Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Jeff NJ's Avatar
 
Join Date: Nov 2013
Location: NW NJ
Posts: 1,171
Super lean on startup today

So my car has been running great for weeks now and I had it out last night with no issue. As I was idling it for a moment before turning it off last night, my AFR was right at 14.3 or so. I didn't touch the car after that.

This morning, I start it up and within seconds the AFR went off the charts lean. I shut it down, checked all the obvious hoses to see if something popped off and nothing looked out of place. Tried it again with the same results.

So I parked it and took the 4Runner to work.

Any first thoughts as to what could change overnight? AFR has been rock solid consistent cold, warm, cruise, boost, etc. since I have gotten it dialed in and it just changed without me touching anything.

I am thinking fuel pump maybe? Anything else I should look at? I guess I need to figure out if it is too much air, or too little fuel that is causing it...
__________________
1988 930 Venetian Blue
Old 05-20-2016, 08:52 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Mighty Meatlocker Turbo
 
Rawknees'Turbo's Avatar
 
Join Date: Apr 2016
Location: North TexASS
Posts: 10,306
Hey Jeff, how was the engine running when you saw the very lean numbers (what did it sound like)? I ask because anything much beyond 15 at idle will result in lean-misfiring/terrible running - same with cruise AFR, except it takes mid-upper 15s and beyond to really notice during cruise. Maybe something is wrong with the AFR meter?

BUTT regardless, you can pull one fuel pump relay at a time to "sort of" check that each fuel pump is at least running - I say "sort of" because the relays are responsible for other components, like power to the WUR and the stock O2 sensor, which affect running. . .
Old 05-20-2016, 09:02 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
Jeff NJ's Avatar
 
Join Date: Nov 2013
Location: NW NJ
Posts: 1,171
That's a great point and it didn't seem to run bad at all. Idle was still a little low since it was just started, but it was not misfiring. I definitely smelled gas in the exhaust on the first start. (Love that smell!) and I was thinking that I was lucky that I was in the car when it happened so I avoided damage, but you're right, if it was that lean, how could it actually run?

The PLX is supposed to be self calibrating, so I am not sure how to test it.

I will put my ear to the pumps with the key in the on position tonight to see if I can hear them and then start looking into what could be wrong with the PLX.
__________________
1988 930 Venetian Blue
Old 05-20-2016, 09:11 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Mighty Meatlocker Turbo
 
Rawknees'Turbo's Avatar
 
Join Date: Apr 2016
Location: North TexASS
Posts: 10,306
Jeff, pumps won't run with just the key on - either the engine has to be running and drawing air over the air metering arm/disc, or you have to unplug the green connector from the back of the fuel head.

I have a PLX also - don't know how to test them, but you could try re-booting it by removing all power to it for a few seconds (might need to disconnect the negative battery cable, depending on how yours is wired).
Old 05-20-2016, 09:20 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
E-85 sippin drunk
 
turbobrat930's Avatar
 
Join Date: Jan 2002
Location: Warner Robins, GA
Posts: 1,506
If your PLX is working correctly, and as are the fuel pumps, it could possibly be a clogged fuel filter.
__________________
Brad...930 gt-1 racecar, increased displacement to 3.6L, JB racing Cylinders, JE 8 to1 pistons, stroked crank, Carrillo rods, extrudehoned 3.2L intake, full bay Bell I/C, GT-2 EVO cams, Rarly8 headers, GTX-35RS turbo, twin plug, P&P heads, Link G4 EFi system, G-50/50 with LTD slip and oil squirters/oil cooler, zork tube, full race coilover system, with carbon fiber body, full cage, E-85 sippin drunk
Old 05-20-2016, 09:55 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered User
 
Jeff NJ's Avatar
 
Join Date: Nov 2013
Location: NW NJ
Posts: 1,171
Quote:
Originally Posted by turbobrat930 View Post
If your PLX is working correctly, and as are the fuel pumps, it could possibly be a clogged fuel filter.
Boy I hope not since it is only about 2000 miles old. But I guess I could test fuel pressure to either prove it is fuel related or eliminate it...
__________________
1988 930 Venetian Blue
Old 05-20-2016, 10:04 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
Registered User
 
Jeff NJ's Avatar
 
Join Date: Nov 2013
Location: NW NJ
Posts: 1,171
Quote:
Originally Posted by Rawknees'Turbo View Post
Jeff, pumps won't run with just the key on - either the engine has to be running and drawing air over the air metering arm/disc, or you have to unplug the green connector from the back of the fuel head.

