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Discussion Starter #1
I recently bought a 2004 Deville/Northstar in great shape with about 106k miles on it. Its my first Cad and I'm loving it so far.

I put new plugs in when I got it and it runs great and passed smog with clean results.

But my wife usually drives it and the other day she called me told me it wouldn't start. This was a cold start in the morning and she told me it would run a little and then die.

I couldn't look at it until the next morning. When i clicked the starter it started but running really rough like it was missing on half its cylinders but after pumping the accellerator I was able to keep it running but just barely, it was really rough.

But then after around 30 seconds it started smoothing out and after about a minute was running totally normal.

I shut it off and decided to try another cold start today. Today its started and warmed up totally normally and runs fine.

The fuel pressure looks correct its around 37 running with the vacuum connected and around 45 with the vacuum disconnected.

We're going to be taking the car on a long trip next week and I was hoping to find out what caused the problem so it doesn't happen on the road.

Does anybody have an idea on what could have caused the car not to start easily those 2 days?
 

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98 DeVille, 97 DeVille d'Elegance
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Pull the codes as described ^^^^ and post along with definitions from links in same sticky above. Post current or history also.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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20,104 Posts
I recently bought a 2004 Deville/Northstar in great shape with about 106k miles on it. Its my first Cad and I'm loving it so far.

I put new plugs in when I got it and it runs great and passed smog with clean results.

But my wife usually drives it and the other day she called me told me it wouldn't start. This was a cold start in the morning and she told me it would run a little and then die.

I couldn't look at it until the next morning. When i clicked the starter it started but running really rough like it was missing on half its cylinders but after pumping the accellerator I was able to keep it running but just barely, it was really rough.

But then after around 30 seconds it started smoothing out and after about a minute was running totally normal.

I shut it off and decided to try another cold start today. Today its started and warmed up totally normally and runs fine.

The fuel pressure looks correct its around 37 running with the vacuum connected and around 45 with the vacuum disconnected.

We're going to be taking the car on a long trip next week and I was hoping to find out what caused the problem so it doesn't happen on the road.

Does anybody have an idea on what could have caused the car not to start easily those 2 days?
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The fuel pressure looks correct
its around 37 running with the vacuum connected
and around 45 with the vacuum disconnected.

37PSI is a little low - could be a bad FPR - or weak fuel pump -

I just checked the FSM - Factory Service Manual -
spec with key ON - engine OFF is 41-47

but because fuel pressure is not monitored -
there aren't any fuel pressure related codes -
 

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Super Moderator
2010 DTS
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87,430 Posts
FWIW, my fuel pressure is about 38 psi at idle. Slightly below factory spec's, but not a problem.

Regardless of the codes you find, it may be time for a good TB cleaning.
 

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Discussion Starter #5
Well I just got another call that it won't start, and this is after I replaced the fuel regulator last night.

I'm going to pick up a fuel pump relay on the way to check the car and I'm taking my fuel pump pressure tester with me. I had already cleaned the TB. The car was running killer before this happened and also ran great last night after replacing the regulator. I hoping the fuel pump relay is just flaking out, I guess I'll find out soon. Thanks for the suggestions fellas, I'll post back what I find out.
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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What spark plugs did you install ?
 

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Super Moderator
2010 DTS
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87,430 Posts
Have you pulled the DTC's as requested? You may have a ripped plenum duct (pretty common). If so you'll have a P0171 & P0174 code.
 

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Discussion Starter #8
Well I put the fuel pressure gauge on the car, turned the ignition on and the pressure shot right up to 45. Hit the starter and it fired right up and runs totally fine.

I did go thru the codes but like a dumb ass forgot to bring a pen but most of the codes were "History" and I don't remember seeing a P0171 or 174 code. Plus once it starts it runs great so I don't think it has a plenum duct problem.

It had the original fuel pump relay in it so I popped in the new one. I'm hoping that the old one was getting sticky and particulary on a cold morning wasn't engaging until the temperature warmed up a little, it was much warmer when I started the car. The terminals on the old relay looked fine so I don't think it was having the overheated terminals problem you can sometimes have with fuel pump relays.

I guess I'll find out, the new relay is in place. If it poops out again I'll do a better job writing the codes down.

I put the AC Delco plugs in it that others recommended on this forum. The old plugs looked pretty good for having 100k miles on them, no oil fouling or anything like that and as I mentioned the car is running great other than this flakey starting problem.
 

