Well I went to Jrats this weekend and we put his wideband on my car for a few prelim runs for AFR checking.

The car is a S4 engine with S5 manifolds and turbo.
-cleaned and tested 550cc injectors.
-Walbro fuel pump
-Racing beat 2.5 down pipe and presilencer
-Corksport 3in catback
-Some ebay cone filter and stock TID.

Now here's some info on the car.
It's a rebuilt engine. It had 1300 miles on the engine at testing time. It now has almost 1500.

I have an inline fuel gauge and it is showing 50-55psi at idle!!!
I have already replaced the FPR so I can only guess the walbro is killing my FPR.

So at idle I was doing around 11.4-8 AFR(can't remember exactly). Can you say pig rich!?!

Under no boost cuising I was seeing 12's or something I think.It was in a good area(Jrat hopefully remembers if that's not the range).

Under 5psi boost I went to 13.5 AFR.
Under 10psi I pulled 13.5 AFR.
These are all runs up to 5k RPM since I don't want to go too high yet since I'm still breaking it in.

It was around 100 outside during this test.

So does this sound ok/normal?

I know that's close to Stoich.

We're thinking the 550's are going to be done after 10psi.
So we are guessing I should go with an aftermarket FPR to hopefully get my fuel rail pressure down to normal ranges.
Then get some 720's for secondaries and get an SAFC to tune them into good AFR's.

This is a daily driver and I want to make this thing super reliable. I don't want the thing to accidentally go lean/stoich.

::edit::
I also forgot to add.
After the run we put the old O2 sensor in and noticed the BAC inlet line had popped off.
We can't determine when It came off.

I could have pulled it off after the run while installing the old O2 or it could have been off the whole time. We assume it came off after because the car idled fine before the run and it should have had a stumble or something if it was off before the run.

 

Are you sure that you didn't put those numbers in backwards? With the walbro jacking up the fuel pressure I wouldn't be surprised to see mid 13's at cruise (which is a fuel point richer than what a stock car will aim for) .

Mid 13's afr's under 10 pounds of boost is very lean. How old is the sensor for the wideband?

 

The sensor is brand new.

I saw 11 at idle
12 or 13 cruising
13.5 under boost.

 

How about you get your rail pressures down to a normal level, THEN do a wide band check?

 

I agree, if you reversed those numbers you would be golden.

Very strange to be at 11 at idle, very strange.

Maybe your wideband is upside down?

 

I bet 11.4-11.8 is about right for a stock ecu. Its hard to get a a rotary to idle leaner at the stock idle rpm or lower. The walbro only increased my fuel pressure by 3-5psi based on my afr drop of .3. You're going to blow your motor soon if you keep boosting it.

 

To add on to that, I have a rock solid idle at 1k and it likes to stay between 11.5 and 11.8. I don't have a fuel pressure guage, but 4-5 psi sounds reasonable. I really don't understand why you're running so lean. With you're supposed fuel pressure problems you should be nearly pegging the wideband out from running too rich.

 

Somethings wrong. Those afr are absurdly lean during boost when you consider your using the stock ECU and no SAFC. I would have expected for you to have seen afr in the mid 10's, especially with the rail pressure as high as you have it.

That fifty psi at idle real funky. If I were to take the vac line off my fpr at idle it will go to 37psi rail pressure (ambient), which is what you should be seeing. I'd be interesting to see what pressure that pump is putting out. Do you know?

 

At that high of rail pressures, maybe the walbro is seriously starting to drop off the amount of fuel it can flow. With 50 psi base fuel pressure, there is absolutely no reason that you should be running excessively lean at 10 pounds. Quite the opposite...

 

Werd, at idle I see about 13.7:1 . I have 550 prim/720 sec walboro with the rewire done.

At cruise it is 14.7 : 1 plus or minus a lil. WOT is around 12.5 : 1

Why is your car cruising around 12:1 AFR. No oxygen sensor? You are just pissing fuel away.

Also, where are you mounting that sensor for your wideband?

I have the Techedge V1.0 which uses the NTK L1H1 sensor. That sensor cannot take the heat of the exhaust if you put it right behind the turbo. You need to put it about 3 feet down stream. Not sure what setup you are using. I would reasearch the temp limits of your sensor.

James

 

hmm.

So how could I test the fuel pump?
Maybe test the voltage so others can post their voltages up to compare???

I have a NA body and haven't done the pump rewire because some had said the NA's didn't have it. I can't verify this though.

