Fuel system is to lean - Page 2

grant66 · 09-05-2002, 11:41 PM

So I hooked up the smog pump. Put a new ACT sensor in the car. Disconnected the negative battery cable and turned on the light switch for way over ten minutes. The I looked at the MAF wiring harnes. It looks fine. Started up the car and did a wiggle test. Wiggled on the wires under the dash by the driver side and by the gas tank. I couldn't get the car to start missing. I ran a code scanner and I passed the KOEO test. The place that I paid to do some work replaced the fuel pump relay and cleaned up the wiring side of the connector. Right now I am a little disturbed and lost.

jimberg · 09-05-2002, 11:48 PM

So you passed the KOEO test which means that all of your sensors passed the quick test. Now it's time to run the KOER test as Chris suggested. Let us know what the results are.

grant66 · 09-06-2002, 02:28 AM

Do I need to reset the computer? Can I run a KOER test while doing a wiggle test. Last time I ran a KOER test. The scanner said that I was running a lean in both banks. Should I do a Key On Engine Running while I drive the car. I am very open to suggestions.

Thank you,
grant66

grant66 · 09-06-2002, 04:28 AM

I am going to run a KOER test in the mourning. I will post.

grant66 · 09-06-2002, 10:26 AM

I ran a KOER test and OTC scanner came up with 41 and 91. Fuel injection system is lean on both banks. I also ran a KOER wiggle test with the OTC scanner I got nothing back. Does any one have any ideas?

Thank you,

grant66

jimberg · 09-06-2002, 12:54 PM

Have you removed the Hypertech chip, yet? If not, I suggest you try that. Clear your codes and then do the KOER test again.

grant66 · 09-06-2002, 08:23 PM

About a week ago I cleared the codes. Took out the chip. Removed the computer and hooked up the scanner. I still received code 41 and 91. I will try it again. If that is what you suggest. Is there any specific test on any sensor that you would like me to do?

Thank you,

grant66

PKRWUD · 09-06-2002, 11:50 PM

Okay, next you need to run the engine at 2000 rpms for 4 minutes, shut it off, wait 10 seconds, and rerun KOER test again. What codes come up?

grant66 · 09-07-2002, 06:16 AM

So I first disconnected the negative post to the battery for eleven minuites and turned on the head light switch to reset the codes. (I don't believe this matters because we didn't have any hard codes in the computer) I took the hypertech chip out of the car. Ran the car for 4 minuites at 2000 RPMS. I then shut the car down for 10 seconds. The next thing I did was started the KOER test with the OTC scanner. The scanner ran me throught KOER test and came up with the 21, 41 and 91.

PKRWUD · 09-07-2002, 06:39 AM

Quote:

Originally posted by grant66
So I first disconnected the negative post to the battery for eleven minuites and turned on the head light switch to reset the codes. (I don't believe this matters because we didn't have any hard codes in the computer) I took the hypertech chip out of the car. Ran the car for 4 minuites at 2000 RPMS. I then shut the car down for 10 seconds. The next thing I did was started the KOER test with the OTC scanner. The scanner ran me throught KOER test and came up with the 21, 41 and 91.

All I asked you to do was run it at 2000 rpms for 4 minutes, and rerun KOER.

Your problem is in one of 3 areas. You either have a fuel pressure problem, a vacuum leak, or a problem with the O2 sensors and/or their wiring. There is only one more test that you will be able to do as far as your sensors are concerned, and that is to check them to see if they can generate the necessary voltage. To determine this, you need to disconnect an O2 sensor, and attach a DMM pos lead to the signal wire from the sensor (either the dark blue/light green wire, or the dark green/pink wire), and the DMM neg lead to the neg battery post. Then run KOER, and monitor the DMM. If the voltage is over .5 vdc, then the sensor is good. If the voltage stays below .5 vdc, then the sensor needs to be replaced. After testing one, test the other.

Did you already check your fuel pressure?

grant66 · 09-07-2002, 09:04 AM

I have brand new O2 sensors. The guys at Stang Auto Tech said every thing is good with oxygen sensors and the wiring leading up to the O2's. I didn't understand what the DMM is? The car has new sensors except for the mass air flow. The last time I tested it seemed to be in the vacinity of its ranges.

I need a place to start in the wiring. I only have an analog meter. It sounds like I need to invest into a digital Volt Olm meter. What do you think?

