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cold start misfire


rockfangd

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Hi all. My 96 Deville is trying to tell me something.

Only on cold startup it pops and misses.

The spell only lasts for a minute tops

the colder it is outside the longer it lasts.

Today I noticed it more because it was 0*f. It smelled like raw fuel coming from the exhaust and it actually sounded like popping from the exhaust.

Once the spell is done it runs great. I drove it all over today and have no issues.

Any ideas? I was wondering if maybe it is the FPR

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If the exhaust doesn't have a coolant smell, and you aren't adding coolant, then it's probably something simple like a dirty air cleaner element or carbon build-up. Try a tank of 92 octane gas. If that clears it up, then you need a road trip.

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maybe you have moisture in your fuel?

what viscosity of oil are you using?, its possible that your lifter is leaking down and taking time to pump up due to thick oil.

Also put a fuel pressure gage on it, maybe your fuel pump isnt getting the pressure up to spec quickly due to electrical resistance when cold or a bad motor that is impacted by the cold

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Ok hope this helps.

I only run 91-93 premium without ethanol

I run 10w30.

No smell of coolant in exhaust. no funny smoke.

car sees 30-40 miles average daily. I drive on the highway all the time and I never baby it.

I run chevron techron every 6 months.

I do have to add coolant once in a while due to a hose leak under the hood. The hose to the water pump housing has a rivet that holds the clamp in place is where it is leaking.

I am afraid to change the hose right now due to risk of cracking the pipe to the rear of the engine. I have all of the new pipes but it is very cold outside to be working in tight places.

tonight was -15*f and it did the usual on the cold startup after work. lasted no more than a minute, no coolant smell

GM FAN FOREVER

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If you're smelling raw fuel, it is running rich or getting unmetered fuel somewhere - leaking injector fuel pressure regulator. The issue ould also be caused by a misfire.

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

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Well I think I am just going to get the FPR. Even if it is not the problem it is probably worth changing. I have never touched it so it is a matter of time anyway. found it on rockauto for 44.00. Not bad

GM FAN FOREVER

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Just a thought

I am working on a 95 Eldorado right now. It runs rough when cold and will stall. When it warms up its fine. Its setting a P036 code, or EGR pindle position code and check engine light. The EGR needs cleaning as the pindle is sticking. Now I know this is not the cause in this thread because you are not getting a code, but I just wanted to post this for informational purposes.

Pre-1995 - DTC codes OBD1  >>

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thanks. Yes that would happen as the egr will stick open and allow too much flow on a cold start. it can also work the other way and stick closed as the engine warms.

And I forgot no codes.

I definately thought maybe coolant temp sensor richening the mixture but I need to know if there is 2 sensors. 1 for the gauge and one for the ecm. I think not on these but can someone confirm this?

see on my k1500 the ecm one went bad and richened the mixture but the gauge worked fine. normal because there was 2 sensors. the one on the driver side head and the other by the thermostat

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Hi Rock, I was looking through my 94 service manual last night and found a paragraph on Fuel Volatility in the Fuel & Air Control System section of the manual. Do you have a manual? I think you should read that section.

It states that low volitility can cause poor cold starts, poor cold weather performance and slow warm ups. Volitility is dependent on temperature, and different fuels are used during certain seasons of the year, thus creating problems during sudden temp changes..... interesting

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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thanks. I will have to look at my manual. The car does not start hard though and it warms up fine. Thats what makes me think it is leaking down and burning it off on startup.

GM FAN FOREVER

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  • 1 month later...

Well finally I was able to order the fuel pressure regulator. the problem is getting more consistent on startup only. Basically I can count on it to happen. I will definately update this when I replace it. anyone have any pointers on the replacement?

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Well finally I was able to order the fuel pressure regulator. the problem is getting more consistent on startup only. Basically I can count on it to happen. I will definately update this when I replace it. anyone have any pointers on the replacement?

Was the FPR leaking fuel from the nipple on the FPR?

Watch the small o-ring on the vertical nipple that inserts into the bottom of the housing. Easy to lose is and a fuel leak will result if it is missing.

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

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I'm with KHE on this one, and my money is on a leaking fuel injector.

But what I really want to know is where you get gasoline of any octane without ethanol in it!!! That would be nice to have if it didn't have a additional charge on it. They sometimes sell the stuff at RV sales places, but the cost is much more per gallon.

Never underestimate the amount of a persons greed.

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I will check the injectors. Any tips on that?

The non ethanol is definately more expensive. I pay 35c more per gallon for non ethanol premium. It disgusts me but doesnt stop me. usually takes around 90.00 to fill my tank.

I just filled my Deville and my truck today. total cost was 210.00. Cost was 4.35 per gallon. Fastrac is the company For that price it should be aat least 93 octane

For my sakes I pray it is not an injector problem but rather the FPR. I dont like to take my deville apart much because it runs good

GM FAN FOREVER

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Back in '99 I complained to the dealer that when I would start the car cold after sitting all night, the engine would buck when it first started (almost felt like it was jumping up ) - I was told I had a leaking injector, and that a new one was put in. When the engine turns over on a cold start, do you feel a surge for about a second?

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No. It is hard to explain. It doesnt feel like a surge but just a stumble. How did they figure out which one was the culprit? It is possible it is an injector issue but I hope not.

Thank you for the info

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Lift the fuel rail, support it and pressurize it by turning on the key (not start obviously), look for drips leave it pressurized for awhile. Then as an added check, turn the key off an look for leaks

Avoid touching the bottoms of the injectors, if you have not replaced the O-Rings now would be a good time to replace them.

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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http://www.cadillacforums.com/forums/cadillac-seville-cadillac-eldorado-forum/114064-help-1994-eldorado-suddenly-runs-very.html

No. It is hard to explain. It doesnt feel like a surge but just a stumble. How did they figure out which one was the culprit? It is possible it is an injector issue but I hope not.

Thank you for the info

Check this out paying particular attention to post #7
look1-1-1.jpg
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Avoid touching the bottoms of the injectors, if you have not replaced the O-Rings now would be a good time to replace them.

Those old O-rings will likely be hard and brittle from the heat. They should be pretty cheap so I'd suggest having 8 (or more) on hand before even starting this job. Of course this will depend on whether or not changing the FPR solves your issue.

Thanks for the info on the non-ethanol fuel. That would be perfect (in 93 octane) for my Volt. I haven't put gas in it yet and would really like to avoid ethanol. I'm looking for the "Fuel Maintenance Required" warning to pop up any time now. It'll run on gas then until it determines that enough of the old stuff is burned up. Maybe I'll check the RV sales locations in Parkersburg tomorrow.

Never underestimate the amount of a persons greed.

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Well I have wonderful news.

I replaced the regulator tonight and found a very obvious problem.

The vacumn line was not hooked up to the intake.

now I dont know how long it has been disconnected but I know I have never touched it. Back when I first bought the car I cleaned out the egr valve and TB. But I dont recall ever touching the line.

the question I have is what would not having the line hooked up do? I assume that the vacumn opens the regulator but dont know anything else.

I will find out tomorrow if replacing the regulator did the trick. I will say that the vacumn line was dry from the regulator, now I am also assuming I have had a vacumn leak since the line was not hooked up. I am surprised I have had no codes or driveability issues other than the cold start miss.

And thank you for the info on the o ring as the old one stuck in the rail.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Without the vacuum line hooked up, the FPR would not be able to regulate the fuel prressure properly.

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

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Without the vacuum line hooked up, the FPR would not be able to regulate the fuel prressure properly.

Can you be more specific? too much or not enough.

I know my fuel economy has been terrible lately

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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