The fuel guage is placed between the primary fuel rail and the fuel filter.

The Wideband was Jrats. Not sure what one it was.
We placed it on the stock location on a racing beat 2.5 downpipe.

I honestly want to get my AFRS in the 12's during boost for safety though.

As an addition.
The ECU is a N333 Chipped with the Rtek 1.5 which lowers secondary kick on to 3.5k rpm and increases the duty cap. It also retards for every degree over 8-9 psi.

Maybe Jrat can chime in if he logs in and see's this. My memory sucks. That same night I had a drunken birthday fest for my friends

 

Okay, let me jump in here.

The idle is rock solid, but it is in the 11.5 range. Mine seems to like to idle a tad bit leaner then that.

Now here is the kicker.. When he went under boost, AFRs went WAAAAAAAAAAAY lean. I cant really explain that. 13.5 or so across the band. I think that maybe another pull on the wideband needs to be done. I told Dig to not boost too much for now, until we can chase this problem down.

*edit* Its an Innovate LM-1 wideband.

 

maybe need a fuel pump rewire.. the pump maybe not getting the volatge it needs under boost?? just a guess

 

****So how could I test the fuel pump?****

Just pulll the fuel line off that runs b/t the filter and the engine feed line and install it in the END of that line. Then jumper the fuel pump check connector with the key to ON. The pressure on a normal car is b/t 70 and 80 generally. See the real figures in the fsm in the Fuel Section.

The chip in the ECU might explain the afr's. Seems they went backwards though. If you get a SAFC you should be able to enrich the afrs.

ACTUALLY I'D REDO THE TEST YOU DID ABOVE. IF THE BAC'S LINE WAS OFF THAT WOULD EXPLAIN THE LEAN AFR'S.......ALTHOUGH IT SEEMS THE CAR WOULD HARDLY IDLE WHEN YOU CAME TO A STOP.

AND RX LIKE TO IDLE RICH. ANYWHERE B/T 12 AND 13 AND THEY PURR JUST FINE. ANYONE WHO HAS A AIRPUMP AND IS SEEING 14 WHATEVER IS JUST KIDDING HIMSELF. iF HE DISABLES THE AIRPUMP THE AFR WILL DROP RIGHT DOWN TO 13 OR SO. I LIKE CAPS. I MAY DISABLE MY CAPS KEY. IT LOOKS SO MUCH BETTER THAN THOSSE POSTS WHERE THE FELLA TYPES in lower case and never inserts a period and slaughters the language worse than me. see? looks terrible without caps at the beginning of a sentance. this has noting to do with this post/thread. it just gives me a way to VENT MY SPLEEN! CAPS INDICATES YELLING ONLY IN GOOFY'S MIND. GOOFY IS THE GUY WHO COMPLAINS ABOUT ALL CAPS, FYI.

 

No more coffee for you, Hailers.

 

So Hailers your saying that If I take my pressure guage and cap off the inlet line to the engine so it's just a pressurized line with no outlet I should see 70-80 psi?

Can I check voltage through the pump relay under the dash?or do I have to do it at the pump/hatch?

The thought on the pump maxing out has got me thinking. If the base pressure nis that high then maybe it is dropping off under boost? Maybe if I got a Aem FPR I can tune the psi down to 28-30 and it would be good?

 

I think we're miscommunicating.

You've a fuel pressure gauge. It has a hose on it. Connect that hose to the outlet of the fuel pump.

Or do you have a fuel gauge that has a seperate sender? Electrical? Then put the sender in the hose coming out of the fuel filter. And as above, jumper the fuel check connector and the pump alone will run and pressurize the fuel gauge.

There's a pic in the fsm that shows how. I can't jpg anything anymore.

 

I have a XRP or something like that 100psi mechanical gauge inline.

It is teed into the line between the fuel rail and the filter.

So I could just cap the Teed part so the pump is just pressurizing the line with the fuel gauge and not going to the engine at all?

 

Yes, I believe its called a Static test. It gives you the max pressure the pump can run. Where Hailers is going with this, I have no idea..

 

I think I'll try and do a static test this weekend to see the max psi it hits.

Fo rnow I could probably check voltage right? Any one know the standard voltage it's supposed to get?(12v?)

 

Well, obviously it should be getting something close to charging voltage with the car on, unless you're routed through a resistor relay or something...

I wouldn't worry about the voltage checks, though- that's something you do when your pressure's too LOW, not high...