Starter diagra

GMC guy

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#1
Please fill out the following to ask a question.

MAKE:
MODEL:
YEAR:
MILES:
ENGINE:
DESCRIBE ISSUE....
 

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#4
Yeah that darned viagra...but ok. 2010 g3 pontiac with standard tranny, 87k its a 4 banger. 1.6-or 1.7? This car has a fully charged battery. No fuel pump or pressure. Cant even hear the pump prime. Turn the key and nothing. I was able to get under and activate the starter with a screw driver but still no fuel pump. So what is deactivating the fuel pump and starter?
 
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nickb2

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#5
Start by checking power at fuses for fp relay and st relay. If juice there, bypass each relay at pin 30 and 87 of each relay with key on.

The ECM controls both the starter and FP relay signal to turn them on. SO if both fuses are good, and you are not getting power to pin 86 of both relays, then you will have to start there. Both these relays ARE NOT on a direct path.

As a matter of fact, I would check all the fuses that have the prefix ECU/ECM/EMS/IGN.

Also, check for codes, you may have something there to help you as a starting point. If the ECM sees a open or short in any of those circuits, it will or should code.

You may have several codes in several modules indicating no communication or such.

So start by putting a test light in the relay pin 86 of starter relay once you have determined it is not clicking when asking to start and all the above fuses are getting power.
 
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#6
Do all the other "normal things" happen when you turn the key to ON? If you've got lights, blower, window. etc, you may have a security system issue.
 

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#7
Start by checking power at fuses for fp relay and st relay. If juice there, bypass each relay at pin 30 and 87 of each relay with key on.

The ECM controls both the starter and FP relay signal to turn them on. SO if both fuses are good, and you are not getting power to pin 86 of both relays, then you will have to start there. Both these relays ARE NOT on a direct path.

As a matter of fact, I would check all the fuses that have the prefix ECU/ECM/EMS/IGN.

Also, check for codes, you may have something there to help you as a starting point. If the ECM sees a open or short in any of those circuits, it will or should code.

You may have several codes in several modules indicating no communication or such.

So start by putting a test light in the relay pin 86 of starter relay once you have determined it is not clicking when asking to start and all the above fuses are getting power.
Yup. When i jump 30 and 87 in relay sockets i get the fuel pump and starter function. Check engine light is not on. Tried to get codes. Cannot get a connection with scanner
 

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#8
Do all the other "normal things" happen when you turn the key to ON? If you've got lights, blower, window. etc, you may have a security system issue.
Yes. I get radio, blower and everything else. Just no starter and fuel pump
 

nickb2

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#9
Yup. When i jump 30 and 87 in relay sockets i get the fuel pump and starter function. Check engine light is not on. Tried to get codes. Cannot get a connection with scanner
Then you will need to probe the power pin of the DLC connector to see if your getting power to the scanner. Pin 16, lower right hand of connector is usually battery postive on most if not all DLC/obd2 connectors. Ground is usually 4 and/or 5, middle of upper row of DLC connector. So checking for power there check both for good ground and B+.

If no B+ there, check DLC fuse. In your case, it will be written OBD, f10, rated @ 10amp in the I/P fuse box.

One this is good, at least you know the starter and FP circuits are good as well as their components. This is sounded more and more like a ECM issue, but before we condemn that, need more testing.

Did you try the other tests I asked about, such and when you attempt to start with ignition switch/key. Are you getting signal at pin 86 ?

Although I like dan's idea that the theft deterrent may be on at this time, a scanner should still connect to the ECM.

So, if you have checked out all the fuses, and all are good, we are more and more looking at a fried ECM. If you have no power to OBD/DLC, and that wiring is good, I would for sure start looking at ECM connections for any sign of corrosion etc.

If you are getting power at pin 16, then you need to check can lines from DLC to ECM. That is the purple wire and the yellow wire. Pins 6 and 14 of DLC. Their respective wires at ECM differ in location depending on what package/trim G3 you have. You can get that with the RPO sticker in glove box or by calling your dealer with VIN#.

See following snapshot. Screenshot (177).png
 

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#10
Yes, i shall check pin 16 when i get a chance. And there is no alarm on this car. No power windows or anything. Key doesnt even have lock unlock. Im Working my full time job til tuesday. Will post what i find, then
 

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#11
There is no power at pin 86 when i turn to start. I still cannot get codes and there is power at pin 16. Fuses are good for dlc. Wiring is ok.
 

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#12
checked ems 1 and ems 2 fuses and they are both good fuses but no power to them. Ems 1 powers the dlc and fuel pump. But the dlc does have power To it...
 

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#14
Sorry for my limited english, but does flipped mean swapped in jargon?

If you flipped/swapped the ecm, which houses the code for antitheft, but yet you say it has none, I would look to a ECM compatibility issue. Cuz the fuel pump now goes, but no starter.

Something happened somewhere that that FP started up again. So half there, now just need it to crank. A step in the right direction at least.

:p;)
 

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#15
Yeah i changed the ecm, and fuel pump primes. I do have the other ecm if it has to go back in.