MAF Sensor Voltage reading odd

[ENDEVR]

Recently I’ve been having problems with my car, found some exhaust leaks and fixed them up,(car is completely returned to stock with factory tune currently) asked a tuner to look over some data logs and got “something is wrong” but not any help on where to look. Car has flashing CEL with misfire codes. On my data logs I’m running rich(hovering around .88 on B2 LTFT, sometimes as low as .7xx) checked over data logs and my MAF signal hovers around 2v at idle, with .8 lb/min, and at 2500 rpm anywhere between 5-6v and 10-14lb/min. is this normal? Something I should try and figure out? Or am I wasting my time? Everything I’ve read tells me this isn’t correct but I can’t find any specific info for our cars. If this is an issue, what should I be checking? I just replaced the MAF sensor and am still getting the same thing. Any help would be appreciated.

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[robvas]

Could be right, depends on engine load

 

[ENDEVR]

Could be right, depends on engine load

Reading the data log, it shows .749 load while at 5.9-6.0 volts, another section of the data log that was at the same voltage shows a .63 load

 

[robvas]

You sure you got rid of all the exhaust leaks?

Posting a datalog might be helpful.

Something is up if it's that rich.

 

[ENDEVR]

I haven’t smoke tested it yet but I took the exhaust manifolds off and back on 3x trying to repair it, right now factory is on and I used proper torque sequence and a torque wrench. Along with some gasket sealer between gasket and manifold but not between gasket and head. I’ve checked my IMRCs and replaced gaskets for the intake manifold, I’ve swapped injectors (upper and lower) I’ve swapped plugs and coils, I was looking over the logs to see if anything looked obvious and the MAF readings are the only thing that’s different from my original data logs (besides the running rich) I’ve got a compression tester coming now but I wanted to see if the MAF was wrong before going any further.

 

[ENDEVR]

Data log

 

[Pistol_91]

Bank 2 fuel trims look jacked up. Bank 2 is driver side. Misfire code you say? Have you looked at the spark plugs? Bank 2 o2 sensor? Weird looking log.
Have you asked the tuner, who tuned it, to look at datalogs for you?

 

[ENDEVR]

Bank 2 fuel trims look jacked up. Bank 2 is driver side. Misfire code you say? Have you looked at the spark plugs? Bank 2 o2 sensor? Weird looking log.
Have you asked the tuner, who tuned it, to look at datalogs for you?

Yeah these numbers are wild, that’s why I originally thought it was just an exhaust leak, it started as a cyl 6 misfire and grew from there to multiple cylinders. Including passenger side cyl 1. Changed out exhaust manifolds and down to just cyl 8 and sometimes 7, my spark plugs didn’t look terrible so I put them back in but swapped them all over to make sure they were all good.
I have asked my tuner, told him my issues and paid $150 and took some datalogs. Got left on “something is wrong” with no other details. I’ve been struggling for months going through the whole car. That’s why I’ve been focused on the MAF voltage and airflow in those data logs, everything says I should be at around 1v at idle and it hovers at 2v. That’s my best lead for an issue currently.

 

[Pistol_91]

How about the o2 sensor and/or wiring? The MAF should be fine, voltage isn't something that people typically change on a slightly modified coyote. If you had a MAF issue your car would run like complete shit from start to stop or not run at all. Let alone allow you to record a log.

A misfire is from bad combustion. Gas and spark create that. So, if there's something wrong with those 2, then you have an issue. The log is hard to get a grip on because of the constant on/off throttling. If that isn't what you're doing with the pedal, then you may have some sort of electrical issue.

If it were my car, I'd start with the o2 and either test the e85 you're using or putting 91/93 back in it for a bit.

 

[ENDEVR]

[/QUOTE]

How about the o2 sensor and/or wiring? The MAF should be fine, voltage isn't something that people typically change on a slightly modified coyote. If you had a MAF issue your car would run like complete shit from start to stop or not run at all. Let alone allow you to record a log.

A misfire is from bad combustion. Gas and spark create that. So, if there's something wrong with those 2, then you have an issue. The log is hard to get a grip on because of the constant on/off throttling. If that isn't what you're doing with the pedal, then you may have some sort of electrical issue.

If it were my car, I'd start with the o2 and either test the e85 you're using or putting 91/93 back in it for a bit.

One of the things the tuner did ask for was new O2 sensors. Put two new ones in right before that datalog I believe. That was me in the log. I haven’t driven it since this issue except around the block because I don’t want to cause any damage. Is there something else I should try while datalogging to simplify it a bit? I could also try putting in some octane booster? Maybe bad gas? I could always buy new plugs if need be. I think I might have a picture of the plugs I pulled. It currently has 93 in it now since I went put all the factory parts back on it including factory tune.

 

[ENDEVR]

Plugs from passenger side, I can’t find the other pics I took of them

 

[Pistol_91]

Check the gapping on those plugs...

Oh, ok so basically you have done everything you needed to fix this issue. Strange.

Are the o2 sensors you replaced, are they factory OEM sensors? I have bought aftermarket ones and had issues with them, but it was extremely obvious in a log. What cold air intake do you have? If you messed with the MAF sensor, are you SURE you put it in facing the right way?

 

[ENDEVR]

Check the gapping on those plugs...

Oh, ok so basically you have done everything you needed to fix this issue. Strange.

Are the o2 sensors you replaced, are they factory OEM sensors? I have bought aftermarket ones and had issues with them, but it was extremely obvious in a . What cold air intake do you have? If you messed with the MAF sensor, are you SURE you put it in facing the right way?

Oh yeah Motorcraft O2s DY 1443/1607
No CAI, 18 intake with high flow filter.
I believe i put it in the correct way, tab upside down with hot wire facing air filter

 

[Pistol_91]

I believe that's correct yes. Very strange indeed.

 

[ENDEVR]

I believe that's correct yes. Very strange indeed.

Agreed lol that’s why I’ve been struggling so much to figure it out.

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