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Post by denada777 on Jul 7, 2008 9:25:48 GMT -6
Was driving yesterday and my check engine light was flashing but not consistently. The light has come on before but never flashed. At that time it was a bad crank sensor and bad catalytic converter.
The engine also seems to be missing slightly during acceleration but not while cruising.
Fuel filter is brand new. I replaced that since that had been an issue before where it seemed under power but only at higher rpm. That is how this issue started until yesterday when it started missing at low rpm and the check engine light flashing.
2001 Aurora v8 202,000 miles
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Post by ntrenn on Jul 7, 2008 11:23:48 GMT -6
Coil pack - read the codes - bet it's coding P0302, 04, 06 or 08......new coil is about $240 +/-.
Had this exact thing on mine - miss at low speed, flashing check engine when you hammered the throttle, no miss at highway speed. Got a front bank coil with a bad number 6 if you want to swap it on for giggles....
If you really want to make sure - have it scanned by somebody with a tech2, but the $90 you'll spend will pay for half the coil...
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Post by aurora2001tan on Jul 7, 2008 15:16:29 GMT -6
good to know, Why else would a light flash and act like this?
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Post by Marc on Jul 7, 2008 18:13:16 GMT -6
The flashing check engine light is caused by a misfire. Have it scanned for codes.
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Post by ntrenn on Jul 7, 2008 18:50:26 GMT -6
Marc's right. The reason the book says they flash the check engine light is that the computer believes there is impending converter damage. If you would like, I can take you through the 3 months it took me to find the bad coil - including new plugs, boots, injector, trip to the tech2 and finally the coil. Apparently the new style coils modulate the spark intensity depending on throttle position and when they get weak, they don't work well at the higher throttle settings.
The car will idle just fine, cruise at light throttle just fine, but when you tip into it - you get the miss. If you pull the plug that's related to the P030X code that Autozone will read for you, you'll probably find that it's fouled, or on its way to being fouled...Remember, front bank is 2,4,6,8. Rear bank is 1,3,5,7....
200,000+ miles - impressive!!! Maybe the winner of the most 2nd gen miles award
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scottydl
Super Moderator
There's nothin' like an American V-8...
Posts: 7,373
Staff Member
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Post by scottydl on Jul 7, 2008 21:57:47 GMT -6
My symptoms like that were fixed by replacing the spark plugs & wires, so the problem is not ALWAYS the coils. But that's certainly a possibility. Do you know if/when those parts have last been replaced on your car?
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Post by intheb0x on Jul 7, 2008 23:12:18 GMT -6
wow 202k?!?! id hate to see how my aurora would be with that high of miles lmao
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Post by ntrenn on Jul 8, 2008 9:29:02 GMT -6
Scotty - good point about plugs (we 2nd genners don't have wires) and boots - will set you back about $100 total plus your time to install. The caddy guys replace the boots at 100K - part of their $400 tuneup. Could have one arcing.
Don't forget the silicone grease!!
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Post by robaurora01 on Jul 8, 2008 12:57:48 GMT -6
whoa hold up here a second, we don't have wires? we just got spark plugs and the coil pack? hmmm may explain a few things. now ive gotta change all my plugs uve guys got me curious, anyone know how hard it is to reach the rear plugs on the 3.5's? even the 4.0 gives me a rough idea.
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Post by ntrenn on Jul 8, 2008 18:34:29 GMT -6
robaurora - The 4.0's not too bad, but you spend some time kneeling on the radiator cross brace and standing on your head to get to the rears - unless you go at them from the side. I found it easier to go over the top - even though I'm old and fat. Tough parts - figuring out the patent on the coil wire connector and sneaking out the coil pack from past the firewall and the EGR valve. Long extension and a spark plug socket with a good rubber retainer in it so the plugs lift out with the socket helps. Took me about an hour to run all 8 as a rookie on this engine. Take a big wallet with you - the right plugs for these motors are NOT cheap....
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Post by robaurora01 on Jul 8, 2008 18:44:20 GMT -6
nah im not expecting to buy cheap plugs and i figure it must be time to change them as im unsure of how long its been since they have been change (had the car for almost 5 months now still gives me a hard one every time i hit the unlock button in the car). I plan on buying high performance ones......hopefully ill be sold the right ones and not the ones for the v8 not sure if it would matter or not but everytime i try and find one for my 3.5 i always get sold the 4.0 the only time i didn't was when i bought the new belt for it.
