I know the effects a boost leak can have on a draw thru setup with maf but what effects will it have on a speed density setup with no maf?

I have machine gun problem when going wot. Backfiring basically. I know its too rich but could it be a boost leak since am running speed density. Car idles fine and seems to run fine off boost. I did a test for leaks with smoke a week or so ago and found none.

 

where did you find the smoke machine or how did you do yours? I had the same problem with mine when I first went sd and it was due to running way too rich and fouled plugs. It will probably be something easy.

 

Speed Density is just MAP vs RPM. If the car was tuned correctly, you should not have any sort of backfiring/fueling issues from a boost leak. It should operate as if you turned the boost down. Now, if you are spraying meth or nitrous as well which are not within the realm of what the PCM can see, then yes, you may have these issues.

 

Ok if a boost leak can't make it backfire like machinegun or antilag on sd setup then its likely tune or wires. Wires are brand new granatelli high temp wires.I guess mabye try to lean out the tune some and see if it improves,maybe simply too rich.

 

Couple local shops have the smoke machines.very handy for vac leaks, boost leaks,exhaust leaks..etc.

Can I have more detail on your solutions .Should I taper the pe table off around 3000 up to be more closer to the boost pe table. Should I be tapering the boost pe table ramping it a bit richer not go to say 11.0 right off the bat?
I pasted the ve as per hptuners instructions. And pretty sure added 25% richer. So guess should dial that back down too?

I figure it has to be wire or tuning. If you are using hptuners would appreciate seeing your tune. I am going crazy here as its so frustrating trying to go wot and getting the machine gun every time pretty much.

 

If you did the generation for the rest of the ve table based upon the hptuners demo/instructions....I have done that several times and it works great. In my experience it does not matter if the car goes directly 10.5 or tapers down from 14's, both will not cause misfires. I've only got misfires in the very low 10's or 9's a/f.

If you think it is too rich to pull through you can see black smoke out the exhaust if the car is not moving alot.

I would also check the wires, coils, and plugs CLOSELY. You can also scan each cylinder for misfires and monitor them while the car is acting up.

 

I did the generation for the table and had it 25% richer as per instructions. I have my afr be set to 1.27 or 11.5 but now that might be 12.0 since running e10 and stock is more like 14.1 stoic so since stoic is set to 14.6xx on hptuners right now would exect to get 12.0 or guess would have to adjust ve more or differently to get the target afr correct.
I just left the pe at like 12.3 across the board again that should be 12.8 with the e10.
It runs half point leaner if stoic is set to 14.6x.
Maybe I should just set the darn stoic to 14.1x? to make it less confusing.I run 94 e10 almost all the time but its not available everywhere so then might have to run 92 e10 or 91 straight gas.
I took the ve table down to 10% richer from 25% now at 315 by pasting the stock last line at 105? and multiplying same line by 10% now at 315. interpolating inbetween.

So try car out again. Also not sure if should be rampinmg timing down to 15 from about
2800 on at .80g?... have my 99 stock timing until 2800 now and above .80.
I was running 15 max most of the way across before even at lower rpm like 2000 at 80 g s and on.
Seems to me if timing is pulled too much and fuel is too rich would get antilag effect which is pretty much what am getting at wot.

I wish there were some more turbo tunes on hptuners site. Very few on there to compare to.

Weather is a bit crappy today but still might try car out if its not pouring and roads dry up. I have as said put the ve now at 10% richer at 315 versus 255 of course its now proportionately less at lower settings since only running to 1/2 bar or about 150kpba now.
Maybe timing for 7.5 psi should be more like 18 or 20. I have 9.5 compression on pump 94 and no alc/meth injection.

I will do cylinder balance test shortly figured out how to do that. I can't do misfire test with 3 bar os. It don't work for misfires. To do that would have to put maf back on, 1
bar back in and relflash write entire at least that what seem to have to do. Its so nice to have misfire detection. Really hate you lose it in 3bar sd.

I will try to check out my wires as well. Doubt its spark blowout .Plugs are gapped pretty sure at .028 to .030 and only running 7.5psi. Plugs are tr6ix.

