Well, I got the car running finally. As expected, I have a few issues to iron out. The car is running a little rough at idle. I'm not getting any MAF codes but when I unplug the MAF sensor, the car runs smoother. I'm getting BLM reading at 150, which I can do a little hunting to find out what that may be, may be the crossover isnt tight enough. I threw a code of 44 which is 02 sensor reading lean exhaust. I would think with the BLM at 150, it would read rich? My TPS is set at .42. I threw the code and the Service Engine soon light came on then went out. I reset the computer, let it idle for a while and didnt get any codes. I did this a few times and it would intermitently come on here and there. Any ideas?
Got the lImited running, code 44, rough idle, BLM 150
- Thread starter jdpolzin
- Start date
any datalogs?
(you are probably already aware of this....) BLM 150 means it is adding alot of fuel.... cause it thinks it is lean..... you notice it being too lean.... or too rich?
When you say it idles bad..... how so...?
A DS datalog.... or powerlogger... would possibly help....
(you are probably already aware of this....) BLM 150 means it is adding alot of fuel.... cause it thinks it is lean..... you notice it being too lean.... or too rich?
When you say it idles bad..... how so...?
A DS datalog.... or powerlogger... would possibly help....
Yep, I have done a lot of hunting for leaks on my GN so I'm pretty familiar with those and I know it dumping a lot of gas. I just figured the O2's would actually be reading rich because of so much gas being dumped. I unfortunately dont have a DataLogger, just a ScanMaster. As far as a poor idle, it stumbles quite a bit. Then with the stumble, it shakes the motor around and tries to find an idle point. The IACs were reading at 21 at idle. The RPMs stay pretty low. I cant drive the car yet becuase it taken apart for paint.
Hi JD -
I got some ideas. This is kind of tough, not knowing what you have NOT done yet. However, my car, like yours ran at 152 then down to 120s, etc.
First, you are right...a code 44 means the 02 sensor is showing a high exhaust oxygen (lean). But this will persist even though the ECM tries to increase fuel delivery. The result is usually a BLM way over 128.
Things to check:
-02 sensor. It can be defective or shorted. Mine was carbonized. Replaced it and BLMs got right into line.
-Then the car would not start. Just coincidentally, the MAF decided to fail. Replaced it too. Now car idles smoother.
-EGR valve and vacuum lines
-Lean injectors
-Water in fuel
-Exhaust leaks upstream of 02 sensor
-Fuel pressure or volume too low
-MAF reading lower airflow than actual
-Vacuum leaks. Be sure to check those hard plastic lines that lead to MAP sensor...be sure to look underneath them...they can be split and you won't know.
-PCV Valve
-PROM calibration problems
Good Luck and please let us know what works for you.
Steve
Sizzlin' Hot in Palm Springs at 115 degrees...my tires act like slicks in this weather.
I got some ideas. This is kind of tough, not knowing what you have NOT done yet. However, my car, like yours ran at 152 then down to 120s, etc.
First, you are right...a code 44 means the 02 sensor is showing a high exhaust oxygen (lean). But this will persist even though the ECM tries to increase fuel delivery. The result is usually a BLM way over 128.
Things to check:
-02 sensor. It can be defective or shorted. Mine was carbonized. Replaced it and BLMs got right into line.
-Then the car would not start. Just coincidentally, the MAF decided to fail. Replaced it too. Now car idles smoother.
-EGR valve and vacuum lines
-Lean injectors
-Water in fuel
-Exhaust leaks upstream of 02 sensor
-Fuel pressure or volume too low
-MAF reading lower airflow than actual
-Vacuum leaks. Be sure to check those hard plastic lines that lead to MAP sensor...be sure to look underneath them...they can be split and you won't know.
-PCV Valve
-PROM calibration problems
Good Luck and please let us know what works for you.
Steve
Sizzlin' Hot in Palm Springs at 115 degrees...my tires act like slicks in this weather.
GNVYUS 1
Well-Known Member
- Joined
- Dec 15, 2002
With the IAC at 21 at warm idle in park you're probably not getting any outside air in there.
What's the base fuel pressure line off??
Maf stock or Chevy?
Reading 4-5 at idle on the Scanmaster?
Denso Stainless 02 for $25 shipped from Rock Auto is probably in need.
What's the base fuel pressure line off??
Maf stock or Chevy?
Reading 4-5 at idle on the Scanmaster?
Denso Stainless 02 for $25 shipped from Rock Auto is probably in need.
Actually the code 44 and BLM 150 go hand in hand. THe BLM 150 just means it's trying to add fuel because of a lean condition. SO LEAN that it trips the code 44. 150 is as high as yours can go, but I'd bet if it could go a lot higher it would.
Your IAC is OK, but the stumbling is probably a result of the super lean condition.
The reason the BLM jumps from 150 to 122 to 150 to 122 is simply because with your scanmaster you can only see one cell at a time. There are 16 cells.
What's happening is the car is jumping betwenn two adjacent cells. ONe with a value of 150, and one with a value of 122.
That's a huge difference in fueling, hence the stumbling and roughness. It's not hanging around in the 122 cell long enough for it to learn "up" to a higher value, which I'm sure it will want to do.
