Problems with SR20DET

[HermaN]

Ok, as I explained in a previous thread, I am going to be mapping a guys Nissan PS13 with S15 SR20DET and S14a ECU in it with a NIStune type 4 board. Got the NIStune software, and got a cable on its way.

However, on Saturday we went out to check the fueling and it was WAAAAAAYYYY off!! On cruise/idle I was expecting to see 14.7:1 AFR as normal, but on idle it was sitting at 18.5:1 and on cruise it was actually at 22.5:1!!

On idle it sounds like it has very aggressive cams in it causing lumpy idle. It has HKS 256 cams, which are not that aggreissive. When cruising along with the very lean 22.5:1 mix the car starts to judder, which just isn't right, and when he puts his foot down and it switches over to open loop the AFR's drop to 12.5 as the turbo spools up, which is fine, but then when on boost it just leans out as the revs rise. At certain points it leans out to 14.5:1, then at the very, very end, just before lifting off the throttle it blips to 11.6:1

So something defo is not right with this car. Also, at cruise, the base fuel pressure is 3 bar (as it should be), but then at 1 bar boost it's at 4.5 bar FP, where as it should rise in a 1:1 scale, so 1 bar boost should be 4 bar FP, not 4.5 bar. However, that should make it run rich, not lean!!

Unfortunately I can't pull the map till I get the cable, but this just isn't right. Things that should make the car run rich, and yet it runs VERY, VERY lean.

Engine spec list is....

S15 Engine
HKS GT-SS Turbo
One Off Exhaust (Dual Pipe with bungs)
Trust Racing BOV
Remapped with NIStune type 4 board not long before the engine let go and was rebuilt
HPI Air Cleaner
Z32 AFM
Metal Suction Pipe
Triple Layer Koyo Radiator
Oil Catch Can
Engine Torque Damper
Oil Cooler
Oil Filter Relocation Kit
GReddy Intercooler
Aftermarket Turbo Outlet
Aftermarket Downpipe
Stainmesh Turbo Line
Master Cylinder Stopper
Yellow Injectors Nismo 555cc
256 Cams
Aftermarket Manifold

Lean on idle & cruise makes me think faulty lambda, but it should not be that lean, it's WELL off! So could well be closed loop is disabled and the previous mapper just made a total hash of it. It has a Skyline fuel pump in there, but if it's weak it could be causing lean conditions on boost. Really need to get this cable and pull off the map.

Anyone got any ideas in the mean time???

[blu3man]

Oil Catch Can

A must for performance!!!

256 cams aren't that aggressive n_n

That hell lean. Just wait for your cable. You may never know.

What kind of wideband are you using?

[HermaN]

Oil Catch Can

A must for performance!!!

Not sure if that's meant to be sarcasm?? Was just listing the cars spec.

256 cams aren't that aggressive n_n

That hell lean. Just wait for your cable. You may never know.

What kind of wideband are you using?

Yea, 256's are not that bad as you say, so should idle pretty well with them in. Fueling is actually dangerously lean, 22.5 on cruise is just silly! Hopefully cable will be here soon. Have ordered it from a UK authorised NIStune dealer, so no waiting ages after it's been shipped to come from another country, should pretty much be next day delivery.

Part of me is hoping the map is the culprit, so we can sort it quite easily, but part of me is hoping it's not the map because if it is then the lad was royally bent over. Cost him around £450 to get it mapped with NIStune by someone who is MEANT to know what they are doing. If we pull the map off and it's a load of rubbish and I were him I'de be demanding my money back, but we'll see what comes off when I get my cable.

Said mapper has done a fair few Nissans, but his reputation is a bit strange. Some say he is the best mapper to ever grace gods green earth, where as others have had their cars mapped by him and it's knocking like hell or running really lean, etc. I understand all mappers will have people bad mouth them at some point, but usually it's 95% good and 5% bad, where as this guys ias 50% good and 50% bad which is quite a lot and doesn't say much for his mapping skills.

I'm using an Innovate LM-1 wideband, so not some cheap chinese made rubbish. Have tested it on other cars, inc my own and compared the AFR results I get with another guys LM-1 and they are virtually identical, so don't suspect the lean AFR's to be an issue with the wideband itself.

When I do get my cable and pull off the map (hopefully this week) I'll post it up on here for folk to have a look at if there is nothing obviously wrong with it.

We'll just have to wait and see.....

Cheers!

[blu3man]

Eh; my wideband unit is so bad...

Note: Some of these "mapping gods" will gladly have a free quick look at your map if you say its megabroke.

Are you leaking any exhaust before the wideband? That would definately make your afr look lean. I took out the silly hot air solenoid recently and am yet to plug the hole.

[HermaN]

Mate, I don't need anyone to look at the map if there is something obviously wrong with it. Would only ask someone else to check it over if it all looked fine and everything on the car was fine too, just for a second opinion.

Anyway, I recieved my NIStune cable yesterday, and when we tried to pull the map off the car, it's locked with a PIN! So only options are to see if the original mapper will remove it for us (he won't give it out, because it's a generic PIN he uses on all his tunes), or we will have to send the whole ECU to Horsham Developments and they have said they can wipe it and re-program it with a base map for £24.99 + £9.99 return shipping, and obv we will have to pay to get it down there, so looks like it will cost about £40 - £45 in total to get Horsham to wipe it.

Original mapper is in Scotland just now, so if he would remove the PIN that would be ideal. Even if he gets all fussy, he can just flash one of the NIStune base maps to the car if he REALLY doesn't want us to see his tune. However, I REALLY would like to see it, even if I only get to look at it on the original mappers laptop, just to see if it really is a bad map.

Exhaust doesn't have any leaks, or at least no major ones, to put the AFR's that far off it would have to be one big exhaust leak! 22.5 @ cruise & 14.5 on WOT is WELL off.

[Fordy]

did the mapper install the nistune board? i've heard reports of one person over here in the uk locking boards. if he supplied fitted and mapped it then he doesnt need to give out the pin code so a reflash of the board is what you'll have to do

if the ecu was supplied with a nistune board fitted before he touched it then he has to give you the pin as he doesnt have the right to lock it

[HermaN]

I'm pretty sure the mapper did supply the ECU and board together, but will double check with the owner. At the moment, the owner is happy to send it away to Horsham Developements who have said they can wipe the board and put a base map on.

Planning on sending it down this Monday.

[blu3man]

Protecting "commercial bins" is like protecting the recipe for a big mac...

Consider this and get back to me.