So i took my car to the Dyno last weekend.. my Bf and a few friends needed there cars tuned and i wanted to run mine just for fun to see what it would do.. i know it feels like its running crappy.. but not much crappier then when i bought it.. i just kinda feels restricted and i thought by doin my exhaust it might get rid of that feeling ( did exhaust last summer and no fix)

Here are my mods to the engine:

AEM CAI
Maintec header, custom 2 1/4 catback exhaust
Jspeed Underdrive pulley
1.8L intake cam swap

And since the dyno :

New fuel filter and Walbro 255L HP pump ( this was given to me at the dyno!) so i figured the problem would be fixed but the car still doesnt feel right.

Problem : We put my car on the dyno, hooked it all up, and he ran it up until about 4500 RPM and stopped .. he said soemthing wasnt right.. i know it should probly be a little lean with my mods, but my air/fuel ration was off the charts lean 18+ :S... and i wasnt running much horsepower.... he then pinched the fuel return line and it gave me 20 more WHP...but u could hear the detonation real bad at high rpms..:S .. The guy at the dyno said its gotta be a fuel problem and to replace the filter first, then pump and then get the injectors cleaned... for some reason im thinking that if the new filter and HP pump didnt fix it.. claning a dirty injector isnt gonna fix it either? 02.gif i dono what else it could be?

The car boggs alot when its cold when u first take off ( which feels like a fuel prob but new pump didnt fix it) and at about 4200RPM theres another bogg that happens... i thought the cam got rid of it.. it made it less prominent but its still there sometimes.. i think ive read that other ppl have had the same prob with he bogging too but im at a loss as to what to do next!


Any suggestions? Anyone with similar probs?

 

I was gonna say the filter, but you replaced that. I had similar problems and it was the filter. How are your plugs and wires?

 

I havent replaced the wires in awhile.. plugs were done not too long ago tho .. its seems pretty drastic to be that simple 02.gif its really frustrating...

When ure filter was clogged did the car bogg alot when it was cold and u just started it? mine seems to do it really bad when its humid outside..sometimes it will even stall if i dont get the clutch back in fast enuf.. its like when i push the gas theres nothing.. the humidity thing makes me think its electronic but i dono... it feels pretty restricted still and it shouldnt be at all!!! my friend gained 25WHP just by adding I/H/E and i have more then just that and my car doesnt seem to perform much better.. a little.. but not much

 

yeah it would bog down alot and just feel like it was all clogged up. I did a major tune up recently, replaced the plugs and wires as well as the fuel filter and even put in a brand new TPS in. I had a CEL for the TPS, and it turned out it wasnt even wired in all along. Now it runs a lot better, but for whatever reason the CEL decided to come back on. Runs fine though despite that.


Which TPS do you have, if its Dae Sung chuck it and put a Kefico in there. Even if that isn't the cause of the problem it's a good idea to do that anyway.

 

check wires, coil pack, injectors...

what HP you put down on the dyno?

 

It is quite possibly your MAF. Its not metering the air coming in, so its not adding fuel, causing you to run lean.

 

Good idea funky... make sure it's at least plugged in.

 

BTW, you can't run a 255LPH fuel pump on a stock fpr. Stock FPR can only handle 190LPH.....

Hook up an OBD scanner and check out your MAF signal and TPS.

Also Check the pressure in the fuel rail and get rid of the 255 or upgrade to a Aeromotive FPR.

 

So you put a 255 pump in the car AFTER the dyno and now it's bogging?

I hope you also installed a replacement FPR with it. If not, that'll definately cause it to run rich now. Especially at low, near idle speeds.


Although the probability is low, it could be that you had a faulty pump to start with, which caused you to lean out at WOT. Then you installed a 255 pump that supplies too much fuel for your regulator, so it's now rich.

Get a regulator installed. Replace the fouled plugs. Then get a dyno with AFR chart, and post it here.

 

It was boggin before AND after switching the fuel filter and Pump.. changing those things did nothing as far as feeling like the car runs better.. at this point ide rather run rich till i figure this out cuz there was terrible detonation sound comin from the motor

At roughly 4500-5000Rpm with AFR at 18+ i had 77WHP and he stopped..did the same thing with the return line pinched and read 97WHP... he didnt wanna run any higher RMPs cuz of the noise ( that i cant hear when im in the car driving) He was damn sure it was the pump and it was just weak.. but this one is DEF not weak and it hasnt made the car any better.. he said ill feel 100% difference when this is fixed...