06 Attak fuel pressure

[Motorhead]

2 stage rear mount turbo with stock fuel pump question. Having a lean fuel problem at anything over 1//4 throttle, exhaust popping at that point. I have been told that it is probably 1 of 2 things, fuel pressure or bad engine manager which is a Dobech TFI Gen III Fuel Injection Boss Noss module. I do not have an AFR gauge but have been told by a few with much more turbo experience than I, that it is popping because it is lean. So I am in need of a bit of knowledge pertaining to my fuel system. Does the stock system have a fuel regulator or is the pump the only reason for poor fuel pressure. I have done some research on this site concerning checking fuel pressure with a gauge, should be 40 at idle and a 1-1 ratio per lb of boost, stock pump can only handle 10 lbs of boost which should be at around 50 psi of fuel pressure. Clutch side of the rail is point to check ?What do I need to do this check ? special fuel line connectors and gauge ? I hate to spend $100 on a set up when one can purchase a used pump for same on ebay etc and rule that out, but then again, if I build one I shall have one. Any thoughts or answers to my many questions ? Thanks

 

[mbarryracing]

Motorhead,
If you had a weak fuel pump that was casuing you to not run right over 1/4 throttle because of fuel pressure then you'd probably have trouble starting and idling as well. fuel pressure at 1/4 throttle isn't that much different then idle to make it run out of fuel unless you are building that much boost pressure in that range.
But to answer your questions, I don't recall my '06 having a test port on the rail. The regulator is bolted right to the outlet of the rail on the mag side then the return line goes from the regulator right to the fuel tank return between your coolant tank and overflow tank. I've always T'd into the feed line between the pump and the rail. I have had in-tank pumps go bad but one wouldn't keep up with volume & pressure over 6 psi boost and the other quit working when it got warm.
In any case, bypass your Dobek TFI controller and try it again, that is a quick test. We will go from there.

BTW, get an AFR gage. First rule with a turbo sled is run good fuel, the second is run an air fuel ratio gage, the third rule is follow the first & second rules...

 

[Motorhead]

Mybarryracing, Thanks for the reply! My Dobech TFI is a piggy back controller ? So it will disconnect from the ECU harness and at that point plug the harness back to it's original position? What should I do with the boost tubing that goes in the TFI? If yes to my first questions, what should I expect when running on just the stock ECU? I know many questions Huh!! So the stock fuel system does use a regulator and a simple change of the pump may not repair a fuel psi problem. Good info. I shall be a bit before I can get under the hood and unplug the TFI because of a busy work schedule, but am shooting for Sunday late day. Thanks Again!!

 

[mbarryracing]

I don't recall which generation the TFI controllers were that I previously had, the first one piggy-backed off the actual fuel injector plugs and the second simply piggy-backed off the main big gray harness connector that is on the left side of the hoop above the clutch guard, the one that you also jumper out to set the CO settings.
Before you do anything, check that your Dobek box ground lead is good and secure, not broken.

If OK then next simply unplug the TFI connectors from which ever factory connectors they are piggy-backed / plugged into and then reconnect the factory plugs back together. Leave the boost reference line to the controller alone, wont hurt anything. Let the controller just lay there.
Put the sled on the jack stand, do a few quick throttle pulls above 1/4 throttle to see if it pops and sputters out. You are just going to see if it rev's up past 1/4 throttle, any change from what you were complaining about.
You aren't going to build anough boost that quick on the jackstand to need any extra fuel so dont worry about anything being too lean.
The stock fuelpressure regulator will accomodate up to 2 psi boost by itself, the principle that YamaCharger operates with because it doesn't use a secondary fuel controller like the Dobek. Actually your TFI programmight not even start adding fuel until after 2 psi boost pressure for the same reason.
Good luck.

 

[Motorhead]

