O2 sensor Fast EZ efi 2.0
Thread Starter
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
O2 sensor Fast EZ efi 2.0
OK still slogging along on this Fast system. Determined to get it running. It is running pig rich! From startup it shows 13.5 then immediately goes to 15.9 and stays there no matter what throttle I give it. It barely stays running and I have to keep it above 1500 rpm to keep it running. My eyes are burning from the rich condition in about 10 seconds of running. The plugs were black. My first thought is a bad O2 sensor. I have not really had a chance to get the car hot and have been in/out of the garage a bunch of times. The O2 sensor sits at about 8 O'clock position. I know this is not optimal but don't have much of a choice. No exhaust leaks anywhere. It just stays locked at 15.9 no matter what. Any ideas?
No codes either. I have tried to reset it back to original specs also with the same results.
No codes either. I have tried to reset it back to original specs also with the same results.
Last edited by Gordonm; Jun 2, 2020 at 03:27 PM.
Advanced
Joined: Nov 2016
Posts: 95
Likes: 28
From: Southern MD
With the O2 sensor sending a lean reading the fuel injection will dump more fuel attempting to get the AFR down to the number it is set for. I would check to make sure that you are not drawing air into the exhaust at the o2 sensor attaching point or anywhere in the near vicinity on the exhaust especially upstream on the pipe.
Thread Starter
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
I have pulled the O2 sensor and checked the bung to make sure no pin holes. I have checked all the header bolts and looked for any little sign of exhaust leak. Nothing there. Bolts tight and no sign of exhaust leak.
Yes it is reading very lean that is why the computer is dumping fuel to try and richen the mixture up. So the computer is doing its thing but if the O2 sensor is just on lean and not reading the rich mixture that is coming out the pipes it will continue to dump more fuel in.
Yes it is reading very lean that is why the computer is dumping fuel to try and richen the mixture up. So the computer is doing its thing but if the O2 sensor is just on lean and not reading the rich mixture that is coming out the pipes it will continue to dump more fuel in.
Melting Slicks
Joined: May 2002
Posts: 2,717
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
have you checked the ref voltage to the sensor while the sensor is powered up?
I'm not familiar with this system, can it be put in open loop/SD to run off the base mapping?
Neal
I'm not familiar with this system, can it be put in open loop/SD to run off the base mapping?
Neal
Le Mans Master
Joined: Jan 2001
Posts: 6,743
Likes: 1,385
Check the continuity of the leads from the sensor all the way back to the connector for the ECU. I would check to ensure that the pins and receptacles at the connector are properly aligned and engaged. If that all seems good then take the sensor out and see if makes any difference if it is out in the open atmosphere (just to check reaction).
Race Director
Joined: Jun 2000
Posts: 10,046
Likes: 675
From: FL
Two things.
1) Check voltage. My FAST XFI had issues when my alternator could not keep a steady 14.2 to 14.4 V at idle. Replaced with an upgraded alternator. Seems like the FAST systems don't regulated a fixed 5V for the sensors but make it proportional to the input. So, if the alternator is weak at idle, the sensor voltages get screwed up.
2) Could be a bad sensor. It does happen. I just had one die after I did used a top-end cleaner (Sea Foam type) on the engine. Probably wasn't a good idea.
I did a little research on the sensor to find the OEM part. My XFI sensor is actually an NTK 24302 (Honda, Acura, Saturn) which was $100 at O'Reilly vice the $255 that FAST wants for the same part.
For the EZ-EFI, I found a thread on CPG nation where the EZ o2 sensor cross references from FAST 170408 to Bosch part# 0258007206.
$60 on Amazon.
May be worth a new sensor and some new plugs. Hope this helps.
EDIT: Info found here: http://www.cpgnation.com/forum/threa...numbers.18670/
and http://www.cpgnation.com/forum/threa...ce-info.25239/
EDIT 2: Comment on this thread. http://www.cpgnation.com/forum/threa...-street.40351/
1) Check voltage. My FAST XFI had issues when my alternator could not keep a steady 14.2 to 14.4 V at idle. Replaced with an upgraded alternator. Seems like the FAST systems don't regulated a fixed 5V for the sensors but make it proportional to the input. So, if the alternator is weak at idle, the sensor voltages get screwed up.
2) Could be a bad sensor. It does happen. I just had one die after I did used a top-end cleaner (Sea Foam type) on the engine. Probably wasn't a good idea.
I did a little research on the sensor to find the OEM part. My XFI sensor is actually an NTK 24302 (Honda, Acura, Saturn) which was $100 at O'Reilly vice the $255 that FAST wants for the same part.
For the EZ-EFI, I found a thread on CPG nation where the EZ o2 sensor cross references from FAST 170408 to Bosch part# 0258007206.
$60 on Amazon.
May be worth a new sensor and some new plugs. Hope this helps.
EDIT: Info found here: http://www.cpgnation.com/forum/threa...numbers.18670/
and http://www.cpgnation.com/forum/threa...ce-info.25239/
EDIT 2: Comment on this thread. http://www.cpgnation.com/forum/threa...-street.40351/
The wideband will die in a short time if runnng rich.
Last edited by SteveG75; Jun 2, 2020 at 10:22 PM.
