cdnsarguy Posted December 7, 2006 Report Share Posted December 7, 2006 New guy with questions.... My newly acquired (June 06) 97 Deville with Northster 4.6 just started doing a very hard morning start. It can take 3 attemps to finally start and run. This has been going on for several weeks.......there are no codes set. Things replaced to date: both crank position sensors, coolant temp sensor, spark plugs, battery. I have tried low test fuel and high test, plus a mix with no change in performance. When I get the car started once it will work flawlessly all day regardless of ambient temperature. We are leaning towards oil viscosity due to the cold here, it get regular oil changes with Castrol 10-30 and WIX filters....... would Castrol 0-30 use be of any value.....not intersted in Synthetic as I have read here and seen leaking problems when older vehicles go to synthetic. Just a a side note there is a friend in town with an Aurora doing the exact same thing for 2 years and he has changed most everthing........... We are learning from his experience and mine but need some help from the folks here........ I do have the best 2 Chevy/Ford mechanics working on this problem, we are using Mitchell on Demand for TSBs and info but to no avail can we find the cure. If anyone needs IDI Ford diesel assistance look for me on..... The Diesel stop ....I would be more than willing to help.... Link to comment Share on other sites More sharing options...
Ranger Posted December 7, 2006 Report Share Posted December 7, 2006 Unless you are -20 degrees, oil is not your problem. 10w30 is fine. Have you checked the FPR? Link to comment Share on other sites More sharing options...
franey Posted December 7, 2006 Report Share Posted December 7, 2006 CHECK your fuel pressure regulator. IT can cause a hard to start issue first thing then start fine after it has been running. Link to comment Share on other sites More sharing options...
JimD Posted December 7, 2006 Report Share Posted December 7, 2006 You mention oil viscosity; are you experiencing very slow crank speeds? I would look at fuel pressure during key on,engine off. The fuel pump will run for 3 seconds and you should see 40+ psi at the fuel rail. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
rmac-etc Posted December 7, 2006 Report Share Posted December 7, 2006 Pull the vacum line off the fpr (its under the manifold cover near the rear drivers corner, search for fpr if you like, its pictured in one of the threads). There should be no fuel present, if there is, that is the problem. Its an easy replacement, but there is fuel under pressure. The cleanest way to reduce the spray is to remove the fuse for the fuel pump and start the engine and let it run until it stalls. The fpr then just unclips out. Be careful with the new o-rings. Link to comment Share on other sites More sharing options...
cdnsarguy Posted December 7, 2006 Author Report Share Posted December 7, 2006 Pull the vacum line off the fpr (its under the manifold cover near the rear drivers corner, search for fpr if you like, its pictured in one of the threads). There should be no fuel present, if there is, that is the problem. Its an easy replacement, but there is fuel under pressure. The cleanest way to reduce the spray is to remove the fuse for the fuel pump and start the engine and let it run until it stalls. The fpr then just unclips out. Be careful with the new o-rings. Thanks for the replies, I did have the mech check the FPR on the Aurora since it was outside at -10F. No difference in starting. I read it can be fuel in FPR from another post that gives high RPM and bad running, I will just replace it....... and post back in a couple days. Pete Link to comment Share on other sites More sharing options...
Ranger Posted December 7, 2006 Report Share Posted December 7, 2006 No need to replace it if it is not leaking fuel when you pull the vacuum hose. Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 8, 2006 Report Share Posted December 8, 2006 Consider that you could have water in your fuel and its freezing get some dry gas in there... 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 Link to comment Share on other sites More sharing options...
The Fred Posted December 8, 2006 Report Share Posted December 8, 2006 Buy some gasoline dryer- It is alcohol, It works wonders when the weather changes suddenly. MerryChristmas Be a Capitalist or work for one. Work for a Capitalist or be one. MerryChristmas Link to comment Share on other sites More sharing options...
cdnsarguy Posted December 10, 2006 Author Report Share Posted December 10, 2006 Buy some gasoline dryer- It is alcohol, It works wonders when the weather changes suddenly. Had occasion to do several hours of highway driving......did 4 off the line racing starts. Man the carbon was horrendous for the first couple and the wife stated "goes like the Vette did" regarding the power. The shop changed the FPR on the Aurora and it made no difference, so I will get some fuel dryer. We have not found any water in the filter, we do check it since replacement just for the water possibility. Thanks for the replies....... keep them coming. Link to comment Share on other sites More sharing options...
What job Posted December 10, 2006 Report Share Posted December 10, 2006 Was the IAC checked for sticking? This was the cause of a problem kind of like this on a Vette I had a few years ago. Link to comment Share on other sites More sharing options...
The Fred Posted December 10, 2006 Report Share Posted December 10, 2006 Was the IAC checked for sticking? This was the cause of a problem kind of like this on a Vette I had a few years ago. Is that similar to the ISC motor I have on mine? MerryChristmas Be a Capitalist or work for one. Work for a Capitalist or be one. MerryChristmas Link to comment Share on other sites More sharing options...
