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Discussion Starter #1
I recently went to my local car lube guys. They did their normal oil change, and I got a new air filter. I run 5W30, which they say they put in. Never change and never have issues. The next day I started having issues with my car not starting right up.
I went back and they're not really mechanics and not paid to be, they ran their normal check point and found nothing but low coolant and topped it off. The starting issue continued.
I've been to AutoZone and had them run a check on the battery and electrical. No issues there. The battery is a few years old but the car isn't having issues with the battery not working, etc. I've dealt with those issue before.
Has anyone else dealt with their G6 having a hard time starting? Specifically, the car doesn't sputter. It turns over, if I use the remote start, it continues to turn for about 5 or 6 full seconds before it finally starts. If I start it with the key, it turns and quits for about two and a half tries, before setting the third try.
This only happens after the car has been sitting for at least a few hours, such as overnight or during the day at work.
Once it does start, it can be shut off and after that it will start immediately like it used to normally.
The hard coincidence is that this did start directly after I had my oil changed...but there seems to be no reason that the oil would be causing this issues. It seems to me perhaps my quote lifetime fuel pump may be going out or needs a new filter, which after research I believe are both inside or near the fuel tank itself.
Any input here would be appreciated.
I guess I will have to break down, no pun intended, and see a mechanic.
 

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Have you ever replaced the fuel pump? If so, what brand is it?

The fuel filter is internal to the fuel pump. Whole thing has to come out and be replaced. Not like the pumps of yester year where you replaced a little sock on them and the filter inline somewhere
 

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Do you smell fuel or see a leak on the ground? That's common with the fuel pumps. Assuming a 3.5 V6? Unfortunately I can't give you any good news. Got a 06 G6 3.5 here on it's third fuel pump. Eats them like potato chips and i'm tired of it. Nothing makes sense on why it keeps doing that
 

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No smell or leak. Just started recently, almost right after I took it in for an oil change. Someone mentioned it could be my fuel pump relay in the rear fuse box. This is the first time I've had any issues with starting other than batteries needing replacement in the past.
 

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Discussion Starter #7
No check engine lights. No error codes thrown. Everything runs fine once it starts. No sputtering.
 

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What you have is a classic symptom of a fuel pump not being able to produce the needed pressure for proper performance . I suggest testing the fuel pump to see how much pressure it's putting out . I would do this ASAP before it fails totally and leaves you stranded .
 

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That's what I was leaning towards, as it seems to make the most sense. I will suck it up and find a mechanic to make sure that's what it is and see how much it's going to cost me.
 

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You may be able to test the fuel pump yourself for free . AutoZone will lend the test tool for free , then just locate the Schrader valve and connect it and have someone crank the engine over to get a pressure reading . I'm unsure of the location of the valve and the pressure spec but maybe AutoZone or another forum member can supply that , and a photo of the valve location for you . . :unsure:
 

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"That's what I was leaning towards, as it seems to make the most sense. I will suck it up and find a mechanic to make sure that's what it is and see how much it's going to cost me."
Well, yeah, how much would that even cost you nowadays?
 

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Since they replaced your air filter; check the connector to the mass air flow (MAF) sensor. It may not be fully engaged or they pulled a wire and you now have an intermittent issue. If you get the engine started, wiggle the connector and harness. Engine will stop once the ECM losses MAF data.
 

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Do you smell fuel or see a leak on the ground? That's common with the fuel pumps. Assuming a 3.5 V6? Unfortunately I can't give you any good news. Got a 06 G6 3.5 here on it's third fuel pump. Eats them like potato chips and i'm tired of it. Nothing makes sense on why it keeps doing that
Did you replace those pumps with ACDelco Pumps or some other brand? I suggest you use ACDelco. They cost more but they use better parts! Also keeping your Gas level at least 1/2 full most of the time helps cool the pump and keeps them from over heating.
 

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Wait a few seconds after you turn on the ignition, in order for the fuel pump to build pressure, before you turn the key to start. If this helps to start faster it may point to failing fuel pump. On some older Hondas the check engine light does not turn off until the fuel system builds proper pressure. Many of us wait for this to happen before we turn the key to start.
 

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Back in the day when aGM fuel pressure regulator had an diaphram leak it would flood the engine as it leaked down after shutdown . If the car sat for an hour or so it would have extended crank times on the first startup and be fine after that if you started it right away or left to sit for several hours where the fuel would evaporate. Fuel would leak through the vacuum hose into the intake manifold. If your fuel pump was bad it would just never start. Throw a fuel pressure gauge n it and watch the pressure at startup and see if it drops slowly after shutdown.
 

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Did you replace those pumps with ACDelco Pumps or some other brand? I suggest you use ACDelco. They cost more but they use better parts! Also keeping your Gas level at least 1/2 full most of the time helps cool the pump and keeps them from over heating.

First was a Airtex. Barely lasted. Second was a Carter (recommended by someone who fixes GM's) the first had a broken fuel level float, so it got warranty swapped. Second one worked fine until it started whining and idling like crap,rpm's surged and then dropped and you had to floor it to get over a hill and points beyond.CEL also flashed indicating a horrendous misfire.

Truly at wit ends with this garbage. I've had folks say delphi is garbage (pump got replaced when bought as it stank like raw fuel and was pissing it on the ground, classic failure of cracked tubes and naturally GM did a recall for every other model but a G6 with the same issue) Airtex is garbage, Carter is good but now trash, Now AC-Delco is good (rebadged delphi???)

