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my 1999 Deville (has Northstar) backfired when I started it the other day and caused a spark that set the hood liner on fire.  I've never had problems with it before, and it hasn't done it since.    The car had set for a few days, when I turned the key I let it set in the on position for the required amount of time, before I turned the key to start (as I always do this).  It started right away, then a loud backfire.  I sat there for a few minutes, car was still running, everything seems fine, so I left, as I got up the road about 500 yards, I started smelling something.  I stopped, opened hood, and there was smoke coming out, and I noticed the liner was on fire.  Luckily I had just passed my neighbors' farm, and I backed up into his driveway, and ran for his water hose.  Fire out, nothing else seemed to be affected.  Is there something I should have checked out?  What would have caused the backfire and spark?

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glad you are ok and saved your Cadillac.  my first guess with northstar backfires is the fuel pressure regulator.  Once a backfire occurs the headliner fire is unlikely but unsurprising. 

Bruce

2016 Cadillac ATS-V gray/black; 2013 Cadillac ATS 2L Turbo Premium (Wife's)

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As a back-fire is caused by fuel/air mixture ignition inside of the intake manifold, there would have to be an open path to the outside of the engine for a hood insulator fire to occur. There are several conditions that can cause a back-fire, but the fact that it occurred after the vehicle had been sitting makes me think a fuel injector leaked fuel and a small "puddle" was sitting inside a cylinder with an open intake valve.

You may have a rodent damaging the intake system. If all the components of the intake were in place the back-fire would have been contained inside the air inlet system.

Has there been any intake air system modifications done?

Did you continue driving after the fire was extinguished without incident or is the vehicle parked at the neighbors?

@BodybyFisher will have some links for you so you can check for diagnostic codes which may give a us a better idea of what happened.

 

 

Edited by OldCadTech

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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Yes, in my signature you will find links on how to retrieve codes, retrieve codes and post them here. 

There is another thread active right now that is experiencing back fires, I will link here:

On Page 2, a member @Trav97dville begins speaking about backfires due to a leaking fuel pressure regulator (FPR). 

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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Always in my opinion check that pesky FPR for a leak , if the diaphragm is compromised it will leak fuel and be drawn into the vacume hose connected to the nipple of the FPR which in my case caused backfires often . With the engine running remove the vacume hose for a minimum of ten seconds if you get any fuel leaking then it's pretty safe to say your fuel pressure regulator needs to be replaced I also had a headliner fire due to this issue , usually when this happens the headliner has absorbed some combustibles (old motor oil) and when the anti backfire valve does it's job the headliner catches fire . All leading back to gas pooling in the intake due to a faulty fuel pressure regulator !! Good luck ! 

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You know, you learn something new everyday.  This is the first I have heard any backfires bad enough to start a fire and here, it has happened twice! 

The learning never stops.

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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2 minutes ago, Trav97dville said:

That FPR is a small but powerful(important)  device eh fisher 

Yeah, I have had a bunch fail but have received rich codes and had hot starting problems, I never experienced the backfiring myself in any bad FPR.  I tend to be a fanatic however and probably check the FPR more that I should admit, :blink:

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 concur with @BodybyFisher , replaced a lot of FPR's never had a fire from one, BUT i sure can picture the relief valve belching fire on the engine belt side  and the hood liner having a nice supply of P/S fluid. :fireman:

Makes me wonder if the beauty cover is still beautiful :unsure:

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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5 hours ago, BodybyFisher said:

You know, you learn something new everyday.  This is the first I have heard any backfires bad enough to start a fire and here, it has happened twice! 

The learning never stops.

This is the first time I have ever heard of a fiberglass hood liner catching fire... Fiberglass will not butn so it must have been saturated with fuel vapors?

