Lots of issues w my 13’ TRD Sport - lean banks 1 and 2, rough idling multi misfires

Hey guys

I am working on getting this truck ready for inspection. Had a faulty purge valve but replaced the solenoid and I can now command open and close the new valve (I couldn’t command the previous valve closed) and this resolved the incorrect purge flow code. I havent performed a fuel pressure test yet, and while watching my fuel trims I do not see a drop while accelerating- my LT trims are reaching 40! Short term are in the norm.

The lean issue has been going on for a while now and im now seeing random multiple misfires - and sometimes when I try to take off it doesnt want to move and when it finally does I hear a fast ticking sound from somewhere in the undercarriage - it speeds up as I finally do. I havent noticed issues starting the vehicle, my plugs were changed around 30k miles ago, I cleaned the throttle body about a year ago and my MAF sensor again recently - a few things showing in the red on my scanner are:

absolute throttle position @ or around 16%

Absolute throttle position B @ or around 48% ( normal range for both shows 0-14%)

Actually right now at idle my ST trims are high - when it misfires or idles rough they jump to anywhere between 15 and 20%.

any suggestions where to start?

thanks

 

New spark plugs and tube gaskets, maybe.

 

While driving my MAF air flow rate jumps each time I hit the throttle its jumping to anywhere between 100 and 300 lbs

 

I’d be surprised if you haven’t done plugs yet, but if you haven’t definitely start there. I would do wires coils plugs if you’re not sure when they were last done. Good preventative maintenance. That’s like $300 for OEM. Then I would check injectors. Good luck.

 

I did the plugs about two years ago at 130k im now approaching 165k.

the lean condition started long before the misfires could they be related ? I am trying to figure out if fuel delivery could be causing the lean banks and the misfires. There are no leaks presently so I am wondering if a bad MAF or Throttle Body could be causing the lean condition and how that could lead to misfires.

I wouldnt think the issue would be related to the not so old plugs but I will have to rule out air intake and fuel delivery first

 

Ahh I doubt it’s the plugs then unless they looked really bad/burnt when they were replaced. In that case I would remove the coils one at a time and see if you can eliminate them as the issue. Probably go through the MAF and TB, maybe replace the former if you cleaned it a year ago?
It’s not throwing any check engine codes?

 

I wouldn't start replacing anything yet, really need to check fuel pressure both at idle and under load (should be about 41 psi).
If that checks good then do a VE test to see how the MAF sensor is doing.

To do a VE test you want to record MAF, RPM, IAT, and BARO. Do a WOT pull through 1st gear, record the peak MAF (you will need to convert it to lb/min or g/sec) and RPM readings, and put those numbers along with the IAT and barometric pressure recorded during the pull into the calculator linked below.
Typically you want to see 90%+ VE if everything is working properly.
https://atgtraining.com/atg-volumetric-efficiency-calculator/

 

thanks I ran that test earlier and ran to advanced auto and an grabbed an OEM Denso MAF and ran the test again with much better numbers. The pic is the first. Im going to check fuel pressure tomorrow am im also going to inspect the throttle Body as those numbers ate still off. I am not sure if absolute throttle position B at idle being almost 50% at idle is a problem or not but im guessing it is. I dont have any sensor codes for the TB.

Thanks again for the help you guys rock!

 

I lied. I did not do that in first gear

 

Hey man

No codes for MAF or TB or related sensors
Just lean codes, rough idle
And mow misfires. Seen cylinder 1 2 5 misfire earlier

 

I wouldn't get overly concerned with throttle percentages or the standard ranges the scan tool shows (those are often not very accurate), you need to figure out why it's lean first. Your over +40% total fuel trim (40-50% is typically the limit) so I really suspect a fuel pressure issue.
You will need a gauge that tees inline like the one below.

$31 BETOOLL Fuel Pressure Test Kit 0-100PSI with 9.497.896.30 Fuel Line Fittings

https://www.amazon.com/BETOOLL-Fuel-Pressure-0-100PSI-Fittings/dp/B07LF26ZTJ?th=1

 

Ok! Thats the gauge ive got ill report back with the values.

 

Yea if your not in fuel control you will have misfires and a rough idle as the PCM isn't able to add enough fuel to the base fuel map to properly run the engine.

 

I tried to perform the fuel pressure test, but the kits quick connects look like theres a lip missing, unlike the feed line on the truck which has two lips and secures the connection pretty tightly. When using the kit, you can easily separate the quick connection female connection w the tabs from the male end that has only one lip. Is that sufficient enough to be pressurized and not allow any leaking?

 

You have a pic of where your trying to connect?
The last one I did I put it between where the line connects to the frame.

 

thats the one. Theres two lines let me tajw sone pics

 

This is the one. And if you look at the bottom
Where the quick connect comes off theres two lips yet this connector only has one. I didnt feel it was connected enough to start the engine

 

I was thinking this was how I going to connect it

 

Are you talking about the safety latch that goes over the top?
If the tool clicks on and you can't pull it back off without depressing the tabs it shouldn't come off.

 

Yes. It doesnt latch as it does when I reconnect the lines in the truck. Im certain the correct link that comes with the pressure kit is the 7.68
I believe it is?