P0300 after Trex install, i've check about everything!
#1
cry-baby buyer
Thread Starter
iTrader: (28)
Join Date: Dec 2002
Location: Summerville SC
Posts: 212
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Unhappy](https://ls1tech.com/forums/images/icons/icon9.gif)
I had a 228/228 tuned and installed for about 4 weeks and no problems. Well that cam wasn't enough for me. I pulled it out and went with the Trex thunder racing cam last Tuesday. I ran a mixture of 112 and 93 and it was running great until Friday (about 20 miles). SES light came on so figured it was the O2's. I bought denso O2 and installed them but that seems not be to be the problem. Took it to the part store and they scanned it...throwing p0300(multi misfires). But it anly does it from 2k-3.5k then clears up. It run great WOT or part throttle.
I know the computer needs more work for this cam 242/246, but would that be the cause from the misfires?? Do you have any ideas?? I searched LS1techs forums and found out it could be abunch of things(bad wires, broken valve spings, ect). Some people deleted that code completely out of there computer with no more problems. But my tuner thinks theres more to it than that. He seems to think it igniton related and doesn't think deleting it will solve anything.
When I installed the first cam, I relocated the coil packs under the cowl with Thunders kit. I have ohm'd out the wires and they are all between .089-.184..seems ok to me. Next I took out the plugs, which were new TR55's when i installed the first cam 4 weeks ago and 1,3,5,7 are black. 2,4,6,8 are clean...maybe alittle lean. I also have the valve covers off and the springs look good with the quick once over i gave them.
What do you think it could be??????? Car's a 98Z M6 btw.
Alan
Blo-byu@sc.rr.com
I know the computer needs more work for this cam 242/246, but would that be the cause from the misfires?? Do you have any ideas?? I searched LS1techs forums and found out it could be abunch of things(bad wires, broken valve spings, ect). Some people deleted that code completely out of there computer with no more problems. But my tuner thinks theres more to it than that. He seems to think it igniton related and doesn't think deleting it will solve anything.
When I installed the first cam, I relocated the coil packs under the cowl with Thunders kit. I have ohm'd out the wires and they are all between .089-.184..seems ok to me. Next I took out the plugs, which were new TR55's when i installed the first cam 4 weeks ago and 1,3,5,7 are black. 2,4,6,8 are clean...maybe alittle lean. I also have the valve covers off and the springs look good with the quick once over i gave them.
What do you think it could be??????? Car's a 98Z M6 btw.
Alan
Blo-byu@sc.rr.com
#4
cry-baby buyer
Thread Starter
iTrader: (28)
Join Date: Dec 2002
Location: Summerville SC
Posts: 212
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
So why do you think it didn't do that at first start?
Why did it wait till after i drove it around awhile?
I'm only asking because the guy who tuned the computer wasn't convinced that the tune was the problem....yes it still needs a tune for the cam but he's thinking it something else!
Alan
Why did it wait till after i drove it around awhile?
I'm only asking because the guy who tuned the computer wasn't convinced that the tune was the problem....yes it still needs a tune for the cam but he's thinking it something else!
Alan
Trending Topics
#10
10 Second Club
iTrader: (5)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by BLO BY U - TA
So why do you think it didn't do that at first start?
Why did it wait till after i drove it around awhile?
I'm only asking because the guy who tuned the computer wasn't convinced that the tune was the problem....yes it still needs a tune for the cam but he's thinking it something else!
Alan
Why did it wait till after i drove it around awhile?
I'm only asking because the guy who tuned the computer wasn't convinced that the tune was the problem....yes it still needs a tune for the cam but he's thinking it something else!
Alan
#11
cry-baby buyer
Thread Starter
iTrader: (28)
Join Date: Dec 2002
Location: Summerville SC
Posts: 212
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by jay_99z
Your car isn't the first car that your tuner has sent out with P300 problems. The two others I've seen tuned by him also had this. Can't say that on SCFYB but he needs to fix it.......that is all you have wrong.
thats funny
![Secret](https://ls1tech.com/forums/images/smilies3/secret2.gif)
#13
TECH Fanatic
iTrader: (1)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Or save the trouble and disable misfire detection.
Misfire detection was designed for the characteristics of a bone stock motor. When you start changing factors such as rotating mass, say flywheel and under drive pulley, and the addition of a cam and stiff valvetrain will make detection and misfire rates invalid.
You can always raise the detection rates. For example, any reading below 3000, raise it to 3000. However on most large h/c ls1's I tune I disable it. Max misfire detection is usually set at 266*, raise the min up to 265* to disable. If there's a true misfire problem you'll feel it anyway.
Misfire detection was designed for the characteristics of a bone stock motor. When you start changing factors such as rotating mass, say flywheel and under drive pulley, and the addition of a cam and stiff valvetrain will make detection and misfire rates invalid.
You can always raise the detection rates. For example, any reading below 3000, raise it to 3000. However on most large h/c ls1's I tune I disable it. Max misfire detection is usually set at 266*, raise the min up to 265* to disable. If there's a true misfire problem you'll feel it anyway.
#14
TECH Junkie
iTrader: (4)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by BLO BY U - TA
Well...
thats funny
He was all but helpful over the phone!
thats funny
![Secret](https://ls1tech.com/forums/images/smilies3/secret2.gif)
all but helpful? so he didnt help? im confused
![Icon Confused](https://ls1tech.com/forums/images/smilies2/icon_confused.gif)
anyhoo, on a large cam LS1, if YOU have HPtuners, YOU know what you're doing, then a minor misfire code is nothing, and YOU can spend the hours/days tweaking the misfire detection so that it doesnt go off when its not supposed to....
but if you're getting a 'professional' to tune it with a large cam, they normally just turn it off... professionals dont have time to spend days with minor things like misfire control, part throttle tweaking, ect.. its just not the way they can do business.
go there, have him turn it off, and you'll be set... or you can chase your tail sending it back 80 times as he tries to get it to not show false counts....
#15
cry-baby buyer
Thread Starter
iTrader: (28)
Join Date: Dec 2002
Location: Summerville SC
Posts: 212
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
[QUOTE=MrDude_1]all but helpful? so he didnt help? im confused
Wasn't helpful....said it wasn't the computers problem, its ignition related. Go though the plug wires, ohm them because they are Taylors...Burnt wire (new, not burnt I said)
But at the same time would turn it off if I wanted him too. Just wasn't thrilled about doing that!
Alan
![Icon Confused](https://ls1tech.com/forums/images/smilies2/icon_confused.gif)
Wasn't helpful....said it wasn't the computers problem, its ignition related. Go though the plug wires, ohm them because they are Taylors...Burnt wire (new, not burnt I said)
But at the same time would turn it off if I wanted him too. Just wasn't thrilled about doing that!
Alan