Thanks a bunch, I shall check the ground wire for the controller and then do as you suggest! Run the sled on jack stand and then take the Dobek spelled (Dobech) on this old model out of the system and try running it again to see if it is doing anything Huh. Hope it acts the same disconnected. Have been trying to repair this prob for quite some time, here's a bit of head banging history of how I got to the assumption of it being a fuel problem. End of last season problem started right about the time that I changed the track to a fully clipped. Also added a heavy duty drive shaft with extroverts. While under sled noticed that the titanium Y pipes were badly dented in by the studs and both clamps were missing, no holes but smashed in, 1 Y lost half of it's diameter the other about a quarter, and they had bent the Ys together causing damage to the y to single pipe that connects to the flex pipe. This past summer I Bought and installed new SS Ys, sent other away to FPP for repair( incredible job better then new with reinforced welds),while I was at it I also added 1/2 dept to my tunnel protectors all the way back to the rear cooler. Sled was bought in that condition nothing I damaged! That brings us to this season, tried clutching, leak down test, compression etc. to try and bring my revs up, or figure out why this sled had lost so much power!! It builds boost at less than 1/4 throttle 4.5 stage 1, 9.5 stage 2, but no sense in using more then 1/4 whereas nothing happened more. No popping, no bogging just stayed at same speed which was not great compared to prior the problem. Then comes a knee and leg injury, could not work, ride or even make it to the garage for most of this riding season. So a couple of weeks ago I finally mended enough to go back to work and think about my sled again. Called a local turbo guy to try and figure this out, he was very busy but did fit me in.( state record holder a claimed 750ish hp RX1) Told him what I thought about the prob and he wanted to start with turbo checks before going to fuel! He pressure checked the charge tube and found that there were 4 drill holes through the under side, from seat side to charge tube!!! Of coarse he had to tear into it to find that, which chewed up his time that he did not have and thought we had found the problem! Took it out on the ice and this time it ran no better with exception that it now builds 5 and 10 lbs of boost and pops through the exhaust now! His thoughts were that it is the cheap controller and I should find out how to adjust the high end to determine if in fact it is working! I did have the color coded starting points from FPP and had made sure they were entered right many times but could not tell him what color was WOT. So this brings me around to where your thought of taking the controller out of the equasion to try and find out if it is working! I really do appreciate your help and patience with this! I am at the point of just buying new controller pump and regulator whereas my snow is almost gone again for another season! Ha Ha

 

[mbarryracing]

Motorhead,
Ah I had been spelling it wrong, it is Dobeck. What matters is we are on the same page... LOL.
Unfortunately you're just swinging in the dark without an AFR gauge, you could be lean or you could be rich too. You could have the Main Red or Boost Fuel too high, or a switch over point too low and it's flogging it out with fuel.
The Dobeck controller only reads the intake pressure (MAP) and the injector signal and then extends the injector signal to add more fuel based on it's interpretation.
If it's acting up based on throttle position only, or just doesn't do much after 1/4 throttle then I'm starting to think it's the programming or setting in the Dobeck box.
Now reading your last post, I recall that when I first started with my stage 2, I had the fuel settings way off from the original FPP base settings and I had to roll into the throttle to get past a certain point or it coughed and popped, wouldn't go too rich. I have a whole notebook and drawer in the file cabinet in my shop full of notes and information I went thru over the years of refining my PITA turbo sled. I could dig thru and see if I can find the last settings I had since your Dobeck box likely has the same program mine did. I could type for hours with tips for you too but it all comes back to me slowly. I've absorbed alot over the years, both experience & knowledge and chemicals, so sometimes it takes me a while to recall and remember LOL.
I think from my notes the original FPP settings were 1, 2, 5, 4-5, 5, 2-3 and the last note I had looks like my final settings might have been 0-1, 5-6, 5, 3-4, 2-3, 2-3.
Yeah its hard to see what mode that programmer is going into when it acts up while driving unless you are hanging over the windshield with your head by the intercooler. Some guys mounted it right on their handle bars. That is why you need an AFR gauge. I actually spent some time intentionally driving my sled in each mode and determining what each one was doing, tuned it before moving on to the next, progressing from idle to WOT.
Are you running a muffler or the glass packed single shorty? In any case, have an O2 sensor bung welded in the turbo outlet pipe.
A good rather inexpensive AFR gauge is the AEM 30-4100, got mine from right from FPP but good deals online too. I can talk you thru how I routed mine and mounted it, etc.

 

[Motorhead]

Had a day off today and a bit of time to play in the garage. Did as you suggested and checked the ground wire of the Dobeck TFI. Hey I spelled it correctly for the first time, thought it had an h on the end of it, but saw your spelling of k and that is correct, cannot make that out on my old unit, graphics are a bit blurred.. But anyways the ground wire was OK so I tried it on the stand, and found that the sled does stumble, at full throttle for a second, but does not when the unit is removed. Checked the settings again and they had not changed, same as what FPP had given me for specs a couple of years ago when it ran strong on both stages. Green-1 Orange-2 Red-5 Green blue-6 Orange blue-5 Red blue 2/3. To answer your question pertaining to my exhaust, I do have the dual outlet trail muffler by FPP and I remember seeing an O2 bung on that system somewhere. I must need that for the AFR gauge Huh?
I did try taking the TFI on and off a couple of times with same results, and whereas it ran real good on my original settings I will replace it. Have also had an occasional stalling issue and I'll be damn as soon as I put that TFI back on it appeared. Take it off and it idles better and does not stutter at full throttle ( again for only a second or so on the stand).
The order email is out. Not sure if there will be any snow left upcountry by weekend, otherwise I shall have to wait and see if more R&D is needed. I shall also replace Ts and tubing during my preseason maintenance. I start early, probably September. Yeah I know, have been addicted for many years now. Ha Ha...