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Thread Starter
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
I’ll check again today on voltage but I think i remember a pretty steady 13.4 to 13.6 voltage at idle once fired up. I did talk to Gordon Levy last night who built the engine and sold me the EFI. From the short conversation he said to try an O2 sensor. So I bought the Fast one from Summit for 96 bucks. The thing that makes me feel it is the sensor is it was running fine last fall. This winter I had the Z06 on my lift and the Cobra below. I pulled the heads on the Z so I had to move the cobra in and out of the garage several times to have access to the Z. So the engine never got warm. Just a start to move in?out. I’m thinking it got moisture on it and since it is not in the best location, no other option I figure it might have gone bad. Due to moisture. I have installed a new set of plugs yesterday and will wait for the O2 sensor to come in. I have reset everything back to where I started. I am going to check all the pins in the sensor also and wiring. Thanks for the ideas.
Last edited by Gordonm; Jun 3, 2020 at 07:52 AM.
Race Director
Joined: Jun 2000
Posts: 10,046
Likes: 675
From: FL
I’ll check again today on voltage but I think i remember a pretty steady 13.4 to 13.6 voltage at idle once fired up. I did talk to Gordon Levy last night who built the engine and sold me the EFI. From the short conversation he said to try an O2 sensor. So I bought the Fast one from Summit for 96 bucks. The thing that makes me feel it is the sensor is it was running fine last fall. This winter I had the Z06 on my lift and the Cobra below. I pulled the heads on the Z so I had to move the cobra in and out of the garage several times to have access to the Z. So the engine never got warm. Just a start to move in?out. I’m thinking it got moisture on it and since it is not in the best location, no other option I figure it might have gone bad. Due to moisture. I have installed a new set of plugs yesterday and will wait for the O2 sensor to come in. I have reset everything back to where I started. I am going to check all the pins in the sensor also and wiring. Thanks for the ideas.
Another thought, check all the connections. The other day, started to run a little off. Had 14.4V at alternator but computer was shown ~13.5 at ECU. Loose connections at the battery. Little things like that.
IMHO, the Holley systems have surpassed FAST. If I didn't already have a good tune, I would probably consider swapping over at some point to a Holley ECU.
Thread Starter
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
I was down to ~12.5 at idle between the dual Spals, EFI, and Aeromotive pump. Changing out the alternator really helped. Went with a Powermaster 140A unit.
Another thought, check all the connections. The other day, started to run a little off. Had 14.4V at alternator but computer was shown ~13.5 at ECU. Loose connections at the battery. Little things like that.
IMHO, the Holley systems have surpassed FAST. If I didn't already have a good tune, I would probably consider swapping over at some point to a Holley ECU.
Another thought, check all the connections. The other day, started to run a little off. Had 14.4V at alternator but computer was shown ~13.5 at ECU. Loose connections at the battery. Little things like that.
IMHO, the Holley systems have surpassed FAST. If I didn't already have a good tune, I would probably consider swapping over at some point to a Holley ECU.
C3. 427, 4-link, c7 z06
Joined: Sep 2019
Posts: 997
Likes: 207
From: Virginia
Hi Gordon,
im going back 10 years when mine was last running. Soon I should get it running again. A few thoughts below.
1. I went through several o2 sensors due to running rich while tuning. When drenched and car ones up they cause problems. It seemed like when they were cleaned up and dried out I could recycle them but I had 3 at one point that I would cycle through. A costly solution I know ...with the 2.9 self learning features my guess is that it is worse
2. I never did get mine to run right in sequential mode. My tuner attributed this to my high lift /duration solid roller cam. .670 and 246 at .5 I think?
3. I ran mine in Alpha N mode and it ran great but always a bit rich. O2 readings were stable as long as I kept a dry/clean o2 sensor in it. Again though. This was NOT the self learning system which I have since upgraded to.
4. I also had power falling off a bit early. 6k b or so. Could have been an airflow issue somewhere because my cam was too much for the heads I think.
not sure if this helps or not, but I’m following your thread.
im going back 10 years when mine was last running. Soon I should get it running again. A few thoughts below.
1. I went through several o2 sensors due to running rich while tuning. When drenched and car ones up they cause problems. It seemed like when they were cleaned up and dried out I could recycle them but I had 3 at one point that I would cycle through. A costly solution I know ...with the 2.9 self learning features my guess is that it is worse
2. I never did get mine to run right in sequential mode. My tuner attributed this to my high lift /duration solid roller cam. .670 and 246 at .5 I think?
3. I ran mine in Alpha N mode and it ran great but always a bit rich. O2 readings were stable as long as I kept a dry/clean o2 sensor in it. Again though. This was NOT the self learning system which I have since upgraded to.
4. I also had power falling off a bit early. 6k b or so. Could have been an airflow issue somewhere because my cam was too much for the heads I think.
not sure if this helps or not, but I’m following your thread.
C3. 427, 4-link, c7 z06
Joined: Sep 2019
Posts: 997
Likes: 207
From: Virginia
One other thought. Long shot. Maybe try To put ant amp meter on it? a different battery? I’ve seen batteries do weird things to electronics when going bad even if they have proper cranking amperage and voltage readings. Sorry if I missed this in your description.