A friend of mine recently installed an ATI kit on his ’02 T/A. This kit contains the P1SC blower and an in-line fuel pump. It uses stock injectors and makes 4.5 to 5 psi max.

Here are the problems/concerns I’m trying to help him with:

1) His fuel trims are maxed out at idle (25% Ltrims), but as you apply throttle they drop to more normal levels like 11 to 17% in fuel cells still under 19. Is this normal? Should they be maxed out at idle? If you take the gas cap off while the car is idling, they drop to ~17%, don’t know if that means anything.

2) The FMU is not working right. Under 5 psi of blower boost it does not raise fuel pressure. We used and air compressor and pumped 95psi through it and it registered a raise on the fuel pressure gage from 60 psi to 110. So it does work, but it’s not budging at ~5 psi. What’s the deal here? I read in another thread about these things not working right, but what’s the fix?

3) The crank pulley for the blower keeps coming loose. What’s is supposed to be torqued to? The same as the regular stock crank pulley?

4) The car is making 21 deg advance @ WOT under boost. Is this about right for a blower application at 4.5 to 5 psi?

The car is throwing lean codes all the time as it sits (it used to throw PO300 random misfire codes to, but that seems to have stopped), and I’m sure it has something to do with that FMU not working right. I read the other thread below about the ATI kits, and it seems that upgrading the fuel pump further gets the FMU working, but is there any other way? Can you guys help us out any? My personal experances with blowers are limited, so please excuse any dumb questions that I might have asked. Thanks.

[ December 18, 2001: Message edited by: RPM WS6 ]</p>

 

Well everything you've said sounds normal. I've been through all this with my '01. I have the same kit right now as your friend.

1) The way the PCV system is setup causes some of the Ltrim problem. The way it is setup the computer sees the PCV air as a vacuum leak. <img src="gr_sad.gif" border="0"> The rest of the ltrim problem seems to be from the air that the blower is shooting across the MAF at idle. Its ALOT. I'm not sure about the gas cap thing. Maybe the fuel pressure raises a bit with the cap off. :Idunno:

2) Did you tee off the vacuum/boost line that is recommended in the ATI instructions? If you tee off the wrong side of that line you will not get a boost signal. I thought this was the problem with my FMU but I had the same problem when I relocated my boost signal line to the brake booster. The only fix that I know of is to send the FMU back and get a new one.(and hope that it works)

3) I had this problem also. LOL What was recommended to fix this problem was to take the supplied crank bolt and cut it down so you only have to use one of the three supplied washers. Also, apply a generous amount of red loctite to the bolt before tightening. If I remember right the bolt should be torqued to 47ft/lbs and then turned another 120° <img src="gr_eek2.gif" border="0"> . A 2ft. piece of pipe on the end of a breaker bar really helps on this one.

4) Don't worry about the timing. With the ltrims as high as they are you will definately loose a few degrees of timing. I experienced the same thing on my '01(sounds like a broken record). <img src="gr_stretch.gif" border="0"> It could probably use a few more degrees of timing with only 4-5psi but, 21° is safe.

I used my MAFT set at +15% so the car would stop throwing lean codes. The lean codes are caused by the ltrims being so high which has nothing to do with the FMU.

Does your friend have anything else on the car that would add power?(exhaust, headers, etc.) If so he should be very careful going WOT with the FMU not working. My injectors were MAXED out on my car without anything else powerwise done to it.(except a ported TB). If he has anything else done to the car he could run dangerously lean without the FMU working. <img src="gr_sad.gif" border="0">

Ask away. I've been through all the problems above and might as well help out with my experiences. <img src="gr_stretch.gif" border="0">

Johnnie

[ December 18, 2001: Message edited by: XLR8NSS ]

[ December 18, 2001: Message edited by: XLR8NSS ]</p>

 

Johnnie...Thanks a lot for the answers, I’ll pass them along to him. <img src="gr_stretch.gif" border="0">

So basically everything looks normal except that FMU not working right (which is apparently also normal <img src="images/icons/rolleyes.gif" border="0"> ) We used the main vacuum line on the passenger side BEFORE the one way valve that holds vacuum for the heater and such. It was hooked up to vacuum on the drivers side before, so we moved it and it made no difference <img src="gr_sad.gif" border="0">

I’ll let him know about going 15% on an MAFT to help the lean code issue. I never would have guessed that the PCV setup would be partly causing the maxed out Ltrims! I can see the extra air across the MAF being part of the issue though. You learn something new every day <img src="gr_images/icons/wink.gif" border="0">

Glad to hear the timing is ok. If you want a good laugh, he’s getting -18* on the upshift due to TM! How’s that for a TM issue <img src="gr_images/icons/wink.gif" border="0">

I’ll also tell him about the crank pulley. I know he’s tried the loc-tite but not the cutting of the bolt.

