jcdubya1

06 SRX 4.6L HELP!! Backfiring wont rev. only 37k miles

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Hey guys, New to the Site. But Thanks for having me. I bought a 2006 SRX out of California. It has 37K miles on it, owned by an elderly woman who quite driving it after it broke down. She was driving and said it made a terrible sound or cough i assume backfire and died she had it towed and didnt want to pay Cadillac to fix it because over the phone they said it could be 11000 for a new engine. Well the Car starts with a little throttle and will run. but terrible. Backfires out the intake at low RPM when Revved it seems to clean up just before the limiter. Codes on the car have only been for a MAP sensor. I replaced the MAP MAF CAM sensors and cleared codes, No codes will return. But still runs the same Way. I can Unplug the WHOLE LEFT DRIVER side bank of coils at an idle and no change to the way it runs. Checked all the fuses, GOOD for maybe the IDM but to no avail. Ran a Compression check on left bank 125 across the board. Gauge is a little funky but they were consistent. Running out of options Fuel pressure GOOD. New plugs Swapped coil packs. Nothing. TOOK it to Cadillac and had them Do the FUEL MAP UPDATE in the ECM nothing....... ANYONE SEEN anything like this. TIA

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Check the fuel pressure regulator.  It is attached to the fuel rail.  Pull the vacuum hose off and rev the engine with a white index card in front of the nipple, if it spits fuel replace it.  A bad regulator will dump fuel causing backfires like that.  Let us know what you find.  

This could be a leaky injector also.  See if you can lift the fuel rail, support it and pressurize it by having a helper turn the key ON NOT START, look for dripping or flow from injector.  DO NOT START ENGINE

@jcdubya1


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Thx bodybyfisher Will check that stuff. I almost feel like its VVT related. Sometimes the Car will not rev At all. it will be lopey idling and I can put it to the floor and it will do nothing barely try to rev. but if i ever so slightly feather the throttle it will climb and rev into the 3-4k once above 2k 2500 seems to pick up. Do these engines have a Sticky Solenoid problem?

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Check the left coil pack also.

Check for spark on the left.

Packs can go bad


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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If it were VVT I think you would be setting codes


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Sticky solenoid?, what kind of solenoid?

@jcdubya1


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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VVT solenoid. But I can unplug the WHOLE LEFT/driver side bank of coils at an idle and it wont run any different. But the car was in california now i have it at my shop in mn Where i can put my snap on Verys on it. Before i just had a code reader. But i do know i switched coils around and no change. As well as switched cam sensors. left to right bank. 

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See if you can get a known good coil pack and plug it in, that may solve your problem

Grab one at a scrap yard if you can

Check the fuel pressure regulator also, this could be 2 problems


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I hate to jump in as I am just a shade-tree mechanic but found a video from South Main Auto (does videos on auto problems) and found a NorthStar that had a fuel pressure problem (good pressure but couldn't hold pressure with pump off).  It's a 20 minute video with his diagnosis process.  May or may not be germane, but here it is:   

 


Chuck

'17 XT5, '04 Bravada........but still lusting for that '69 Z-28

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1 hour ago, jcdubya1 said:

SO are you saying that if 1 pack is bad on the left bank it will take down all of them??

You have a 4 coil assembly with module.  It is $139 at rockauto.  I will call @Logan here to see if that module can cause problems with the entire bank.  My inclination is yes.

Screenshot_20190516-144439_Samsung Internet.jpg


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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If you decide to buy at rockauto here is a 5 percent off certificate good till 6/2

Screenshot_20190516-145647_Email.jpg


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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yes, that was. I Was upset at the Site because they had me pay 31.00 to ask 1 question then nobody replied to me for 2 days and then the mechanic said to call him and it would be another 26.00 for the call. After i spoke with him again he told me Whatever he told me i wouldn't be happy with so declined my questions. I was not too pleased with the way it was handled is all... I appreciate the help and Knowledge But if i have to pay 50 bucks to ask a question hopefully i Get a helpful answer is all i was sayng. 

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Well we are a LOT cheaper than that.  Haha!

Lets see what @Logan thinks about this.  

In the meantime see if you can swap in a known good ignition coil bank.  


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Bought a new ignition coil bank put valve cover back on Nothing!! I am assuming the FPR is the round DISC on the Metal line right at the Return and there is no vacuum line attached to it. 

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Can't get my Scanner to Communicate with the car. Checked under the hood fuses for CIG. lighter and power ACC port fuses are good. Can't find the In cabin fuse box it says it is under the back seat pass. side but i don't see how i could get to it without removing the seat.

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What do you mean by nothing?

Were you able to communicated with your scanner before?

Upon further research your fuel pressure regulator appears to be part of your fuel pump.

Have you put a fuel pressure gage on your fuel rail to see what fuel pressure is?


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Nothing as in No change. lol. sorry, And yes i was able to communicate with the car before. Im trying to see if its my wireless for my snap on. Gonna plug in my truck. but I noticed that as well. is there a Fuel Pressure sensor. I google it and it looks like a MAP sensor. I am just going to take a video of what the car is doing and upload it,

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If the scanner communicates with the truck but not the car, try disconnecting the battery for 5 min


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Saw a interesting video that may provide a clue.....even bank fuse.....odd bank fuse...

https://www.youtube.com/watch?v=Lt7GtMTfN3Y

 

As for codes......the thing to understand is......there has to be code written to be able to see a problem. Sure it can detect a misfire.....but it cannot detect a bad PCM ground. 

The scan tool not working is itself a clue. 

Car may have no external fuel filter (in tank pad).......and no fuel return line..... 

maybe high pressure direct injectors...but may be a little early for those..

could be a cracked intake....etc

Everything you know.....has changed.

I would doubt what the little old lady said.....believe nothing of what you hear. She may have run it out of oil for example....you just don't know til you start inspecting the systems.

 

UPDATE:

Did look in the GM service manual. The 2006 SRX has...

Inline fuel filter. It appears to still use a fuel return line. 

Fuel pressure should be 55-65 psi @ idle. 

There is .....a 15a fuse used for odd bank coils.....and a 15a fuse used for even bank coils.  Both fuses are in the underhood fuse block. 

 

 

 

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Hey guys I bought it new coil pack bank replaced it I didn't run any different. I have checked the odd and even bank fuses in there both good. I was going to go back through the wiring harness see if I can find a bad ground or something somewhere or maybe go to the junkyard and try to get a PCM and replace it and see if that fixes anything. I have checked the compression on that bank all came back good, so that leads me to believe that it is not sticking solenoid holding the valve open because that bank would have less compression than the other. I don't think it's a fuel problem because when the car is running I can spray ether starting fluid in the throttle body and no change.b So that leads me to believe it's a spark issue on the left Bank. when I unplug all 4 coils the car doesn't run any different.  let me know if anybody else has any more input thank you, and I have checked my fuel pressure seems good.

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What I dont understand is why no codes are showing up.  You would think misfire codes would show up.  Have you looked at real time misfire data?

Is there a CAT on both banks?  Have you considered a clogged CAT?


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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