dazman

got my car back together... 97 corvette

ms4
prc heads
underdrive
ls6 intake
headers

car cranked GREAT first time and idled great, ran it to the top of the road. idled great, but when i got it back to the house it would not find idle and just kind of ran crappy - missing, puking, bucking ... but now will not do anything. it is deader the hell and throwing p1571 p0171 p0174 will not even start


please help!!!!

1mofbody

Any tune???

redtail2426

iTrader: (10)

is it tuned at all for the added mods?? the ms4 is pretty big for a stock tune.

dazman

MY BAD...


YEAH its tuned by texas speed... it ran GREAT for a while, idled on its own, everything, now it will not hit ONE LICK.

thanx

mike

dazman

asr desired torque .....what the hell is that???

dazman

now car will not start for anything....

brad8266

iTrader: (23)

2 of those codes are lean codes, you likely have a intake vacuum somewhere near the manifold or you forgot to hook a vacuum line up when you put the intake on. Search for a vacuum leak first.

dazman

there is only one vacum hose that i could see would be a problem ( that little bitch in the back ) and im pretty sure it was hooked up... besides it if was that then the car would at least start wouldnt it?? could a vaccum leak really cause the car to not even start?

mike

brad8266

iTrader: (23)

A big enough vacuum leak could cause that, and you are throwing lean codes for both banks which indicates a major lean condition likely from a vacuum leak.

A cam like that will typically run rich untuned yet you are running lean. Couls be a head sealing problem too. Im gonna ask a stupid question now, sorry, but did you use port gaskets on your new manifold?

marv

iTrader: (40)

Check your O2s....I had one go bad after my first swap and the car would not run for crap. Idled high, bucked, popped....ran terrible...but was driveable.

Changed out one O2 and it was fine...

Might be worth a shot...

dazman

yeah, i deffinitely know what ya mean....and NO i did not port the intake... LOL.... but i did put it on and take it back off about 7 times due to a head issue. intake feels good on the motor and the gaskets look good.

i am throwing a p1571 h c and that is a code that can stop injector firing which is why i think that the lean codes came in.

do you know how many vaccum lines there are besides the big obvious ones on the front?? the only other one i can think of is that little one on the back, but where the hell does that thing go?? could it be undone on the other end???

thanks for your help

mike

brad8266

iTrader: (23)

O2's are not used at all until the car is warmed up and enters closed loop. That rules out O2 sensors.

Dont waste time or $$ messing with O2 sensors. You cant even get the car started right now so it definetely aint O2's.

dazman

i bought all new 02 sensors just to head off this problem back when i was building the car.

i think the problem is comeing from this p1571 c. but i really have no idea. or anyone that i know has any idea....

thanx

mike

brad8266

iTrader: (23)

There are 2 little *** ones on the back, one goes to the HVAC control door by the PCM and the other goes to the AIR solenoid on the driver side of the intake. You also have the brake booster (big hose) and the PCV valve hose. Make sure the PCV hose is firmly plugged into both valve covers in the back and into the manifold up by the TB. Might also be a good idea to replace the PCV valve too while youre at it.

You did also swap the MAP from the old intake to the new one right? And you did use port gaskets on the intake right? I didnt ask you in my last post if you ported the intake, i asked if you used port gaskets on the new manifold, lol.

Try resetting the PCM to clear the codes and then see if it starts up.

marv

iTrader: (40)

Well, he said he ran it to the end of the road and let it idle...I would assume it was warmed up by then...and if restarted after that, I would again assume the motor would be hot.

Mine ran pretty well right off start up...then as I took it down the road it progressively got worse...then my tuner told me left bank O2 wasn't switching...

Just a shot in the dark...

dazman

i only noticed one little one on the back.... on the valve covers i plugged up one with a bolt, becaue my new valvecovers did not have a provision for it (the one on the back of the pass. side valvecover. ran the other one to the front of the motor where it goes. and the last one to the brake booster.

my buddy was the one that did the intake each time ( we all had a job and just did that job each time when it came) i know that there is a sensor on the back, and one little vaccum hose.

brad8266

iTrader: (23)

yeah but if he cant get it start again when cold that rules out O2's the car just runs straight off the fuel tables when cold, no fuel trims to deal with.

O2's dont like cammed cars very well, mine never had a switching code thrown till i got a cam. They switch good enough for me though.

dazman

as far as the gaskets i just used the ones that came on the ls6 intake i ordered

brad8266

iTrader: (23)

there are 2 tiny vacuum lines that connect to the back of the manifold. What exactly did you plug was it the hole for the PCV hose? If so you need to fix that so the engine can release pressure. The PCV hose needs to go from the front of the manifold to both the pasds and driver side valve cover rubber grommet. The brake booster hose goes from the manifold to the booster

dazman

i plugged the one that went to the back of the pass. valve cover. and im pretty sure there was only one little one on the back...