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TEC and PO300


MIke D

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I had an intermittent skip that over the last week has become a more "constant" skip. on a few hard accelerations it coughed back through the intake. after searching here and seeing that my intake was loaded up with carbon a few months back (starter work) I tried a TEC. Now the more constant skip is a steady misfire. I mean one or more of my cylinders are not working. What was a po300 in the history every once in a while is now a flashing DIC and even when cleared comes right back. on WOT it's like I'm running on 6... What's our next thought...

History:

new plugs 20k ago

new wires 10k ago

this started happening when it warmed up.. I.E. in the 40's on up. it does not matter whether the car is warm or cold. I was originally leaning to a bad ignition pack but why would TEC make it worse so does it mean it really is carbon?

Thanks in advance MD

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93 STS 225,000 Miles

99 STS 111,000 Miles

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What is TEC? Are you speaking of Techron? Techron if used in the wrong manner could cause problems but lets not go there yet.

Where they OEM wires? Did you use dielectric grease with those wires? If you did, that is wrong, the OEM wires COME with dielectric grease impregnated in them and IF you use more grease you can cause a misfire.

Look in every spark plug hole for OIL build up from a leaking CAM seal.

Determine which cylinders are NOT firing and check the plug and wire carefully.

see this

Dielectricgrease.jpg

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1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

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By the way FORGET about the 'carbon' you found in your intake totally, its insignificant, a non factor. What you found was NORMAL... Its condensation of EGR gases, and it creates a GOO.. Ignore it as a factor

I really hope you did not attempt to clean it out.

What did you do with the intake?

When you replaced your starter what did you do with the intake gaskets?, re-use or replace?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

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What is TEC? Are you speaking of Techron? Techron if used in the wrong manner could cause problems but lets not go there yet.

Where they OEM wires? Did you use dielectric grease with those wires? If you did, that is wrong, the OEM wires COME with dielectric grease impregnated in them and IF you use more grease you can cause a misfire.

Look in every spark plug hole for OIL build up from a leaking CAM seal.

Determine which cylinders are NOT firing and check the plug and wire carefully.

see this

Dielectricgrease.jpg

TEC is Top Engine Cleaner GM part #1052626 used for carbon build up. I'll try to attach the service bulletin.

Plug's were done by my dad (mechanic) and i'm sure he put in the right ones. He's very by the book. also the wires are delco and we did use the the dielectric grease.

My question is how would too much grease take 10K miles to act up? Where did you get your article so I can send it to my dad?

I'll wait till morning to check the plugs. let the heads to cool down. Don't want to tear out the threads.

CarbonRemoval.pdf

Cop didn't see it, I didn't do it!

93 STS 225,000 Miles

99 STS 111,000 Miles

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Using the dielectric grease is potentially your problem, pull the plugs and clean it off carefully. The 10K miles is about perfect time for it to leach down to make a connection. Clean it off good, use electrical contact cleaner. Its not necessary and could be the root of your miss.

You say how much grease?, I say ANY grease is too much grease, if you read that clip I put up from the FSM. Also check your plugs for cracks in the porcelan. Look down each plug port and see if you see OIL welled up also. Make sure each plug wire is securely snapped on.

One more thing, the new fuel rails cause the plug wires to be pinched between the vanity cover and the rail, check for arching there, I think PAUL had this problem and I have evidence of arching, I used wire loom at each contact point.

That carbon removal is carbon on the TOP of the pistons to stop the CCR not carbon IN the intake if that is what you are talking about.

The guru was never concerned with the carbon primortial goo in the intake or carbon around the ERG ports, just clear it off and drive it, it needs cleaning at 100K

Mike

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

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One more thing, the new fuel rails cause the plug wires to be pinched between the vanity cover and the rail, check for arching there, I think PAUL had this problem and I have evidence of arching, I used wire loom at each contact point.

That carbon removal is carbon on the TOP of the pistons to stop the CCR not carbon IN the intake if that is what you are talking about.

The guru was never concerned with the carbon primortial goo in the intake or carbon around the ERG ports, just clear it off and drive it, it needs cleaning at 100K

Mike

Good to know. I did pull the plastic cover to look for the wires getting pinched. I also popped the hood last night and did not see any evidence of arching... I did hear noise around the coil packs but I think it's just the pcv making noise. Someone once mentioned taking a squirt bottle and lightly spraying the coil packs at night to see if it is arching... might try that next.

I do have to leave for a trip tomorrow morning and wont be back till sunday... might have to wait till then for pulling plugs... can I just pull the plug wire one at a time while running to see which one is not firing. IE if the skip get's worse then it's not that one? can I get a good jolt doing it?

MD

Cop didn't see it, I didn't do it!

93 STS 225,000 Miles

99 STS 111,000 Miles

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One more thing, the new fuel rails cause the plug wires to be pinched between the vanity cover and the rail, check for arching there, I think PAUL had this problem and I have evidence of arching, I used wire loom at each contact point.

