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P0102 & P0172 with symptoms

J

Jrs1987

New member
so like the title says, i have DTC's. here are the symptoms

i turn the key and it cranks for 5 to 10 seconds then turns over, after which time i have to hold the gas down to keep it running. after another 5 to 10 seconds i can SLOWLY let off the gas and it will idle fine. seems to drive fine after than except for a few random uncommon stalls. i can shut the car off after running it for ANY ammount of time and the whole process is required exactly the same way to get it running. cold or hot engin id doesnt matter, same results.

things i have changed:

plugs & wires,air filter, gaskets from the block up(very thurough cleaning durring the process). cleaned the injectors and electrically tested them properly (passed). baskets inside are squeeky clean. engine coolant temp sensor replaced. new front o2 sensor. rear o2 emulator as there is no cat anymore. IAC was cleaned with carb cleaner. FPR does not leak into vac lines.

after scanning the obd2 these are the parameters i get:
MAF is reading about 8-9 g/s @ idle
spark is about -22 degrees @ idle
ECT sensor reads fine.
TPS fine.
IAT is typical temp
O2 is varying from .1 to .9 @ idle
fuel system 1 says OL
fuel system 2 reads "--" im not sure what that means.

i feel like im missing other parameters idk.

this is frustrating me! PLEASE HELP!!!!!
 


OPlease read up on those codes on gearchatter.com and report back what the diagnostic aids say.

then please tell us what the codes are.. I think one is maf and the other is rich bank 1, but I'm not 100%
 
Ok, please read up on those codes as I suggested. You mention changing a whole pile of sensors and checking a lot of stuff. But you don't mention touching the maf or looking into the low input that might be causing the rich code.
 
i listed in the parameters my scan guage was telling me that the maf sensor was reading 8-9 g/s at idle which with my research i found is the readout of a properly working maf sensor.
 
also... thank you for the link. its extremly resourceful. ive been trying to find such a detailed diagnostic procedure for certain conditions for a long time.

do those procedures apply to any late modle gm or just the corvette and other v8 based vehicles?
 


They sure do. When I've checked those vs the GM manuals I have they are the actual GM manuals and for the codes we are talking about they are considered generic obd2 codes. So it applies 100%.

While your reading is showing as good for idle. There might be dead spots etc that are causing you to get the low input code. Without going and reading back up..I'm thinking low input means the pcm isn't getting a good amount of air reading from the sensor. Therefore the pcm might be overfueling based on the maf reading and that's likely causing the rich condition.
 
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