I have a PLX also - don't know how to test them, but you could try re-booting it by removing all power to it for a few seconds (might need to disconnect the negative battery cable, depending on how yours is wired).
Hmmm. Then what is that buzzing I hear when the key is in the on position before I go to start? I always thought that was the fuel pumps buzzing. I once figured out my yellow relay had a bad connection because it was eerily quiet and wasn't getting fuel.
__________________
1988 930 Venetian Blue
Old 05-20-2016, 10:07 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Work in Progress
 
Rich76_911s's Avatar
 
Join Date: Jun 2004
Location: Ardmore, PA
Posts: 3,037
Garage
Jeff,

That seems strange. Your warm idle from the night before isn't a good reference for a cold running issue with CIS. But cold running from the day before with cold running today is a good comparison. I'm far from an expert on CIS, but here are a couple of my thoughts. Two cents might be overpayment.

I'm guessing a bad pump would lead to lower fuel pressure, hence a richer condition. Same with a clogged fuel filter screen.

It seems counter intuitive to me that you are smelling fuel with a lean condition. That seems more like something you'd experience with a rich engine.

do you have CIS guages to check fuel pressures?
Have you checked that your WUR is getting power?

If your WUR is not getting power and your control pressure is static to run with a good warm condition, then your cold control pressure would be too high causing a lean condition.

Are O2 sensors accurate as soon as the car starts or do they need some time to warm up to become accurate? How long were you running at 15 AFR?
__________________
"The reason most people give up is because they look at how far they have to go, not how far they have come." -Bruce Anderson via FB
-Marine Blue '87 930

Last edited by Rich76_911s; 05-20-2016 at 10:12 AM..
Old 05-20-2016, 10:09 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Mighty Meatlocker Turbo
 
Rawknees'Turbo's Avatar
 
Join Date: Apr 2016
Location: North TexASS
Posts: 10,306
Quote:
Originally Posted by Jeff NJ View Post
Hmmm. Then what is that buzzing I hear when the key is in the on position before I go to start? I always thought that was the fuel pumps buzzing. I once figured out my yellow relay had a bad connection because it was eerily quiet and wasn't getting fuel.
If you are hearing fuel pump buzzing with just the key on, then something is not right with some part of the fuel head safety switch system (really clear diagnostics right thar, right?!?! ). Recently, I had a situation like that (fuel pumps on with key on = not supposed to work like that) . . . it turned out to be a bad connection with one or more of the pins & socket for the yellow relay. I found out by accident while wiggling the relay in its socket while the key was on (pumps would stop and start). I fixed it by cleaning the pins & socket, and also using a little bit of silver conductive grease on the pins - fix has lasted more than six months so far.
Old 05-20-2016, 10:25 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Mighty Meatlocker Turbo
 
Rawknees'Turbo's Avatar
 
Join Date: Apr 2016
Location: North TexASS
Posts: 10,306
And regarding the fuel pumps, here is a thread by some freaky guy who had that problem, spent a lot of time chasing his tail, butt eventually figured it out.

Fuel Head Pumps Switch Troubleshooting Help
Old 05-20-2016, 10:30 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)
Registered User
 
speednme1's Avatar
 
Join Date: Nov 2007
Location: New Jersey
Posts: 2,202
If your car was just started and idling plus all sounds and smells seemed normal then more than likely nothing is wrong or could be that the sensor went bad. Give your car a few minutes to warm up then lightly depress the throttle if your afr's come back to normal you're fine. I've had sensors go bad on me before...and they read crazy before kicking the bucket.
__________________
Rey....77 930 "the Mistress"
Old 05-20-2016, 10:42 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)
Registered User
 
Jeff NJ's Avatar
 
Join Date: Nov 2013
Location: NW NJ
Posts: 1,171
Quote:
Originally Posted by Rich76_911s View Post
Jeff,

That seems strange. Your warm idle from the night before isn't a good reference for a cold running issue with CIS. But cold running from the day before with cold running today is a good comparison. I'm far from an expert on CIS, but here are a couple of my thoughts. Two cents might be overpayment.

I'm guessing a bad pump would lead to lower fuel pressure, hence a richer condition. Same with a clogged fuel filter screen.

It seems counter intuitive to me that you are smelling fuel with a lean condition. That seems more like something you'd experience with a rich engine.

do you have CIS guages to check fuel pressures?
Have you checked that your WUR is getting power?

If your WUR is not getting power and your control pressure is static to run with a good warm condition, then your cold control pressure would be too high causing a lean condition.

Are O2 sensors accurate as soon as the car starts or do they need some time to warm up to become accurate? How long were you running at 15 AFR?
Good point on the fuel pumps causing lower pressure and more flow. I do have CIS fuel pressure gauges, but not installed.

Yesterday, the cold start AFR was like any other; it started out at about 11 and then climbed to 14ish as it warmed up. I started the car cold twice yesterday (about 8 hours apart) without issue.

