How do you check for vacuum leaks? (code 44 AGAIN!)

[d0n_3d]

I have posted this problem numerous times on this board...but I am STILL getting a code 44 at idle! Let the car idle for about 1 minute warm or cold and then the computer goes into open loop and the engine "chugs" like it's researching for the idle...then the SES light pops on and a code 44 shows up everytime...when i push the gas pedal it goes back into closed loop and SES light goes away...

this is per gnttype.org

CODE 44

Trouble Code 44 indicates that the O2 sensor is showing a persistently high exhaust oxygen content (lean), despite the efforts of the ECM to increase injector on-time (thus increasing fuel delivered). Integrator and BLM numbers may indicate > 128 by a substantial margin.

The conditions for setting this code are:

no Code 33 or Code 34 (MAF Error) present, and
the O2 sensor voltage remains below 250 mVolts, and
the ECM is in Closed Loop control, and
the above conditions exist for more than 50 seconds.



Typical causes for this code include:

1) O2 sensor defective or lead shorted
2) Lean injectors (dirty or blocked)
3) Water in fuel
4) Exhaust leaks upstream of O2 sensor
5) Fuel pressure or volume too low
6) MAF sensor reading lower airflow than is actually present
7) Vacuum leaks
8) Incorrect or poorly calibrated PROM

well let's see...#1 i have tried both an ac delco, and my current heated o2 sensor kit...same thing happens with every o2 sensor i use
#2 my 50 lb injectors are brand new...also this code came up with my stock injectors
#3 i have tried 5 different fuels...no matter what is in the tank it still shows up a code 44
#4 i replaced my cracked ds header, ps is not cracked, checked crossover and looks good, no leaks in the intake or anything!
#5 i have tried ALL kinds of fuel pressures...ranging from as low as 35 line off to 50 line off...does not matter what the fuel pressure is set at...right now it's set at 37 line off but 50's shouldn't need high fp
#6 my MAF numbers are always 5 or higher...it's a brand new LS1 MAF and translator setup with a cold air kit...has done this with stock maf sensor and stock air box...
#7 NOT SURE ABOUT THIS ONE...don't know how to look for vacuum leaks...to my knowledge i can't see any leaky or cracked vacuum lines...i did remove the cruise control unit completely and plugged up two lines going to the cruise unit with some a screw and a nail but figured it wasn't drawing vacuum???
#8 have tried 5 different kinds of chips from street to race...does the same thing on all chips...

also please note i have tried using a pcv inline check valve with the delco pcv valve...still same crap...removed inline check valve and ran just the pcv valve...still same crap

SO WHAT GIVES!

is it the old cruise control lines doing this??? should i plug those up better or something? otherwise i can't think of any other ways to cause this annoying problem...

 

[Eric Stage I]

Keep looking for a vacuum leak. You might want to go to the parts store and get some vacuum caps, and disconnect some of the vac lines and cap them off. Don't drive it around like that, do it just to see if there's a hidden leak somewhere. Do that with the pcv also.
If that doesn't get you anywhere, you could have a leak between the intake and heads, or plenum, etc.
Another option is poor grounding causing the o2 not to work right. If you don't have the ground stretcher kit from Caspers, now might be a good time to try it.

Good Luck,
Eric

 

[blackbuick87]

Too much anti seize on the O2 sensor making it lose its ground?

You can spray WD40 around the base of the intake, and the doghouse, and if the engine changes the way it is running briefly, there is a vacuum leak

 

[d0n_3d]

Originally posted by blackbuick87
Too much anti seize on the O2 sensor making it lose its ground?

You can spray WD40 around the base of the intake, and the doghouse, and if the engine changes the way it is running briefly, there is a vacuum leak

i don't use antiseize on my o2 sensor...i just screw it in by itself...is that a no-no!? would a loose o2 sensor cause it? and what are you guys talking about a bad ground? i thought there was only one wire coming off the sensor and it connects to the wiring harness...what ground?

 

[6=8]

I think the "Ground" that is being referred to is the chassis/case ground for the sensor. In other words, your sensor ground is being questioned. I don't think this is your problem.

I have an idea... Do you have a vacuum gauge? Why not post what the vacuum reading is when this code is generated? Someone on this board must have a similar setup to yours, and you can then compare a working vac reading to you non-functioning reading and go from there.

For example, my stock, high mileage engine produces 16-18 in hg at idle. It would be interesting to see what your engine is reading.

When I am looking for vacuum leaks, I use carb spray (WD-40 is a lube and leaves an oily deposit... This attracts dust.) Target areas are the gaskets at the vacuum block, dog house, plenum, intake, PCV grommet, EGR lines (At the valve and solenoid), and the vacuum canister itself.

 

[6=8]

Oh yeah,

As for the Anti-seize compound on the O2 sensor... Yes, you should use a little. This will prevent the threads on the sensor from "Cold Welding" to the bung. Makes replacement much easier, say, 1 year from now.

Just a small amount though... And keep the stuff on the threads. It will ruin a good sensor if any gets on the element.

 

[blackbuick87]

The stock O2 grounds itself through the threads on the exhaust pipe. Your heated one probably does not. Thats why too much anti seize can screw up the ground

I think you problem is vacuum related also. With a stock cam you should pull quite a bit of vacuum, like was stated above.

