Two issues on V-6; pinging under load with 91 octane and hesitating from idle (no load).

well, i guess its good to look at the calculated and measured MAF readings. calculated, your truck was compensating for more air intake than your MAF was reporting. usually that's a vacuum leak issue. but in this case, hey, bad MAF!

 

Hungover does not count as being sick.

It might be interesting to run a test comparing resistance on the old unit to the new one. With full voltage, no flow, then with measured air hitting the film, say from a air nozzle on a compressor. The resistance should drop at a similar rate if good, if not the old one will drop less/slower.

 

I CANT HANDLE THE ANTICIPATION

 

I drove a bit more tonight. Like 20 miles. The jury is still out on the pinging issue, but I think the hesitation problem has been resolved.

Here are some old MAF sensor / new MAF sensor comparisons. I forgot to do 2500 RPM no load but you get the idea.

Notes:

• Trims are much closer to zero with new MAF. I don't think I've seen any double-digit readings yet.
  
• Both trims are almost always at 0.00 under load with the new MAF sensor.
  
• MA g/s readings are about 30% lower with new sensor at idle. I think this explains why the ECM had to lean down the mixture so much at idle before; the old MAF was overstating the airflow big time.

Old MAF Idle:


New MAF Idle:


Old MAF ~ 65 MPH on freeway:


New MAF ~ 65 MPH on freeway:

 

I like those fuel trims now!!!!!! did you clear your DTCs with a scanner after swapping? not for re learning process, but for emissions. it takes a few days or even weeks for the emission system of our trucks to go through a self test phase. that's all you may need to wait on for an official word on how it's doing.

however, your readings are still suggesting that there is a slight vacuum leak (and very minimal of one). did you change the fuel filter yet? is yes, look for the vacuum leak. if no, replace and report back.

 

If DTC's = CEL / trouble codes, no, because I never had any.

Have not done anything else besides MAF because I've been sick.

 

oh, DTCs are more than what can cause a CEL to turn on. they also contain the info for the fuel trim matrix and emissions self testing in the computer

you can read up on the OBD readiness monitors here (which are the emission self tests i spoke about). I didn't look through it but im hoping the title is accurate in what it talks about.

look at the section for non-continuous monitors.

 

Wow. The more I know, the more I realize I don't know.

I don't think my Ultragauge can play in that arena. So I guess I'll just need to do a whole bunch of daily driving and see what happens?

 

or off roading? but yes. more driving

 

Roger.

I'm not working this week but by the end of next week I'll have plenty of new miles on her.

 

any news?

 

Now who WAS that guy who has been saying MAF sensor since the start? Oh yeah, That guy ^^^^


By the way, these issues are exactly why I like my MaxiDAS scan tool instead of an UG to diagnose issues like this. I can get live, raw data from it. This way I can watch active changes as it occurs. But I admit I DO love my UG for general driving around. lol. Plus with the big tires and the new gears I need it to tell me the correct speed I am going! haha.

 

Today is my first day back to work. So not a lot to report. However:

- Hesitation is ~75% gone
- Have not heard her ping yet, but I have not driven her in hardly any relatively warm weather
- Ultragauge looks like it needs to be recalibrated as it appears to have underestimated my MPG going to work today (I typically get 21 to 22 in the winter and almost 23 in the summer, VERY CONSISTENT) and got less than 20 today). I'll redo the calibration procedure over the next few tanks.

Fuel filter is supposed to arrive this week. The stealership wanted $53 and it would have required two trips there (one for the deposit and one for pickup) so I paid $36 to have one delivered to my front door.

 

Ya mon. Good call.

 

Good news so far! Great to hear!

 

Another satisfied customer.

Call BMA Auto for those parts, i got an OEM filter for less than $20.

 

I still haven't cracked 20 MPG on my morning commute. But the 'remaining gallons' on my Ultragauge seems to be out of whack with my fuel gauge, showing more in the tank than the Ultragauge estimates. So I am hoping it's a calibration issue. Otherwise this 'fix' is taxing me with a ~10% hit to my fuel economy.

I also still haven't heard a ping, but it's been fairly cold (less likely to ping) and wet (less likely to hear a ping). But certainly she's not pinging in second gear like before and I would definitely hear that even with a wet road.

By now I am probably close to 87 octane in the tank as my last two or three fill-ups were 87 octane and I refuel when it's around 1/4 of a tank. Good news. But saving 6% on my gas won't make up for a 10% hit in MPG's!

 

Have you installed the fuel filter yet or are these just your findings after the new MAF?