I just put the built ls head on my motor today, it took me and a buddy about 12 hours to do it. everything is torqued to spec, there are zero leaks around any gasket, it runs extremely smooth at cruising or accel. The base timing is perfect, the white line is at TDC when the cam gears are also zeroed in to each other. (I can get pics to make sure im not wrong) I am running skunk 2 cam gears BTW, as of right now they are at 0,0 degrees.
We jumped the ecu and then hit it with the timing gun. When we hit it with the timing gun the red timing mark jumps around a lot. I will come to a light and let off the gas and the car will drop to 1000 rpms for about 5 seconds, and then it will drop to about 200rpm and wanna die. If anyone has any info PLZ PLZ PLZ help me out.

 

My bet is tunning. The 403s have much less vaccum at idle than the stock cams, which requires much less fuel. Your probably running pig rich and blowing out the spark.

 

any way to dial that out or fix it with what Ive got?

 

not really.

You need something to remove fuel, and removing fuel via a FPR isn't a good idea because you will just end up running lean in the higher RPMs.

I would pick up an e-manage, or hondata as soon as possible.

 

hmmm, I have an SAFC the thing I dont understand is, crower says that the 403's should have a close to stock idle without any fuel modifications.

 

Crower says a lot of things

I have a friend who installed 403's, and he said untuned when they first started the car it sounded like ***.

If its only misfiring/acting weird at idle, it sounds like you are running too rich at idle.

 

cool thx for the help man

 

I just went and started cranking the motor by hand so I could do the valve lash, and I forgot to take out the spark plugs, and I heard a hissing noise almost like a compression leak. Is this due to the cam overlap or is it serious? My friend is cruising over now so he can crank it and I can listen for the hiss more closely, oh man this is starting to get frusterating.

 

Um I just thought of this, possibly my cams are not timed correctly? On the skunk 2 cam gears are the degrees supposed to be facing each other? or are the two little dimples.

this is how mine is set up.....




and this is what the cam lobes look like at TDC on Cyl one




PLZ PLZ PLZ help

 

use the safc to lean out the fuel 8-10% at 1000rpm and that should solve some of your 'close to stalling problem' but of course you should get it dyno tuned for optimum performance.

as stated earlier the cams created less vacuum at idle so the ECU thinks it need more fuel so it's dumping it under 1000rpm.

you can also try adjusting the idle screw on the throttle body to try and help smooth the idle out a bit.

hope that helps.

 

oh and your codes 71 and 73 are missfire codes. sounds like your running OBD2 which detects the "lumpy cam" as missfires.

nothing you can do other than switching it over to obd1 or some how getting it to run as smooth as possible at idle so that the ECU wont detect the lumpy at idle.

 

I have never had missfire codes on my 404's and OBD2

 

I played with the idel screw and re did the valve adjustment, and it still idles like ****, so unless there is another way to **** with the idle I think Im screwed.

 

If you dyno it....

...it will idle.

 

HAHA good deal style, my only other problem which is keeping me from going and getting it dynoed, is I did a compression check and the numbers are as follows,

175, 180, 160, 190

If I have to rebuild then why dyno.

 

i just got my car running with 63403's and i also have the skunk2 cams gears. If you notice on the cam gears there are 3 dimples. the middle one is what you are going to base TDC off of. Turn the crank until the middle dimple is facing up on BOTH cam gears...hence being TDC. Now check to see if everything else is at TDC. BTW my 403's are also at 0,0. It idles fine...just a very small bump in the idle.

 

do the dimples that are supposed to be pointing at each other look like mine in the above pic? Cuz I am pretty sure that I have the timing correct, all the TDC lines up.

 

Did you do a compression test before putting the new head on? It is possible that one of the cylinders has a slightly bent valve or really leaky valve seals.

It might not be your rings.

 

the valve seals were replaced, and the machine shop that did the valve job was supposed to check the valves. But to make sure I will do a leak down test when I go to school.

 

Hmm, sounds like rings then unfortunetly.

On the plus side a rebuild is very easy to do yourself if you have a helms. Might be nice to have a brand new motor.

 

HAHA, yeah but I dont have the time to do it. I cant afford the down time, so most likeyl I will have to buy a used block and rebuild that one then swap it some weekend

 

ok I installed the safc and leaned it out at idle, the misfires stopped in cyl 1 but 3 still misfires like woah. And it still almost dies at idle, I know it needs to be tuned but what would only cause cyl 3 to misfire and thats it?

 

ok my car is possessed, it is now not throwing any misfire codes but is now throwing a MAP sensor code. Can someone maybe shed some light for me, im so lost now

 

make sure the s-afc doesn't have a lose connection somewhere. That could definetly throw a map code.

for example, I disconnected my e-manage once by accident and threw a map code.

 

Thx styl, that was it, the MAP sensor or pressure input was unplugged. I advanced each cam one degree to make up for the headgasket, and it still runs like ****. I have pretty much run out of options and I cant keep driving this thing like this. So I am pulling the cams today and putting the stock ones back in. I might even pull the whole head next week and sell it I have not decided yet.