I couldn't find any thing wrong with fuel pressure when the car is working correctly. I don't know about it when it fails to work or get under load for long periods of time.

The car doesn't like to be very warm for long periods of time.

How about those codes I get after the car doesn't want to work?
Can they lead me into any direction?

PKRWUD · 09-07-2002, 10:35 AM

The other codes were for the ACT sensor, which you replaced, the MAF, which you said tested good, and that it's wires looked good, and the fuel pump circuit, which you serviced with a new relay, and by checking the wiring. Unless those codes come up as current, there is no way to determine the source of them, other than what you've already done. The codes that are current are 41 & 91, so those are the only codes we have to work with. If your mechanic says the O2 sensors and wiring are good, then that leaves fuel pressure or a vacuum leak. You said the fuel pressure tested okay, which leaves a vacuum leak. A vacuum leak would create a high idle that wouldn't change much when you created a new vacuum leak. You said you inspected the vacuum hoses, and didn't find any problems. You have eliminated all of the possibilities.

The reason why I suspect the problem may be in the O2 sensors or their wiring is because the spark plugs didn't read lean. If the system was lean, from either a vacuum leak or a lack of fuel, your spark plugs would be bright white, but they weren't. That makes me think that things are fine, but the O2 sensor circuit thinks, for whatever reason, that things are not fine. Odds are you have a bad ground contact somewhere.

My recommendation is to go to your mechanic, and have him diagnose it for you. I really don't know what else to tell you to do. According to you, you've passed all the tests.

Take care,
~Chris

jimberg · 09-07-2002, 12:05 PM

Speaking of bad ground wires for O2 sensors, you have that orange wire with the eyelet on the end hooked up to the block somehow, don't you? It's located toward the back and has a black, cloth cover on it.

grant66 · 09-08-2002, 04:38 AM

What side of the block are the O2 sensor grounds on? How do I do some of the fuel pressure tests? Not hooking up the gauge, but procedures and starting points. Is there guages for checking vacuum leaks. What is the DMM mentioned by PRKWUD. I want to check the HEGO's Maybe hook up new wiring for the HEGO's. Is there a harness that I can purchase. Has anyone redone their wiring to the O2 sensors? I am very lost!

09-05-2002, 11:41 PM	#21
grant66 Registered Member Join Date: Sep 2001 Location: Avon, CO, USA Posts: 63	Test finished So I hooked up the smog pump. Put a new ACT sensor in the car. Disconnected the negative battery cable and turned on the light switch for way over ten minutes. The I looked at the MAF wiring harnes. It looks fine. Started up the car and did a wiggle test. Wiggled on the wires under the dash by the driver side and by the gas tank. I couldn't get the car to start missing. I ran a code scanner and I passed the KOEO test. The place that I paid to do some work replaced the fuel pump relay and cleaned up the wiring side of the connector. Right now I am a little disturbed and lost. __________________ If it isn't broke you are not trying.

09-05-2002, 11:48 PM	#22
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	So you passed the KOEO test which means that all of your sensors passed the quick test. Now it's time to run the KOER test as Chris suggested. Let us know what the results are. __________________ 351W 89 Mustang GT Convertible

09-06-2002, 02:28 AM	#23
grant66 Registered Member Join Date: Sep 2001 Location: Avon, CO, USA Posts: 63	KOER Do I need to reset the computer? Can I run a KOER test while doing a wiggle test. Last time I ran a KOER test. The scanner said that I was running a lean in both banks. Should I do a Key On Engine Running while I drive the car. I am very open to suggestions. Thank you, grant66 __________________ If it isn't broke you are not trying.

09-06-2002, 04:28 AM	#24
grant66 Registered Member Join Date: Sep 2001 Location: Avon, CO, USA Posts: 63	KOER TEST I am going to run a KOER test in the mourning. I will post. __________________ If it isn't broke you are not trying.

09-06-2002, 10:26 AM	#25
grant66 Registered Member Join Date: Sep 2001 Location: Avon, CO, USA Posts: 63	Results from this mournings test I ran a KOER test and OTC scanner came up with 41 and 91. Fuel injection system is lean on both banks. I also ran a KOER wiggle test with the OTC scanner I got nothing back. Does any one have any ideas? Thank you, grant66 __________________ If it isn't broke you are not trying.

