Mechanics

- RICH FUEL/ROUGH START & IDLE

1987 Buick Lesabre

My parents left me their 1987 Buick Lesabre V6 3.8L MPFI with about ~110,000 miles on it to work on over the summer. They haven't taken much care on the car throughout its lifetime and so parts were hardly or not replaced at all.

It has an extremely rich fuel smell and sometimes I can get 'rotten eggs' smell if I ever get it started.
Starting the car on the other hand is another story, 90% of the time it refuses to start or will give a small hint with a silent puff*. When I get it started it seems to idle inconsistently and I get a rich fuel smell from the exhaust. I haven't tried driving it because it will stall within a minute after starting it.

The car drove somewhat fine before it had any work done on it last year. It only had the occasional jerks/deceleration in which my parents' mechanic pointed it out to be the unchanged fuel filter (of 20 years).
After awhile when the fuel filter was replaced, the sudden jerks/deceleration stopped but the engine stalled once a while. Thus my parents took the car to the mechanic again and he said it was the Distributor/Ignition Coils and had those replaced as well.
He also noted that the Catalytic Converter had a hole in it and replaced it as well. We never saw any smoke come from around there or the smell of fumes but my parents paid for the replacement anyways.
The car seemed to drive fine for a while afterwards but started to stall again and more to the point where the car refuses to start and idles extremely rough and had a lack of power.

I recently replaced the fuel injectors, spark plugs & wires(which were in terrible condition), and some rubber hoses which I believe were vacuum lines. The car still idles rough and stalls within a minute. I'm tempted to replace the fuel pressure regulator to see if that corrects my rich fuel mixture. As for starting problems I've heard that the crankshaft position sensor could be the cause, but I haven't a clue on where that exactly could be.
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Hiddenfalls
June 13, 2007.




I have a 94 lesabre. My car was running rich also. It drove and started fine but got like 10 miles the gallon. Is the service engine soon light on? And also were the plugges carboned up? Well I had the computer replace and it took care of everything. But now it is still doing the same thing it was before. (Which is not a symptom of your) anyway I think my problem is the crank sensor too. And I know how to replace them.
Ok. The sensor is located on the passenger side of the motor. (Belt side) now before you raise the car up. Remove the serpentine belt. Pull of the pass. Front tire. Remove the plastic cover that is in front of the harmonic balancer. You will see the bottom pulley now. (Harmonic balancer) the sensor is behind that. They make a tool to remove it. It's like 15 bucks. With an air gun. Remove the center bolt 28mm. Place the balancer puller on the balancer and remove it. Now you will see the sensor. Now just replace the sensor. And reverse your steps. If you want a short cut. Then just dont put the tire back on and drop the car. Put the belt back after you put on the balancer. And see if it starts. The sensor cost about 50 bucks. If you need more detail let me know. Post a reply. I will awnser asap.
How this helps.
Kyle

Tiny
Kylemcneel
Jun 13, 2007.
Thanks this actually helped locate it.
I was actually able to get around to work on it today, but it started raining before I was able to get the balancer off so I stopped.
Is there more than one sensor? Because I noticed that there were two sets of wires that were plugged in that general area.

Tiny
Hiddenfalls
Jun 15, 2007.
Well the sensors on that side of the motor. The camshaft positioning sensor, the oil level or pressure sensor and the crank sensor. The a/c compressor has a connector also. I don't think there are any other sensor. Als o there will be a cover over the crank sensor. Don't break it getting it off. Any other questions just shout back.
Kyle
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Tiny
Kylemcneel
Jun 15, 2007.
Alright the crank sensor did the trick for my starting problems and it runs much smoother. Thanks for the help =]

Now I'm stuck with a sensitive throttle, like if I push the gas down and let go right away the engine will choke and stall. I'm thinking that could be my 'Idle Air Control Valve' since when I removed it when I was getting to my fuel injectors, it was gunked up with grease/carbon and possibly just old age.

My rich fuel mixture I'm not sure about anything else, but I believe most of my sensors need a replacement anyways.

Tiny
Hiddenfalls
Jun 15, 2007.
Ok. The idle air control runs about 75 bucks. First check vacuum lines. All of them. Look at the vacuum tower off of the throttle bdoy. Follow your lines from there. Pull your air duct off the mass air flow. Spray a bottle of carb. Cleaner in that till it's clean. There will be a honey comb lookin' thing. Well try that. I'll write more later.I gotta run. Any other question just shout.
Kyle

Tiny
Kylemcneel
Jun 15, 2007.
Ok I tried the carb cleaner as you said. Sprayed the MAF sensor clean(which appeared to be pretty clean in the first place) and I had the throttle body removed and cleaned as well as the area where the vacuum tower sprayed mirror clean. Still has similar problems.

I also noticed a small leak by my oxygen sensor before the cat converter. My dad removed that and put it back in and I cant seem to tighten it back where it would quit leaking. I'm assuming there could be some slight rust along the threads allowing exhaust smoke to pass through.

Tiny
Hiddenfalls
Jun 17, 2007.
Update on what I've done recently.

I changed the MAF and that settled most of my problems. I still get a hint of rich fuel in the exhaust even after the engine warms up.
EGR or bad ECM?

Tiny
Hiddenfalls
Jun 23, 2007.

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