I bought my vacuum gauge at car quest for 12 bucks I think, cheap and easy to use

 

[BobbyBuick]

Do you have aftermarket Pcv ..if it is idleing to code a 44 and your blms go nuts.hell just do this plug the line that goes to the pcv valve .see what happens to your blms and crosscounts .also check to make sure your egr is seated and clean,.......................ILL BET ON PCV

 

[equalizer442]

When I am looking for vacuum leaks, I use carb spray (WD-40 is a lube and leaves an oily deposit... This attracts dust.) Target areas are the gaskets at the vacuum block, dog house, plenum, intake, PCV grommet, EGR lines (At the valve and solenoid), and the vacuum canister itself.

use one of them small bottles of propain and crack the gas on, dont light it! then run it around the vacume lines, if you have a leak it will suck the propain up and burn it increaseing the idle speed. it works just as well as the other stuff like wd40 and it dont leave a mess.

 

[BobbyBuick]

i use propane bottle with a rubber hose and valve

 

[tc86gn]

The best way to safely check for vacuum leaks is with water. Been doing it for years. If it leaks you will definitly hear a difference!!!

 

[Dan K]

I have the same thing going on.
I'm hoping it's just a vacuum leak. I'd say keep looking for a leak somewhere.
I'm sending my intake/tb to JJ and when I put the top end back together I'm going to check everything really well and replace all the gaskets.
If you figure out what your problem is, let me know.

 

[turbodave231]

I made a tool to pressurize the intake manifold with regulated shop air. The tool clamps to the throttle body (or the inlet to the turbo). You need to take at least one of the rocker shafts off to keep the intake valves closed.

I can pressure test the whole intake tract for leaks this way. You'd be suprised what leaks!!! PCV without a check valve leaks HUGE! The EGR valve leaks really bad too. Oh yeah I also found a VDO boost gauge that reads 2psi low (headgaskets waiting to happen)

Dave

 

[d0n_3d]

the pcv valve i use is the oem replacement ac delco...

my car smells like it's running rich also...fuel pressure is only at 37 lbs line on 42 line off...i mean i have a hollowed out cat but still the exhaust smells really rich...but i get a code 44 which shows lean...ha these cars are crazy

ok tomorrow i am checking for vacuum leaks...i might get a gauge and test the vacuum readings...i knew i should have got the boost/vac combo gauge instead of just the 30lb boost gauge...oh well...i will know better for my next TR

 

[turbodave231]

If you think the car is really running rich, is it misfiring? O2 sensors only read Oxygen not fuel. A misfiring engine will read lean because the oxygen in the intake air never burned.

If you're not misfiring, have you checked and cleaned your ECM grounds? (Rear of pass side cyl head).

One way to check your O2 sensor circuit is with a scan tool:

While monitoring O2 voltage on scan tool
1. Disconnect O2 sensor and ground the purple O2 signal wire.
The scan tool should indicate O2 voltage at or near zero mV

2. Using a piece of wire or paperclip to get contact to the terminal on the purple wire, hold on to the terminal with one hand and touch the battery positive post with the other. The Scan tool should read Full rich 1.00mV. (You are using your body as a big resistor with this step)

These tests will quickly tell you if the ECM can read the O2 sensor correctly.

You might try a different MAF sensor (if you can borrow one). a bad MAF sensor can cause a problem like this too.

 

[captrob]

Smells like fuel cause...

the ecm is sensing a lean condition and pouring fuel to it. I had a vacuum leak when I put on the RJC power plate. Not a problem with the plate, but a dap of rtv on the gasket sealed it right up.
HTH, CaptRob

 

[d0n_3d]

well guys i hooked up turbolink to the car tonight and ran some checks...here is what i got (also just installed a fresh new set of ac CR42TS plugs) please note this was at idle ONLY

blms - ranging from 128-148, never stays in one spot
integrator - PEGGED at 150 does NOT move at all while in open or closed loop

maf counts - 5 GPS
tps - .44

02 mvs - between 28-35
02 delta counts - ZERO does NOT move...constantly at zero

engine idle speed - 750-850 rpm
still pops a code 44 after letting idle too long...car goes into open loop

sooooo looks like the 02 sensor gets my vote for the culprit...does anyone think this thing is bad? i thought it should be reading in the 100's at idle...so much for the heated o2 kit

 

[BobbyBuick]

a codee 44 is made when you have no cross counts for I think 2 minutes not sure though.try plugging the pcv vacume line leaving the throttle body and unhook it .if you start getting cross counts look their.if not go to the o2 and either you have a bad gorund ,voltage drop in the connection or a bad o2

 

[d0n_3d]

guys i made a mistake...my integrator is usually around 128 but my blms are PEGGED at 150...it doesn't move from 150 at all...that means the computer is constantly adding fuel at idle right? i mean my fuel pressure is low and the exhaust still smells REALLY rich...

i just changed the o2 sensor back to my oem delco sensor...it is reading cross counts now and mvs are in the 70's at idle in closed loop

i just found out that one of the bolts that holds the upper plenum (and my powerplate) is stripped...back passenger side is stripped and it was finger loose...would that cause the problem? i need to tap that hole out and redrill threads...does anybody know what size bolt (shaft) fits in that hole and what size should i drill out?

also i have an original vacuum block with original vacuum lines going to it...is it time for a new vacuum block??? mine isn't cracked or anything from my eyes...

 

[BobbyBuick]

guys i made a mistake...my integrator is usually around 128 but my blms are PEGGED at 150...it doesn't move from 150 at all...that means the computer is constantly adding fuel at idle right?

YES,the computer is adding fuel and adding at a rate that you still get no cross counts .if you go off idle and it gets cross counts you need to look for a vacume leak .have you checked your pcv valve like i posted twice.if you have than look for another vacume leak.obviously the upper plenum needs fixed and can be the culprit.have you plugged the pcv valve yet?