09-06-2002, 12:54 PM	#26
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	Have you removed the Hypertech chip, yet? If not, I suggest you try that. Clear your codes and then do the KOER test again. __________________ 351W 89 Mustang GT Convertible

09-06-2002, 08:23 PM	#27
grant66 Registered Member Join Date: Sep 2001 Location: Avon, CO, USA Posts: 63	Hypertech chip About a week ago I cleared the codes. Took out the chip. Removed the computer and hooked up the scanner. I still received code 41 and 91. I will try it again. If that is what you suggest. Is there any specific test on any sensor that you would like me to do? Thank you, grant66 __________________ If it isn't broke you are not trying.

09-06-2002, 11:50 PM	#28
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Okay, next you need to run the engine at 2000 rpms for 4 minutes, shut it off, wait 10 seconds, and rerun KOER test again. What codes come up? __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

09-07-2002, 06:16 AM	#29
grant66 Registered Member Join Date: Sep 2001 Location: Avon, CO, USA Posts: 63	Results to KOER So I first disconnected the negative post to the battery for eleven minuites and turned on the head light switch to reset the codes. (I don't believe this matters because we didn't have any hard codes in the computer) I took the hypertech chip out of the car. Ran the car for 4 minuites at 2000 RPMS. I then shut the car down for 10 seconds. The next thing I did was started the KOER test with the OTC scanner. The scanner ran me throught KOER test and came up with the 21, 41 and 91. __________________ If it isn't broke you are not trying.

09-07-2002, 09:04 AM	#31
grant66 Registered Member Join Date: Sep 2001 Location: Avon, CO, USA Posts: 63	The wiring to O2 sensor I have brand new O2 sensors. The guys at Stang Auto Tech said every thing is good with oxygen sensors and the wiring leading up to the O2's. I didn't understand what the DMM is? The car has new sensors except for the mass air flow. The last time I tested it seemed to be in the vacinity of its ranges. I need a place to start in the wiring. I only have an analog meter. It sounds like I need to invest into a digital Volt Olm meter. What do you think? I couldn't find any thing wrong with fuel pressure when the car is working correctly. I don't know about it when it fails to work or get under load for long periods of time. The car doesn't like to be very warm for long periods of time. How about those codes I get after the car doesn't want to work? Can they lead me into any direction? __________________ If it isn't broke you are not trying.

09-07-2002, 10:35 AM	#32
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	The other codes were for the ACT sensor, which you replaced, the MAF, which you said tested good, and that it's wires looked good, and the fuel pump circuit, which you serviced with a new relay, and by checking the wiring. Unless those codes come up as current, there is no way to determine the source of them, other than what you've already done. The codes that are current are 41 & 91, so those are the only codes we have to work with. If your mechanic says the O2 sensors and wiring are good, then that leaves fuel pressure or a vacuum leak. You said the fuel pressure tested okay, which leaves a vacuum leak. A vacuum leak would create a high idle that wouldn't change much when you created a new vacuum leak. You said you inspected the vacuum hoses, and didn't find any problems. You have eliminated all of the possibilities. The reason why I suspect the problem may be in the O2 sensors or their wiring is because the spark plugs didn't read lean. If the system was lean, from either a vacuum leak or a lack of fuel, your spark plugs would be bright white, but they weren't. That makes me think that things are fine, but the O2 sensor circuit thinks, for whatever reason, that things are not fine. Odds are you have a bad ground contact somewhere. My recommendation is to go to your mechanic, and have him diagnose it for you. I really don't know what else to tell you to do. According to you, you've passed all the tests. Take care, ~Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

09-07-2002, 12:05 PM	#33
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	Speaking of bad ground wires for O2 sensors, you have that orange wire with the eyelet on the end hooked up to the block somehow, don't you? It's located toward the back and has a black, cloth cover on it. __________________ 351W 89 Mustang GT Convertible

09-08-2002, 04:38 AM	#34
grant66 Registered Member Join Date: Sep 2001 Location: Avon, CO, USA Posts: 63	O2 sensor grounds? What side of the block are the O2 sensor grounds on? How do I do some of the fuel pressure tests? Not hooking up the gauge, but procedures and starting points. Is there guages for checking vacuum leaks. What is the DMM mentioned by PRKWUD. I want to check the HEGO's Maybe hook up new wiring for the HEGO's. Is there a harness that I can purchase. Has anyone redone their wiring to the O2 sensors? I am very lost! __________________ If it isn't broke you are not trying.

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