few issues with motor help me out?

SON240sx Automotive
1

Okay so I’ve recently been having some isses with my car. I seem to be bad at explaining issues in sentences, so I’m going to just do it point form haha. Here we go.

Motor: s13 blacktop Sr20det with 75xxxkms
Mods: megan exhaust mani, 3" exhaust w/high flow cat, mid mount intercooler, manual boost controller.

  • heavy hesitation at low rpm if I put my foot to the floor (up til about 2k - 2.5k)
  • car running very lean all the sudden (gauge marker all the way to lean side with screen reading “—”). AEM UEGO wideband.
  • will still go down to proper AFR but at random times, and not for long.
  • horrible gas mileage (40kms to 1/4 tank, 91 octane)
  • stock turbo is blowing oil (this has been for a while now)

Any help/ideas will be greatly appreciated! Thanks.

2

does it idle fine?
u just swaped this correct? or it worked fine post swap?
TPS? FPR? ECU?

3

Sorry yea it idles like shit too. Hella backfires at 1500rpm on decel.

Its basically done the idle and hesitation thing ever since I blew my ignitor chip and blew open/melted a coupler.

I have a chipped ecu too. Maybe the chip fucked off?

4

well it wouldn’t hurt to try swapping ECU’s

but right now i think it could be a lot of things so maybe someone else more experienced can chime in

5

check some vacuum lines, might have a leak somwhere

---------- Post added at 02:36 PM ---------- Previous post was at 02:34 PM ----------

oil might be from blow by, if you dont have a catch can.

6

My money is still on fuel pump Trnkasaurus

7

but his fuel pump running lean would not cause it to get terrible mileage

id say its a combination of things , ecu, maf, fuel filter… just start swapping parts

8

i agree with peter, running lean and terrible fuel economy don’t usually go together. check your TPS, if it goes bad the computer will go into limp mode and just dump a shitload of gas into the motor regardless of what RPM. will run better when the engine is at a speed/load that would actually require that much fuel. wouldn’t hurt to check the knock sensor either

---------- Post added at 05:48 PM ---------- Previous post was at 05:47 PM ----------

actually jesse pull your ecu out and read the codes from it. i think a chipped ecu will still go into diag. mode

9

I’ll go into further details later, when I’m not running around and on my cell phone. I’ll just use points to answer stuff again haha.

  • my ecu has no lights on it to do diagnostics. Guess they were removed or something.
  • all my vacuum lines are good. Pretty much brand new still
  • think I fixed my running lean issue. May have been a problem with the wires going to the wideband sensor.
  • I still can’t really see it being my fuel pump. I had no cutouts or signs or bad fuel pump while under full boost (13psi). I would assume a bad fuel pump would mess up during something like that?
  • maf is clean as a whistle
  • I should check tps voltage? (Anybody know proper tps voltage levels?)
  • I don’t have a catch can, but my turbo has LOTS of shaft play
  • I’m pretty sure fuel filter is clean, but it can’t hurt to check.
10

TPS voltage i don’t know off by hand but if the car is hunting for idle its a sign… i do think its 0.44V or 0.55V? at idle but thats just coming across online somewhere. quick search should fix that.

Swap ECU’s if you can…

Check plugs

Vacuum lines/ couplers

Grounds
etc

basically what peter said

11

I had this EXACT problem last week. I … checked leaks, changed ecu, changed maf, change plugs, changed coil packs, changed fpr, checked tps, triple checked timing, checked grounds, checked alternator (just for kicks), checked all fuses and much more. Was pulling my efing hair out and it turned out to be the freaking KNOCK SENSOR!! I unplugged the harness to the knock sensor and the car ran flawless. luckily i had one from my old motor, and its a bitch to change but that was my problem and i hope it helps you out. just unplug the connecting harness on top of your intake mani. I think the wires are yellow w/ black stripe and black. Good Luck!

12

cool thanks guys. it seems my running lean and shitty mileage problems have been solved. so now it’s just basically the hesitation. i’ll try out the knock sensor thing tomorrw at some point! steve, it’s not really constantly hunting during idle. it’ll idle at 850 one time, then i’ll drive and stop and it’ll be at 750, then it may go up to 850 after a few seconds of sitting. more of less just burping and popping during idle.