LT1 1993 Vett SWAP Running rich (Page 1/2) str8maxn MAY 19, 12:31 PM Hello Everyone, My 93 Vett Swapped LT1 is running super rich. I don't have any CAT's on it and the Gas smell is a bit overwheling. Can anyone offer any suggestions to make it run leaner? Thank you all jelly2m8 MAY 19, 02:50 PM Have a proper tune done and add Evap and Cat's if you wan't to get rid of the gas smell Most mail tunes are on the rich side for engine safety reasons. str8maxn MAY 20, 10:39 AM I'll work to get some cat's on it . ty 82-T/A [At Work] MAY 20, 12:46 PM Did you keep the factory ECM from the C4? The C4 has a weird system where they were trying to be fancy by incorporating a pre-OBD2 type system. There's actually a couple of computers... not sure if you included those in the swap, but there's the dash computer which is kind of like a body control module. It gives you codes in a different manner, and communicates directly with the ECM. The ECM does not require any of that stuff... but just asking in case they included it. Are you using the C4 gauge cluster? Otherwise, the ECM itself can still be accessed the old fashioned way with a paperclip in the ALDL connector. I would check to make sure you don't have any codes. I always run cats on my cars... but even with them off, the fuel smell shouldn't be overpowering... it's likely doing that because your oxygen sensor is starting to go bad (or something else). Sometimes, the O2 sensor can have premature failure on OBD1 systems, but still be within range and not give improper readings. You'll notice because fuel economy will drop significantly, and you'll start smelling fuel more. So... check the codes if the install was done properly... and report back. str8maxn MAY 20, 01:13 PM quote Originally posted by 82-T/A [At Work]: Did you keep the factory ECM from the C4? The C4 has a weird system where they were trying to be fancy by incorporating a pre-OBD2 type system. There's actually a couple of computers... not sure if you included those in the swap, but there's the dash computer which is kind of like a body control module. It gives you codes in a different manner, and communicates directly with the ECM. The ECM does not require any of that stuff... but just asking in case they included it. Are you using the C4 gauge cluster? Otherwise, the ECM itself can still be accessed the old fashioned way with a paperclip in the ALDL connector. I would check to make sure you don't have any codes. I always run cats on my cars... but even with them off, the fuel smell shouldn't be overpowering... it's likely doing that because your oxygen sensor is starting to go bad (or something else). Sometimes, the O2 sensor can have premature failure on OBD1 systems, but still be within range and not give improper readings. You'll notice because fuel economy will drop significantly, and you'll start smelling fuel more. So... check the codes if the install was done properly... and report back. Did you keep the factory ECM from the C4? I didn't do the swap myself; but I do have a reprogramed factory C4 ECM. I have paper work for it. Are you using the C4 gauge cluster? No, I have the factory Fiero dash gauges Gas milage sucks.... 8-10 miles per gallon I have an ODB1 port located at the rear for the C4 ECM. However, I am not sure if it's wired into the Fiero's Engine Check Light. I haven't tried the paper click hack yet but I feel it will not lightup the fiero dash. I was thinking of purchasing an ODB1 reader. But I am not sure which one to buy. I've seen some GM readers for $50 on ebay. The oxygen sensors are Bosch with lessen than 1500 miles on them but the car has been running rich since I got the car 4 years ago. When I got the car, the cat's (universal) were bad and blowing out chunks of honey comb thus I cut them out and ran stright pipe. Amazon has universal CAT's for $80, do you think these will work? The CAT's have on oxygen sensors bong on them. Do I run the oxygen sensors here or keep them on the hearders? Thanks for the help. JM 82-T/A [At Work] MAY 20, 02:59 PM quote Originally posted by str8maxn: Did you keep the factory ECM from the C4? I didn't do the swap myself; but I do have a reprogramed factory C4 ECM. I have paper work for it. Are you using the C4 gauge cluster? No, I have the factory Fiero dash gauges Gas milage sucks.... 8-10 miles per gallon I have an ODB1 port located at the rear for the C4 ECM. However, I am not sure if it's wired into the Fiero's Engine Check Light. I haven't tried the paper click hack yet but I feel it will not lightup the fiero dash. I was thinking of purchasing an ODB1 reader. But I am not sure which one to buy. I've seen some GM readers for $50 on ebay. The oxygen sensors are Bosch with lessen than 1500 miles on them but the car has been running rich since I got the car 4 years ago. When I got the car, the cat's (universal) were bad and blowing out chunks of honey comb thus I cut them out and ran stright pipe. Amazon has universal CAT's for $80, do you think these will work? The CAT's have on oxygen sensors bong on them. Do I run the oxygen sensors here or keep them on the hearders? Thanks for the help. JM Can you show me how close on the headers the O2 sensor bungs are? They shouldn't be directly in the fire, so to speak, but should be at the Y-pipe / collector pipe. The 4 cyl Fieros have them further down just above the down-pipe. It's still in the exhaust manifold, which is why it works so well, but it shortens the life if they're getting direct flame from the exhaust ports. I would keep them at the header, rather than putting them on the catalytic converter. I definitely agree with going with cats... it'll improve some of the around-town driving... but I don't think it'll fix your problem. If you can manage it... figure out which leads come off the ECM and which is supposed to go to the check engine light. You really want to be able to know what your ECM is doing. There are SOME scanners that work, but for your year... they should be compatible. It gets iffy on cars like the early ECMs... but you've got one of those ECMs that's more modern and meant to sit inside the engine bay with the newer connectors. It's like a neutered OBD-2 system almost. Almost any OBD-1 compatible scanner should work on your ECM. Do that first before you get new cats, otherwise you're just masking a symptom (in my opinion). Patrick MAY 20, 03:13 PM quote Originally posted by str8maxn: ...the car has been running rich since I got the car 4 years ago. When I got the car, the cat's (universal) were bad and blowing out chunks of honey comb thus I cut them out and ran stright pipe. It's quite possible the cats went bad because the engine was running way too rich. If so, new cats will be destroyed in the same manner. Fix the engine problem before replacing the cats. str8maxn MAY 22, 08:33 PM Hello all, I purchased small ODB1 plug in reader 'INNOVA 3123 GM OBD1 Code Reader ‘ hoping that would trigger the check engine light on the fiero’s dash. Unfortunately , this was not the case. I don’t think Check Engine Light is wired into the VETT ECM. Is there a way to wire a light to the factor VETT ECM? Patrick MAY 22, 08:41 PM quote Originally posted by str8maxn: Is there a way to wire a light to the factor VETT ECM? Having a functional Check Engine Light would be nice... but now that you have a reader, is having a CEL really all that necessary? Your reader should be able to tell you if there are any stored codes. str8maxn MAY 22, 09:03 PM The INNOVA 3123 GM OBD1 Code Reader doesn't have a screen nor light on it that blinks out the codes. I was hoping it did. I think all this does is act as a jumper.