Misfire in #7

[black_yukon]

Finnaly got the ATAP running and found that I am having a misfire in #7. I changed the plug and switched the wires with a different cylinder but am getting the same SES code. What could be the problem?

[1999stepside]

Hopefully it's not this...if it is...you better start looking for a new motor.

http://www.ls1tech.com/ubb/ultimatebb.php?ubb=get_topic;f=18;t=002897

http://www.ls1tech.com/ubb/ultimatebb.php?ubb=get_topic;f=18;t=002929

Good luck, Kent.

[black_yukon]

Oh GOD Please say it ain't so!!!!! How do i know if the piston is blown? The truck idles and runs okay.

[black_yukon]

Okay worse case scenario, if the piston is blown, can I just rebuild the block or am i screwed?

[Flyer]

Worse case scenario I would say you just need to rebuild the bottom end. As long as it isn't spooging oil out of a hole the size of a piston in the block, I would think it should be just fine. You might take it and get it bored out a little though. I would put forged crank, rods and some nice rod bolts in it while I was in the bottom. If you feel like maybe even a cam and get the heads port and polished.

Sry .. was getting off track and day dreaming a little. If it is just the piston, all you would need to replace THE piston. It would be more logical to replace them all as a set though. You may consider getting the rods inspected too, just to make sure one isn't bent.

[1999stepside]

You should probaby get a compression test done. If there is some internal engine damage, I have a great shop in Monrovia off of the 10 fwy that you should check out, works only on LS1's and LT1's, with great prices.

Good luck, Kent

[AZ_Matt]

Sorry to hear about that!

But on the bright side, if you do have to rebuild, look for a 5.7 or 6.0 short block on EBay... Stoopid power!

Matthew

[black_yukon]

Hey Kent, what's the name of that place in Monrovia. I was thinking about going to Morgan Motorsports in Reseda, but i know they are kind of pricey.

[1999stepside]

Andy's Auto Performance in Monrovia...talk to Mark. He is the one that rebuilt my tranny and installed my converter, and many other things. Check over in the Western forum on ls1.com and there are tons of his customers there.

http://www.andysautoperformance.com/main.html

Kent

[Y2KLimited]

if i were in cali I'd check morgan motorsports....

they do some awesome work, this month I picked up a new Z06 vette http://james.jaguar.net/y2klimited/vette10.jpg

needless to say its fast, and I love my procharger on the truck, why not the vette too, right? I saw a dyno yesterday of a Z06 they put their custom made supercharger kit using a P1 or D1 headunit on, long tube headers and their custom in house dyno tune. 607 RWHP!!! off a car that does a stock baseline of 330ish (405 crank) with 9 lbs. Those guys know their LS1 engines, I'd definetely check them out, if my truck was the new body style I'd be talking to them already. Called about the vette, guy seemed very knowledgable on the phone and talked with me for at least a good half hour. Seem like real decent guys, but I'd do the compression test first. I was having misfires way back when (fouled plugs) on my truck, even with a blown headgasket my pistons were fine.......I doubt you blew a piston, but we are talking two different engines here from teh 5.7 to a 5.3

[black_yukon]

I had my truck dyno'd at Morgan and the guys there were awesome. They deffinitely know their stuff. They are pricey though, but then again, if the work is worth it, then I'm willing to pay a little more. I'm gonna go to a local mechanic for the compression test though.

[1999stepside]

Any update on this?

Kent

[black_yukon]

unfortunately not yot, I was suppose to get a compression check last monday, but my backyard fence blew over because of high winds and I had to get it fixed so my dog wouldn't escape!!!!!

[Procharged LM7]

What's the verdict Pete? You get it checked out yet? Hope it's fine dude! Sam

[black_yukon]

finally got the compression check done last monday. My friend is taking a mechanic class that the local junior college and we did it there, real easy. The cylinder seems fine, good compression, so now I need to figure out how to test the fuel injector.

Now that I have atap running, I found that it only missfires under 1000 rpm.

I'll keep you guys updated...

Another thing that I noticed while working on the truck was that I was getting a lot of oil in the air filter elbow. It was coming from the crank case vent line that is rerouted to the elbow. My ricer friend suggested I get an oil catch can to relieve this.

[Procharged LM7]

AWESOME!!! do a search on LS1Tech. Remeber me asking you bout this a while ago? There are lots of threads about it.
Good to hear things are solid! I did my PCM relocate today, and bolted up my FMU the other day. I know, I know, it's alot for me though. Should have her on a week or two :D

[Flyer]

Try pulling the injector out and clean the hell out of it. Maybe it has some trash in it. When you get up over 1000 rpm the fuel pressure is enough to overcome the small piece of trash.

Just a thought ...