HELP : missfire and sparks plugs fouled ...low idle ...!!

[smokingjoe]

Hi !
I'm in Spain , so please excuse my bad english ...:
I've a 94 R/T (68000 miles ), and after engine broke (high speed highway..:200mph...), we install a 96 gts engine !and discard the cats !because then burned on the first trip : (to much fuel ...), and started to burn the side sills and inside the car : the carpet ..!
The problem is : engine start very well , but after a minute or two , the engine almost stall ,idle down at 400 rpm , and stink gas ...so much that we cannot stay around the car !!
when accelerating slowly , engine seems to missfire at about 2500 , until 4000 , at WOT no more missfire !
I must say that the engine i bought (the 96 gts ) is almost new : 2000 miles , but came without wiring , so we did install the stock wiring of the car , and i've a violet wire ,( on the right side , near the iac ) left alone ...no way to go ?
i'dont have a scan tool , but have seen a 12 code !? what's that ?
O2 sensors are stock ,(i've tried to open the small holes : same ) may be burned ? sparks plugs and wires are new , but i've keep the R/T coils , because wiring plugs are not the same as the GTS .
Any help would be WELCOME !!
JO.

 

[Russ M]

What fuel injectors are you using? Gen 1 or Gen 2?

I am assuming you have the factory 94 ECU?

 

[Fred(DrivingSchool)Kinder]

I think you will need to get a new ECU for the GEN II engine. A Viper "Tuner" or good Tech. should be able to give you a solution to smooth out your GEN II. Suspect lots of little changes like throttle body sensor, Oxygen sensor, ECU programming for different Cam, etc.

 

[ArlyDude]

Hey, I pretty much have the same problem on my 97 GTS. She works fine for a few seconds on startup, then she starts to stutter and almost die until I step on the gas for a little at about 3000RPM. Then all is well until I shut her off for a few minutes then try again. Then same problem.

 

[Schulmann]

As Fred says you need a 96 or older PCM. Since you removed your cats you also need cat sims. However I have no idea if the wiring is right in your car. Have a look on this web site: www.roeracing.com. Call or write them directly. They can help you with precise technical advises and can provid the right parts for you. Between 96 and 2002 you can swap alot of parts between Vipers but before 96 ... it won't work engin is just too much different.

 

[Gerald]

If you DID replace the ECU, etc and you still have that problem it sounds like your O2 sensors took a crap. I've the same symptoms you explained, especially about running rough, smelling like gas, etc.. Good Luck
And if you did remove your cats you might need sims in the rear (since you HAD a genI and now a Gen II motor, do you need rear 02 simms?)

G

 

[smokingjoe]

Thanks everebody !!
I'm gonna change the O2 sensors first (as Gerald say )! may be injectors after that (will install injectors from the gen 1 ) ! i've no wiring or pcm from gen 2 ...all the parts are gen 1 except for the engine .
Any idea about code 12 ?
Thanks , JO.

 

[Jack B]

Only the front O2's have input to the PCM. You really ought to call the Wizard for an accurate assessment. I don't see how it can work, especially in open loop it will run very lean.