having problems getting above 8-10 psi

[nb07bcar]

I am having problems getting consistent power above 8-10 psi. I am leaning out and not creating power. I have 42lb injectors and would of thought that they were capable of this psi? Anyone running smaller injectors with that psi? I'm fine up to about 8 but then I start to lean out . My safc setting is on high is +50 almost across the board. I have a z32 maf. I'm running 38psi fuel pressure with a 1:1 fpr. I have a msd btm that I run about 1-1.25 degrees retard. I don't know why I can get power above 10 psi Maybe the turbo. It kinda small. Any thoughts. I don't know what the size of the turbo is. Its made by mitsubishi for the newer volvo. the engine its goes on is a 2.5L engine.The run thier psi at 6psi so I thought 8-10 would not be a streach. I've heard of other volvo guys running it up to 15psi. I'm sure the efficency is not that great up thier. Anyone have a thought?

[S14tat]

who are you sure its leaning out? do you have a wideband? and if your getting inconsitant power, it sounds more like a misfire from spark break up, or running too rich. what kind of plugs are you running, and are you running the stock gap?

[Edub1]

What kind of fuel pump?

[nb07bcar]

I have a wideband plx m-300. I'm running around 11-12 at full throttle around 8psi and then when I hit 10-12 it leans out to about 14 and I start to lose power. I have nkg plugs one degree cooler gapped .035 . I have a holly high flow elecrtic pump. I have a fuel cell with 3/8 fuel line all the way through. I have a brand new msd high flow fuel pump that I might switch over.
Modified by nb07bcar at 1:31 PM 11/24/2005

[s14det]

Might try Raising your Fuel pressure. I run my 50lber's at 50PSI base. That is what Scott told me to but them at for his ECU tune. I have a walbro pump fyi..

[nb07bcar]

The pump I have is sufficent. Walbro works in the stock tank, but I have a fuel cell. The only problem I have when I turn up the pressure I cant get my idle afr up to 14.7. Its around 12-13. That a little rich for idle. I'll try it. My injectors are from the ford lighting so I want to find the stock fuel pressure for these injectors.

[nissanfanatic]

Plug gap. Does it break up as well? When your car misfires, it can cause lean readings on the wideband. Go ahead and gap them down to .028-ish and see if things get any better...

Ensure that the wiring to your pump is good as well. 12gauge positive and negative wires at least. Use the stock power wire(white w/purple stripe on S13s, Black w/yellow stripe on S14s and harness side of S13s) for the relay trigger wire And get your power directly from the battery. Pump shoudl be running well then.

[Jookmasta]

ya lower the gap on the spark plugs to where nissanfanatic said.................

[nb07bcar]

I have a good wire up on the pump. My pump is like a foot from the battery and I used 10 gauge wire for everything else. I will try to lowwer the gap. It does start to really miss around 10-12 psi. Thats when I get out of it. I'll see idf that works. But does it seem normal to have +50 on my safc at only 8-12 psi?

[240SicknessX]

humm, +50 on safc. weird. How far away from the turbine do you have your o2 sensor? what are you in and out settings for the safc. everything works fine at lower then 8psi? everything functions and works. I would eliminate the possiblilty for a problem by gapping your plugs to .026-.028. Find out the base pressure for the injectors you are running and put your fuel pressure there.

lets see what ya have to say. maybe ill get more ideas later.

what volvo turbo is that, 13g, 15g, 16t? not a 19t.

dose the wideband respond to the safc changes in percentages? its possible to get a semi correct fuel curve while in boost with larger injectors with no corrections.

[nb07bcar]

24" from manifold. Thats what the wideband said to do. 2in 5 out I think. Ya I have good power below 8 psi around a 12-13 a/f. when I hit above that it goes to 14-15 and starts to miss . I usually get out before it gets there. I'll try the gaps. I believe its a 16T. Ya the wide band corrected it somewhat. I'm now at +50 almost all the way across the board and I used to be at about +30. I saw the change from 13-14 a/f with +30 to 12-13 a/f with +50.

