Leaning Out Help.

[RPR33]

Hey guys I’m having some trouble with my car (r33) at the moment. When coming on boost hard it pings! On the dyno putting the hammer down from 2000rpms it runs fine most times However. Putting the hammer down from 3000rpms and upwards, when it shoots straight on to boost its leaning out for a few seconds. As far as I know it has not always done this, As I’ve never heard it ping before and its always ran rich. What should I be checking out? The dyno operator thinks it’s the jap tuned ecu (re-mapped stock ecu). I think if that was the case it would have always had this problem! I have turned down the gain and boost on the boost controller (greddy pro fec b) and recently changed the o2 senor. I have just put in new spark plugs and oil. I’m thinking clogged fuel filter maybe? Where else should I be looking. I also cleaned the afm which had a fair bit of crap in it. but it didn't help out

Mods I have if this helps.

Exhaust turbo back 3 inch

Front mount Cooler 600x300

And high flow fuel pump

Stock turbo running stage 1 9psi and s2 12psi its ping’d on both these levels of boost. although top end boost is always the same as it drops to 9-10psi

Thanks

Russ

[RPR33]

also my timing was out it was down 1 deg? but I think that would give me less chance for a leanout so i left it.

[tridentt150v]

fpr maybe?

[RPR33]

hhmmm maybe the fuel seems to get there just not fast enough at the start

[700HP-GTR33]

Faulty fuel pump?

Blockage in the fuel filter?

Injectors need cleaning?

Coils are arching?

Spark plugs gapped incorrectly?

AFM ?

When you say ping..you mean.starving of fuel..like a cut out...or a fart,kick and bang?

Is it fuel or ignition?

What is your revs and AFR reading when it pings?At this point what is your ignition timing?

More info required

[paulr33]

a scan of the dyno sheet showing AFR will reveal a lot of info - can you post it up ?

[RPR33]

no sorry never got it printed out.

The car does not fart, bang or kick or anything it would just all of a sudden make this kinda rattle/tapping noise under heavy load. I was hearing this noise on and off as i gassed it, so i did an oil change and had it put on the dyno.. on the dyno we got it leaning out from what a understand just a little say 13-13.4 a/f mix spike between 3-4000rpms just after or as it came on boost. it would start to richen up, say move from 15:1 just holding 3000rpms to 12:1 once the foot went down then back to 13.4:1 for a sec and drop right down to 10.5:1 af mix. now on the dyno i did not hear any strange noise the dyno operator said he heard it ping a few times just briefly. I was just watching the a/f mix. he then told me that when ever i'm driving around and giving it a bit it'll could be doing damage? so i'm like well how can i stop this. will i be able to hear if it leans out?

thanks guys

[Duncan]

yeah I would guess a fuel pressure problem - put a gauge on it and make sure you are not short of flow up high. dying fuel pump, fuel pump wiring, blocked filter etc etc etc. some of the jap ecus are a bit leaner than we like but they should not be causing it to ping all the time

[Mr. Untouchable]

hmm could be a few things.

I'd also try a stock computer, just to see what happens.

Not saying its the most likely problem but i'm sure someone has one kicking about they would let you borrow and will cost you nothing to try.

also you say hiflow pump, what type? brand, specs etc? if you havent had it out i'd pull it out, check it out, check the wiring, earth it out to the body if you already havent, check the voltage its getting etc.

i doubt it would be the filters, but wouldnt hurt the check out the pickup, and replace the filter.

other than that, try new FPR.

I'd try to borrow someones AFM too, just put it on and see what happens. Doesnt cost anything to swap things over.

[RPR33]

I have no idea on the pump. The stock one died not long after I got the car and I had it replaced though warranty. The mechanic just said he had a high flow one lying around so he put that in. I was told it was band new. I’ll see if I can get a mate around with a multi meter and fuel pressure gauge. What should the pressure be?

I think it was around 42psi last time I checked at idol.

Apart from the lean patch coming on boost the a/f mix was the same as all my other dyno runs, would that count out the afm?

Also what do you think would be the best way to check for internal damage? Leak down test?

Thanks guys

[Strik3r]

if its pinging at 3000-4000rpm, you might be a bit lucky and escape any major damage.. few scorch marks maybe... i wouldn't be pushing your luck tho. I believe 40psi is fine on the fuel pressure, so assuming you have that, most likely culprit is the tune on the ECU... either too much timing or too lean a tune in that rev range... Go aftermarket and get a tuner to do a proper tune or get a stock ecu to replace it.

yes it could be the AFM reporting incorrect (too low) air flow causing the ECU to think their is less air than there is and consequently injecting less fuel, causing detonation. again, borrow one to test.

What sort of fuel are you using ??

[700HP-GTR33]

Borrow a AFM....see if this fixes it.

At the same time change your fuel regulator.

Your pressure is being tested prior to this unit and not after.

[RPR33]

bp 98 octane maybe I've just had a bad batch in the last few tanks.

but if it was the afm then wouldnt it be lean all the way? or up and down? I don't think it is the ecu cause as far as I know Its never run lean untill now! unless its always had a lean spot hit R&R and thats why its always run so rich up top. I'll check out the fuel filter and pump voltage first a guess.

[RPR33]

I can get a afm but I don't think I'll be able to get a reg. I'll look into it.

Thanks

[RPR33]

ok I'm going to put a new fuel filter in and put on another afm and back to the dyno. can anyone think of anything else I should check before doing this?

[GeeTR]

Sounds like fuel pressure to me.

~42lbs base, (engine not running / no vacuum in the plenum) so u should have much less at idle.

Try and get a gauge on it for the dyno session; even feed the voltage from a o.pres sender into the dyno, so its plotted along with the rest.

Are you sure your ignition system isn't weak (for all the usual reasons) and your mis-firing?

A mates S14 was breaking down at peak tourqe (~3600 rpm) which caused mis-fires, and pinging. The lean spikes on the readout are from unburnt fuel past the 5 wire. SplitFires fixed that issue.

Edited March 25, 2008 by GeeTR

[R338OY]

My car was running like crap. Took it to a tuner, threw it on a dyno, attached a fuel pressure gauge, found it was running lean.

Was told to change the pump. Did that, and did the filter too. Helped but was still running sluggish esp. near redline. Needed my timing adjusted and serviced my AFM. Squeezed like an extra 10rwkw just from that and gave me much smoother power curve.

That's my story

Edited March 25, 2008 by R338OY

[r32-25t]

you might find the fuel pump controller isnt switching over proparly,

what you need to do is find the earth for the fuel pump and earth it straight to the body of the car

fixes leans out 99% of the time

[Ad_N]

I have no idea on the pump. The stock one died not long after I got the car and I had it replaced though warranty. The mechanic just said he had a high flow one lying around so he put that in. I was told it was band new. I’ll see if I can get a mate around with a multi meter and fuel pressure gauge. What should the pressure be?

I think it was around 42psi last time I checked at idol.

Apart from the lean patch coming on boost the a/f mix was the same as all my other dyno runs, would that count out the afm?

Also what do you think would be the best way to check for internal damage? Leak down test?

Thanks guys

Just because you were told that it was replaced for a new one, doesnt mean it happened. Sounds a bit untrustworthy but I myself have been bitten before. Could be worth a look. Just a thought.

[RPR33]

Hey guys how do I tell if its pinging from lack of fuel or ignition problem? I just put a new fuel filter in and its still the same..... I did put new plugs in a while ago they were NGK 's BKR6E?