Author Topic: Random misfires (P0300) - variable cam timing ?? (Read 46041 times)

Chemist · « **Reply #75 on:** January 15, 2011, 01:54:12 PM »

Quote from: NormSky on January 14, 2011, 10:09:59 PM

Thought maybe you'd pull the head yourself. Yeah, I don't have a heated garage either.

I have a Ph.D. in Chemistry which equips me to _pay_ someone to pull the head.

Chemist · « **Reply #76 on:** January 21, 2011, 12:23:06 AM »

Well, the Prodigal has come home! After nine weeks in the shop and the exchange of a chunk of $$, she seems to be running as well as ever.

The exhaust valves on #3 cylinder were indeed the culprit in this drama. After a full valve job and head resurfacing, I'm back up and running.

Again, I appreciate everyone's input on this. Hope none of you have to go through similar travails.

NormSky · « **Reply #77 on:** January 21, 2011, 02:00:58 AM »

Did you ever have a plugged cat? What is your exhaust setup now and total mileage.

Kelu · « **Reply #78 on:** January 21, 2011, 03:27:00 AM »

Glad to hear that Chemist

enjoy it as much you can

back to permagrin

1KULSOL · « **Reply #79 on:** January 21, 2011, 07:06:59 AM »

Quote from: Chemist on January 21, 2011, 12:23:06 AM

Well, the Prodigal has come home! After nine weeks in the shop and the exchange of a chunk of $$, she seems to be running as well as ever.

The exhaust valves on #3 cylinder were indeed the culprit in this drama. After a full valve job and head resurfacing, I'm back up and running.

Again, I appreciate everyone's input on this. Hope none of you have to go through similar travails.

Byron,
glad it all worked out for you ...

GXPinKC · « **Reply #80 on:** January 21, 2011, 08:09:11 AM »

Quote from: Chemist on January 21, 2011, 12:23:06 AM

Well, the Prodigal has come home! After nine weeks in the shop and the exchange of a chunk of $$, she seems to be running as well as ever.

The exhaust valves on #3 cylinder were indeed the culprit in this drama. After a full valve job and head resurfacing, I'm back up and running.

Again, I appreciate everyone's input on this. Hope none of you have to go through similar travails.

Wow, it has been an adventure for sure. You are back to

So glad that the perma grin returns Chemist and you are good to go

!

Chemist · « **Reply #81 on:** January 21, 2011, 09:02:52 AM »

Quote from: NormSky on January 21, 2011, 02:00:58 AM

Did you ever have a plugged cat? What is your exhaust setup now and total mileage.

Not to my knowledge. I installed a ClearImage high flow cat (with their Shorty Headers) at 15,000 miles. I had DDM's long tube headers and high flow cat installed with the S/C (stage II) at 34,000 and have about 63,000 miles as of today.

To all, again, I thank you for your concern and your friendship.

Brad Kenny · « **Reply #82 on:** January 21, 2011, 09:24:36 AM »

Quote from: Chemist on January 21, 2011, 12:23:06 AM

Well, the Prodigal has come home! After nine weeks in the shop and the exchange of a chunk of $$, she seems to be running as well as ever.

The exhaust valves on #3 cylinder were indeed the culprit in this drama. After a full valve job and head resurfacing, I'm back up and running.

Again, I appreciate everyone's input on this. Hope none of you have to go through similar travails.

The real question here is, "Why?"

What was the cause for the failure, just use (daily wear) or the S/C putting extra stress on the engine? This is a very informative topic. Thanks Chemist for letting us into your engine problems.

smartin · « **Reply #83 on:** January 21, 2011, 11:12:02 AM »

Way to go, Byron!

Critterman · « **Reply #84 on:** January 21, 2011, 11:15:24 AM »

#3 - interesting, most everything I have read is either #1 or #4 but most of those are the LNF engine. Did they say what was wrong, burnt, bent ??

Chemist · « **Reply #85 on:** January 21, 2011, 12:48:02 PM »

CT_Solstice:

I put the question of cause to the shop owner. His conviction is some "silent knock" (i.e. undetected detonation) that caused some initial pitting which then led to valve malfunction which led to more detonation which led to more pitting, more valve malfunction, etc. While the S/C certainly could have accelerated the process, I do not believe it to be the proximate cause. I should also mention that all four valve guide had greater than normal play, this also could have contributed to this.

