Starting Vibration

[Digiphaze]

Sorry to pick your guys brain, but i'm kinda stumped atm.

Starting the vehicle in the mornings after sitting for the night, its a very very rough start. By that I mean the engine will vibrate hard, makes the entire car shake. To avoid severe shaking I turn the the engine over for 2.5 to 3s, then try again. The second start attempt gets it going all the time.

If I've driven it within the past hour, I get the same effect. But It turns right over within 20min of turning it off.

The car runs perfectly on the highway, burns a little oil it seems. But other than that runs smooth as ice on the highway. (I do a lot of highway travel)

I've run sea foam through multible times. Doesn't seem to do anything.
Changed fuel filter.. No change.

Only thing I can think of, is leaky fuel injectors? Or something wrong with my coils?

Oh and no SES light.

What are your guys thoughts?

[cam98aro]

Re: Starting Vibration

my thoughts?

its completly normal.

[Digiphaze]

Re: Starting Vibration

So your v6 does that too?

[cam98aro]

Re: Starting Vibration

So your v6 does that too?

yes, the engine isnt warm, they all do it.

and by all, i mean every engine.

[Digiphaze]

Re: Starting Vibration

Maybe I didn't make the "severe vibration" part clear enough. This isn't my first car here.

[av6xperience]

Re: Starting Vibration

pump and/or injectors maybe?

[bah]

Re: Starting Vibration

it sounds like my misfire a couple of weeks ago

[BLLDOGG]

Re: Starting Vibration

I'd be looking in the fuel direction

[slow6]

Re: Starting Vibration

The car runs perfectly on the highway, burns a little oil it seems.

Maybe you should do a compression check, that would tell me alot.

I think a leaky injector would be very obvious. I think it would leave a pool of gas on your lower intake manifold and would smell like gas.
You should look, but probably wont find anything.
I'm no expert though

[BLLDOGG]

Re: Starting Vibration

it would most likely leak into his cylinder over night or time, if it was that. I have learned a little tip that if you have a missfire when it's cold and it goes away when you get to operating temp, then its fuel. and if it's good when it's cold then misses when you get up to temp, its ignition.

[Digiphaze]

Re: Starting Vibration

Maybe you should do a compression check, that would tell me alot.

I think a leaky injector would be very obvious. I think it would leave a pool of gas on your lower intake manifold and would smell like gas.
You should look, but probably wont find anything.
I'm no expert though

Thanks for the replies!

Actually it does smell like fuel vapor. Right after I get it started and back up, I get a good whiff of gasoline. So I guess I'll probably have the Injectors replaced and see how things work from there. If I do, I'll probbaly go with bigger ones in anticipation of forced induction upgrade in the future.

Will I have to remap the computer with bigger injectors? Or only when I get the Turbo/SC installed?

Thanks for the help guys!

[97rs4life]

Re: Starting Vibration

bigger injectors will call for a pcm tune

[borispeed]

Re: Starting Vibration

bigger injectors will call for a pcm tune

If you don't mind to burn more gas

[brandini61787]

Re: Starting Vibration

Hey... I was searching the posts and found this description to be exactly what my car is doing right now. I was just wondering if it was ever determined what was causing it? I've got a 1997 Camaro RS, a4 with the 3.08 rearend. We just put a motor and transmission w/65k miles on them in about 2 months ago (out of my old 97 camaro), and have replaced the plugs and wires, harmonic balancer, fuel filter, air filter, and MAF sensor. We also had the injectors cleaned at the local Chevrolet garage right after the motor was put in. I really have no clue what could be causing this, but I'd love to fix it.

[Fred]

Re: Starting Vibration

My car has always had a vibration since I bought it with 34,000 miles going now on 89,000. The vibration can be felt throughout the whole car. Does everyones 3.8 vibrate?