ok I replaced the faulty injector and that got rid of the misfire cylinder 1 code but i still cant get her to stay at and idle. she will start right up and i can hold it at like 1300-1400 rpms and shes fine but as soon as I let off it will start to backfire. the full specs of the cam is a comp cam 224/224 .563 and 112 lsa. I was wondering if the low lsa could cause that? I have an hp tuner and was searching for a base tune just to get her to a dyno tuner but i couldn't find anything.
again thanks for all the help

 

PM me If I live close enough to you I will come help you get it running. You said you have tunners right? You can take a scan and a copy of the tune ill take a look.
~Derek

 

out working on the car again i've got several people saying it could be a vacuum leak but we checked all the lines and sprayed down the lines and couldnt find anything. also there is a loud squeal that sounds almost like a bird coming from around the throttle body area. and its not the belts..... the problems just continue.

 

It's the tune. I just cammed my truck and had the same issue. Started up and idled perfect on the stock cam open loop SD tune. Went back to take it for a drive and it wouldn't idle for **** and died. The PCM makes airflow corrections which screws up the fueling. Bottom line....tune.

 

fwiw i was looking over the tunes again and as soon as the car starts to warm up the short term fuel trim on the drivers side goes from 2 and steadily climbs to 25 at which point the car backfires. its only on the drivers side any what that could be from?

 

O2 sensor. Do you have all 4 on or are the rears deleted? I had two O2's die on the dyno. They flatlined at idle but would come on when the engine was reved up. The voltages would go from 0 to .7, but threw no code. Make sure they are switching and the voltages are right. I believe around .1 to .9
its been a while; anyone else know for sure?

 

In his second post, he did say it was throwing an O2 code so that's prolly the cause for the FT issue ...

 

I have the rear 02's deleted I'll go ahead an invest in a new set of 02's i could use them anyway.

 

I hope this fixes it. I need some closure! As I am sure you do too.

 

Man i was hoping to click onto pg 5 with problem fixed.. ill check back to see what happend, sucks that this happened.

im sure it will be somthing small.. always is!

 

Sure sounds like the pushrods are too long. You can't assume anything. If the base circle on the cam is larger or you changed lifters the lifter preload may have changed , that could cause the valves to hang open slighly causing the backfiring and poor idle.You need go back thru and double check the lifter preload/ pushrod length.

I rushed thru my last motor and assumed everything was OK. I had backfiring and car would not idle. I had used morel lifters and come to find out the seat in the lifter is a little higher than the LS7 lifters. I found I needed to get 7.300" length pushrods to get the right preload. Preload is now at 3/4 of a turn. Car runs great now.

Good Luck, Hope you find your problem soon.

DJ

 

well I finally found time to get back out and work on the car. we tore it back down and rechecked the timing and came to the conclusion that I might be 180 degrees out. but everything I've ever heard of says it won't run that far out of time. but again everyone I've talked to including gm techs says 100% its timing. yall have any feedback

 

So with the dot on the crank pointed up, the cam gear dot is at 12 o clock instead of 6?

 

he keeps "tearing it down" and doesnt recheck the preload. idk how many times ppl install cams here and dont check their preload or torque rockers on the base circle of the lobe they are torquing.

htf do you tear it down and THINK your 180 out?

 

So you came to the "conclusion" that it "might" be 180 out? How did you come to that conclusion? You already stated the dots lined up. Have you tried swapping 02's from right to left to see if the fuel trims follow?

 

Finally got the time to finish up the car and we adjusted the timing and it was 180 degrees out, the crank gear has two dots and we happened to just not be on the compression stroke. any ways we put it back together and started her up and she started great and idled about 1400 but the idle would fluctuate between 1300 and 1500 as if it were camming. after about 2 minutes i noticed it sound as if it had a slight miss in it and the passenger side header was glowing red. she is running extremely rich and i know that's because of the tune but would that cause any of that? also in the time i had the car on i was not throwing any codes.

 

so we set base timing, torqued everything to spec (INCLUDING ROCKERS), all plug wires F.I. Coils etc are plugged in.
car runs ok, idles up and down, misses when it warms up.
ONly backfires once or twice when started.

Possible wiped cam?????

What else i dont know, i love seeing it in my driveway but not that much hahahaha

 

Workin on satans camaro...got TDC and timing set, everything back together.... went to fire it up..
1st start ran good, 2nd start rank ok, warms up throws a TPS code, 3rd start runs ok, warms up...throws a misfire cyl #1 code....4th start- Idle weird, up and down. Went to Vac test for leaks, engine warms up and starts backfiring like it did before.also threw a p0303 code, misfire cyl 3
I think he got robbed on a used cam. Guy said it ran fine when removed, but hell he can say anything now. plus, coulda got dropped in shipping or something too...... hmmmm
WHAT DO YOU GUYS THINK?

 

Oh, and on the pushrod deal, rods are said to be stock length, but matched to the .224 cam