89 LeSabre running rich

Question

Hi all, been a while since I posted but I've got a problem that stumping me pretty good. First, some specs:

-1989 Buick LeSabre T Type with a little over 200k on the chassis

-Vin C motor with about 70k miles on it

-2.79 ratio transmission with about 150k miles on it

Here are my symptoms:

-Sulfur smell after a quick acceleration

-Rich gas smell on startup

-Occasional puff of smoke

-Slow acceleration

-Idles at around 550-650 RPMs but its rough-smooth-rough-smooth-rough-rough-ro... after the motor warms up

-Car seems to have better throttle response after resetting the ECM but the problem comes back after its had enough time for a learning cycle

Here are some facts and parts that I've eliminated:

-Flowmaster muffler about 8k miles ago

-High flow cat converter about 15k miles ago (CarSound Magnaflow)

-Belden wires wrapped in loom

-Type II ignition swap (blue on the underside of the coils)

-NGK Iridium plugs (overkill I know now but not at the time I got them)

-NTK (division of NGK) O2 sensor, less than 10k miles on it

-FWI with K&N filter (system worked great on my '88)

-JB welded cam magnet from a code 41 about 10k miles ago

-No codes/SES light

-Correct ECM programmed for 2.79 trans and it is known to be good

-Adjustable vacuum modulator

-"fresh" rubber on the vacuum lines

-No squaling or clunking from the engine

-very slight damage to MAF screen but it has a known good MAF sensor

-I have cleaned the intake recently but the first time 20k miles back or so I did it I used carb cleaner (d'oh!) and since then the MAF has been replaced

-IAC has been swapped out with a known good one

-I don't smell fuel in the FPR and the idle doesn't change when I spray WD40 into it (checking for a pinhole leak)

I think the next step is to check the TPS but otherwise I'm stumped. As far as I can tell it should be running right but its not.

Suggestions would be greatly appreciated as I'm going nuts trying to fix this

Answer 1

The sulfur smell would lead me to have the catalytic converter checked out. They smell horrid when they're not properly functioning and mess with the performance of your vehicle too.

Good luck!

Answer 2

carburetor maybe?

that's all i can think it is, good luck

Answer 3

I am guessing it is the spark plugs, when you increase you hp with high flow intake and free flow exhaust you are supposed to lower the temp of your spark plugs about one level for every 100 hp gained.

I haven't heard of FWI but if it is a cold air intake, that usually brings 100 hp with free flow exhaust. You should replace you spark plugs unless you already to into consideration the temperature difference.

I am not sure if all your parts are compatable, but I would try replacing the spark plugs first, then I would go to a tunning shop and have them adjust your timing or recode your ecu for your specific application

Good luck

Answer 4

THis is a shot in the dark...Bowl Vent Control Valve ? little valve near the carb....four hoses..one out of the carb bowl vent...one going into the intake...and 2 smaller ones..if you take it off...turn it so the 4 ports are facing down...and fuel pours out...BINGO !..raw fuel is being dumped into the intake...you might also see if the carb has any Charcoal in it from the canister that could mess up the carb..but my money in on the bowl vent control. Good luck !  PS Most of the time this sets a rich code...but stranger things have happened.