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Discussion Starter #9
Same deal, wife calls and says car won't start. When I can get to it a few hours later I pop on the fuel pressure gauge, with ignition on the pressure pops right up to 45 and the cars starts immediately and runs fine.

I did pull the codes this time. The only thing from the engine codes is a PCM P1106, which apparently is a "MAF intermittent high voltage" code. So it looks like the MAF is acting flakey but is a bad MAF really enough to keep a car from starting?

Its looks like the NAPA store close to me has a "rebuilt" AC-Delco MAF ($89.), is this a part that should only come from AC Delco or are these rebuilt ones OK?
 

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2001 DeVille
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P1106 is MAP (manifold air pressure) Sensor intermittent high voltage not MAF (mass air flow). You probably just made a clerical error. The MAP is what I suspected based on your symptoms of open loop fuel ratio problems but I was waiting on your codes to comment. Another guy last year was having similar problems and I diagnosed it as his MAP and that's what it was, he didn't have codes though. A bad MAF would more likely cause problems all the time whereas the MAP establishes a base line for the fuel injection to go by until the O2 sensors get hot enough to start giving feedback.

You could try pulling the little MAP out and cleaning it of any built up residue but they don't cost a bunch and I'm sure your wife is good and ready for you to just fix it so I'd just pull it out and replace it. It's on top of the coolant cross-over in the bridge between the throttle body and the intake manifold boot. It's the small square body three wire sensor.

Vernon
 

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Discussion Starter #11
Vernon, thanks for pointing out that I misread the code, you saved me from buying the wrong part, I owe you a cold one.

I agree that a flakey MAP problem makes more sense with the problem I'm having, hopefully it will do the trick.

I'm pretty surprised that this code doesn't also cause the check engine light to come on. I had pulled all the OBD2 codes also and it was clean which was making me think it was s fuel delivery problem. Well I learned my lesson, always check the internal codes first.

I'll report back if the new MAP finally does the trick.
 

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Discussion Starter #13
"It should. Any P code should trip the SES light."

That's what I would have thought also but the light wasn't on and the OBD2 scan came up clean but the P1106 was definitely in the DTC list.

Is it possible that since the problem in intermittent and only happens occasionally during startup and then the engine runs fine that its clearing the SES light and code from the OBD2 record?

I've seen this happen with a P0306 misfire code on a Tahoe I had with a cylinder that was getting the plug oil fouled from a bad valve guide. If you ran it hard it would clean the plug off and SES light would go off.
 

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2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
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Not all P codes will trigger the SES light, only emissions related codes.
 

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Discussion Starter #16
Wow, this is bizarre. I put in a new AC Delco MAP sensor this morning. Then started it up, started immediately, ran fine for me like it always does.

Just got a call from my wife, same deal. She says it runs for about 4 or 5 seconds then quits.

One other thing, I think it was just before all this started happening, she lost her set of original keys (what else is new) and had copies made from mine, which is the only original we have left. I've still been using my original which has always started the car. There was one time right after this started happening when it started really rough for me but it was possible I was using her key copy that time.

Is there something about the ignition locks on these cars that can cause them to act flakey with key copies?

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Ok, I'm officially a dumb ass. I noticed my key had PK3 stamped on it and searched these forums on that and realized that it does have additional security features and you can't just use any key blank. I wish the Ace hardware guy that made the copies had been smart enough to know that but I guess that's expecting too much.

Oh well, it looks like my MAP was occasionally acting flakey, at least I got that swapped out and also learned how to dump the DTC codes.

Thanks for the help fellas.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Don't know about the later 2004 cars, but the earlier ones can be very security-conscious if the proper key/type/transponder is not used. Do you see any security messages in the DIC, and does the SECURITY light perform as the owner's manual says it should ?
 

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1995 Sedan DeVille , 1967 Eldorado
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445 Posts
If you went to Ace you have a PK3 key as they are required to give you what ever security key your vehicle uses. I tried getting a regular key blank for my car from them just to open the door and they wouldn't do it because of some law. You should have the key you need it may just need to be programed.
 

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1995 Sedan DeVille , 1967 Eldorado
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There's no such law, they just wanted more money.
That wouldn't surprise me. I miss spoke its not a law but I was told that it had something to do with a law suit because of people getting the regular key and locking their security system so now they won't make a regular. Went to the dealer and just got a Chevy key no trouble.
 
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