That carbon removal is carbon on the TOP of the pistons to stop the CCR not carbon IN the intake if that is what you are talking about.

The guru was never concerned with the carbon primortial goo in the intake or carbon around the ERG ports, just clear it off and drive it, it needs cleaning at 100K

Mike

Good to know. I did pull the plastic cover to look for the wires getting pinched. I also popped the hood last night and did not see any evidence of arching... I did hear noise around the coil packs but I think it's just the pcv making noise. Someone once mentioned taking a squirt bottle and lightly spraying the coil packs at night to see if it is arching... might try that next.

I do have to leave for a trip tomorrow morning and wont be back till sunday... might have to wait till then for pulling plugs... can I just pull the plug wire one at a time while running to see which one is not firing. IE if the skip get's worse then it's not that one? can I get a good jolt doing it?

MD

There are two problems with that 1) it will knock you are your azz and 2) sparks can fly around and damage electronics. Check your codes you might get a P030X where X is the cylinder #.

Use one of these to contain the high voltage

http://www.thetoolwarehouse.net/shop/LIS-50850.html

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/

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There are two problems with that 1) it will knock you are your azz and 2) sparks can fly around and damage electronics. Check your codes you might get a P030X where X is the cylinder #.

It just comes up as po300 has not tolm me which cylinder yet. I did just pull the boots off the plugs and cleaned them. No sign of deposites on the top end of the plugs (i'll wait till it's cold to pull the plugs out to look.) and I also checked the ends up at the coil packs and there were no signs of burning or crbon. Is there a way to pull the ignition pack one at a time and look for signs of malfunction? when they fail is it an internal failure or is there arching associated with it that's visible via a burn mark or melting?

BTW, I originally did the TEC because it was backfiring into the intake manifold. We assumed carbon on the valves.

thanks again, MD

Cop didn't see it, I didn't do it!

93 STS 225,000 Miles

99 STS 111,000 Miles

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If I were you I would

1) buy a new coil and swap it into each position to see if you can eliminate your problem, they fail internally and externally but you would hear and see it if it was external, see this link > http://caddyinfo.ipbhost.com/index.php?showtopic=16967

2) test each ignition wire with an ohm meter to see if you have a wire that has a problem and check the plugs and look for oil in the plug wells.

3) definately do a compression test on each cylinder, maybe you have a burned valve we have seen that, I think either Paul or Growe had one. Bad compression will cause a mis-fire.

Good Luck, let us know what you find

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/

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If I were you I would

1) buy a new coil and swap it into each position to see if you can eliminate your problem, they fail internally and externally but you would hear and see it if it was external, see this link > <a href="http://caddyinfo.ipbhost.com/index.php?showtopic=16967" target="_blank">http://caddyinfo.ipbhost.com/index.php?showtopic=16967</a>

2) test each ignition wire with an ohm meter to see if you have a wire that has a problem and check the plugs and look for oil in the plug wells.

3) definately do a compression test on each cylinder, maybe you have a burned valve we have seen that, I think either Paul or Growe had one. Bad compression will cause a mis-fire.

Good Luck, let us know what you find

Have to buy a multimeter... It's about time. I cant do a compression check unless I head back up to my dad's shop. Hope it's not the valve! Thanks again for all your help. MD

Cop didn't see it, I didn't do it!

93 STS 225,000 Miles

99 STS 111,000 Miles

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You can buy a compression tester very cheaply. You just need to disable the ignition so it does not start and have a helper. Keep in mind that your compression tester must reach down the spark plug port.

If you had this popping back into the intake before you did the wires, the first thing I would do is a compression test to eliminate that as a cause. A bad coil shouldn't cause popping back into the intake I don't believe.

I am sure others will chime in here with their thoughts, I am off to NJ and will be back late tonight, Mike

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

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Does the miss disappear? Car will run normal and then start to miss usually after let off the gas? Does flooring the gas pedal clear it up? I have that problem also, it is a pain to find out what is causing it. I had my friend hook a scan tool up, and it would be random missfires on the rear bank, probably the reason the PCM wont narrow it down to one cylinder,then it would just start firing on all cylinders again. There is no ryme or reason to it, it just comes and goes which makes it hard to nail down. Temp, weather,fuel level,rpms,voltage, none of them have an effect. I don't think it is the coil pack but we will be switching the front and back on Saturday to see if the miss moves to the front bank. If you figure it out. post back. I will do the same.

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Does the miss disappear? Car will run normal and then start to miss usually after let off the gas? Does flooring the gas pedal clear it up? I have that problem also, it is a pain to find out what is causing it. I had my friend hook a scan tool up, and it would be random missfires on the rear bank, probably the reason the PCM wont narrow it down to one cylinder,then it would just start firing on all cylinders again. There is no ryme or reason to it, it just comes and goes which makes it hard to nail down. Temp, weather,fuel level,rpms,voltage, none of them have an effect. I don't think it is the coil pack but we will be switching the front and back on Saturday to see if the miss moves to the front bank. If you figure it out. post back. I will do the same.

