ride home ,only got half way (5ks)and the vn started to missfire bad and die half way up a hill,thinking now that the alternator is cactus,after the tow home i checked the alternator with a muli meter,the new battery tested 12.48v,started the car and the battery tested 14.37,i pulled the plug from the back of the alternator and tested it,but could not get a reading,the vn runs but with a bad missfire ,having another alternator handy i swapped it from a vn that runs fine,and that made tha car run fine ,without any issues at all,for 5 days ,it was parked in the arvi and went to go in the morn and it had created the missfire again ,thinking now the coils ,changed that(coils) from the same car as the alternator was pinched,but made no difference ,i have now changed, for new, the spark plugs and the leads ,which made it run fine for about 30 seconds ,i have run out of ideas ,any help would be great
thanks

 

[Ghost]

Try swapping the map sensor over and do an error code check

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[MrNutter]

DFI module perhaps? If you have a spare one laying around try that, they aren't cheap. If that doesn't help I'd be going over all the sensors & checking the connections.

 

[Ghost]

Yeah +1 swap the dfi module then map sensor

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[skeeta1]

just done the error code check and only came up with 45 (oxygen sensor rich),so going to replace that

 

[hi_ryder]

oxy sensor might not be your problem. running rich could mean your fuel reg is letting in too much pressure stuff like that. all that its telling you is that its getting too much fuel.

 

[skeeta1]

when i changed the coils over i swapped the dfi modules as well as a hole unit and it made no difference to the missfiring,
after changing the plugs and leads it did run perfect for about 20 sec or so but has less of a miss now ,instead of sounding like it was running on 3 cylinders ,it is now running on 5

 

[FXST01]

Check the condition of the wiring at the DFI plug. Get in there and have a good look.

 

[skeeta1]

thanks fellas,got her going now ,so thought i will let you know what i done ,
changed the oxygen sensor for new and done an error check that came back as a 12 all systems good ,but still had the missfire ,so changed the map sensor from the spare car i got ,and tried that ,too my suprise it was like setting off a smoke bomb,white smoke pillowed from the exhaust,thinking i have to reset the computer,i disconnected the battery for a few minutes and reset it all ,started the car again and held it on 3000 rpm for ten seconds ,and the smoke had all but dissappeared,and the car seems to be running fine ,done another error check which came back as 12,so happy with what i have done i left it at that ,i have also run some injector cleaner through the tank as it now has a rough start up ,but clears itself once up to running temp,i am thinking of an injector service to hopefully clear that up ,any ideas would be great