He has absolutely no other mods at this time. Other than the blower and a ported MAF (which is probably also helping to cause the maxed out Ltrims). He still has the stock cat-back even.

So did ATI ever get you an FMU that worked right? I’ll tell him to call them and get a new one sent or have them repair it or whatever they do. How many tries did yours take?

Thanks a lot for all the info. You’ve been a big help <img src="gr_stretch.gif" border="0">

[ December 18, 2001: Message edited by: RPM WS6 ]</p>

 

1) My idling LTrims are at 25 also.

2) Since I have the GWP Stage II kit, I don't have any experience with ATI's FMU; I'd sure ask ATI about it. On my Stage II, I LOOK FOR Fuel Pressure consistency, not a rise in pressure, but Stage II has larger injectors than stock.

3) What XLR8NSS said <img src="gr_stretch.gif" border="0">

4) My Timing at WOT is between 19 to 21. When I had my 5PSI Pulley, they were 24 to 25. Sounds like you are in a very safe range. You WILL run stronger if timing were increased to about 24 degrees. <img src="gr_stretch.gif" border="0">

I also get lean codes at idle. I got a used MAFT to see if I can solve this annoyance, but haven't used it yet.
(I WON'T be using it to change A/F mixture under throttle. I'll leave that to my Superchips programming.)
When I clear it, I get the code about 2 minutes after cranking it up usually when it's cold.
After clearing the code, it doesn't come back unless it has sit for a while and I crank it cold again.

I'd make sure I monitor O2's averaging above .900 minimim at WOT and hear no ping.
I'd also dyno and get A/F ratio throughout the run during WOT to see if i is safe.
Tome, those would be the defining data as to whether your fuel situation is OK.

Good luck, and post if you have more questions!

 

High Tenor...I can see what you mean about fuel pressure consistency being important (I know that’s what I look for in my NA motor), but the whole job of the FMU (if I’m understanding correctly) is to allow you to run lower fuel psi under low load and then raise the psi under boost. The ATI manual says the it should be at 58 to 62 psi at idle (which it is) and 85 to 95 at WOT under full boost. The problem is, the fuel gage never moves from the ~60 psi at idle no matter how much boost the blower is making.

I’ll also tell him that 21 deg is safe, but 24 would be alright once the FMU issues are sorted out, correct?

I did notice his O2s going as low as .850 just before a WOT upshift <img src="gr_eek2.gif" border="0"> But by adjusting the valve on the FMU we got it up to about .890 (valve totally closed), but that’s still not quite enough. So the FMU is doing something, just not enough. No matter how much you adjust it, it won’t register an increase on the FP gage under boost @WOT like ATI says it should. ATI will have to help him on that one. At this point I think a new FMU is in order.

 

Hi Mike

One thing about the timing. The '01-'02s have more advance ground into the cam than previous years. The most timing I ever saw while N/A was around 25°. I'm not sure these years deal with the extra timing very well. Check out this atap file. This is after tuning, which is being taken care of. <img src="gr_stretch.gif" border="0">

Engine Speed,MAF Air Flow Rate,O2 Sensor - B1S1,O2 Sensor - B2S1,Ignition Timing Adv,Throttle Pos Ang,Knock Retard
2612,18.14,0.920,0.925,26.0,100.0,0.0
3462,26.25,0.935,0.930,26.5,100.0,0.0
3501,28.68,0.925,0.935,26.5,100.0,0.0
3568,27.69,0.920,0.930,26.0,100.0,0.0
3652,29.18,0.930,0.930,26.0,100.0,0.0
3735,30.55,0.935,0.920,25.5,100.0,0.0
3822,30.89,0.920,0.925,25.0,100.0,0.0
3900,32.79,0.930,0.925,23.5,100.0,1.1
3981,34.07,0.930,0.925,23.5,100.0,1.2
4072,37.64,0.935,0.935,23.0,100.0,1.4
4144,35.87,0.910,0.925,23.0,100.0,1.3
4226,38.03,0.930,0.935,23.0,100.0,1.2
4294,39.12,0.920,0.930,23.0,100.0,1.1
4379,39.38,0.930,0.925,20.5,100.0,3.7
4450,40.57,0.935,0.930,20.5,100.0,3.5
4515,38.81,0.925,0.920,20.5,100.0,3.3
4584,43.12,0.935,0.930,20.0,100.0,3.2
4654,45.98,0.935,0.930,20.0,100.0,3.0
4730,45.98,0.935,0.930,19.5,98.1,2.8
4790,46.40,0.915,0.920,20.0,72.6,2.7

Notice the timing and the KR values. The initial KR was slowly going down when blammo! it got real bad(actually audible) <img src="gr_sad.gif" border="0"> . This is with only 23° of timing advance at that time.