 

I have had broken plug make the motor sound like it was hitting a 2 step. I was at the track and pulling plugs to see what they looked like, a friend was helping me and cracked one tightening it up. Put a new one in that hole and it was golden. I forgot about losing the misfire with 3 bar.

It takes alot of fuel and negitive timing to get anti-lag, you probably have an ignition problem or its too rich.

 

I took car for drive after leaning out BE and reducing ve.No real improvement.Still sounds like machine gun at wot. No knock retard but it does it every single time go wot .

I don't think its tuning. I see no knock retard and can't check misfires .Couldn't do balance test either for some weird reason it says ect too low. yet my same scanner shows 196 F then the balance test screen shows like 80F??WTF? So it wouldn't let me run the test.

So if did want to run misfre I can put in the maf, 1bar map and then do write entire back to previous pre sd tune then check misfires and then go back to SD tune by doing another write entire? Bit of pain but sounds like might be good idea to track down which cylinder has problem.

 

What dwell you running on the coils, and do you have any coils you can try ?

Also, what plug gap ?

If you were getting missfires, they would show on a wideband as lean moments.

And describe exactly the circumstances when it happens...and what happens boost etc during the problem.

 

It does it wot when floor the car at 3000 or so. In third normally. Not too good to floor car in 1st and 2nd since have no traction.
Not sure what happens to the boost. What am I looking for? So no way a boost leak can cause backfire anitlag feeling at wot since running sd.Even with maf don't think can have these symtoms since factory setup is blow thru not draw thru.My draw thru talons sure did get these symptoms with boost leaks..

 

I would imagine there is some sort of coil "on time" or dwell table ? I dont use HPT, so dont know.

So it does it before you are making any boost at all ? just as soon as you go WOT ? Or is it making any boost, you still havent described.

A boost leak would not cause the symptoms you describe, and if it was that big, you'd easily hear the leak.

What are you looking for...simply anything strange that doesnt make sense.

What AFR's, MAP and timing values are logged during the problem

 

Pull all the plugs and put new ones in. You might have a small crack in one.

 

Draw through means the air get's metered, then you have a leak and the fuel is still there making a rich condition.

 

If it's misfiring the A/F will go lean.Of course you need to be monitering both banks though.If both 02's are still hooked up just see if 1 bank goes lean when the problem happens.

 

I thought misifring would make it go rich from the fuel not being burnt? I can of course monitor the narrowbands. I have single wideband in passenger side ypipe.

I am going to try balance test too and will check those o2s.
Just got a flash drive so can get also post my tune and log the problem.

 

Guy that helped me tune used 2.23 beta so looks like no one will be able to read my tune. I put 2.22 non beta back in so can test powerbalance.

I may do a read in 2.22 and then would think should be able to post the tune so its compatible with most peoples version of hptuners. Or may simply replicate and flash a 2.22 version of it.

Also to test misifre and to go back to maf and 1bar for testing do I have to do a write entire with a 99 stock file or do I simply flash the 99 stock file without a write entire? and do I need to flash the 3bar back in or do a write entire for the 3 bar when go back after misfire testing. Pain the 3 bar can't do misfire!

 

I should be able to read it (as well as many others). Or you can post screenshots.

 

Still sounds ignition related to me. ie cracked plug, bad wire, etc

You don't need to reload your MAF tune to get your misfire diags back, just turn the maf back on with the 3 bar setup. However you could also just watch your two front O2 sensors if they are still there to at least determine which bank is having the misfire.

 

Misfire is probably ignition related, such as fouled/cracked plug but certainly could be from a poor tune as well.

You should set PE and boost PE to whatever air/fuel ratio you want.

Then you should dial in the VE table up to 100kpa using wideband or narrowbands.

After that you start building the rest of the VE table, monitoring air/fuel with a wideband and making changes to the VE table so actual air/fuel matches commanded air/fuel.

If it is super rich there is no reason to continue going WOT.

Adding 25% to the VE table is probably just a very loose rule of thumb to give you something to start with.

I have many excellent turbo speed density tunes. If you would like to buy a base file email me at jim@speedinc.com and I'll get you set up.