[240SicknessX]

i hope your afrs arent 12-13 wot @ full boost. maybe a 12.60ish if you had strait 116 octane in. are you sure that you have lightning injectors? kinda seems as if they might be smaller then what you have specified. try maybe 4-5 psi and see if you can get a proper afr though out the entire boost range wot. i would really look into the base pressure issue for those injectors as eliminating another varible.

if its the 16t there is no problem with it being too small. a friend of mine has had a 2.3l 5 cylinder turbo (s70 t-5 manual) holding 15psi until redline semi effeciently. turbo will make 22-23 on a spike and drop to about 17=18 by redline. anything after 15 psi on the s70 is ineffecient. i have the compressor map around here someplace if you would like.

fresh fuel filter? are you able to watch your fuel pressure while you are running. maybe you are dropping fuel pressure there for you have to have the safc so rich........ you shouldnt have a problem with your pump setup but its something to check.
Modified by 240SicknessX at 1:55 AM 11/25/2005

[nissanfanatic]

What year KA is this?

[KATwo40]

Ummmm....you know, many of the Holley high flow pumps are not high pressure.

Have you checked to make sure this pump can handle the pressure demands of a fuel injections system?

I run 370's, SAFC2, stock MAF, TD04H-13C (very small for KADET, but works), Walbro 255, FMIC (30x6x3), 2.5" turboback custom exhaust. This system runs 10psi spikes, falling to steady 8-9psi with no ill effects. Power is good, but chokes a little up top from lack of flow on the small turbo.

[nb07bcar]

I just put my msd high pressure pump on and moved the spark plug gaps to .028. It helped a little. I can get a good run to about 10 psi but then it starts to lean out. maybe the 42lb injectors are only good for that many psi. I have the fuel pressure set at 43psi and have a 1:1 fpr. The motor is out of a 1991 240sx. I put the holly pump on my flow meter and it peged it. The gauge only goes to 4 bars. So its a high pressure pump. But its not the pumps fault. maybe I need some 550cc injectors.

[nissanfanatic]

No...

42lb/hr injectors are the equivalent of 441cc/min injectors. They max past 300whp which you are not making...

What coil are you running? I know my stock coil crapped about a week after I turbo'd making my car non-boostable for about a month until finally one day my car didnt' start. At that point, I put in some 4wire coil out of an S10 in my car and all the sudden, boost was back.

Try picking up a MSD Blaster II coil and rewiring it. Instructions for rewiring it are in the sticky at the top of this page.

[Jookmasta]

ya either the msd blaster II coil or the msd blaster ss coil. the blaster ss will make for a easier installation and iirc, its a better coil than the blaster II coil. also ur size injectors can handle that psi as i am running 12 psi on my big t3 with sr 370cc injectors.................

[nb07bcar]

Ya I was goignt o try that on sat. I have a aftermarket coil just laying around from another project. Hope that works. Maybe some day I will have repaced everything and i won't have any more problems. thanks for all the help. I keep U informed of progress.

[nb07bcar]

I put a new coil on it and it works a whole lot better. Had a question? How do you guys tune your high throttle. Do you start out in third gear and floor it and see where you wide band reads through the rpm range. Mine is compleatly rich untill about 5,000rpm then it leans out to 11 or so and I feel alot more power. I try to lean it out in the lower rpms but I'M AFRAID to go to lean. and sugestions?

[nissanfanatic]

That is exactly how I did it. 3rd and 4th gear pulls.

Trust your wideband. I used to be afraid to lean out as well...but man...the car runs so much better and stronger with a solid 11-12:1 on the wideband. Just remember that 11.5:1 is considered a "safe" tune. 12.5:1 is for maximum power. You can lean out more on the top-end as well. I go to right where its touching 12s at the end. From 4k-5k is where you need to ensure that it reads 11.5:1 for your "saftey". For if it is going to knock, that will be the place. PCP occurs in that area on stock cams/stock intake manifold. PCP is the area where detonation is most likely to occur.