First day on the road .... Not a good day
#51
05-17-2012 | 10:10 PM
Thread Starter
|
Mudding
Joined: Jan 2012
Posts: 137
Likes: 0
From: Vancouver, Canada
Was just going through and trying to find the idle control value unit to clean and noticed - there is a hose going from my brake booster that connects to the drivers' side front of the top of the engine (front drivers' side of plenum/intake unit). I would assume this would be a vaccumm hose but the weird thing is that the end that goes into the engine has a metal piece on the end with a clip like fitting instead of a normal vaccum hose connection ...
Anyway it is just hanging there ... i can hold the cable and move it in and out without any resistance.
How is this supposto connect on?
Could this be causing issues - i.e. vac leak making rich = failed emissions and spit codes?
Anyway it is just hanging there ... i can hold the cable and move it in and out without any resistance.
How is this supposto connect on?
Could this be causing issues - i.e. vac leak making rich = failed emissions and spit codes?
#53
05-18-2012 | 06:43 AM
Rock Crawling
Joined: Oct 2011
Posts: 480
Likes: 11
The readiness test not complete is for the Cats, not the O2 sensors, apparently. Don't know if these are related.
My understanding is that the downstream O2 sensor does little other than work as a tool to test cat efficiency and also act as a backup if the front one fails. Is this correct?
My understanding is that the downstream O2 sensor does little other than work as a tool to test cat efficiency and also act as a backup if the front one fails. Is this correct?
The downstream sensor is stuck at 5v. The ECM needs to see the correct voltages from both upstream and downstream sensors to measure the catalyst efficiency. ALL sensors are needed to calculate fuel trim even if you think they do very little. None of them work as a back up for another.
I would order 2 X O2 sensors for bank 1 (as I haven't had any bank 2 codes since I got the truck) but just want to make sure I am not reverse diagnosing (i.e. the O2 codes are being cuases by misfires vs the bad mixture from the O2 causing misfires).
First and foremost though I need to establish if my head gasket is broken. If so, replace. If not, get the damn air out of there. #1 - I'm sure air in the system would affect NOX. #2 the water under the dash noise is driving me crazy.
Don't waste your time cleaning the stepper motor (iacv)
The Brake booster line clips to the manofold, If you think it's leaking
plug it off.
OR
You can run the engine and put your hand over the mass airflow and stall the engine. If you have a vacuum leak you'll hear it.
Note: I learned this one from rovenforlife... Who says you can't teach an old dog new tricks??
A P0300 (random multiple misfire) code can be logged due to low fuel pressure
I'm going to again suggest again that you check your fuel pressure.
I'm betting you'll find it's low and/or leaking down.
If it's low
You have a clogged fuel filter or faulty pressure regulator
If it's leaking down
You have a faulty pressure regulator or a leaking check valve in the fuel pump return line.
As I said one step at a time.
Cheers
Last edited by threalassmikeg; 05-18-2012 at 12:46 PM.
#54
05-18-2012 | 07:15 AM
Pro Wrench
Joined: Oct 2010
Posts: 1,669
Likes: 2
From: San Juan, Puerto Rico
There is no way for the catalyst to measure it's own efficiency.
The downstream sensor is stuck at 5v. The ECM needs to see the correct voltages from both upstream and downstream sensors to measure the catalyst efficiency. ALL sensors are needed to calculate fuel trim even if you think they do very little. None of them work as a back up for another.
Really, You need to put a scan tool, or an Ultra Guage on, and read all the OX sensor voltages. Replace any sensor that is slow in response time or close to 5v or 1v and not switching. I can't tell you if the others are good unless I actually see the readings. I can tell you that the ONE definitly needs to go.
First and Foremost, forget about the water sound for now. You have plenty of time to establish if you need head gaskets, and you can live with the noise.
Don't waste your time cleaning the stepper motor (iacv)
The Brake booster line clips to the manofold, If you think it's leaking
plug it off.
OR
You can run the engine and put your hand over the mass airflow and stall the engine. If you have a vacuum leak you'll hear it.
Note: I learned this one from rovenforlife... Who says you can't teach an old dog new tricks??
A P0300 (random multiple misfire) code can be logged due to low fuel pressure
I'm going to again suggest again that you check your fuel pressure.
I'm betting you'll find it's low and/or leaking down.
If it's low
You have a clogged fuel filter or faulty pressure regulator
If it's leaking down
You have a faulty pressure regulator or a leaking check valve in the fuel pump return line.
Cheers
As I said one step at a time.
The downstream sensor is stuck at 5v. The ECM needs to see the correct voltages from both upstream and downstream sensors to measure the catalyst efficiency. ALL sensors are needed to calculate fuel trim even if you think they do very little. None of them work as a back up for another.
Really, You need to put a scan tool, or an Ultra Guage on, and read all the OX sensor voltages. Replace any sensor that is slow in response time or close to 5v or 1v and not switching. I can't tell you if the others are good unless I actually see the readings. I can tell you that the ONE definitly needs to go.