Rear fuse block might be causing issues is other information i've read, but since it's a $200+ part i'm not going to blow money on a vehicle that is amounting to a money pit with a poor resale value. Taking it apart and analyzing it showed nothing internally least I drill out the Rivets which destroys it... Ugh

(Rock Auto shows Ac Delco pumps which have "AFCO" stickers on them, (Bosch/Denso joint venture) a internet search turns up that the company shuttered it's doors in 2018. So now there are pumps on the market with no recourse except keep swapping the junkers until something works or the stock runs out?

And I thought pt cruisers are unsufferable with their issues. Hah
 

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Well, you are the first person I have heard of that has had this many problems with a Fuel pump! If I were you, I would be looking for electrical connection problems causing a large Voltage drop somewhere! From the Fuse panel to the connector at the Tank! I would bet you are not getting enough Voltage and current to those pumps! A low Voltage condition will cause them to run hot! Measure Voltage, and Voltage Drops at every point. Clean every connector socket and pin with WD-40 Electrical Contact Cleaner and then apply dielectric grease!
 

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Well, you are the first person I have heard of that has had this many problems with a Fuel pump! If I were you, I would be looking for electrical connection problems causing a large Voltage drop somewhere! From the Fuse panel to the connector at the Tank! I would bet you are not getting enough Voltage and current to those pumps! A low Voltage condition will cause them to run hot! Measure Voltage, and Voltage Drops at every point. Clean every connector socket and pin with WD-40 Electrical Contact Cleaner and then apply dielectric grease!
That's the confusing part, those have been accounted for. Even got new wiring because of the fuel pump harness changes. No burned/bubbling/etc wiring in the distribution block located in the trunk.

As this forum has mentions of 05-06 G6's having electrical issues, i'm off to a junkyard wednesday armed with part numbers for a "newer" fuse block hoping that solves the issues. So far they seem to have newer part numbers out there, which I am not sure if that means just a supplier change or they fixed some screw up silently and didn't bother telling the customers/owners.

I come from the ford corral where part number changes could usually easily be decoded down to "the supplier just changed" or "oops, we screwed up and did a major revision on the part" No idea in the GM corral.

While the butt end is in the air,going to go through the wiring yet again.

In the mess that is this project also around the time we purchased the vehicle and got the fuel pump replaced due to a cracked line, I could swear there was a code set for the evap system not working. One of the PXXX codes. Now no matter what is done, the Evap system will not set the codes in the OBD-II system readiness monitors.

As the state here allows one failure code due to the age of the vehicle, (straight from the dmv smog tech test book) I ignore it. Is there some possibility this could be killing the fuel pumps also?
 

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I suppose anything is possible but I have never heard of an Evap system damaging a fuel pump. You might need a better scan tool to give you more information? Did you go to a shop and get a print out of the code information or did you use a tool at an auto parts store or your own? If you have replaced the cable to the pump and the connectors checked out okay on both ends then I guess the fuse block is the next step. Do you have a schematic of the Fuel system? Did you make sure the Fuel Pump Relay is allowing full voltage with no drop across those contacts? You can measure Resistance if you can pull it out of the circuit and apply Voltage to the coil. You should be seeing Zero Resistance across those contacts. I do not know how you tested things and what kind of test equipment you have. Did you check for Voltage out of the PCM? If all the components check out okay then you might have a problem with your PCM! It is all a process of testing and elimination.
 

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I suppose anything is possible but I have never heard of an Evap system damaging a fuel pump. You might need a better scan tool to give you more information? Did you go to a shop and get a print out of the code information or did you use a tool at an auto parts store or your own? If you have replaced the cable to the pump and the connectors checked out okay on both ends then I guess the fuse block is the next step. Do you have a schematic of the Fuel system? Did you make sure the Fuel Pump Relay is allowing full voltage with no drop across those contacts? You can measure Resistance if you can pull it out of the circuit and apply Voltage to the coil. You should be seeing Zero Resistance across those contacts. I do not know how you tested things and what kind of test equipment you have. Did you check for Voltage out of the PCM? If all the components check out okay then you might have a problem with your PCM! It is all a process of testing and elimination.
It was just basic testing with a multimeter. Have a grey market GM Tech II here actually, but aside from differences like the fuel trim and all that it spit out the same error codes as a plug and play code reader.

This is what the plug and play reader spit out when it was revving high and barely getting out of it's own way:

(Have no way of using the tech II on it currently, I pulled the battery and analyzed the fuse panel in the back trunk for any visible signs of melted wires/other issues. Blew dust out of it)

Thanks for your help. Currently i'm compiling part numbers on fuse panels and hitting two junkyards to harvest them and hope that eliminates some/all of the issue. I did replace the MAF sensor, that code keeps flaring up which makes no sense. Brand new AC Delco part and it's still throwing codes? ugh

P0174
P0171
P1111
P0113

Fuel Sys 1: CL
Fuel Sys 2: CL
Calc Load (%) 37.3
ECT (F) 190
STFT B1(%) 0.0
LTFT B1(%) 21.9
STFT B2(%) 3.1
LTFT B2 (%) 21.9
MAP(inHg) 13.3
Eng RPM 835
Veh Speed (mph) 0
Spark ADV (Degrees) 26.5
IAt(F) 154
MAF(lb/min) 0.9
TPS(%) 15.3
Command EGR(%) 0.0
EGR Error (%) 0.0
Command EVAP(%) 0.0
Fuel Level(%) 76.1
Warm-up DTC Clr 128
Clr Dist (Miles) 1937
Evap VP(InH20) -2.053
BARO(InHg) 13.3
Cat Te 11(F) 1201
CAT Te 21 (F) 1201
ECU Volts (V) 13.195
LOAD Value (%) 28.2
EQ Ratio 1.004
Rel TPS(%) 5.1)
Ambient (F) -33
TPS B(%) 15.3
ACC Pedal D(%) 0.0
ACC Pedal E(%) 0.0
Command Tac(%) 15.3
 
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