Jump to content
SAU Community

Fueling Problem!

Daboss

By Daboss,
in Engines & Forced Induction

 Share

Recommended Posts

Daboss Experienced

Daboss

Posted
Posted

Hey guys need some expert opinion again. Ok here is the deal at wot full boost my afr's are in the mid 13/14's. They use to be in the high 11's/12's, but the other day as I punched it it started to miss horrible after I went into cruise. When applying load it was fine but at cruise horrible miss, got her home to find the number 2 and 4 spark plugs were damaged. Insulators were cracked and on the number 2 the tip of the plug was gone was able to glance at the wideband and afr's were in the mid 13's/14 during that pull. Replaced the plugs miss went away but left the leaning out problem. I am using a chipped ecu on 10 psi stock turbo. Now that setup should not be able to flow enough air to make me lean out that bad. So I tried to compensate by adding fuel with the piggyback no luck as soon as full boost comes in afr's lean out. So I figured my problem has to be fueling, I clamped the return line and the fuel pressure sky rocketed depending on how tight I clamped it and stayed at that level showing me that the fuel pump is up to scratch. I let it go and the car automatically leaned out at idle, afr's in the 17/19's and didn't level out until I increased fuel pressure through the regulator. 1)What I want to know is if it supposed to do that when I release the clamp or is this a sign that the regulator is shot? I also noticed that on the fuel pressure guage attached to the regulator that when car is off the needle sits at about 8psi and with the regulator increase and the piggy back adding 15% fuel when full boost kicks in the car still has afr's in the 13's. Under cruise and light load everything is fine, but as soon as full boost is in the car leans out not as bad as before but still bad. I have walbro 255lph fuel pump with direct power rewire mod and have already established that the pump gets full voltage from the battery the pump is probably 18-24 months old. I am not running the car just allowing full boost to kick in at 3000 rpm and checking the afr at that point. 2) What do you guys think it is and also is there a way to just test the regulator without running the car at full boost?

Link to comment
https://www.sau.com.au/forums/topic/270073-fueling-problem/
Share on other sites
Daboss Experienced

Daboss

Posted
  • Author
Posted
AFM, Wrong heat range on spark plugs, Bad fuel.

But I am guessing your spark plugs were bad from the start.

Hmm that could be. I had or at least still have denso, coppers gapped at 0.8 heat range 6. I will be sticking with the same except moving the heat range to 7 as it is always hot here. Had the spark plugs in there for maybe a month. The two that were bad I just replaced with two old plugs I had taken out to put in the denso's the other four are still from the same stock. Will change the lot this weekend. How would I check the afm? Just swap it with a known working one and that's the only way. I have a z32 installed. Quick question bad spark plugs or the wrong heat range can cause a car to lean out? What about the fuel pressure regulator, from what I described it seems to be ok then?

Link to comment
https://www.sau.com.au/forums/topic/270073-fueling-problem/#findComment-4595509
Share on other sites
blind_elk Grand Master

blind_elk

Posted
Posted

Which side of the FPR - engine or return - is the fuel pressure gauge sitting? Because if it's on the engine side, it should basically show around 2 bar when the engine switches off (unless you don't have the non-return valve in the pump).

What pressure does it show with the engine idling?

Link to comment
https://www.sau.com.au/forums/topic/270073-fueling-problem/#findComment-4595624
Share on other sites
Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted

do this test and get back to me, take your air flow meter off, CLEAN IT with contact cleaner or brake cleaner. get it as clean as possible. re-fit it and check the AFR's and let me know what happens.

was the car tuned with the z32 afm? or was it tuned with a stock one and you changed it later?

cheers

Link to comment
https://www.sau.com.au/forums/topic/270073-fueling-problem/#findComment-4595665
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Manur33
      Vag Coil Diy loom wire guage selection

      By Manur33 · Posted

      Can u check this way it works for power supply?
    • Manur33
      Vag Coil Diy loom wire guage selection

      By Manur33 · Posted

      These coils draw 10amps that what i read online
    • nouveau_poor
      Unknown sound similar to BOV on positive boost with partial throttle RB26

      By nouveau_poor · Posted

      I appreciate the detailed explanation, think I understand now. I spent the better part of last night reading what I could about shuffle and potential solutions. I had replaced the OEM twin turbo pipe with an alternate Y pipe that is separated further away from the turbo. The current one is from HKS and I had a previous pipe that was separated even further away, both have shuffle. I had heard that a divider can be welded in to the OEM pipe to remove turbulence, and figure that aftermarket pipes that are more separated would achieve the same thing. From what I read, most people with -10 turbos get shuffle due to their size, though it's a bit less common with -5s on a standard RB26. I think Nismoid mentioned somewhere it's because OEM recirculation piping is common in Australia with -5 cars. It seems that the recommendation tends to vary between a few options, which I've ordered in what I think is most feasible for me:  1. Retune the MAP or boost controller to try to eliminate shuffle 2. Install OEM recirculation piping 3. Something called a 'balance pipe' welded onto the exhaust manifolds. I don't know if kits for this are available, seems like pure fabrication work 4. simply go single turbo My current layout is as follows: Garrett 2860 -5s HKS Racing Suction intake MAF delete pipes HKS racing chamber intake piping hard intercooler piping,  ARC intercooler HKS SSQV BOV and pipe Haltech 2500 elite ECU and boost solenoid/controller HPI dump pipes OEM exhaust manifolds HKS VCAM step 1 and supporting head modifications Built 2.6 bottom end All OEM recirculation piping was removed, relevant areas sealed off I'll keep an eye out for any alternative solutions but can get started with this.  Only other question is, does shuffle harm the turbo (or anything else)? It seems like some people say your turbo shafts will explode because of the opposing forces after a while and others say they just live with it and adjust their pedal foot accordingly. 
    • codygrimm27
      Can you mount the ATTESA pump in other locations?

      By codygrimm27 · Posted

      That worked out PERFECTLY! Thank you big time to JJ. He was able to swap me his stock diff. He drove all the way to me as well. Killer! Removal & install was pretty straightforward. The diff itself is HEAVY. So that’s a 2 man job.  Man does the car drive nice now! Couldn’t have worked out any better 👌
    • DannyDee2
      First time owner v35

      By DannyDee2 · Posted

      Welcome mate!
×
×
  • Create New...