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scottydl
Super Moderator
There's nothin' like an American V-8...
Posts: 7,373
Staff Member
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Post by scottydl on Jul 9, 2008 12:57:09 GMT -6
Oops forgot about the (lack of) 2nd-gen wires! rob, don't worry about anything "high performance" when it comes to plugs. Just stick with factory AC Delco.
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Post by robaurora01 on Jul 9, 2008 14:20:47 GMT -6
may i ask why scotty?
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Havoc
Aurora Groupie
2001 3.5
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Post by Havoc on Jul 9, 2008 15:45:46 GMT -6
It took me almost an hour to do the plugs in my 2001 3.5.The hard part was figuring how to get the rear coils /cover out..i think I removed the mount for the vaccume hoses and it sort of twists as it slides out.The first time doing something is always the worst.Just be careful and take your time and all will go smoothly.Make sure the spark plug boots are seated properly when you reinstall the covers. Also the AC Delco plugs when you open the box are NGK..not sure if they are the same as the ones Can Tire sells but theres a pretty good price difference..anybody know if the AC Delco NGK platniums are the same as regular NGK platniums????Took me 3 different dealers to gather up 6 freakin AC Delco plugs.
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scottydl
Super Moderator
There's nothin' like an American V-8...
Posts: 7,373
Staff Member
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Post by scottydl on Jul 9, 2008 15:57:43 GMT -6
From members' experiences here primarily... ACDelco or NGK are what work best in these engines. Some folks have done fine with cheapo Autolites or similar (which I have used in other cars, just not the Aurora) but more often than not the Northstars get finicky and develop strange problems. Bosch plugs seems to be especially bad in our cars, and that's what many parts stores will try to sell you. As far as "high performance", I don't think there's really any such thing when it comes to spark plugs. I mean come on, all they do is *spark*. Those claims are just gimmicks IMO.
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Post by robaurora01 on Jul 9, 2008 16:46:47 GMT -6
good reasoning on it and ive never liked Bosch stuff to be honest (even tho this is my first car i use to work in auto shops reparing vehicles before i made a big decision and moved to a big city). does anyone have pictures of how or what needs to be taken off? im sure i could figure it out im just more weary on it since im use to working on non-luxury cars with about 50 million less sensors in the vehicles specially the ones that apperently will ask you a question if your still turning or not lol.
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Post by ntrenn on Jul 9, 2008 17:23:24 GMT -6
When I pulled my plugs at 59,000 miles, they were Denso's. Not sure if the previous owner had changed them, but why would you change a 100,000 mile plug before 40,000 miles? Not for me to reason.
The AC Delco plugs LOOK exactly like the Denso's, and they were made in Japan, either by Denso or NGK, but they said AC Delco with the AC Delco part number. From working in manufacturing, I know that you never know what they put inside it if it's not properly marked, so stick with the Delco's. Most local parts houses can order them in here in the states - just be ready for $7 a plug.
While in there, the plug boots are supposed to be changed at 100,000 miles, so for a measly $5 a boot and $4 for the silicone - save yourself a trip and spring for them as well...(if you don't silicone the boots, you may not be able to get them out in the future)
I've never had a problem with Delco plugs in my GM vehicles, but as Scotty says - many here have had trouble with Bosch - it's just not suited to our engines.
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Post by robaurora01 on Jul 9, 2008 18:18:08 GMT -6
boots and silicone? what the.....seems like i might need a brush up on my maintence stuff. what ever happened to good old plugs and wires lol. if im going to do it im going to do it right now that i have the proper information ill buy new boots and silicone and so on and so forth but i would of really never of known otherwise. (plus no idea if they ever changed it before.)
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Post by ntrenn on Jul 9, 2008 20:26:55 GMT -6
Welcome to the world of Coil On Plug design. I was similarly surprised about the lack of plug wires.
The silicone is so the boots don't stick to the plug - apparently when you run them 100,000 miles, they can stick together like superglue and skin.
