Gotcha, Wouldn't it cause both banks to read crazy numbers? It's only bank 2. Now I do have some black build up on the backs of the valves. I thought it was from the pcv valve that was broke. When I first got the car running I didn't know the pcv valve was broke and the car smoked at times so bad I thought there was a major problem. It was burning oil so bad at times. I then found the broken pcv, I fixed it and the smoking issue was gone. So with that being said I thought that was why the backs of the valves had a little build up.
When the other shop did the compression test they used a borascope and looked at the pistons and bank1 the bank that is ok was clean and bank2 the bank that is running lean had a lot of build carbon build up. The compression test came back ok bank1 was right on point and bank2 was a little higher. The shop said this is common with the build up. Basically they said the build up was causeing the reading to be a bit higher. If what you are telling me is true ( I not questioning you at all ) then that would explain why the build up is there correct? Or could be why? I know anything is possible at this point.

 

Quick update, I talked to the shop today and they did a smoke test and no exhaust leaks....... I guess we can count that out now. Somthing else I guess. The shop said they were gonna start really digging into it today so I keep ya posted so as I hear somthing. If anyone has any input please post it. Thanks!!!

 

huh, that's odd. So this is going to be some complete nightmare of a problem then.

The black on the valves is from oil coming down the valve shaft. Some oil will always leak down through the valve stem seals otherwise nothing would lubricate the valve stems as they pass through the guides. It's normal to have some build up on the back of the valve after a good amount of time on an engine.

 

make sure you have a hard stop on the amount you want to spend. egg hunts can go insane with billable hours so just a heads up.

 

Good advice, I thought the same thing when he posted that.

So I noticed you said the pistons on the good bank were clean while the pistons on the bank running lean had a lot of carbon buildup.

Could this be a case of running so rich the O2's could be reading a lean condition? Could be possible, just a thought.

EDIT: Usually you get backfires from this which you have not mentioned you are getting but thought it was worth mentioning.

 

Yea well what can I do. I hoping it's not a egg hunt but I do no enough to figure it out on my own. Either it gets fixed or it sits till it rots away. This sucks!!!!! I can't believe this is going on right now!!!!!!!! What else is new my luck is terrible and always has been!!!!!! If it's going to happen it will happen to me!!!!! Bout to just light it on fire!!!!!!!!!!!!!!!!

 

What else could it be? Did compression test that was ok, did the injector test that was ok, did the smoke test that came back ok. That leaves wiring issue, fuel pump issue or somthing on them lines, or a computer issue correct? I mean this is crazy... If it were you what would you do next? thanks brotha!!!

 

what about leaks between the top of the plenum down to the heads? one time i found a leak right at the injector seal. I sprayed carb cleaner on it while the car was on and saw bubbles.

 

so is all this based on what the AFR gauge says? the car is completely undriveable, or does it only hang at 2500 rpms and then corrects?

 

From what I have seen in these discussions this is what I understand.

Bank 2 has his widband on it and it matched the dyno's wideband.
Bank 1 originally had the dyno's wideband.
The Dyno's wideband was replaced to make sure reading were correct.
His wideband was moved to Bank 1 to verify.

AFR on Bank 1 shows extremely lean but the car drives, in his word, great. This is confusing because if it is hitting 18:1 at near atmospheric, it should buck. At cruise (in vacuum) I could see 18:1 maybe not bucking since 18:1 is what is concidered "leanest possible cruise".

Now I read a post from him yesterday that said they borascoped both banks and the pistons bank 2 (the bank running correctly) were clean. He then stated the pistons on Bank 1 (the bank reading lean) had a ton of carbon build up. This makes me wonder if this is a case of running so rich, it runs lean.

If this is the case, it may be a little easier to diagnose.

 

All of wht GAMERMODZ has said is pretty much what has went on or what has been going on. To answer wht you have asked. Pretty much we have been past 2500rpm with it. The other shop was using a dyna pack dyno. From what he explained to me he set the dyno so the car would no go past 2500rpm. This way he can step on the gas ( wot ) and it not go passed 2500rpm. Basically he was starting to tune the car and right off the bat this is what he ran into. So like I said we have not pushed it passed 2500rpm. This leaning out only happen under load. Driving around the car rund fine. This is all under load, when there is a demand for more fuel. Also from what I understand the other shop has told me that when it was under load and it was reading lean the car was not bucking or poping. I don't know this is a issue that I don't know noting about. Hopfully this has made it a litte bit clearer for you. If not let me know and I'll answer anything you got to the best of my ability.. Thanks

 

if it wasnt bucking or popping, then its not really running lean/rich enough to matter. esp at 2500 rpms.

What you need to have done is a full dyno pull from 2000 rpms to redline with AFR being logged.

a lean blip at 2500 doesnt matter. I dont even know why your tuner would stop at 2500 rpms. You have no idea whats even going on in any of the driving cells. You need to have a full map built before you can go back and start to nitpick a few load cells.

Nothing about this makes any sense.

 

It was on a load bearing/steady state dyno which held it at 2500 RPM's for tuning. The reason to tune on this type of dyno IS to create load to tune across the targeted RPM range. So even though it didn't exceed 2500, it still experienced load. Depending on his turbo spool, it could have experienced load all the way in to boost even though it was only at 2500 RPM's.

 

ya i ninja edited my post...

still, why stop at 2500. you have no idea whats going on then. I;ve never seen any tuner focus on 1 load cell when the map isnt even roughed in. Doesnt make any sense to simulate a 6th gear pull high load low rpm pull, when you dont even have a base map.

