• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Fuel Pump

BillBoost37 said:
Oh.. once your issue (which seems to be a reasonable stumper) is cleared up.. you should go read though Jeff's multipage thread. It was a stumper as well, right up until I saw the picture.
Click to expand...

I will. I just get that typical nagging feeling when it comes to these sorts of things. At the end of the day it is a GM, and in my experience, when GMs hit 100k miles things like this seem to always start going out. It has 103k on it now.
 


Yet I have the opposite feeling. I have driven and purchased these cars with many more miles and many less issues, having been neglected of maintenance for years.

Something odd is going on with it, that's for sure. A fuel pump shouldn't behave the way yours is..if you could test it driving..that would tell you w/o question. As should watching the O2 go lean.
 
BillBoost37 said:
Yet I have the opposite feeling. I have driven and purchased these cars with many more miles and many less issues, having been neglected of maintenance for years.

Something odd is going on with it, that's for sure. A fuel pump shouldn't behave the way yours is..if you could test it driving..that would tell you w/o question. As should watching the O2 go lean.
Click to expand...

I will get it figured out one way or another. At least I know this one was never neglected.
 
J57ltr said:
If the fuel pump is weak then it will go lean. I didn't get any codes when I wasn't getting a signal to the MAP under boost if I didn't stay in it. It would go pig rich, set timing to 10* ATDC and I would get a MAP MAF correlation error and it would throw me into reduced engine power mode, and lock me out of the throttle. I have an 05' though. The only time I got a code was if I forced it to the floor and stayed into it. If you still believe that the fuel pump is the issue, then look at timing, O2 sensor, and MAP and watch what they do. You can even log the data and put it into a spreadsheet. Set the sample rate to 100ms (.1 Second)

Jeff
Click to expand...

BillBoost37 said:
Yet I have the opposite feeling. I have driven and purchased these cars with many more miles and many less issues, having been neglected of maintenance for years.

Something odd is going on with it, that's for sure. A fuel pump shouldn't behave the way yours is..if you could test it driving..that would tell you w/o question. As should watching the O2 go lean.
Click to expand...

Lets make sure I got the right dials to monitor what you two are suggesting. I set the dials to use digital display.

Format example: Monitor Name = Dial Name

O2 Sensors
Fuel Trim Bank 1 Short Term = STFT1
Fuel Trim Bank 2 Short Term = STFT2
I assume the readings here, if functioning properly need to be in the range of .45 volts. Voltage .1 = lean, Voltage .9 = rich. However, these dials are showing measurements with %.
I see a long term option as well, but for this purpose short term seems more appropriate.

MAP Sensor
Intake Manifold Pressure = Intake

Timing
Timing Advance = Timing

As far as logging, If I tell the Torque app to start logging, will it log "everything" by default or do I need to set the data points to log?
 
rkm said:
Lets make sure I got the right dials to monitor what you two are suggesting. I set the dials to use digital display.

Format example: Monitor Name = Dial Name

O2 Sensors
Fuel Trim Bank 1 Short Term = STFT1
Fuel Trim Bank 2 Short Term = STFT2
I assume the readings here, if functioning properly need to be in the range of .45 volts. Voltage .1 = lean, Voltage .9 = rich. However, these dials are showing measurements with %.
I see a long term option as well, but for this purpose short term seems more appropriate.

MAP Sensor
Intake Manifold Pressure = Intake

Timing
Timing Advance = Timing

As far as logging, If I tell the Torque app to start logging, will it log "everything" by default or do I need to set the data points to log?
Click to expand...


Don't worry about the long term and short term for now, you want to look at 02 voltage and set it for graph where it is a line graph that moves up and down and leaves what looks like an EKG type graph. It will say O2 1x1V
 
J57ltr said:
Don't worry about the long term and short term for now, you want to look at 02 voltage and set it for graph where it is a line graph that moves up and down and leaves what looks like an EKG type graph. It will say O2 1x1V
Click to expand...

Do I want to look at both banks or just one? O2 1x1 and O2 2x1?


I noticed something that may not be working right, not sure. However, it only seems to read only on Bank 1, if I add the Bank 2 it does not respond. This is constant with several other sensors. One side will read but not the other.

Using what I posted earlier as an example for the short term dials, STFT1 is working, but STFT2 does not show anything.
 


The car only has one bank, B1. On B1 there's S1 (in rear manifold) and S2 which is post cat.

The only sensor that makes sense is B1S1, if you watch voltage.. when you stuff the pedal, it should go upwards of 800 and stay there until you let off.
 
BillBoost37 said:
The car only has one bank, B1. On B1 there's S1 (in rear manifold) and S2 which is post cat.

The only sensor that makes sense is B1S1, if you watch voltage.. when you stuff the pedal, it should go upwards of 800 and stay there until you let off.
Click to expand...

That explains a few things. Know what they say about assuming things.....
 
I see a few instances of KR coming in.

[TABLE="width: 500"]
[TR]
[TD]H2OS(mV)
[/TD]
[TD]KR[/TD]
[TD]O2 Volts 1x1
[/TD]
[TD]Intake PSI
[/TD]
[/TR]
[TR]
[TD]60.75999832
[/TD]
[TD]0.3515625
[/TD]
[TD]0.87
[/TD]
[TD]18.12971687
[/TD]
[/TR]
[TR]
[TD]889.70001221
[/TD]
[TD]0.79101562
[/TD]
[TD]0.875
[/TD]
[TD]21.17551041
[/TD]
[/TR]
[TR]
[TD]859.32000732
[/TD]
[TD]0.08789062
[/TD]
[TD]0.90999997
[/TD]
[TD]20.4503212
[/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[/TABLE]
 
I am thinking you may be looking at the wrong MAP signal, one is in absolute pressure and the other is in pressure and vacuum. If you subtract 14.7 from all the MAP data points you only see a few instances of you actually getting into boost. Looking at the O2 at that point it looked as though it was lean, at about .6V but there wasn't enough samples to tell.

Do this: When you have a chance and everything is clear Start logging then start from a dead stop accelerate to 60 mph then stop the log. The amount of KR is negligible from what I saw, less that 1*. Try this a couple of times then post those logs.

Jeff
 


The one I selected is called 'Intake Manifold Pressure'. This was just an excerpt of what I saw in the log. I posted the entire log earlier as a zip file.

I will do the 0-60 later today.
 
I saw the entire log and went through the data and graphed it by doing a short log it will spread out the information and allow for a more detailed graph. I end up having to split them up into different graph as trying to read a 0-1V signal with a manifold pressure drowns out the Oz output. There are 2 PID's to log from one try the other one I think it is turbo boost and vacuum gauge at the bottom of the selectable PID's, I did the same thing when I was trying to log data, although it's easy enough to subtract the 14.7 psi to show boost.
 
I'm back. I had to go off the grid for awhile and take a break from life.

I got it fixed once I got back on it. Took all of 15 minutes and just so happened to have a spare laying around from another project.
It was a boot on a plug wire, when I changed the plugs I missed it. It had a small crack in the boot and it was not containing the spark and it was jumping across to the manifold.

Replaced the boot and all is well. But there is another small mystery to take care of, I will start another thread on it.

Thanks all for the help, especially for keeping me hesitant so I did not just replace something that did not need replacing.
 
You must log in or register to reply here.
Back
Top