1998 Lexus GS400 - P0172 - Runs Rich
#34
Maintenance Moderator
iTrader: (2)
again, I know how weird it is, but sometimes its just how they are... I'm sure if we were to look deep into the toyota programming, it might be evident why, but that is way too much work...
#35
Hate to say it, but the CEL came back today. Same P0172 code.
After reading through this thread, I'm wondering if it is the fuel pump starting to go?
https://www.clublexus.com/forums/gs-...n-problem.html
The car starts hesitating and barely starts after its been driven for a while.
After reading through this thread, I'm wondering if it is the fuel pump starting to go?
https://www.clublexus.com/forums/gs-...n-problem.html
The car starts hesitating and barely starts after its been driven for a while.
#36
Lexus Test Driver
iTrader: (22)
Hate to say it, but the CEL came back today. Same P0172 code.
After reading through this thread, I'm wondering if it is the fuel pump starting to go?
https://www.clublexus.com/forums/gs-...n-problem.html
The car starts hesitating and barely starts after its been driven for a while.
After reading through this thread, I'm wondering if it is the fuel pump starting to go?
https://www.clublexus.com/forums/gs-...n-problem.html
The car starts hesitating and barely starts after its been driven for a while.
#38
Maintenance Moderator
iTrader: (2)
I know you tried a different mass air flow, but there are only two real options at this point - the computer is reading too little air or fuel pressure is way too high...
by your scanner, what is your airflow in grams / second? (or any other measurement besides hertz)
need idle and 2500 rpm...
#40
I'm really leaning towards the fuel pump. When I start the car after driving home from work (25 miles), it'll barely start and stay at 200RPM for a quick second, then bounces up to normal. Also, when the car is warm and has been driven for a while, when I initially press on the gas, the RPM will go up, go down a few hundred RPM, then back up.
#41
Maintenance Moderator
iTrader: (2)
nope, not the fuel pump... at least not based on those numbers
your idle lb/min is good, however at 2500 rpm in neutral, should be significantly less than where you are at...
convert to g/s, and you are at 4.5 g/s idle, 28 g/s at 3000 rpm... at 2500 rpm, you should be reading 16 g/s... granted your number at 3000 should be higher than at 2500 rpm which is where Lexus publishes their specs at, but you are way more than where you should be...
your idle lb/min is good, however at 2500 rpm in neutral, should be significantly less than where you are at...
convert to g/s, and you are at 4.5 g/s idle, 28 g/s at 3000 rpm... at 2500 rpm, you should be reading 16 g/s... granted your number at 3000 should be higher than at 2500 rpm which is where Lexus publishes their specs at, but you are way more than where you should be...
#42
Lexus Test Driver
iTrader: (22)
That's actually live data, not freeze frame. But base on that data you have given, I doubt it's the MAF sensor. My educated guess is since it's rich on both banks, I would check fuel pressure to see if it's high and make sure the EVAP purge valve is not stuck open. That's all I can offer over the internet. GL man.
#43
That's actually live data, not freeze frame. But base on that data you have given, I doubt it's the MAF sensor. My educated guess is since it's rich on both banks, I would check fuel pressure to see if it's high and make sure the EVAP purge valve is not stuck open. That's all I can offer over the internet. GL man.
I am only looking at a P0172, which is a bank 1 only code. I will check the fuel pressure today after work and will report back with my findings.