First and Foremost, forget about the water sound for now. You have plenty of time to establish if you need head gaskets, and you can live with the noise.
Don't waste your time cleaning the stepper motor (iacv)
The Brake booster line clips to the manofold, If you think it's leaking
plug it off.
OR
You can run the engine and put your hand over the mass airflow and stall the engine. If you have a vacuum leak you'll hear it.
Note: I learned this one from rovenforlife... Who says you can't teach an old dog new tricks??
A P0300 (random multiple misfire) code can be logged due to low fuel pressure
I'm going to again suggest again that you check your fuel pressure.
I'm betting you'll find it's low and/or leaking down.
If it's low
You have a clogged fuel filter or faulty pressure regulator
If it's leaking down
You have a faulty pressure regulator or a leaking check valve in the fuel pump return line.
Cheers
As I said one step at a time.
#56
05-18-2012 | 10:16 PM
Thread Starter
|
Mudding
Joined: Jan 2012
Posts: 137
Likes: 0
From: Vancouver, Canada
There is no way for the catalyst to measure it's own efficiency.
The downstream sensor is stuck at 5v. The ECM needs to see the correct voltages from both upstream and downstream sensors to measure the catalyst efficiency. ALL sensors are needed to calculate fuel trim even if you think they do very little. None of them work as a back up for another.
Really, You need to put a scan tool, or an Ultra Guage on, and read all the OX sensor voltages. Replace any sensor that is slow in response time or close to 5v or 1v and not switching. I can't tell you if the others are good unless I actually see the readings. I can tell you that the ONE definitly needs to go.
First and Foremost, forget about the water sound for now. You have plenty of time to establish if you need head gaskets, and you can live with the noise.
Don't waste your time cleaning the stepper motor (iacv)
The Brake booster line clips to the manofold, If you think it's leaking
plug it off.
OR
You can run the engine and put your hand over the mass airflow and stall the engine. If you have a vacuum leak you'll hear it.
Note: I learned this one from rovenforlife... Who says you can't teach an old dog new tricks??
A P0300 (random multiple misfire) code can be logged due to low fuel pressure
I'm going to again suggest again that you check your fuel pressure.
I'm betting you'll find it's low and/or leaking down.
If it's low
You have a clogged fuel filter or faulty pressure regulator
If it's leaking down
You have a faulty pressure regulator or a leaking check valve in the fuel pump return line.
As I said one step at a time.
Cheers
The downstream sensor is stuck at 5v. The ECM needs to see the correct voltages from both upstream and downstream sensors to measure the catalyst efficiency. ALL sensors are needed to calculate fuel trim even if you think they do very little. None of them work as a back up for another.
Really, You need to put a scan tool, or an Ultra Guage on, and read all the OX sensor voltages. Replace any sensor that is slow in response time or close to 5v or 1v and not switching. I can't tell you if the others are good unless I actually see the readings. I can tell you that the ONE definitly needs to go.
First and Foremost, forget about the water sound for now. You have plenty of time to establish if you need head gaskets, and you can live with the noise.
Don't waste your time cleaning the stepper motor (iacv)
The Brake booster line clips to the manofold, If you think it's leaking
plug it off.
OR
You can run the engine and put your hand over the mass airflow and stall the engine. If you have a vacuum leak you'll hear it.
Note: I learned this one from rovenforlife... Who says you can't teach an old dog new tricks??
A P0300 (random multiple misfire) code can be logged due to low fuel pressure
I'm going to again suggest again that you check your fuel pressure.
I'm betting you'll find it's low and/or leaking down.
If it's low
You have a clogged fuel filter or faulty pressure regulator
If it's leaking down
You have a faulty pressure regulator or a leaking check valve in the fuel pump return line.
As I said one step at a time.
Cheers
- I must have been confused on my understanding of the downstream O2 sensors. Thanks for clearing that up. On a related note, the O2 code came at the same time as a misfire code and went away on its own in the next drive cycle and has not returned 300 miles later. In fact I have driven 300 miles and no codes have come at all - although it likely is just a matter of time. But I have my Ultra Gauge on order last week and hopefully will get it soon ... Have just been trying to do what I can without it. Sorry for wasting everyone's time.
- The booster cable connector is definately broken and the cable can be moved in and out with 2 fingers. It is getting some vaccuum (I pulled it out and the engine stalled) but I can't see how a cable in this state can not have a leak. Maybe this is part of the thing contributing to my 11 MPG highway driving today and the excessive CO, HC and NOX....
- Sorry if I was misguiding myself with my head gasket comment - I look at O2 sensors etc as automatic tuning equipment (adjusts mixture, etc) and therefore thought of this as trying to do a carb float adjustment on an engine with a broken head gasket (kinda like doing icing before baking the cake) .... As you say though, I guess I am not overheating and can always do the head gaskets late.
