stock rb20 getting less then 300 km a tank...

[magular]

alright so yeah,

i got a motor swap done, blew the HG in my original motor in my sedan gtst. and i could get about 460 on a good tank. step on it here and their.

just got another 20 put in just before christmas and their has been some issues getting to run properly.

like the coils were stuck, some injectors were stuck, coil harness was pretty haggard. and it running really rough.

i got the injectors cleaned, and their all back to mint, changed fuel filter, got coils, brand new coil harness and brand new 02 sensor arriving in the mail this week. and next pay check im getting a walbro 255... so everything i thought that could have an effect of the motor running like crap should be taken care of.

yes i am running a mines ecu stage 1. but the ecu is the same as before, and i dont see it affecting the other rb20 anyy different. so it sucks paying 70$ for a few days of easy driving. all my buddies with 400 hp in their cars are getting 500 a tank easy. so not sure whats the deal.

ANY info is helpful, i think i did a good job changing all those things, but what else could have changed it?

plz help!

[Voodoo_ChildR32]

Either a fuel leak or it's running pig rich. I would lean more towards the fuel leak first, you're going through an awful lot of fuel in a really short time.

[Supraclean]

What's it got for spark plugs?

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[magular]

oh it does run rich, was just driving around town, and my brother was fallowing me and he said that i was shooting flames all the time... just normal driving, not even ripen'

but just having my car parked in the garage the garage smells like fuel like crazy. so maybe its a combination of both, and theirs a good chance something got bent or whatever from the swap...

[magular]

the spark plugs are brand new ngk... forgot to add those to the list of things changed.

and its the towns skyline mechanic that put em in, a good friend of mine, im sure their fine lol

[Supraclean]

Buddy had this same problem. Fuel line was crack from the top of the tank that then runs to the engine. More noticeable when warm obviously aswell as the seat in the trunk. I'm pretty sure the line itself was to blame for most of the gas vaporizeing? Off gasing? You know what I mean.

I would ditch that Ecu man for a Stock Gtst one.

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[cooke24]

i get between 325-380 max soo your not too far off

[magular]

alright so after taking a closer look i found it... the leak.

im now at 65 km since fill up and im pretty much at half... yeah, ouch. thats not cheap so i was determined, so i turned it on and wiggled some lines and at one angle it was spraying out like crazy. so i went to lordco and paid 2$ and went hope and fixed it. ( i really hope so )

i will be really happy if thats it, but who knows, all the lines are 23 years old. ill post the next amount of km i get on a tank and will give me a good idea if that was it or not.

lets see if i can get close to 400.

[MKIV]

No lie, I used to get 500~ per tank after getting tuned. Stock 20, Gtr injectors, 3"inch exhaust.

[M13]

I get 450-500KM/60L on a 400BHP RB20 street driving.

[magular]

wtf. really? so a tune would be a good idea i guess.

its just im starting to build my rb30 this summer, and i want to same all the money i can for that motor instead of buying some cheap ecu that can just have a simple tune. or buy the ecu ill want for the 30 and tune it for this motor for now? damn i dunno.

i have 3.5 full exhaust, no cat, big front mount, 2.5 piping, apexi air intake, set 12 psi on boost controller, just fleshly cleaned injectors, aftermarket coils, brand new coil harness, brand new 02 sensor, brand new fuel pump ( walbro 255 ), brand new fuel filter, cleaned maf sensor. fixed the fuel leak.

and im at 214 km and just under half a tank. and im trying to not pin it. but if i do just 1-2-3 my needle moves and doesnt come back. so lame! like 180 whp and i get worst gas milage then everyone.

ok so if i want to get it tuned, WHAT STEPS would i take, cheapest ( if possible, just needs one more summer out of this motor pretty much )... to get it tuned/tunable.

[M13]

are you sure all the gas is entering your engine w/o leak? if so, I'd be worried for your piston rings.

Have you done a compression check?

[magular]

no i have not...

and im not sure theirs no other leak, im still nnew at this kinda stuff so seems impossible to find it on my own.

[ZinnZ32]

Ok 1) You still don't know the exact NGK part number of your spark plugs, they have to be the right dimensions, and heat range. This is suspect.

2) When you say you "Moved the [fuel] line and fuel sprayed out" and fixed it via 2$ lordco purchase, what did you actually fix it with? You realize most off-the-shelf fuel line (5/16" diameter in your case) is rated for carbereted, and NOT fuel injection vehicles. Your Lordco jobber probably doesn't know the difference. IE: There are two kinds. One will have your car leak proof and happy for thousands of miles to come, one will leave your car in a burning pile on the side of the road (Ever hear of some guy's Z32 which caught on fire on Highway 1 in Vancouver? Yeah, there you go. Guess what? That was a fuel line, and your car is related! Yay)


I would suggest you fix all your suspect fuel lines with proper 5/16" SAE J30R9 fuel injection hose. And proper new fuel injection clamps (not worm-gear clamps). You don't really seem too car savvy, but I suggest you put some effort in it before a fuel leak in your engine bay ignites. (If you smell gasoline when driving, that's a good indication too). Or get someone that knows what to do

[Dragon Humper]

Well, you did make an improvement. I would check every soft fuel line on your car and make sure you dont have another one ready to pop, even if you dont smell fuel any more. Are you sure the base timing is set correctly? If you feel way down on power that could be the answer for both your issues. Even a 10 to 15 retarded base will make a huge dent in both power and economy in a low comp. turbo motor.

Even if you didnt touch the CAS on the replacement motor, whos to say that it was even correct in the doner car.


Jon.