Any codes, or just the idle miss?
What did you do to your NNBS GMT900 Tahoe/Yukon Today?
- Thread starter phattyford
- Start date
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.99 cents each, less than 1 cent each? LOL
$11.88 + 9% tax that usually last's me about 3 months roughly, 2 bottles per truck on a full tank, usually filling these things up about once a week give or take.
I take turns on them drive one then drive the other one the next day, roads trips usually in the Yukon, I want to buy a G8 GXP, maybe a SS if the price is right but I like the Pontiacs more.
No codes, just the miss. And it’s only occasional and brief. Never persists more than a second or two. I can’t replicate it on demand.
you could hook up a scanner and see if there is any actual spark miss going on, then maybe check the fuel pressure just to verify it's good at idle, if there is no issue then I would just clean up everything and do the injector service, if that doesn't fix it maybe move on to basic tune up, plugs, wires, if it persist's and is not a spark miss then maybe replace the throttle body.
if there is a spark miss it could be plugs or coil packs, injector, or the harness, vacuum leak, cam sensor. and worst case scenario internal engine damage.
i'm probably missing something and if it's running fine otherwise then it's probably something simple
what is the mileage? after about 160k the maf's are questionable in my book and should be replaced those things can do all kinds of stupid stuff, make the engine run like ******* and cause the transmission to shift weird among many other things.
Have you had the plugs out? I had a low idle miss that seemed to come and go, also no codes. It turned out my plugs had gotten fouled from oil consumption, a few much worse than others. In my case it was the whole AFM relief valve, down rev valve cover, that lead to a downward spiral of oil consumption and the miss was just the canary in the coal mine of bigger issues.
Not saying that is that case here, might just be a marginal plug, wire or coil pack.
As @Doubeleive mentioned, a cheapo ODB scanner might allow you to isolate which cylinder(s) has the miss. You could just sit and watch the counter increment as you felt the miss.
So, today I got some more information. I don’t know yet if this is the same problem causing the idle miss or an all new separate issue.
Truck runs fine all morning, then way back in the mountains on a dirt trail in 4 Low it starts stalling and the MIL comes on.
P069E status $07E8 Fuel Pump control module requested MIL.
P0191 status $07 EB Fuel Rail pressure sensor circuit range/performance bank 1.
P0171 status $07E8 system too lean bank 1.
I was able to limp it out a mile or so by intermittent rest after it stalled. Each start it would start out running OK and within a minute progress to stumbling, losing power, and ultimately stalling again. This behavior had me thinking it was heat related.
Once I got to a better piece of trail I took a longer break. Opened the hood to vent heat; hosed down the FPCM with brake cleaner to chill it.
After that I departed in 4H and with enough travel speed to help cooling. No further problem 60 miles back home. Over mountain passes where it was WOT at times, and interstate speeds. So it’s absolutely not a clogging filter or inability of the fuel pump to deliver.
???
Truck runs fine all morning, then way back in the mountains on a dirt trail in 4 Low it starts stalling and the MIL comes on.
P069E status $07E8 Fuel Pump control module requested MIL.
P0191 status $07 EB Fuel Rail pressure sensor circuit range/performance bank 1.
P0171 status $07E8 system too lean bank 1.
I was able to limp it out a mile or so by intermittent rest after it stalled. Each start it would start out running OK and within a minute progress to stumbling, losing power, and ultimately stalling again. This behavior had me thinking it was heat related.
Once I got to a better piece of trail I took a longer break. Opened the hood to vent heat; hosed down the FPCM with brake cleaner to chill it.
After that I departed in 4H and with enough travel speed to help cooling. No further problem 60 miles back home. Over mountain passes where it was WOT at times, and interstate speeds. So it’s absolutely not a clogging filter or inability of the fuel pump to deliver.
???
RooTBeeRthe1st
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Very peculiar
swathdiver
Full Access Member
Some bad fuel was my first thought until seeing this post with the fuel pump related codes. Have the Tech-2 run an injector test, maybe one got stuck or something.
my guess is the fpcm or fuel pump is becoming problematic
might want to pick up a fuel pressure tester, there cheap like $30 at harbor freight, you should have a I think a minimum of 42-43psi at idle but most will run a tiny bit higher like 45-50 or so if normal.
the fpcm harness are known to get corroded, might want to get under there and inspect it, pull the harness off and clean it up if needed.
might want to pick up a fuel pressure tester, there cheap like $30 at harbor freight, you should have a I think a minimum of 42-43psi at idle but most will run a tiny bit higher like 45-50 or so if normal.
the fpcm harness are known to get corroded, might want to get under there and inspect it, pull the harness off and clean it up if needed.
that lean code would indicate low fuel pressure so would the miss
Yeah I am thinking wiring fault, bad connection either with the FPCM or the pressure sensor because of the sensor code. And if the control module can’t get an accurate pressure, what does it do then? Worst part is it’s intermittent. You can’t fix what isn’t broken. Could also be the module is heat sensitive.
And I am constrained in my options for diagnosis and repair. Summers we travel and mostly live in RV parks. Vehicle repair is usually discouraged or forbidden on the premises. So when we’re on the road I have to outsource things I would DIY at home.
And I am constrained in my options for diagnosis and repair. Summers we travel and mostly live in RV parks. Vehicle repair is usually discouraged or forbidden on the premises. So when we’re on the road I have to outsource things I would DIY at home.
Is your fuel pump original?
you could check and clean up the fpcm harness anywhere, walmart parking lot, that's the first thing I would check, testing the fuel pressure is just a screw on valve I think it's called a Schroeder valve on the fuel rail, the fuel pressure tester will come with a couple different universal fittings. $30 diy and you can monitor it for as long as you need to
testing the fuel pressure will tell you if the sensor is working properly or not, I would use a scanner and the tester at the same time and see if they match up, if the fuel pressure is good with the tester and the sensor is giving erratic readings then you know. the only catch is the stupid sensor is only $25 or so......
Seems right to me. The FPCM is known to get water inside it and wreak havoc. A few of the YouTube regulars seal new ones up with RTV before installing them.
If you do get an analog fuel pressure gauge, it should run pretty consistently on the rail at 43 PSI +/-. If the pressure varies widely with load changes, pretty likely the pump. I bought this one a while back, it is a surprisingly good piece.
Amazon.com: Actron CP7818 Fuel Pressure Tester Kit,Black: Automotive
Buy Actron CP7818 Fuel Pressure Tester Kit, Black: Fuel Pressure Testers - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
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I think mine is this one or one just like it
Amazon.com: FAERSI Fuel Injection Pressure Test Kit - Universal Fuel Oil Engine Diagnostic Gauge Tester Set with Fittings, Instructions, Storage Case for Car Motorcycle Truck RV SUV & ATV, 0-100 PSI / 0-7 Bar: Automotive
Buy FAERSI Fuel Injection Pressure Test Kit - Universal Fuel Oil Engine Diagnostic Gauge Tester Set with Fittings, Instructions, Storage Case for Car Motorcycle Truck RV SUV & ATV, 0-100 PSI / 0-7 Bar: Fuel Pressure Testers - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
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Tonyrodz
Resident Resident
Cheaper then HF.
I bet you could check the fuel pressure of a Moto Guzzi with that kit!
ya it cover's old school and new school for the most part, I was going to try and test my neighbors lexus with it but would have had to cut the fuel line stupid thing didn't have port on it and it was routed all weirdI bet you could check the fuel pressure of a Moto Guzzi with that kit!
it is if you don't have to pay tax and buy something else to hit the minimum free shipping total, I don't use "prime" but I do have a resale account so no tax
these cookies usually do the trick
