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Discussion Starter · #1 ·
Hi First of all i'm not sure this is the correct forum for this question, in case is it not please correct me.

I'm comming to you because after 1 month and a half my car is still running pretty bad. It is an Impala SS 2007

The SES is on and the codes are as follo:
P0106 (map)
P0171 (bank 1 lean)

The symptons are as follow:

Sometimes it will just keep cranking and cranking for 5 seconds or more sometimes starting, sometimes not, for the second try it always starts; it doesn't matter if the is cold or fully warmed, just shut down or sitting all night.

The Engine will not sustain idle for more that 5 minutes without stalling, the moments before stalling the rpms will start to bounce between extremely low and normal until it finally shuts down. It will restart no problem. If you turn on the A/C it will take a lot longer to start showing sings that it is going to stall.

If you are driving the engine will not stall or act strange.

Parts Replaced until now:
Map (New AC Delco)
MAF (New AC Delco)
New Air Filter (Millard)
Reapired the wiring going to the map according to a tsb (i don't recall the number, the new cable portion was soldered and taped, the old wires were in fact showing the interior cooper strings)

Parts Checked:
All fuses OK
All Relays Ok
Fuel Pressure Between 55 and 48psi
No other cable injuries found
Grounds OK

I'm lost, i have alredy spend a lot of money and not the dealer or various shop have fixed the problem. Please HELP ME.

Thanks in advance for your advice
 

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Makes your VISION, stop & stare
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Discussion Starter · #3 ·
Thanks for your response, I Actually change the map and maf for new AC delco units and nothing change. Cleaned the connectors really well and still nothing.

In the dealer and shops said that they tested the sensor and parameters with the engine running and said it was ok.

Do you know where i could get a FSM for this car? (In Venezuela we doesn't have chilton or hayness and we have to default to downloaded FSMs).
 

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Makes your VISION, stop & stare
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have you checked for vaccum leaks? most of the time it will cause sputter and throw codes.

check pcv valve and leaks at the IACV. check line leading to the MAP sensor and to the manifold.
 

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Makes your VISION, stop & stare
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also when you replaced the MAP and MAF. did you disconnect the battery to reset the codes? if not then the computer is going to read as if the parts were never replaced.
 

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Discussion Starter · #7 ·
Yes, after replacing all the sensors the battery was disconected for abouth 10 minutes and the key was cycled.

Ok i will check the pcv valve, the vacuum was checked in the shops and they all said there were no leaks, and alla the cylinders have compresion values in the same range (repeating their words).

Thank you very much.

Buying it in us currency is out of the question this year because we only get to use 400$ a year in online shopping and i alredy spend mine :gaah:
 

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Makes your VISION, stop & stare
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your welcome hope you get your problem fixed.

did you solder the map wire yourself or did a shop do it?
if sent to a shop why didnt they resolve the problem? was it a quick test?
 

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Makes your VISION, stop & stare
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i say take it to another shop and get a second opinion.
 

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Discussion Starter · #10 ·
Hi how are you? Thanks for your responses. Some updates from todays's work so far, I tigthened the Intake manifold bolts (they weren't loose but adsolutly not tight) disconected the hose from the pcv system (it doesn't have a valve, how do i clean it?) makig sure to plug the hole in the manifold.

With this the car ran A LOT better, so far it's strating in the firts try. The rpm are bouncing but way less than before and in about 80 mins of running time (yeah gas is pretty cheap here :roll: ) Only shut down 1 time.

It has been alredy to 2 shops and a dealer (nobody found the reason) but these cars are pretty rare here, where only sold for 1 year and are the only ones with a ls4 in the national market so the mechanics are to experienced with then.

The map cable was soldered by my brother (he is a telecom engineer and knows his way with small cables and soldering irons).
 

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If it runs that much better just from tightening the intake manifold bolts, I'd guess you found the problem. A loose intake is a severe vacuum leak. I'd get the gaskets redone at this point.
 

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Discussion Starter · #12 ·
thanks for the advice, i was thinking of doing that but firts i'm going to try and clean de pcv orifice because today i changed the hose leading to it because it was showing some cracks and the rpms are bouncing less but i can hear some sort of whistle coming from where the hose connects to the pcv orifice.

Also i think that i have 2 diferent issues and the extended cranking time might have to do with the fuel pump. Do you by any chance have the reference values for fuel pressure? I cannot find a concrete answer on the internet (yes i searched quite a lot). Thanks in advance.
 

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Fuel pressure should be about 47-50psi, engine running or not.
 

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Discussion Starter · #15 ·
Update: For anyone having this or similar problems, it turned out to be the injectors o rings were toasted and they would let air get past them leaning out the engine and causing all the issues i was having.
 

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Wow, glad its figured out!
 
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