The US EPA has driven a lot of changes in the automotive world. Emission warranties of 100,000 miles virtually eliminated aluminized steel in exhaust systems - 409 muffler grade SS is the standard now. 30,000 mile spark plugs became 100,000 mile spark plugs, etc. Ever noticed how small the auto section is at your local Wally World? Shrinks by the day as the parts that need replacing keep having lower and lower volume. Who changes their air filter every 7500 miles like Fram wants you to? GM recommends 30,000 mile intervals on virtually everything. I haven't changed a set of points in over 20 years - and that was in my 50 year old tractor.
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Post by robaurora01 on Jul 9, 2008 21:29:52 GMT -6
hmm i tend to change my air filter well not anymore i did when i bought the car (thank god it was dirty as heck) and put the CAI on it which i say makes a HUGE sound difference in the car.
as for the rest of these things there is no Wally World here, and all of our auto shops get nothing but bigger due to i live in a rural province and we all just love to buy older vehicles and repair the crap out of them. As each day goes on i tend to think the previous owner of my car did try and take care of her but it probably became to problematic so they gave her up to the dealer i bought it from (which i honestly didn't know the amount of things that was wrong on it and was a tad bit over excited to really double check.) because some of the main issues that you guys say has happened and tends to be a common issue has yet to happen in mine possibly because it was fixed before or im just one of the lucky guys aside from my AC issue that i need a new/referbished one for just a pulley issue.
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Post by mmorrison1976 on Jul 16, 2008 21:12:39 GMT -6
I have a 2001 3.5L Aurora with 55,000 miles and I have had issues with the cgeck engine light flashing and have hesitation on slow acceleration. I have looked at various parts websites and it appears that you can buy just the coil pack or the entire unit that includes the ignition control module. WHich do I need? Is it just the coil pack that needs replacing?
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Post by ntrenn on Jul 20, 2008 21:42:18 GMT -6
Mine's a 4.0, but after months of chasing it from part to part, mine ended up being the coil pack. Best thing you can do is read the codes and work from there. If it's in the ignition/coil pack it should show up as a P030X misfire or the general one. In increasing cost - Plug Boot, Plug, injector, coil pack......just about the order I swapped parts.....
It's possible it's something other than ignition-related - that's why it's key to read the codes first.
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Post by mmorrison1976 on Oct 29, 2008 19:20:23 GMT -6
More and more fun. I had the flashing check engine light at 58,000 miles. I pulled the plugs and sure enough, number 6 is fouled and full of gas. I found a used coil pack online that came from a car that ran fine. I took bothe the front and rear coil packs out and changed the plugs. I installed the boots using the proper grease, installed the coil packs and the car ran beautifully for about 150 miles and then the engine light started flashing again. I pull the #6 plug and it is full of gas again. Any ideas? Is there a way to check the coils at all? The botts were put back on in no specific order so would be odd that the boot would be bad. Am just puzzled!
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Post by aurorabrain on Oct 29, 2008 19:51:59 GMT -6
Maybe a leaky fuel injector?
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Post by aurora2001tan on Oct 29, 2008 20:09:04 GMT -6
A GM tech that knows anything will tell you running a plug over 60k is hard on the coils. You risk burning them up going the 100k. To me the 100k plugs is just a stupid marketing selling point. Anyone can maintain a motor, doing it the best way isnt always in the book.
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Post by mmorrison1976 on Oct 29, 2008 21:18:52 GMT -6
I swapped the coil packs around to see if I could find anything out. The only thing that seem constant was a misfire...not always right away but always occured within 10-15 miles. This is just driving me nuts. What is involved in changing out a fuel injector on the 3.5L?
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Post by ntrenn on Oct 29, 2008 21:25:11 GMT -6
What code are you getting? Can you feel a miss? Swap injectors between 5 and 6 and see if the fouling runs to number 5. Pretty easy on a 4.0 - once you figure out the patent on the electrical connector... Also - AC plugs? The smart scanners can tell you spark voltage and if the coil is putting out the right voltage. They modulate the new ones with throttle position - more throttle - greater voltage.
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Post by mmorrison1976 on Nov 2, 2008 8:43:54 GMT -6
I am running Autolite plugs at the recommendation of my mechanic. I can feel the miss and the car sounds terrible. When I pull the lugs, clean them and re-install, the miss goes away for a while, so I am thinking that it might not be the coil. How hard is it to switch or replace injectors? Anyon have a step by step instruction on changing injectors on the 3.5L.?
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