I had originally posted this in the tuning section.. but it doesn't seem to be tuning (timing/idleing problem)

Here is a list of my mods;

2000 SS
98 Ported and polished Heads (2.02 1.56 Ferra Valves) milled 30 over.
MMS 229/229 566/566 112lsa
Grot LongTubes
98 valve covers with 99 coils
tr55 plugs
msd wires
PI 3800 multi-disk TC (guess that really doesn't matter here)
all the free mods
Shaner S2 TB
lid/filter
BV Perf. dyno tuned (before heads/cam swap)
Prolly some more stuff i forgot as well, but those are the biggies.

I orig. had MTI B1 in there with stock 2000 heads.
I just put the heads/valve covers and new cam in and now when i start it.. i first have to give it some throttle to start and then it won't idle. The engine is shaking really bad and when i let off the throttle to let it die it makes the most god awful backfire i have ever heard.

I have no fluid leaks anywhere and everything "looks" ok. My car sat up for 2.5 months while waiting on the head and misc parts, so i though i may just need to run it for a bit to get all the fluids back in the engine and blow out all the crap (dust/debris from sitting) no dice. If i try to keep it idleing at around 1k my A/F gauge reads really lean.. so i killed it (or should i say let it die) and booom nasty backfire.

the throttle response is really **** poor as well.
I'm at my wits end with this.. i did all the work myself (minus the port and polish on the heads)
and i thought i have checked everything twice??

Here are some small things in putting it back together that i know that of;

1.)egr assmb. that connects to the headers, isn't bolted all the way (one bolt is tight, the other is not tightend all the way) I didn't think this was a big deal considering the codes are delted anyway.
2.) The AIR tube on the drivers side is similiar, one bolt is tight and the other I couldn't get to thread because i have the wrong air tube. However, the one bolt is really tight and doesn't seem to be leaking or anything.
3.)I did use a new head/install kit (new bolts, gaskets, etc)
Nothing that i did seems to be on wrong.. torque specs on the heads were followed, etc.

Somebody have an idea on why it's running so bad?? Any help would be much appreciated...

signed,
About to scrap the LS1 and put in a 504 BB and tub it.
akaevin
<img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

PS: sorry about the book, but i wanted to relay all i could.

 

Spray some carb cleaner around those EGR and AIR parts and see if your car throttles up. Those are really bad places to have an exhaust leak.

How big of a hole do you have in the throttle blade, you have a lot of cam now.

 

If you get air entering those areas, it will cause a faulty O2 reading. Hook up an ATAP or Tech 2 and see what some various sensors are reading.

If the Misfires across the board are roughly the same, it could be an injector. If there are misfire spikes, then its prolly a misfire.

 

If i have a leak in the egr and air tube.. would that cause my engine to shake and backfire that bad.. also, I put in some comp 7.35's rods.. should i try going back to 7.40's?? if the valves arent closing all the way that would cause the symptons i having right?? I can't express how bad it's running... I know i'm still running the Long tubes open right now.. but it makes a sound like i blew a head off the car and it only does it when you start it or when it's gonna die. Also, the throttle response when i give it gas is waaay off.. almost a delay before it revs'

<small>[ September 18, 2002, 03:26 PM: Message edited by: Willwork4mods ]</small>

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"> If i have a leak in the egr and air tube.. would that cause my engine to shake and backfire that bad.. also, I put in some comp 7.35's rods.. should i try going back to 7.40's?? if the valves arent closing all the way that would cause the symptons i having right?? </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">If you put back the 7.40 pushrods, it is then you would have to worry about too much lifter preload and the valves not closing.
Did you bleed the air out of the fuel rail using the schrader valve? Sometimes after having the intake off, air pockets in the fuel rail will cause the car to stumble and backfire for 5 to 10 minutes at throttle and it won't idle.

<small>[ September 18, 2002, 03:40 PM: Message edited by: StevieZ ]</small>

 

First off, don't change anything until you make a good checklist based on our posts. You would be nuts to change pushrods without first checking for vacuum leaks.

-Does the car idle high after warmed up? Low?
-What size hole in TB?
-Idle rpm?

Car might be superrich now, does the exhaust puff black when you launch?

 

I had a similar problem with a 99 that a customer did himself. He had also gone to the older 98 head setup and had to mount the coils onto the cover and get rid of the bracket. He had a bad misfire and **** poor performance such as you describe. The problem ended up being he had the coils mounted backwards front to rear on the drivers side and had not disconnected the coil harness from them. This had the coils wired 7-5-3-1 front to back instead of 1-3-5-7 front to back. Easy harness reroute and running great. Hopefully it is something easy like this for you.

Later,

Mike

 

stevie -

i had a tnt kit on it before i went all motor with the heads.. so i had the scrader valve completly out of the rail. Replaced it when it went back together.

prostockjohn -
car won't idle at all.. if i let off the gas it will die and backfire.
throttle body hole is only one size larger (forgot exactly the way it came from shaner)
the idle was tuned for 850 in park and 900 in gear.

mike-
that's a good point.. i'll check the coils tonight
is there a way (numbered or something) to tell which coil goes where?

 

Mike Norris! I did the exact same thing to 2Bseens car <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> it was awful...but would run...and backfire.....at the time thru open headers <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />
Once I heard it in person it was immmediately apparent that something was wrong with the firing timing. I am glad to hear I'm not the only one who has done this.....bet you got a kick out of telling them what it was...I know I still haven't lived that down...

 

Mike -
If your ever in Dallas, I owe you a beer <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
That was it fellas', the passenger side coil harness was backwards.. i know, i musta caught a case of the dumbass when i put it on.
I reversed the harness and it fired right up and idle is fine.. a little choppy, but that's to be expected until i re-tune for the heads and bigger cam. I still need to work out the egr leak.. but at least it's running.

Thanks again to all you guys for you input.

Devin.

 

devin, you work to fast. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> or were the girls -helping- you <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> got my popping out also (cold startup)it required custom programming. later

 

I learned this lesson a few years ago, get a day or two of opinions before tearing into poorly running setups. I tore down the timing chain setup when it was something else.

 

I was going to suggest the coil packs were put on backwards but everybody beat me to it. A friend of mine did the same exact thing a few months back.

 

Jeff -
Glad you got it worked out, the wife and girls are in AZ for the week.. which is kinda like a vacation for me also <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Prostock John -
agreed... once Mike said that, i thought back and it dawned on me.. that is was a pita to get the harness plugged in *(light bulb on)*
It was literally a 5 min fix. It's running a whole lot better, and the sotp feel is "oh my". I can't wait to get it broken in a little and change the oil again... and then go cobra hunting <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

again, i appreciate the input (other boards don't even respond to my posts, but i won't name any names <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

now i just need to make a coupler to fit my mufflex onto the ory and i think i'll be track ready (Open Grot's are really loud)

Devin.

 

Any misfires? Broken Spring?

 

it's setting off a ses light when i'm stoped. gonna a-tap it here in a bit to see what code it is. no broken spring ..yet anyway. Seems to surge alot also.. when letting off the throttle on the highway.

 

Devin,

Glad it worked out for you. Simple fixes will drive you crazy. The SES light is probably a misfire code if it is just stopped and the surging is just a matter of getting the IAC countsand TPS in sync most likely. I'm on the way for that beer. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

Later,

Mike