It does not always clear up on WOT. Some times it feels like 6 are running, sometimes 7, sometimes all 8 cylinders. I did pull the front plugs last night and 2,6,8 were white with powder and #4 was a black powder. not wet and oily just a caked on black powder. It also looks like the gap was much larger that the others... I "cleaned" it off and my misfire cleared up a little. (like now i'm back on 7 cylinders instead of 6)... when I get back from my trip sunday I'll be pulling all 8 and see if which ever coil runs #4 and ??? will that plug be the same way? if so I say coil. if not then time for all new plugs and start over!

Now off topic when I pulled the #6 spark plug there was oil ON TOP of the plug. What I mean is it was in the cavity for the plug but did not leak down onto the threads or ignitor. Is there a valve cover gasket that is supposed to seal this area off? It was pooling up a bit!

Thanks again guys! MD

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93 STS 225,000 Miles

99 STS 111,000 Miles

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THAT is exactly what I have been saying OIL in the spark plug PORT!!!! There are CAM cover oil seals at each plug port that can leak oil into the spark plug port. That facilitates a path of the spark to ground... clean out ALL oil with a vacuum

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/

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THAT is exactly what I have been saying OIL in the spark plug PORT!!!! There are CAM cover oil seals at each plug port that can leak oil into the spark plug port. That facilitates a path of the spark to ground... clean out ALL oil with a vacuum

ok. thanks again.

Any take on why #4 was black when #6 had the oil problem? Is it just too wide of a gap on #4?

Cop didn't see it, I didn't do it!

93 STS 225,000 Miles

99 STS 111,000 Miles

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THAT is exactly what I have been saying OIL in the spark plug PORT!!!! There are CAM cover oil seals at each plug port that can leak oil into the spark plug port. That facilitates a path of the spark to ground... clean out ALL oil with a vacuum

ok. thanks again.

Any take on why #4 was black when #6 had the oil problem? Is it just too wide of a gap on #4?

Hard to tell why, #4 and #6 are not on the same coil, if they were it would be possible for the oil welling on #6 to provide a path to ground on #4.

Check the gap, black is an indication of a rich mixture and it could be unrelated to your mis. I would fix the mis first then investigate the #4.

It could be a leaky injector and it could be low compression, as I noted you should perform a compression test to eliminate any mechanical issues, if you have a burned valve you need to know that.

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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Did cleaning the OIL out of the spark plug well/port improve the mis?

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/

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So after the car sat while i was away on my trip..... No more backfire! Yea! I guess those WOT and the TEC blew out the carbon... I'm not thinking it's a burnt valve because I don't hear it firing through the tail pipe (never did) or the intake anymore. I just think it was a little carbon on the intake valve...

However, I'm still down 1 or 2 cylinders. Did the plugs yesterday and found that my #4 and my #1 were black (rich) and the other 6 looked all the same. I did clean out the oil on #6 valley... The misfire is still there. Definitely feels like two cylinders are bad, It comes and goes but when one plug is firing I'm still getting a skip, just smaller. AKA it's like a two stage skip. sometimes bad. sometimes really bad. I think that since #1 and #4 are rich then I will replace that coil pack (since it's on the same one).

I do not have the opportunity or the tools do do a compression check. Unfortunately I have a trip in 2 days (gone for 4) and when I get back I'll be having surgery for a hernia then I'm laid up for a few weeks...

I might also get a multi meter first and measure the resistance of the coils to see... Any other idea's?

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It was the coil pack! $75 and i've solved the problem.. Well I feel better. Thanks for all your help guys. MD

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It was the coil pack! $75 and i've solved the problem.. Well I feel better. Thanks for all your help guys. MD

NICE, Mike, glad you got it fixed.

Do me a favor, if you don't want that coil could you send it to me? I would like to take some resistence readings on it to see if we can determine what a BAD coil looks like. If you don't mind sending it to me PM me and I will provide you with my address

Thanks, Mike

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/

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Send your info to Davism4@juno.com and it's yours! Thanks again for your help.

Cop didn't see it, I didn't do it!

93 STS 225,000 Miles

99 STS 111,000 Miles

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Send your info to Davism4@juno.com and it's yours! Thanks again for your help.

Thanks Mike, I sent you my address, I will post my measurments in a thread that JimD started, where we are exploring coils. I will post your coil's resistence readings in this thread:

http://caddyinfo.ipbhost.com/index.php?showtopic=16967

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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Send your info to Davism4@juno.com and it's yours! Thanks again for your help.

Thanks Mike, I sent you my address, I will post my measurments in a thread that JimD started, where we are exploring coils. I will post your coil's resistence readings in this thread:

<a href="http://caddyinfo.ipbhost.com/index.php?showtopic=16967" target="_blank">http://caddyinfo.ipbhost.com/index.php?showtopic=16967</a>

Glad to hear it's all worked out for ya!

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