Misfire when hot.
Discussion
Just fired up the new ( to me ) 1998 Viper.
Starts good, idles good when cold but as soon as warmed up, it idles at about 450 and is rough as hell - seems to be running on 5 or 6 cylinders. REVS UP oK. Took out old plugs, seemed OK but kinda white - like very lean.
All new plugs made no difference. Car has 40k miles on it.
Any ideas ???????
O2 sensors maybe ??????
Starts good, idles good when cold but as soon as warmed up, it idles at about 450 and is rough as hell - seems to be running on 5 or 6 cylinders. REVS UP oK. Took out old plugs, seemed OK but kinda white - like very lean.
All new plugs made no difference. Car has 40k miles on it.
Any ideas ???????
O2 sensors maybe ??????
how does £25 per hour sound ?Hensen said:
Just fired up the new ( to me ) 1998 Viper.
Starts good, idles good when cold but as soon as warmed up, it idles at about 450 and is rough as hell - seems to be running on 5 or 6 cylinders. REVS UP oK. Took out old plugs, seemed OK but kinda white - like very lean.
All new plugs made no difference. Car has 40k miles on it.
Any ideas ???????
O2 sensors maybe ??????
What plugs are you using? Are the HT leads the originals? They may be breaking down under load? You could try turning off all lights in the garage, rev up the engine and see if you can see any blue sparks running along the HT leads (I had that problem years ago on my old camaro, you could clearly see the arcing on the leads).Starts good, idles good when cold but as soon as warmed up, it idles at about 450 and is rough as hell - seems to be running on 5 or 6 cylinders. REVS UP oK. Took out old plugs, seemed OK but kinda white - like very lean.
All new plugs made no difference. Car has 40k miles on it.
Any ideas ???????
O2 sensors maybe ??????
Resistance minimum 250 Ohms per inch, 3000 per foot / Maximum 1000 Ohms per inch, 12,000 per foot.
Plugs should be Champion RC12LYC, Dont bother with anything else.
What exhaust system is on the car? Side pipes or rear exit, cats or no cats?
be very wary of cars sold in Texas...
fatboy18 said:
Nice looking car Hensen, notice in the pics it still has pilot sport one's fitted, if the car is still in the USA you should get some new rubber fitted. 'Viper Parts America' are doing some great prices on pilot sport 2s at the moment, look them up on line 
Tyres Fatboy pot kettel black 
Loooong time since I worked on one, does it use the 2 coil-pack system? (I can only refer to the GTR-S's we raced) Might be one of the coil packs failed. Seem to remember there being one with 6 leads and 1 with 4, bad electrical connection to the smaller pack? Might be talking out my arse though......
With these feet said:
Loooong time since I worked on one, does it use the 2 coil-pack system? (I can only refer to the GTR-S's we raced) Might be one of the coil packs failed. Seem to remember there being one with 6 leads and 1 with 4, bad electrical connection to the smaller pack? Might be talking out my arse though......
That about sums it up, I posted a lengthy post about diagnosing this stuff a last month but as no one took any notice then i leave it to someone else to click on the search button. actually about 4 clicks should get you there from here providing you don't get sidetracked on the imtermweb.
fishboy said:
buy 4 new plugs like you did with the last one ,that will do it !!!!
Glad you mentioned that car, I used 4 old plugs to check it out, turned out to be the 6 coil pack, but Napa sells them. It also had a bent conrod and other problems, but I fixed it quite easily with parts shipped from the USA. It ended up a very good car, you can have a look here...enjoy.
http://www.youtube.com/watch?v=u80z4LgbhXY
Gassing Station | Vipers | Top of Page | What's New | My Stuff