Too much fuel

[tandm]

My Shadow just gulps fuel like it's nothing. It uses more fuel than the T/A. I tried some STP fuel system cleaner and that seemed to help a bit, 2 tanks later and I'm back to the ame ol' crap. There seems to be black smoke at times, and the engine has a somewhat smooth idle but will jump at times. I'm just not that great with cars so does anyone have a general suggestion. I've tried to do some research and I will probably replace the O2 sensor(I think it has just one). Another place said to check the plugs, wires, and distributor. I just dont' know what to do, HELP

[axoid]

I had a simular problem a while back and didn't realize it until I installed the headers. The plugs were black with carbon. I replaced the plugs, Cap and rotor (90K of ware), wires and the O2 sensor. It's been running fine ever since.

[Guest Computerguy5]

Hey Steve,

Here are my suggestions:

 

1) The first thing I would do is check the O2 sensor voltage (there is just one and it shouldn't be too hard to get to), and if thats bad, replace it. On these engines, a bad O2 sensor will cause black smoke and drop gas mileage from ~35 to about 10mpg or so.

 

2) The next thing I would do is clean or replace your plugs, as needed: they'll probably be pretty well covered in carbon. I wouldn't worry about the distributor, it sounds like its fine (the hall effect sensor is the weak point on those and it sounds fine since you have a relatively smooth idle and you're not experiencing issues where it dies and you can't restart it for 20 minutes)

 

3) the wires I would consider replacing, not too huge of a deal, as would I consider replacing the rotor. The cap doesn't need replaced as the wires themselves are what actually make contact with the rotor; the cap doesn't have any plug wire studs. I would only do step 3 if 1 and 2 don't help much, but I would almost guarantee its the O2 sensor and you're likely to have to do something about the plugs too.

[Joe]

The voltage jump from the cap to the rotor can cause carbo tracking and general deterioation of both contact points, its always a good idea to replace both the cap and rotor together.

 

As for running rich, i would do a general tuneup, as well as chek O2 sensor output voltage. it should fluctuate from about .2mv to approx .9mv Just make sure it doesnt spend more time on either side of .5 than the other side, as this indicates a problem. Also, might give fuel pressure a check.

 

hope this helps!

[stolen 5.0]

get a new fuel filter too

[Guest Computerguy5]

Hey Steve, have you made any mods to your shadow? and I mean aside from the "custom ram air" tongue.gif

[tandm]

No, Shadow is completely stock, I can't afford to get the thing running right, let alone mod it It would be fun in the future though, they're great little cars.

[Guest Computerguy5]

Hehe, then I could definately bump you off the selective comp list tongue.gif To be honest, I wouldn't think it would be worth it to do *too* much to that drivetrain, but I do know a guy that has taken it and doubled its output while remaining N/A. Pretty extreme stuff though for a beater, but he is autocrossing the car and didn't want any turbo lag. he does pretty well with it too.

 

EDIT: I forgot to mention, if you do end up needing to replace that O2 sensor, get a Mopar unit. Use an aftermarket (they typically all do the same) and you're likely to be replacing it again in another 10-15K miles, but the mopars tend to last at least 80K. (my original O2 failed on my daytona at about 58K, but that was because of my own stupidity tongue.gif )

 

[ 27 September 2002, 12:13 PM: Message edited by: Computerguy5 ]