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Oldcadtech - no, no modifications were made.  Yes, after fire extinguished, we looked for any burned wires, etc. nothing other than liner.  So yes I continued to drive the car the remainder of the day and had no problems. WOW after reading TRAV97 posts, I'm thinking I may have a lot bigger issue, with all my problems affecting others.  I do have a coolant leak as well, but I never see a puddle sitting on the ground anywhere. It apparently leaks out while I am driving it.  Its a slow leak, I can drive it over 100 miles before my check coolant level message appears.  My other problem is I always get the message that my "a/c is off, fluid low".  BUT, my fluid is full, and a/c isn't working, it will blow out hot air on one side, and warm air out the other side.  My prior post on this forum addressed the a/c issue and was informed I may need to replace the blend door actuator.  I haven't done that yet as when I looked on line to purchase I had a multiple choice of 4 different looking ones.  Now I'm thinking all this together means it is something definitely beyond my mech aptitude. OH geez, I can only imagine what a Caddy shop in Lexington will charge me to fix my issues. (180 mile trip for me - 1 way) Plus a motel costs while they fix it. 

Things to check tomorrow: 

Fuel pressure regulator   ( With the engine running remove the vacuum hose for a minimum of ten seconds if you get any fuel leaking then it's pretty      safe to say your fuel pressure regulator needs to be replaced)

Codes and post here for more of your wonderful assistance.

I want to say thank you to all, I actually love this forum.  You all actually give me great advice and concern unlike other forums who just like to mess with my head because they think I am a stupid woman; ok yea I am stupid when it comes to mechanical problems, that's why I appreciate this forum so much.  You all are so willing to share your knowledge and lead me in the right direction, instead of misleading me to do stupid things.

Edited by KYwomanJT
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Hmmm, coolant low light after 100 miles of driving is not good. Do you smell coolant, getting in or out of the vehicle? Top it off, and start with the cheapest thing first - put a new pressure cap ( looks like radiator cap )  on. See if that helps. I know @BodybyFisher will want you to do the test for exhaust in the cooling system and it IS an easy test to do............. ( how's that BBF?? ) but not the cheapest ;)

Definitely do the FPR test, if the FPR is leaking replace it ( have someone with fair mechanical ability do it ) they're pretty easy. If it checks good then we will need to do a little more in depth diagnosis. 

AND, don't forget to do the codes....

After you have finished with writing the codes down, clear ALL the codes start the engine and see if the A/C works.

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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I have checked the codes multiple times today, at no time do I get an option to clear the codes. (confused)

Also, I've been searching for over an hour to try to find a diagram showing me where the FPR is located in order to follow your suggestion to check for a leak. (frustrated)

Here are the codes that came up when I ran the check:  PCM P1599 history, ACM B1340 history, ACM B1347 current, SDM U1255 history, no IPC codes, no TCS codes, no PZM codes, no IRC codes, no RFA, no MSN, no MMM, no PHN.

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17 minutes ago, KYwomanJT said:

I have checked the codes multiple times today, at no time do I get an option to clear the codes. (confused)

Also, I've been searching for over an hour to try to find a diagram showing me where the FPR is located in order to follow your suggestion to check for a leak. (frustrated)

Here are the codes that came up when I ran the check:  PCM P1599 history, ACM B1340 history, ACM B1347 current, SDM U1255 history, no IPC codes, no TCS codes, no PZM codes, no IRC codes, no RFA, no MSN, no MMM, no PHN.

DTC P1599 Engine Stall or Near Stall Detected (probably related to the backfire)

DTC B1340 Air Mix Door One Movement Fault (this is an actuator problem, which will cause heat when you want AC), I have a link to my 96, where I changed it, Ill post later)

DTC B1347 Very Low A/C Refrigerant Warning (this indicates that your refrigerant is low, you need to have the system evacuated and recharged, when they evacuate, if you have a large leak it will become obvious, have them use dye so that if you do have a leak it will be obvious)

Here is the FPR, its located on the stainless steel fuel rail under the beauty cover

FPR_zps2fmf801m.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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When you get all the way through the codes the last screen will display (ALL?) you push the temp up button and one of the selections comes up clear all? push the temp up button again. It should display ( All Codes Clear ).

I'm going by memory and if CRS hasn't come up you should be good :wacko:

 

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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