Critterman,

As I said above, the valves were excessively pitted, allowing leakage. I have all new valve seats now, freshly ground valves, and a resurfaced head (with all new gaskets, of course). My duty now is to make sure I'm running the correct octane fuel at all times. I'm planning/hoping to get the car back to them ASAP to have them do a full-on dyno tune to get me tuned for the (max) 91 octane I can get in Lubbock, TX.

To all, (smartin in particular

)

Thanks for your concern and kind words, and again, your input on this.

--Chemist

Yogi · « **Reply #86 on:** January 21, 2011, 02:10:17 PM »

WOW! A burned valve! Seems like that would have shown up in a compression test early on. Did they run a compression test when you first took it in?

Glad to see that you are back in the saddle, Byron! Thanks for sharing all of your info!

LatinVenom · « **Reply #87 on:** January 21, 2011, 05:06:36 PM »

Glad everything is working now.
I would stay with 91 octane if you can.

Critterman · « **Reply #88 on:** January 21, 2011, 05:08:32 PM »

Can't get 93 in Texas the gas and oil state? What is this country coming to.

Yogi · « **Reply #89 on:** January 21, 2011, 06:02:31 PM »

It's a regional thing. We have 93 in Greater Houston Area.

Chemist · « **Reply #90 on:** January 21, 2011, 09:35:10 PM »

I can get 92 _most_ of the time in Lubbock. That's as high as it gets, as we are 3400 ft above sea level.

LatinVenom · « **Reply #91 on:** January 22, 2011, 05:44:42 PM »

Then if you can stick with 92 all the time.

Chemist · « **Reply #92 on:** January 22, 2011, 07:46:32 PM »

Quote from: LatinVenom on January 22, 2011, 05:44:42 PM

Then if you can stick with 92 all the time.

I have done so, whenever possible. I think I've put one tank of anything below 90 and few below 91 in 63,000 miles.

LatinVenom · « **Reply #93 on:** January 23, 2011, 07:21:49 PM »

The question then to you would be as follows.
Did you drive it the same as when you use the 92?.

NormSky · « **Reply #94 on:** January 23, 2011, 07:57:23 PM »

Probably happen again if you don't monitor knock. Weigh what you just paid to a $270 Aeroforce Interceptor to clear codes and monitor your operating system.

Chemist · « **Reply #95 on:** January 23, 2011, 08:51:37 PM »

Quote from: LatinVenom on January 23, 2011, 07:21:49 PM

The question then to you would be as follows.
Did you drive it the same as when you use the 92?.

Driving with the tank of sub-90, I babied it until I could get 92+. That specific tank was more than 18 months ago, BTW.

Quote from: NormSky on January 23, 2011, 07:57:23 PM

Probably happen again if you don't monitor knock. Weigh what you just paid to a $270 Aeroforce Interceptor to clear codes and monitor your operating system.

Thank you, Cassandra. Your concern is noted.

I have had a DashHawk since long before I had the S/C in this car. I've monitored the system as best as I can. Mechanical things are subject to breakage, sometimes even in the face of our best efforts to protect them. In light of the fact that systems similar to mine have been run harder than I have run mine for a longer time than I have run mine, I chalk this up to the unfortunate occurrence of a low probability event. Of course, since determining the proximate cause of my recent ills is speculative at best, I'll just have to drive watchfully and see.

Critterman · « **Reply #96 on:** January 23, 2011, 09:05:15 PM »

As they say "$h!t happens" just sucks when it happens to you.

anyone know how many stock 2.4's have bit the dust. All we ever hear about is the 2.0's giving up the ghost.

NormSky · « **Reply #97 on:** January 23, 2011, 09:15:02 PM »

Just DDM Supercharged ones like Byron and Jimmy.

That's why I was looking at octane, plugged cats and KR monitoring. But both of them have DashHawks.

Critterman · « **Reply #98 on:** January 23, 2011, 09:48:50 PM »

But Norm they are not stock which is the question I asked. Are you saying they are the only twq 2.4's that have had engine problems? I find that hard to believe. Solefood blew up and that was a Hans turbo, and then there was one more I can think up. Guy bought it and it came aI part, it was forced induced at well. I belive that one now has a V8.

That is 4 I can think of, all forced injected, none stock. I will ask again how many so stock motors have gone south? Everyone I read about has been an LNF not an LE5.

Sol Asylum · « **Reply #99 on:** January 23, 2011, 09:58:02 PM »

And how many of the LNF that failed were still stock?

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Author Topic: Random misfires (P0300) - variable cam timing ?? (Read 46041 times)