What job Posted December 11, 2006 Report Share Posted December 11, 2006 Was the IAC checked for sticking? This was the cause of a problem kind of like this on a Vette I had a few years ago. Is that similar to the ISC motor I have on mine? Not sure if the idle speed control motor works the same as a idle air control or if these systems even use the IAC but thought the idle circuit staying open / cloosed may have had something to do with the problem since it sounded so close to what I had with the Vette. I'm no expert on injection by any means but should be after having to replace just about every part the tech could think of before finding the problem. Do the Northstars have a cold start mode that gives the engine a shot of fuel when the key is turned on like the tuned ports have? Link to comment Share on other sites More sharing options...
WarrenJ Posted December 11, 2006 Report Share Posted December 11, 2006 Let's simply forget oil viscosity for the moment. It has nothing to do with your start problem (give or take a few tenths of a cranking second). Neither does the Aurora; let's stop confusing matters. Regards, Warren There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises Link to comment Share on other sites More sharing options...
Cadillac Jim Posted December 11, 2006 Report Share Posted December 11, 2006 The Northstars do have a feature that "gives the engines a shot of fuel" on a cold start: the fuel pump turns on for two seconds when the key is first turned on to pressurize the fuel system. This is needed because a safety feature is that the fuel pump doesn't run when the engine isn't running -- except for that two-second period when the key is turned on. If this two-second FI pressurization isn't working, you must crank until the oil light goes out for the fuel pump to turn on. I don't think that's the problem here, alghough I did think about it early on, because the problem is that the car won't start only when the temperature is below 32 degrees. That isn't a magic temperature for anything except water, so I would venture that there is water or condensation in something in the fuel system. Others have already suggested an additive that picks up a small amount of water in the fuel system and gets it through the engine. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
Ranger Posted December 11, 2006 Report Share Posted December 11, 2006 The '97 Deville uses an IAC valve. It is a throttle plate air bypass circuit which controls idle speed as opposed to an ISC motor which mechanicaly presses on the throttle linkage to open the throttle plate a little. Link to comment Share on other sites More sharing options...
The Fred Posted December 11, 2006 Report Share Posted December 11, 2006 The '97 Deville uses an IAC valve. It is a throttle plate air bypass circuit which controls idle speed as opposed to an ISC motor which mechanicaly presses on the throttle linkage to open the throttle plate a little. Ah, I see... thanks for explaining that to me (I had never heard of an IAC) MerryChristmas Be a Capitalist or work for one. Work for a Capitalist or be one. MerryChristmas Link to comment Share on other sites More sharing options...
Ranger Posted December 11, 2006 Report Share Posted December 11, 2006 IAC = Idle Air Control (valve). Link to comment Share on other sites More sharing options...
cdnsarguy Posted December 29, 2006 Author Report Share Posted December 29, 2006 The Northstars do have a feature that "gives the engines a shot of fuel" on a cold start: the fuel pump turns on for two seconds when the key is first turned on to pressurize the fuel system. This is needed because a safety feature is that the fuel pump doesn't run when the engine isn't running -- except for that two-second period when the key is turned on. If this two-second FI pressurization isn't working, you must crank until the oil light goes out for the fuel pump to turn on. I don't think that's the problem here, alghough I did think about it early on, because the problem is that the car won't start only when the temperature is below 32 degrees. That isn't a magic temperature for anything except water, so I would venture that there is water or condensation in something in the fuel system. Others have already suggested an additive that picks up a small amount of water in the fuel system and gets it through the engine. Link to comment Share on other sites More sharing options...
cdnsarguy Posted December 29, 2006 Author Report Share Posted December 29, 2006 Sorry to be away so long........ I did view some new posts, but had no further info until today. Had a bad miss start this last 2 days at varying highway speeds........ tried to pinpoint to actual MPH......40-50 with slight accelleration and again at 70-80. Had code check done again and tech put car in gear locked the brakes and gently accellerated....... the miss became horrendous under power. To make a long story short (no pun intended) at least one or two spark plug wires were allowing the spark to short to the block....... so a new set of wires is on the way. I feel not much maintenance has been done to this car other than oil/filter changes. Back with you later, thanks for the help so far. Pete Link to comment Share on other sites More sharing options...
Cadillac Jim Posted December 29, 2006 Report Share Posted December 29, 2006 Let us know if the plug wires solve the hard-start problem, too. Good luck, and Happy New Year. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
Ranger Posted December 29, 2006 Report Share Posted December 29, 2006 Sorry to be away so long........ I did view some new posts, but had no further info until today. Had a bad miss start this last 2 days at varying highway speeds........ tried to pinpoint to actual MPH......40-50 with slight accelleration and again at 70-80. Had code check done again and tech put car in gear locked the brakes and gently accellerated....... the miss became horrendous under power. To make a long story short (no pun intended) at least one or two spark plug wires were allowing the spark to short to the block....... so a new set of wires is on the way. I feel not much maintenance has been done to this car other than oil/filter changes. Back with you later, thanks for the help so far. Pete If you do a search for "Stutter, Engine or Trans", you'll find that I had the same problem after the fuel rail recall. After much head scratching, a set of A/C Delco wires solved the problem. Link to comment Share on other sites More sharing options...
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