Hope to hear from Justin soon concerning a new Dobeck TFI or similar piece, also looking into an AFR gauge for the near future( Summer Fun). I too will go through FPP for that.

Thanks again for your suggestion of removing the TFI for test run purposes. You Da Man Mybarryracing !!!

PS: I too have forgotten more then I care to share, but yeah what was absorbed does find it's way out, sometimes..

 

[mbarryracing]

Hey before you yank that TFI controller off, try putting in the settings I had listed above. It will idle better if you drop the green from 1 to 0-1 (1/2) so then it's not adding fuel at idle. Also your WOT stumble might just be you have the accelerator setting or the transition too high.
Worth a shot anyhow. Also keep in mind that I had a secondary inline Walbro high pressure pump so that can make a difference in base fuel pressure and on the settings that it likes too.

 

[Motorhead]

Will give it a try. I was on the Dobeck website and found the tuning instructions for the 3.5 model, mine is the gen 3 model, so hopefully I will have some time this weekend to look at sled again. Long hours at work do not allow weekday or night play right now. I shall try your tuning numbers. Thanks!

 

[mbarryracing]

I know, I am in the same boat my here too.
TIP: The first green light mode affects idle. Usually they get set inadvertently to 1 and are adding fuel because there is no "0" light to distinquish between, can tell by 1st green light blinking slow. Use the "-" to drop it down to a stock setting so the green light is blinking fast, then it's not adding fuel there.

 

[Motorhead]

Well tried to differentiate an idle mode when adjusting the TFI, and there is not a difference no matter what I do with controller settings. Does not seem to lean or fatten it up.

Also tried to adjust idle with the black plastic nob on the left side of manifold and also no difference in idle speed even if screwed in all the way. I did back it back out to where it was after I was done testing. I was able to adjust the idle with this knob at beginning of the season though, 1/4 turn was all I needed back then to bring it up, and then turn it back out a bit afterwards to idle down to my desired level.

Low fuel pressure or vacuum leak ?

So multiple symptoms now.
Popping thru exhaust at more then 1/4 - 1/2 throttle, no gain in power after 1/4 - 1/2 maybe even a slight loss of power, and now no adjustment to idle whether trying to add or minus fuel with TFI, or idle adjustment knob!

I will have a AFR gauge before next season !
Where is yours mounted?

 

[mbarryracing]

And you said it doesn't run that way when you remove the TFI from it? If it was a fuel pressure problem it wouldn't change with or without the programmer. But if it was a programmer failing, then the programmer might not make a change with adjustements.

Here are some pics where I mounted my AFR gauge.

 

[Motorhead]

Very hard to note a difference with or without TFI, and at all idle settings of TFI. But on stand when throttling it, it pops with TFI and does not without! And with the new found non idle adjustment, jeez!!! I shall replace both pump and TFI and wait for next season. eBay pump is cheap money, 50 bucks shipped. Less then one days fuel on normal ride.

Thanks for the pics, your gauge pod is the same type that I use on boost and M20 air pressure, so yeah that style is nice because of the snap in and out accessability! Will get that same style thru FPP. Like your location, not too busy, I shall copy that.

 

[mbarryracing]

Most guys put the boost gauge up top where they can see it, but AFR is the most important to me. I mostly look at AFR and the Tach, tells me Boost pressure is close if it's running the right RPM and AFR... The AEM boost gauge is still viewable, just have to lean up a little and look down to see it past the brake res.
Before you tear apart the in tank pump, and waste $$$ if it's not the issue, I'd still verify the fuel pressure first.
I put this Mr. Gasket Barb Fuel Pressure Gauge Fitting and a Gauge from JEGS inline between my fuel rail and fuel tank. When my fuel pump was failing, it was slowy dropping from 43 psi to 35 psi as it warmed up but it didn't break up like you describe. I'd just like to know what that pressure really is doing first.

 

[Motorhead]

I put the sled away in the trailer, so that I can take the bikes out in a short while. So my sled will have to wait a bit before I resume.

But when I do, my next test will be fuel pressure. I checked out my fuel rail when The TFI was taken off and on from the injectors and noticed that the incoming fuel line has a fuel injection type connector which connects it to the rail. I thought one would have to make a pressure gauge fitted with this style connector on either end to be able to simply plug a gauge inline. Your pic of a barbed T suggests that you cut the fuel line to place this T inbetween ?
No problem with that? I do not have a crimp set for fuel line T, so I would have to use hose clamps type?
I was going to try and make a gauge with fuel injector fittings for a simple plug and play whereas I would not want to cut the fuel line.
I call the fittings fuel injection type because a Skidoo 600 SDI that I had for a short while had that same style fuel disconnect fitting so I figure they must be on other auto fuel systems ?

Shall buy a fuel injection pressure check set (cheap at Harbor Freight)and some tygon tubing along with the T and clamps, that way my original fuel line stays intact!