YOu've got
1. a massive vacuum leak, or many leaks
or
2. pre turbo exhaust leak(s)
or
3. bad maf.
etc.
etc.
Yeah, i would check for vacuum leaks,maf as said above, I got a code 44 once in my GN, I traced it down to a clogged fuel sock, I got a bad load of gas with a bunch of sediment in it and it clogged the fuel sock which caused a code 44, oh and a bunch of sediment in the fuel filter.
I'm going to jump out to the garage this afternoon since I got off work early. The O2 is a brand new ACDelco. I have changed every vacuum line with new ones. I took the car entirely apart for this restoration and everything is new that can wear over time. The car is completely bone stock ----chip, injectors, FP Regulator, etc. I had my brother put the crosspipe on so i'm going to check there. YGETV8 has my Known good MAF sensor and is bringing it over to test with. I didnt change the fuel filter, I'll pick one of them up as well. Good Ideas guys, I'll keep you posted!
Well, I have been wrenching this entire day and I have just about had it. I rechecked all of the vacuum lines and changed all of them, checked the headers and crossover pipe, swapped out the ignition module-coil pack-MAF sensor-IAC sensor, changed computers, swapped between two different chips, checked my injectors harness, changed fuel filter, changed gaskets on the throttle body and put gasket maker just to make sure it is sealed. When I spray brake cleaner around the the TB the RPM change even after making sure it is sealed up????? Jay Jackson came over to help today and he couldnt figure out anything either. I did have the check valve between the EGR and hard vacuum line backwards but I changed it. Jay pulled the cam sensor plug while t was running to see if it changed anything, it didnt. BLM's are still at 150. Car still idles rough. WTF can I do next?
Well, I have been wrenching this entire day and I have just about had it. I rechecked all of the vacuum lines and changed all of them, checked the headers and crossover pipe, swapped out the ignition module-coil pack-MAF sensor-IAC sensor, changed computers, swapped between two different chips, checked my injectors harness, changed fuel filter, changed gaskets on the throttle body and put gasket maker just to make sure it is sealed. When I spray brake cleaner around the the TB the RPM change even after making sure it is sealed up????? Jay Jackson came over to help today and he couldnt figure out anything either. I did have the check valve between the EGR and hard vacuum line backwards but I changed it. Jay pulled the cam sensor plug while t was running to see if it changed anything, it didnt. BLM's are still at 150. Car still idles rough. WTF can I do next?
Take your vacuum block off and make a blank gasket ( no holes ) and re-install block. This will take all of your vacuum lines out of the equation.. Start there.....
OK, that a good idea to see if the leak is at the exhaust or through the VAC lines. I didnt think of that. I did however put gasket maker on the gasket to make sure the stock plastic vacuum block isnt leaking. I'll have to hit up the parts store for a sheet of gasket material. Will this cause other issues elsewhere because blocking off the sensors?
Our buddy Razor told me that trick years ago
I've used a box top off of a rice box or something like that, there is no need to get fancy here :biggrin: You should have the most vacuum at idle, your not trying to run your car down the road with this setup.
Obviously your fuel pressure will go up, your PCV will not be working, EGR, etc... however good enough for this test
Let us know what happens
Well, thats definately going to be my next test. Jay thought the seal on the TB rod for the flapper might be bad? The car is not a high mileage car so he thought that shouldnt be the case though. I'm just flabbergasted as to why the RPMs went up when I sprayed the TB?????
OK, spent the day playing around with this thing today and I actually made some progress. I first reset the ECM and fired it up to see if it magically cleared itself overnight............it didnt. Then I was listening to it idle and all of the sudden, it started whistling at me. I couldnt figure out where the heck it was whistling from but did a little digging and figured out the plenum to intake gasket was leaking. I re-sealed it up with a little gasket maker and fired her back up. Sure enough, BLM's were back up to 150. But.....it did idle much better and the MAL code 44 didnt pop back up. So i blocked of the vacuum port, cleared the ECM, and fired it back up. BLM's went straight back up to 150. So I sprayed some brake cleaner around the TB and there was no change in RPM's. My only idea is that I dont have the headers sealed up. I'm going to pull the crossover, re-install it and fire it back up to see if that changes anything before I go ripping everything back off again. Any other ideas would be helpfull. I am glad to clear that lean condition though!!!
It might take a little while before the BLM's drop back in place..... if you reset the ECM.... then drive it for 20-30 min... that should be sufficient time to see if she is going to settle down....
Sounds like you are making progress none-the-less.
Keep going.
Sounds like you are making progress none-the-less.
Keep going.
I suppose, I just think that after the ECM is reset, it is then learning the system new. Thats why it starts off at 128 until the car warms up and runs a little then creeps its way back up to 150. Am I wrong? Can anyone confirm this? If so, I'll wait till the car is ready for the street to go any farther! THAT WOULD BE A BONUS!!!!!!! I do know on my GN, I had readings of 150 and after I found the crossover loose and re-tightened it. I reset the ECM and it never went past 130 since. It would be awesome if it was actually fixed!
bmackinnon
Active Member
- Joined
- Feb 24, 2005
I read the whole thread, and no where did you say you checked the fuel pressure? Sure it's fine? Sometimes its the simple things......