 

He only stopped at this point because it doesn't matter if you run the RPM higher or not. Let me try and explain.

So you start tuning you fuel map (never touch timing until fuel is done). You set the dyno to hold for, lets say, 2500RPM. Now you start rolling and get in to the gear of your preference, perferably a gear tall enough to allow you to keep it in a "load" cell easily.

Once you are in that gear, you hold the gas pedal just enough to get you in your first cell, lets say -7 PSI. Now you tune for your target AFR at 2500 RPM & -7PSI. Once that is done, you give it enough gas to get to the next cell in the 2500 RPM row (or colum depending on your ECU). So now you are holding it in the cell of 2500 RPM & -5 PSI and tuning that cell to your target AFR. This continues all the way to 2500 & 0 PSI or higher. As high in the load point of that RPM range as you can get to. Usually on a boosted car, around 5 PSI or less per RPM range.

You do this for all RPM ranges except for really high ones. On our car I would say load bearing any higher than 5,000 would not be necessary as you should have more than enough info to estimate what those cells would be and you can move on to ramp runs.

Of course an experienced tuner may not have to go as high or in to as much load areas as I discussed because they are experienced enough to estimate accurately based on the previously tuned cells.

I know that's a long explanation and you may not need that much information, it's just a good example to anyone that "load" isn't RPM and you can simulate high loads at any RPM on a load bearing dyno.

This is why I can see why he said the tuner stopped here. He increased "load" while holding it at 2500 and this lean condition started happening and based on the chart, it kept leaning out for a while.

 

Yes, I am aware how you dial in a car on load dyno.

But you cannot do that until you have a full base map. Maps need to be smooth. dialing in individual load cells is the last step, after you run thru a full map. Doin cell by cell from the start will give you a super choppy map as you chase AFR's. The OP's car is perfect example.

Plus its a waste of time initially bc who lugs their car in 6th gear up a hill. Thats the only way you'd ever get high load at 2500 rpms for any given amount of time.

Normal driving will have you zip thru the 2500 rpm column, regardless of load (load being MAP)

His new shop needs to do a full map pull from 2000 to WOT. There prolly isnt even a problem in the higher rpms. Its well known that our plenum design shows bank to bank differences. This is probably the 1st instance that shows the extent if the tuner held a fixed rpm and looked at that entire column.

 

Depending on the fuel tuning method (VE, Duty cycle, Pulse width, pulse width plus injection time) will depend how accurate your starting map needs to be. If you are tuning VE, you could just drop 80 - 90% over the whole VE table and start tuning, albeit on the rich side but it's better than lean! For others, you would have to guess a little based on variables like injector size, engine size, etc to create a base fuel table.

While specifically created basemaps for a particular engine are ideal and "usually" available, they are not required to start tuning a car.

Also, on a modified engine, it is not a good idea to take someone else's map and start doing ramp runs (WOT pulls). There could be just enough difference to blow it up. If you have a basemap, the same tuning process should take place, it would just take less time since everything may be close.

Even outside of fuel, if you take someone else's map to use as your base, you should immediately pull timing to be safe.

A basemap is just that, a base. It's a starting point to save the tuner time and thus the customer money. Using a basemap and immediately doing WOT pulls is dangerous and many people blow their motors because of this. Every engine is different especially when modified and even more when highly modified.

By going cell by cell, you will create a smooth map. Do you have to go through every single cell one at a time? You don't have to but it would be better if you did. Typically (and most tuners do this) you can hold a rpm and load point at every 3 cells (or more) and then linearize between the last and the new cell to speed up the process and get very close to where it needs to be.

WOT pulls are no where near the first steps. The first step is to go through some cells and get the map as close as possible and cells that you have not gotten in to should be made richer than your estimate.


Absolutely not. If that bank IS running lean, that motor will pop. You need to be certain of 2 things before you WOT pull. 1. That the map is safe (tune cells you can get to and richen what you can't). 2. That there are NO issues. To assume that bank isn't running lean and doing a WOT pull is a huge gamble and any quality tuner would not risk his customers engine.

Diagnose and fix the issue, then continue.

 

Not true. In lower gears, yes, in taller gears say 4th, 5th, or especially 6th at 2500, when you press the gas pedal, the load will increase significantly before it gets above 2500.

 

Got acall from the shop today. I had to be quick cause I was very busy with work. So far he has found a issue with the exhaust selanoid ( i know I spelled that wrong) on bank2 not sure what yet. He said he was going to load a map he had from a greddy tt kit and did small pulls to see what was going on and how the car would react. That was when he said the car was reacting ok to the adding and subtracting of fuel. I have no idea what the other shop was doing but Vince said the car was responding to adding fuel and taking away fuel. He pretty much said it wasn't leaning out as bad as J tune said it was. Although bank2 is a little leaner. Not really sure how the other shops dyno print out said one thing and Vince said when he did it he didn't get the 18.1 a/f reading. Idono......He still is saying there is a issue with the exhaust selanoid or the exhaust cam gear. Somthing about the exhaust valve opening to much. Idono....... Somthing is going on in that area tho. I don't know how much further he got since I talked to him, but he was going to start testing a few things and digging further into it. So I think this was some positive news so far. I know this prob. does not make sense but I tried to explain the best I could. I don't know about all this s**t. I will ask him to chim in and explain a little better.

 

I am a little confused. Did he solve the lean issue on bank 2 and now it's only reading a little leaner than Bank 1?