gibsonj4

Just recently did a intake manifold, fuel rail and ls6 valley cover swap. Ive had boyh off the car multiple times in the past and never had any issues. Car will crank and crank and try to start but just won't start. I have checked the following:

-Spark: car is getting spark after checking multiple coils. Battery has been tested and is strong.

-Compression is fine

-Fuel: fuel pressure is normal however, 2 plugs on each side are black with fuel while the other 2 are clean. Could some of the injectors be stuck open?

-Car is throwing no codes. I have also tried to unplug the MAF and start the car with no change. I have removed the plugs and cleaned them off and let the engine sit and still have a no start condition.

I am at a loss on what else to check. Not getting any codes for crank position sensor or cam sensor and those seem to be the last possibilities.

HPS MASTER TECH

check the ground on the back of the drivers side head

gibsonj4

I checked the ground strap before but maybe it became loose. Ill check it again. Im getting pretty fast at taking the intake manifold off now lol

gibsonj4

So, ground waa fine on the back of the head. Everything else looked good but I am going to replace the MAP sensor as the housing as a crack in it. If I still have a no start, where would you go after that?

Rob 02

Coil wire harnesses.

HPS MASTER TECH

check your injectors. put a test light on one and see if it lights up while cranking.

Rob 02

If the two middle plugs are showing signs of a rich mixture while the outer plugs are not then there are signs of a warped head or stretched head bolts.

Head gaskets are not a normal wear item contrary to hot rod belief.

gibsonj4

It wasn't those plugs. Im thinking it may be a few coils or the harness. I tested two coils and they were fine but I am going to test them all.

gibsonj4

So, replaced the MAP sensor, reinstalled the intake, cleaned the plugs, wires and coil connections. Also retested all the coils and they all are firing. Injectors are also all firing yet the car still will not start. I did het a p1514 code now (which is new) so coukd it be the MAF? I tried to start the car without the maf but didn't see a change in how the car cranked.

Rob 02

I have started mine without a MAF several times.
Check the connection to the throttle body and TPS.

gibsonj4

Checked both and both are good an tight. Harnesses are getting juice. Im at loss on what else it could be. Maf code hasn't come back after cranking it multiple times after clearing it.

Rob 02

Do you have fuel pressure at the rail?

It may be something unrelated by to the work you did coincidence. Maybe something in the fuse box. Maybe the wire that connects the interior box to the one under the hood.

Did you double check the thick grounding strap near the steering shaft? They have a tendency to rot.

gibsonj4

yes, 50psi at the rail. I actually even tried a bew battery tonight since the car was due for one and no change. I will check other grounds. I did notice a couple weird things. The belt lools like it has rust on it. Also, I am getting short backfires out the exhaust as I try to crank thr car.

foggy

Cam position sensor located on back of engine under Intake Manifold..
That's my guess
Either unplugged or by coincidence has gone bad

gibsonj4

yup I checked the sensor for being unplugged and it was fine but that is what I am thinking too

Rob 02

I seen a video one time where some guys installed a blower and forgot to take the cardboard off of the bottom.

Were there any protective materials blocking air flow? Maybe a plastic bag getting sucked into the filter?

gibsonj4

At this point, I wish it was something that easy lol. No, def didn't leave anything like that which woukd block airflow. I ordered a new cam sensor so I will try that.

Rob 02

During the build, was anyone present that would sabotage you work?
Any possibility of having a broken valve?
Simply changing an intake shouldn't keep the car from starting if it ran fine before unless there is a massive vacuum leak.

gibsonj4

Nope. Ive had the manifold offprobably 10 times before this and I have never had an issue remotely like this. In fact, I have never really had any issues with the car until this.

Rob 02

Check where the wire harness connects to the TB. If the wires are damaged the PCM may not see a TB present. Same with the throttle position sensor.