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2002 Cadillac Deville
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69 Posts
Discussion Starter #1
Long story short, I have had the SES light on for a couple months with Lean Bank 1 and 2 codes and a intermittent Misfire code as well.. Ok taking from what I learned from the Haynes manual and from the DIY in the Tech Tips section of this forum, I think I should be able to do this.. One thing I don't see though in the tech tips how-to that the Haynes manual says to replace the intake manifold gaskets. Is this necessary? I almost ordered the Felpro set from Advance but remembered someone telling me that Felpro for the most part made trash..

Also, what other routine maintenance should I accomplish while doing this? The car has 110k miles on it and have only owned it for 10k of those.. While my fuel system is depressurized I will be changing the fuel filter which seems pretty easy.. Any other ideas? Here are some of the things I have already done.

  • Changed spark plugs <100 miles ago with 41-987 ACDelco (100% sure the ones still in there were OEM cuz the part number was different and they almost looked rusted in)
  • Cleaned TB
  • Cleaned EGR valve
  • Checked FPR for sufficient vacuum
  • Checked PCV valve for sufficient vacuum
Any other ideas?:stirpot:
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,007 Posts
Take your time, check the starter motor mechanical and electrical connections, and take a hard look at the manifold seal rings: if they come out flattened with no "life" in the bead, replace them. Cheap insurance. The manifold bolt torque is 89 in/lb (about 7.5 ft/lb) so go easy or you'll crack a bolt boss. Oil the lower fuel injector O-rings - it will make dropping the rail back in much easier.

Remember that the plenum is held on by 3 long bolts through the throttlebody. The "nuts" on the plenum stamped frame are welded on.

Do NOT mess with the honeycomb flow straightener on the MAF, and be careful of the tiny heated resistors on the wire bridges. When you install the intake air ducting, remember that ANY air leak from the MAF to the throttlebody will set mixture and O2 sensor codes. Our divorced MAF setup is different from pre-2000. Check your ducting and clamps.

Get rid of the Haynes and either get a real Helm/Cadillac Service Manual (ebay) or subscribe your car to www.alldatadiy.com. (For $15 a year, ALLDATA has so much GM shop manual information on your car and its recalls and TSB's that you'll never be able to read it all.)
 

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2002 Cadillac Deville
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69 Posts
Discussion Starter #3
Hey having a bit of trouble.. First off, I have the fuel rail bolts off and the injectors unplugged and cant seem to get the fuel rail and injectors to pull out from the manifold.. ALSO Alldata and haynes manual say to remove the fuel inlet quick connect fittings (metal pipes) and I cant seem to get them to pull apart.. What gives?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,007 Posts
Those quick connect fittings have a pair of nylon retainer fingers up inside: you use a quick connect release kit from NAPA ($7) - a correctly-sized split top hat slips up into the large metal funnel and trips the latches. You have to "exercise" the correct sized release tool - they're pretty stiff out of the box. Smear a drop of engine oil on the fuel rail pipe tips when you put it back together.

The fuel injectors may be stuck - those 2 O-rings get tight over time. Spray a shot of PB Blaster or WD-40 down into each fuel injector lower O-ring area and let it soak for 20 minutes. Smear a drop of engine oil on the injector lower O-rings before you drop the rail back in.

To start the car (when all's back together): Turn the key: ON for 10 seconds, turn it OFF for 30. Do it again, then start the car - this re-primes the fuel rail.
 

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01 DTS,02 Deville,94 Concours,50 Sedan,03 S55,03 Excursion
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105 Posts
When I changed my gasket I didn't need to pull the rails completely off. It was just a slow delicate process.
 

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2002 Cadillac Deville
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69 Posts
Discussion Starter #6
UPDATE:
First off, much thanks to SUbmariner and Ranger for their advice and help through this process.. You guys put a lot of hours into this site and are greatly appreciated..

Ok guys got this finished the other day, havent been able to get on here since then (busy with work) but happy to say that this was the cause of all the problems my car has been having.. High idle after foot off accelerator, jumping idle at stops, poor gas mileage, codes P0171 and P0174 and the intermittent misfire, etc.. Hopefully this helps anyone having any of these problems that may find this thread in search.. Forgot to mention that the rip in the plenum was HUGE (about 3 inches) and it was right underneath the clamp so it was invisible from all sides..

I did notice that the inside of my intake manifold was caked with black gunk that got all over my nitrile gloves so now I am thinking of doing some kind of induction cleaning.. Wondering if anyone has any personal experience with using SeaFoam on this car.. I read one thread that I cant find for the life of me now about some GM engine cleaner, is that the better route>?

Also, is there any GM certified mechanics or good mechanics in the Greater Tampa Bay area that would be willing to fix a front motor mount?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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DO NOT use or spray anything into the intake manifold - leave the crap there - it's a byproduct of condensation of oil vapor and nasties from the PCV system. The manifold itself is complex and literally impossible to clean thoroughly unless you can do an extended soak and agitation in a parts cleaner tank. About the best you can do is to do a thorough throttlebody cleaning with rags, a toothbrush, and TB cleaner spray, and don't get much of that into the manifold, either. (The real time to do the TB was when you had the manifold off........) The GM Engine Cleaner is a product and process for removing carbon from the piston crowns and ring grooves. Don't go there, either.

If you really get antsy over the manifold, get in touch with Jake at Northstar Performance, work out a fair price and shipping, and drop a brand new one on there......... or look at www.gmpartsgiant.com.
 

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2002 Cadillac Deville
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69 Posts
Discussion Starter #8
Well it definitely didn't erk me enough to consider buying a new one.. I already cleaned the TB and butterfly on an earlier date and they were still sparkling when I did the plenum job.. I am super excited to drive my car again, the idle is perfect and the gas mileage has gone from 12.3 to 14.4 in 75 miles of driving and I expect it to go much higher than that.. It was great also when before I did the job the range was at 75 I did the plenum and was able to put 180 miles or so until I needed to fill up..

I havent done the ATF fluid or filter or put it new brake fluid so i think I'm going to try to do those soon along with new brakes.. They seem good but sometimes squeak on medium pressure braking (weird) so I think its something else and not the wear clip.. Also have a shimmy at highway speeds, had the rotors lathed and brakes redone all around when I bought the car (June of 09) and it still shimmied.. Technician at Tire Kingdom said they should be replaced next time and not relathed cuz they are starting to get thin.. Do you think this is why they still shudder on high speed braking? Also, where would I find good rotors at a decent price? Are the eBay drilled one's any good?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,007 Posts
Get out on a quiet Interstate (Hah !!!) and accelerate to 65+. Now do a very aggressive slowdown (do not engage ABS) to 10 mph, accelerate and do it again. Drive a couple of miles to let the rotors cool and do it again. Let the rotors cool: DO NOT stop and hold the brakes with the rotors hot after one of these aggressive slowdowns.

What you have just done is scrub dirt, rust, and resins off the rotors. Is your braking now any smoother and quieter ??

Your Deville, running 87 octane gasoline, should produce 12 - 17 mpg in the city and above 25 on long haul Interstate runs. Maybe about 20 - 22 in combined city/beltway/Interstate drives.

Get into www.ebcbrakes.com (left column, automotive brakes) and do a lot of reading on their advice and products. If you decide to take the plunge, www.placeforbrakes.com sells the Black Dash rotors and Redstuff pads, shipping included, for $475. Use the popup 12% discount at the top of their home page. (I would never buy a drilled 2X4 off eBay)
 
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