- Regarding fuel pressure - I am not fully making the connection of how a rich mixture and low fuel pressure are relate but obviously I have proven I don't understand how this stuff works ... Will post info on fuel pressure as well when I get my UltraGauge next week .... I have replaced the fuel filter about 5 days ago (sorry if I didn't mention this) so I don't think its a clogged filter. I haven;t had any starting issues as of late which is good but that could just be luck. Also, fyi, the misfire codes have not returned in the last 400 miles or so but obviously it could just be a matter of time ...
Thanks again for your help. Will let you know the O2 results some time next week ...
Cheers.
#57
05-18-2012 | 11:05 PM
Just to set the record straight, the DI did not have post cat O2's until the truck became OBDII compliant.
All pre-'96 DI's have 2 O2's, those are the fronts, the fronts are what controls the air/fuel ratio and there are no rear O2's on those trucks yet they run the same and get the same MPG as a truck with 4 O2's.
The rear O2's do nothing other than tell the ECU if the cats are working or not as is required to be OBDII compliant, it is all about reducing emissions.
Thats what OBDII was originally designed for, if the MIL is on, you are polluting more than you should be, it's that simple.
Google it, do your own research, you will find out that post cat O2's do nothing for the engine fueling.
All pre-'96 DI's have 2 O2's, those are the fronts, the fronts are what controls the air/fuel ratio and there are no rear O2's on those trucks yet they run the same and get the same MPG as a truck with 4 O2's.
The rear O2's do nothing other than tell the ECU if the cats are working or not as is required to be OBDII compliant, it is all about reducing emissions.
Thats what OBDII was originally designed for, if the MIL is on, you are polluting more than you should be, it's that simple.
Google it, do your own research, you will find out that post cat O2's do nothing for the engine fueling.
#58
05-19-2012 | 02:02 AM
Thread Starter
|
Mudding
Joined: Jan 2012
Posts: 137
Likes: 0
From: Vancouver, Canada
Just to set the record straight, the DI did not have post cat O2's until the truck became OBDII compliant.
All pre-'96 DI's have 2 O2's, those are the fronts, the fronts are what controls the air/fuel ratio and there are no rear O2's on those trucks yet they run the same and get the same MPG as a truck with 4 O2's.
The rear O2's do nothing other than tell the ECU if the cats are working or not as is required to be OBDII compliant, it is all about reducing emissions.
Thats what OBDII was originally designed for, if the MIL is on, you are polluting more than you should be, it's that simple.
Google it, do your own research, you will find out that post cat O2's do nothing for the engine fueling.
All pre-'96 DI's have 2 O2's, those are the fronts, the fronts are what controls the air/fuel ratio and there are no rear O2's on those trucks yet they run the same and get the same MPG as a truck with 4 O2's.
The rear O2's do nothing other than tell the ECU if the cats are working or not as is required to be OBDII compliant, it is all about reducing emissions.
Thats what OBDII was originally designed for, if the MIL is on, you are polluting more than you should be, it's that simple.
Google it, do your own research, you will find out that post cat O2's do nothing for the engine fueling.
#59
05-19-2012 | 07:49 AM
Super Moderator
Joined: Jan 2011
Posts: 16,322
Likes: 84
From: Savannah Georgia
from the RAVE shop manual brake section -
I would be tempted to use some heavy wall rubber hose and clamps. It is just vacuum, not very high, but you don't want wimpy hose that would be sucked flat when vac goes high (let off gas) just as you are about to apply brakes and avoid a Jeep.
The vacuum necessary to operate the brake servo on
petrol engine vehicles is provided by the engine inlet
manifold. During normal operation of the brakes only a
small volume of air is drawn from the servo and into
the inlet manifold or plenum chamber. However any
excessive air leaks due to damage in the brake servo
system or manifold hose connection, will effect the
mixture strength and ECM fuelling calculations on
engines equipped with an MFI system.petrol engine vehicles is provided by the engine inlet
manifold. During normal operation of the brakes only a
small volume of air is drawn from the servo and into
the inlet manifold or plenum chamber. However any
excessive air leaks due to damage in the brake servo
system or manifold hose connection, will effect the
mixture strength and ECM fuelling calculations on
I would be tempted to use some heavy wall rubber hose and clamps. It is just vacuum, not very high, but you don't want wimpy hose that would be sucked flat when vac goes high (let off gas) just as you are about to apply brakes and avoid a Jeep.
#60
05-19-2012 | 08:17 AM
Baja
Joined: Mar 2010
Posts: 5,584
Likes: 7
From: Pittsburgh PA suburbs.
Another thing to keep in mind, the LR manuals say to avoid extended attempts at cranking or you risk severe damage to cats. You are basically loading them up with raw fuel and shorten their life span considerably.
Apparently dogs are not affected just cats.