Take it easy. <img src="graemlins/gr_chug.gif" border="0" alt="[chug]" />

Johnnie

[ December 18, 2001: Message edited by: XLR8NSS ]</p>

 

Not to insult anyone, but let's start simple. You guys are aware that the FMU is adjustable correct? It's outlined in the manual...

 

[quote]Originally posted by Rock:
<strong>Not to insult anyone, but let's start simple. You guys are aware that the FMU is adjustable correct? It's outlined in the manual...</strong><hr></blockquote>

Yep, the thing is that alot of the FMUs don't seem to work no matter how you adjust them. I'm not sure if its a pump issue or if its just bad FMUs.

Hows your kit coming Rock? Did you get everything? <img src="gr_stretch.gif" border="0">

 

Still waiting on the GWP stuff. I was told it shipped last week... so any day now. If all goes as planned, I'll be blown this weekend.

<img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />

 

[quote]Originally posted by Rock:
<strong>Still waiting on the GWP stuff. I was told it shipped last week... so any day now. If all goes as planned, I'll be blown this weekend.

<img src="graemlins/burnout.gif" border="0" alt="[Burnout]" /> </strong><hr></blockquote>

That's good new, Rock!

I can't wait to hear how you like it! <img src="gr_grin.gif" border="0">

 

[quote]Originally posted by RPM WS6:
<strong>High Tenor...I can see what you mean about fuel pressure consistency being important (I know that’s what I look for in my NA motor), but the whole job of the FMU (if I’m understanding correctly) is to allow you to run lower fuel psi under low load and then raise the psi under boost. The ATI manual says the it should be at 58 to 62 psi at idle (which it is) and 85 to 95 at WOT under full boost. The problem is, the fuel gage never moves from the ~60 psi at idle no matter how much boost the blower is making.

I’ll also tell him that 21 deg is safe, but 24 would be alright once the FMU issues are sorted out, correct?

I did notice his O2s going as low as .850 just before a WOT upshift <img src="gr_eek2.gif" border="0"> But by adjusting the valve on the FMU we got it up to about .890 (valve totally closed), but that’s still not quite enough. So the FMU is doing something, just not enough. No matter how much you adjust it, it won’t register an increase on the FP gage under boost @WOT like ATI says it should. ATI will have to help him on that one. At this point I think a new FMU is in order.</strong><hr></blockquote>

I think you are right about hte FMU... using stock injectors, the additinal Fuel Pressure at boost gives you the additional fuel you need, I guess... I just don't know.

I wouldn't worry too much about being above .900 on O2s during the upshift moment. Remember torque management is killing timing then, and the motor is cutting back.

Just make sure you are above .900 (I'd say .920 or so average is safe) while at WOT otherwise. <img src="gr_stretch.gif" border="0">

Even running rich at .960 or so, I get occassional dips into the high .8xx's for no apparent reason. Autotap is not complete gospel all the time either. Take EVERYTHING with a grain of salt and use you head in every way you can. <img src="gr_stretch.gif" border="0">

Good luck...

Oh... call ATI soon about that FMU operation. I've heard people complain about their customer service, but I haven't had a problem getting answers once I reached them. Call in the morning and in the afternoon... not too close to lunch time or late in the day. <img src="gr_images/icons/wink.gif" border="0"> Just have the Serial number ready.

 

Thanks for all your help guys. <img src="gr_stretch.gif" border="0">
I’ll pass all the info along to my friend...

 

Buy a MAF extension kit and see if you can move the MAF to the intake side of the blower.
Then install a one way check valve in your PCV and block off the fresh air line on your throttle body. reroute the fresh air hose from the valve cover, extend it and place it within one inch of the airfilter.
This will cure all your problems with high LTRIMS, and vac leaks.
Cheers,
Chris

 

[quote]Originally posted by Chris ARE 360:
<strong>Buy a MAF extension kit and see if you can move the MAF to the intake side of the blower.
Then install a one way check valve in your PCV and block off the fresh air line on your throttle body. reroute the fresh air hose from the valve cover, extend it and place it within one inch of the airfilter.
This will cure all your problems with high LTRIMS, and vac leaks.
Cheers,
Chris</strong><hr></blockquote>

Thanks <img src="gr_stretch.gif" border="0">

He has the TB hole blocked off, but I’ll tell him about the one way valve and moving the line.

Relocating the MAF might be difficult as space is an issue, but I’ll tell him to look into that also.