The AFR sensor is very quick. It starts at about 14.7 and within a few seconds drops to 11 as the rich exhaust starts hitting the sensor for the first time then slowly starts rising. Today, it started out at 14.7 as usual, but within seconds started going up instead of down, so that tells me it was lean from the start. I don't think this could be AAR or WUR connector because it would be at cold start temps and just not warm up, and then just stay there if that had stopped working so my warm AFR would be overly rich then, correct? I have verified a couple months ago that the WUR and AAR connectors have voltage and with the way it was running yesterday, it had to be working then.
__________________
1988 930 Venetian Blue
Old 05-20-2016, 10:57 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)
Registered User
 
Jeff NJ's Avatar
 
Join Date: Nov 2013
Location: NW NJ
Posts: 1,171
Quote:
Originally Posted by Rawknees'Turbo View Post
And regarding the fuel pumps, here is a thread by some freaky guy who had that problem, spent a lot of time chasing his tail, butt eventually figured it out.

Fuel Head Pumps Switch Troubleshooting Help
I never liked that guy.
__________________
1988 930 Venetian Blue
Old 05-20-2016, 10:58 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #13 (permalink)
Registered User
 
Jeff NJ's Avatar
 
Join Date: Nov 2013
Location: NW NJ
Posts: 1,171
Quote:
Originally Posted by speednme1 View Post
If your car was just started and idling plus all sounds and smells seemed normal then more than likely nothing is wrong or could be that the sensor went bad. Give your car a few minutes to warm up then lightly depress the throttle if your afr's come back to normal you're fine. I've had sensors go bad on me before...and they read crazy before kicking the bucket.
So if it truly was that lean, it would not run correct? I just want to make sure I don't make things worse by letting it idle too lean.
Maybe I'll pull the sensor from the exhaust and see what it looks like.
__________________
1988 930 Venetian Blue
Old 05-20-2016, 11:02 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #14 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 13,493
Garage
This is a gauge issue.
Your engine will not start or stay running when cold if lean.
If the WUR is unplugged the engine will start as normal then begin to run poorly as the mixture remains rich and the engine warms.
__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 05-20-2016, 11:10 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #15 (permalink)
Registered User
 
speednme1's Avatar
 
Join Date: Nov 2007
Location: New Jersey
Posts: 2,202
Quote:
Originally Posted by Jeff NJ View Post
So if it truly was that lean, it would not run correct? I just want to make sure I don't make things worse by letting it idle too lean.
Maybe I'll pull the sensor from the exhaust and see what it looks like.
As Rawknees(wonder why his knees are raw?..hmmm) mentioned, the car would mis-fire. Sort of like having a vacuum leak. If you were driving your car and decided to get on it a bit and the afr took off....then I would worry.
__________________
Rey....77 930 "the Mistress"
Old 05-20-2016, 11:13 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #16 (permalink)
Mighty Meatlocker Turbo
 
Rawknees'Turbo's Avatar
 
Join Date: Apr 2016
Location: North TexASS
Posts: 10,306
Quote:
Originally Posted by Jeff NJ View Post
I never liked that guy.
Yes, a complete, good for nothing toolbag with a filthy mind, right thar - cross the street quickly if you ever seem him headed your way !!!

Quote:
Originally Posted by speednme1 View Post
As Rawknees(wonder why his knees are raw?..hmmm) mentioned,
How do you think I pay for parts for my car (mainly a/c componentry and gear, buttofcourse)?!?!?!
Old 05-20-2016, 12:19 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #17 (permalink)
Registered User
 
Jeff NJ's Avatar
 
Join Date: Nov 2013
Location: NW NJ
Posts: 1,171
Well, I disconnected the battery to reset the plx, checked the connectors to the far sensor and started it up. Ran fine. I let it warm up for a few minutes and took it for a spin.

Ran great! Was able to get full 1.0 bar boost and it pulls strong as ever. So I guess it's the bosch sensor or plx box. Of course, 1 yr warranty and it's like 14 months old... time to call them and *****.

Thanks for all the advice guys! Much appreciated!
Old 05-20-2016, 01:36 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #18 (permalink)
Registered User
 
speednme1's Avatar
 
Join Date: Nov 2007
Location: New Jersey
Posts: 2,202
When I had my last wideband kit...I lost the sensor twice and once on the new system. These turbos can get hot. Now I use a heat sleeve around the wiring near the muffler....no issues.
__________________
Rey....77 930 "the Mistress"
Old 05-20-2016, 01:42 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #19 (permalink)
Mighty Meatlocker Turbo
 
Rawknees'Turbo's Avatar
 
Join Date: Apr 2016
Location: North TexASS
Posts: 10,306
Jeff, like Rey, I was also going through sensors at a quick pace with it mounted so close to the turbine housing, so here is what I've done - an Innovate bung extension/heat sink I bought on eBay for a good price, and a home-made heat diffuser that wraps around the sensor body - good for about a year so far.


Last edited by Rawknees'Turbo; 05-20-2016 at 01:59 PM..
Old 05-20-2016, 01:56 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #20 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 06:29 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.