Rough Running Motor

[Jonnychadootz]

Ok, I've had my 97 Prelude now for a lil over 3 years. Recently (within the past month or so) I've noticed the motor was running kinda rough. I dump 2 STP Fuel system cleaners in it and the motor runs fine. Then the tank runs out so I fill it up and it pulls the same rough running shit. So I dump 2 more STP Fuel system cleaners in it. Once again the motor is running fine. I also notice when I don't have the fuel system cleaners and I let the car idle for 10-15 min or so and then rev a lil I get the lovely unburnt fuel cloud coming from the tail, very briefly though. It's definitely not oil blow by or any of that shit, I know the difference in smell and color.

Whatcha guys think? Air/Fuel problem? Timing? I know the fuel system cleaners don't really do a shitload more than raise the octane rating slightly. Thats why I'm kinda leaning more towards air/fuel mixture or maybe the gas station I usually go to has shitty gas atm? I don't know, hit me with some ideas :thumb:

[Traction Issuez]

same gas station with both fill ups?

[01mmmz28]

try this: change plugs and gap them according to factory specs, change fuel filter, run a full tank of 93 octane to help clear things out on top of a bottle of fuel injector cleaner. How does your fuel pump sound when you just turn the key forward w/ out starting it? It should make a slight hum when you turn the key forward and stop after 4-5 sec. If it makes a loud hum and takes longer than 4-5 sec. to pump in itial start up fuel, time for a new fuel pump as well. Cover the entire fuel system is your best bet.

[Jonnychadootz]

No, actually the gas station that I usually go to is 6-7 blocks from where I live ( the 1 I think the fuel could possibly be shitty from) When I go to the parts store which is in another town (5-7 miles away) to get the Fuel cleaners, I use a gas station in that town. Always 93, nothing other than that has ever been put in the car. Figured I'd add that the cat and oxygen sensors are basically brand new as well and I have no check engine light on either Something definitely feels wrong

In reguards to your post 01mmmz28, plugs are brand new Bosch (u know the 4 post jammies) and Fuel filter has just been changed. As you can see above nothing ever went into the tank other than 93. Oh yeah and I checked the fuel pump like you said and it sounds fine and starts no problems l

[01mmmz28]

my money is on bad fuel delivery system, injectors and the pump. Just because you use an injector cleaner does not mean that they are clean. The solvent that a garage uses is alot moer potent than what comes in the bottle from autozone.

[Jonnychadootz]

Originally Posted by 01mmmz28

my money is on bad fuel delivery system, injectors and the pump. Just because you use an injector cleaner does not mean that they are clean. The solvent that a garage uses is alot moer potent than what comes in the bottle from autozone.

That brings me to another problem :mecry: I don't trust any of the pricks around where I live. Every time I bring my car to some1 (even Honda) I get either the well it needs $1000 worth of service routine ( u know what I mean) or I get my car back and 2 days later something else goes wrong. After that shit a few times I just started working on the car myself. Seems to have worked out better that way and I have had way fewer problems with the fewer people that touch my car other than me. Of course though there is always some shit thats gonna come up that you can't fix Such as a motor (neither have the space nor equipment) or a tranny. The car is rather well maintained, I hope its something stupid.

[Turbo AWD]

It's possible you have a stuck open injector that is just dumping fuel. It's also possible the exhaust valve(s) have a problem and are thus letting unburnt fuel past them.

So either you've got too much fuel in the cylinders, or the exhaust valve(s) are shot. You can check the valves easy with a leakdown tester. You should be able to rent one from an autoparts store. You bring the piston to TDC and apply compressed air to the cylinder. If you lose pressure, feel the tailpipe for leaking air.

Once you rule out the valves, you can be confident it's a bolt-on affair and can begin troubleshooting the fuel path (injectors, fpr, etc.)

[Jonnychadootz]

The stuck injector would explain the shitty gas mileage and power loss, but wouldn't the check engine light come on if an injector was screwin up? Also, I find it weird that dumping 2 fuel injector cleaners seem to (in most part) take care of the problem temporarily

How do I check the injectors? If I take them off and inspect them would it be obvious if 1 was messed up? Or do you just check each 1 to see if it sprays right

[EH!]

i would check both injectors and exhuast valve...