Thread: What is my car trying to say? Fuel Pump MAF or Vacuum issue?? VIDEO

Hey guys,

Well since I went turbo Ive had a ton of little Gotchas, I wouldn't say major problems at all just little issues 1 by 1 im overcoming..

Basic Info before I go off on tangent.

• Avenir DET ( 9lbs stock boost )
• N62 MAF in Billet MAF box ( blow thru ) 12" from TB
• Greddy Type S ( venting to atmosphere ) 6" from MAF
• CALUM Basic
• 370s @ 3 bar
• Stock Fuel Pump ( walbro 255 is enroute )
  

OK so I get the car up and running and theres a high idle, 1500-1800 RPM and once it warms up it was fluctuating ( 1000 / 1800 or so )
back and fourth but never once wanted to die.. Led me to think IACV vacuum was always 20hg or so.

When going full throttle the wideband would read 12-12.5 perfect.. Besides the wierd idle car would start right up, Blows no smoke ran great.
Just had the wacky idle.

Fast fwd 100 miles or so and I noticed the wideband on full throttle would be 12.5 / 13.0ish and then i stopped getting on it hard but once in a while i would monitor
and lay into the throttle and see 13-14 almost no 12s. Mind you these were super short pulls. After that I figured this pump seems to be getting a little weak Ill just baby it around.

Went to drive home from work and at light throttle it would drive then just started to buck like it had no power you could put your foot to the floor and just nada wouldn't rev..
Put in neutral REV it and it would feel fine without load. When the bucking would occur the gauge would go really rich sometimes but idle would be lean.

Then I came to a red light and it would stall out repeatedly.. Wideband would read rich when this was happening sometimes and at idle it would be pegged lean.

Went back to work for 4 hours and when I left still had my idle issue but car drove fine. * sweet made it home *

So now that the troubleshooting has begun I have no clue what it is. I have no codes occasionally ill get a maf code but I believe that maybe from the VENTED BOV.

If I go and cold start it , it idles high but steady at 1800 but doesnt try to stall, Once it gets warm wants to stall right out and you cannot drive it, it will hover at 700rpm/1000rpm
If you rev it in neutral parked it pretty much revs fine and smooth, but you could try a second time and it wont even wanna rev and just falls on its face.

Check out these videos - not the best but if you double click they will go full-screen CLEAR they are 720P HD Should help.. Dying to drive this car!!!


Data log video ( Nissan Data Scan & Wideband while trying to idle )

[youtube]YzwJbnROLqY?hd=1[/youtube]

Fuel Pressure Gauge Vid ( not sure what is normal ) Stock Pump.

[youtube]2GEFLLV0gpg?hd=1[/youtube]



Any help would be appreciated I think maybe part could be a fuel pump but then again im not 100% on that ( ordered walbro 255 regardless ) Just wanna enjoy this car in the perfect weather.

it seems like people always have issues when they modify the maf or change the housing. maybe try one thats in stock condition.

Also have you set the timing / idle properly by getting the car in timing mode via rain dance or a consult program? that usually really helps the wondering idle issue.

changing the fuel pump and actually tuning the car will prolly help alot as well.

I put the car in timing mode with the consult program and set the timing to 15 degrees. The car minus the idle was running great pulled nice and hard through all gears with no smoke no back fires no misses at full or part throttle. Really was running probaly the same as any JWT setup pretty much great like a stock car except the idle issue. And then just started doing this.

Before it totally started acting up I noticed it not getting as rich on boost as it was.. 12.0-12.5 it would start staying around 13.0 and as soon as I noticed that I knew something was going on possibly pump related so I would just drive it not really in boost until my new pump arrived. And then it started not even idling the same day.

well use the consult to put the car in timing mode again and use the iacv screw to adjust idle, be sure care is fully warmed up.

as for the other problems, maybe you fuel pumps dying. but check your grounds and connections and especially the maf plug. wiggle wiring around while the cars idling if it dies or just better all the sudden well you might have a poor connection somewhere.

Possibly coolant temp sensor if the engine thinks its always cold and never fully warmed up. Check in the consult if the temp is reading correctly.

I see a few things.

Your fuel pressure is low. 1 bar = 14.5 psi, so with the vaccum hose disconnected from the FPR, you want 43.5, where you're at 38 now when you pinch it.

Your vacuum is low, but that may be because the idle is so high. Check the tension on the throttle cable, and make sure the throttle plate isn't partially pulled open. Go a little further, and make absolutely sure the plate is 100% closed by pulling your intake pipe off, and eyeballing it. If it's not, you're going to need to readjust the TPS after fixing it. Do you have thermo spacers on the TB & intake?

See how your stock o2 sensor in Nissan Data Scan doesn't move at idle? That sucker should be constantly fluctuating. That could be because of the low fuel pressure, but keep an eye on it after you fix the FP.

Also, have you verified the Innovate gauge against the LC1 output on your laptop?

And what's up with all that squeaking and shit when you're revving it? Is your BOV leaking at idle? Put your hand over the discharge port to seal it up, and see if it makes any difference.

Did you ever do a boost leak test?

C

Hi Chris,

I wouldn't call that a true test. The 'pinching' that was done in the video couldn't have closed off ALL vacuum to the line. What he needs to do is either take the hose OFF or truly create a 'crease' in the hose.

@Quick: Take the hose and bend it to make a closed 'V' in the hose so that it's completely blocked off. Hopefully my explanation makes sense. Hold it for a minimum of 7 seconds or until the needle stops moving up. Also, your 13-14 AFR may be OK(The 13 maybe..14 still kinda lean) as long as it was below 4000 RPM or so. At the start, the AFR will be a little lean, but it should richen up proper as the car starts sucking in a lot more air. If you are getting 13-14 AFR ratio above 4000RPM at full throttle I wouldn't be boosting the car because that's way too lean.

-G

I will look into this, Both temp sensors are new from GregV but I can check in consult vs my innovate gauge. Pretty sure they are dead on.

New Walbro 255 on the way




Yeah Before the wierd stalling stuff it was rock solid at 20inHG even with hunting idle.



Will def check this.



I have no spacers but will re-try setting the TPS, I set it per what I read on here im at 4.36 at full lock and .46 when not touching it.



Thanks Chris, Its the DET stock one... If it doesnt change when I swap the pump ill swap for my old US DE one.



This I have not done, I need to get a serial to usb converter to do this which I will do asap.. Def didnt chince on the gauges / software so troubleshooting wouldnt be as hard... Looks like its going to pay off.



The squeeking is right after I rev it when it gets done to like 700rpm and is trying to die.. The camera just makes it sound worse.



BOV is a Greddy Type S - It leaks at idle but from what I read all Greddy Type S's leak like that and its normal ( I could be wrong ) I have not found a way to get it to stop leaking at idle.



I did not leak test it with pressure, But I did water leak test all the pipes that I made. It was boosting good im in blow through so I dont think this would affect the idle.

Here you can see MAF / BOV location ( this pic doesn't have the vacuum hose connected as its an old pic )

I will try testing FPR with hose off, But I think the pump is dying and a 255lph pump is enroute.

AFRS were spot on at 12-12.5 on full boost prior to this issue which partially I think is a failing pump.

I wouldnt boost it much with 14AFR trust me ahhah.