Ok this is my first post so hello and thank you in advance for any help.

I recently rescued a 92 dodge dakota. When I brought it home the guy was running it with absolutely NO exhaust or anything on it. So I went out bought a muffler, new catalytic converter, O2 sensor all the exhaust stuff and my husband had his friend (who is a mechanic) install it all.

I filled the tank a couple days ago and added a fuel additive and right now it's at 1/4 tank of gas (with the additive). I used the lucas fuel additive. I drove the truck around probably about 30 minutes this morning and then took it straight to the emissions place to get tested.

Well my truck failed! The hydrocarbons are at 2.39 and they allow 1.6 for passing and my nitrogen is at 4.22 and they require 3.0 to pass. They tested and detected NO Hydrocarbon leaks though after they saw my hydrocarbons were so high. The carbon monoxide, gas cap pressure, and catalytic converter all passed though.

My husband is thinking maybe the additive caused the truck to fail since we installed everything brand new. Is this a possibility? I can't get ahold of his friend but their requiring us to take the truck to a certified mechanic now so we wouldn't be ablet to take the truck to him anyways. I am just really curious if the additive could have caused the truck to fail?

 

A few things. First I would run it more, fill the tank with premium (shell or BP), throw a can of Seafoam in, and run the tank down, preferably highway miles. Most additives are supposed to be added to a full tank, hard to say how it affects the exhaust. If you just got the truck back to running condition it probably needs to be run some more. Reset the computer also, then take it on the highway to reset YOu should be able to take it back for a preliminary test prior to having to show receipts, at least in IL I can. I just go back in and try again, although my first gen is exempt now.

Also not sure if a new cat has a break in period or not.

 

yeah I did fill the tank when I put the additive in, I used mobil gas since my father-in-law was so kind as to use his mobil card to fill it up from EMPTY. It was..."running" when we got it but like I said no exhaust, he did a crap tune up on the truck and everything. When I got it I barely limped it the 20 minutes home. I think I will just try that, my husbands gonna take a look at it tonight too because I didn't exactly drive it on the highway but it was a nice ride I took it on today was going about 60+ in some areas. The truck runs BEAUTIFUL now though since we did all the work to it and put the exhaust on and redid the "tune up" and every other problem that we found along the way (spent $500 on the truck and have spent just about $500 to get the truck running agian but it's so worth it).

The cat is marked as passed (well it just says presence of catalytic converter and has a passing mark in that section). Not sure about that, would figure my husband's friend would have warned me about that since I told him I was gonna take it to get tested today. I have atleast a 30 day temporary plate on the truck now though thankfully.

Since we got the truck and put everything on and filled the tank I have driven it about 230 miles (+/- 5 miles).