need some help after Head and Cam install

**cm2papa** · 05-07-2007, 07:39 AM

Hey guys I need some advise. I just finally finished my heads and cam install on my 98 SS M6 (took me forever to do it) and when I had everything completed the car fired right up and idled great. I took it for a test drive with no problems. The next day, however, the car has decided to not start. It cranks and cranks, and I smell fuel but it wouldn't start. I have been able to finally start it but it has done this like five times over the weekend. The times that it wouldn't start I would leave it alone and then after alot of cranking it would finally slowly fire up. I have checked that I am getting spark and I'm not out of gas (though it could be old--3 months) The last couple times the car fired right up. Could this be a loose wire or computer related problem. Here is what I did to the car:

Stage 3 heads, Comp Cam- DUR @ .050" 222 / 228, LSA115, upgraded valvetrain with Comp 1.8 rockers, ported oil pump, double roller timing chain, pulley. I didn't get the LS6 intake yet (soon) but I do have full length 1"3/4 headers with Bassani's true duel minus cats. I plan to get the car tuned soon and can't wait to see the dyno numbers.

Maybe the car will now start everytime but I'm worried about getting stranded. Any advise appreciated. Thanks again.
Jeff

**SSpdDmon** · 05-07-2007, 12:03 PM

You can try reseting the PCM to clear the LTFT's and all. But, you really need to get a tune. You really shouldn't be driving it until you do.

**Sarge** · 05-07-2007, 12:33 PM

You got a loose connection. Check your harness back to the ECM man.....check the wiring to and from your alternator also.....something is loose.....

**cm2papa** · 05-07-2007, 05:17 PM

I agree about the loose wire but I also just thought about something else. On my 98 valve covers there were 2 breather tubes on the passenger side, one that connected to a hose that connected to driver side valve cover and another that I think connected to the throttle body or intake. My new heads needed the '01 valve covers and since there wasn't the extra breather tube coming out of the back section of the passenger side I just plugged the tube. Was I supposed to do something with it? It sounds too silly to be causing any problems.

**0rion** · 05-08-2007, 12:45 AM

that's your pcv system and won't cause the problems you're describing. Do you give it any throttle when trying to start it? After my heads and cam my car would barely start up unless I gave it some gas when trying to start it. Check the grounds on the back side of your drivers head and make sure they're on good but my bet is it's your tune. Also, get that old ass gas out of there. What's the lift on that cam?

**cm2papa** · 05-08-2007, 11:55 AM

I'll definitely double check the ground on the back of the heads. Yesterday the car, started everytime perfectly...wierd. Haven't run it yet today.
The lift on my cam is LIFT .551 / .551

Thanks again everyone for the advise.

**slims00ls1z28** · 05-08-2007, 12:13 PM

You did break in the cam properly right? Definately sounds like something loose.

**DKSS00** · 05-08-2007, 12:42 PM

A friend of mine had this same problem but on an LT1. It was a fuse for 4 of the fuel injectors not sure if this helps any.

**Wheeler99WS6** · 05-09-2007, 05:29 PM

Originally Posted by slims00ls1z28

You did break in the cam properly right? Definately sounds like something loose.

Hydraulic roller cams do not need to be broke in,.....I agree with said above, something is loose and you definitely need a tune, are you M6 or A4. if A4 then I would definitely say its the tune. M6 is a little more leanient on the tune with a cam as long as it is not to aggressive.

**john5632** · 05-09-2007, 05:40 PM

when my car was stock I had this same exact internmitten start up issues.Some days it would be perfect and other days it would do what your describing.To make a long story short it ended up being an ignition relay.I replaced it and all was good

**408WS6** · 05-09-2007, 05:51 PM

You definitely need a tune. A heads/cam install is a major modification not to have the PCM retuned.

**mrr23** · 05-09-2007, 07:28 PM

Originally Posted by cm2papa

Comp Cam- DUR @ .050" 222 / 228, LSA115, upgraded valvetrain with Comp 1.8 rockers

i thought you got the vinci/crane stuff? sounds like the vinci XXX cam and crane 1.8 rockers to me.

**cm2papa** · 05-10-2007, 04:46 PM

Hey Rob, yes it's the Vinci setup. I ended up doing it all myself, and if anyone wants the meanest sounding car....this is setup. It idles great and sounds wicked through the Bassani setup

My car hasn't Not started since Saturday, wierd...must be the computer. Now here is a stupid question, why is it so important to get a tune if the car idles fine. Is it to set the Air/fuel mixture so the car isn't so rich?

**mrr23** · 05-10-2007, 04:51 PM

you have changed the way the engine ingest and expels air and fuel by changing the cam. the volumetric efficiency of the motor has changed significantly. so, the VE table and timing tables need to be modified to match the 'new' engine. the compputer can only compensate so much, due to the parameters set in these tables.

you know, i'm wondering if we've met? i remember giving someone a ride in my wife's car that had a SS and then had vinci install the bassani later on.

**cm2papa** · 05-10-2007, 05:29 PM

Yes that was me

Now that I have my ride back together we will have to go cruising sometime. Thank you again for talking me into that exhaust setup it is great. I was planning on putting a few hundred miles on the car before getting it tuned but can I hurt anything driving it around? It runs so well right now.
Jeff

**mrr23** · 05-10-2007, 05:30 PM

nah, should be ok. i drove around on stock tune when i had heads and cam on the wife's car.

**rajiv1998** · 05-10-2007, 06:11 PM

Originally Posted by mrr23

nah, should be ok. i drove around on stock tune when i had heads and cam on the wife's car.

Agreed. Although a tune is crutial, i dont think its gonna get to the point where the car isnt gonna start. He fired it right up after the swap, so obviously theres nothing wrong as far as tuning goes. Something is loose or ur not getting enough spark somewhere. Is the SES light on? But i agree w/ others, u wanna getta tune quickley and not play around with it.

**cm2papa** · 05-11-2007, 10:59 AM

Thanks everyone again for the help. I'm going to just go get a tune in a week or two and be done with the guessing but at least the car has been starting up fine since the weekend. I also thought about the ignition relay but I switched it with the starter relay (being the same) and the starter still worked yet the car wouldn't fireup when the problem was happening. For now all is good.