Mikes67

I'll try to keep this short. I have a 67 camaro with an Ls1 and a T56. The car was running, even drove it around the block. Had a better tune flashed on it and installed new injectors in preparation to get tuned this weekend. Now I have no spark. Here are the details.

411 pcm
checked all fuses and relays
checked all grounds
58 psi fuel pressure
replaced crank position sensor
injectors fire - checked with noid lights- plugs wet with fuel
coils have 12volts going to them with key on and cranking
coil signal wires only have around .2 volts when cranking

I don't know what else to try. Looking for suggestions. Thanks

TurboChapman

Can you run a jumper wire to the coils from either a keyed source or from the battery and see if the car fires and runs? If it does I'd look to see if a terminal on the ecm that allows the coils to get voltage has either been damaged or if the ecu is damaged.

Pasnawtz

Did you check if the ground that you have the wire going to the back of the cylinder head has continuity with the negative battery terminal? (can use multimeter to do this)

Mikes67

Turbo
Which wire are talking about jumping? The pink wire that supplies power to the coil packs?

Mikes67

I do have continuity to the grounds on the back of the heads as well as the grounds on the plugs for the coil packs.

Pasnawtz

Stupid question.. is the cam sensor plugged in?

G Atsma

It will run without the cam sensor, just start hard the first hit.
It will not run without crank sensor.

Pro Stock John

iTrader: (34)

It cranks though?

How about the crank sensor?

Mikes67

Yeah, cam sensor is plugged in. Also make sure I 12v going to crank sensor.

G Atsma

Crank sensor was replaced according to first post, BUT even new ones can be bad. Use GM parts...

Mikes67

I could only get an ac Delco crank sensor, but the original one I pulled out only ha 12k miles on it.

78TranzAm

I had a no start issue with my swap. Took a couple days of agony to figure out. I put a new crank sensor in, after the 4 days of exhausted options I said what would it hurt to throw the old one back in. And sure enough it fired right up. So, id grab another crank sensor just for the hell of it to see. You can always return it.

jrs396

I suggest taking a multimeter that has a min/max function and do a voltage drop test on the coil power and ground circuits under both static and cranking conditions.

Mikes67

I did check it under load. I don't remember what the exact numbers were, but there was not much difference. I also checked the signal wires to the coils while cranking. I only had about .20 volts there.

Mikes67

So mystery solved. After checking everything and finding nothing I replaced the new ngk plugs with another set and it fired right up.

Pro Stock John

iTrader: (34)

...old ones fouled out?

Mikes67

Put the new 60 lb injectors in . Maybe the old tune with the old injectors were rich. Had Matt Happel, my tuner, over checked and tried a bunch of things. It stumped him too. They were definitely wet with fuel. Put the new plugs in and immediately ran.

Pro Stock John

iTrader: (34)

Hmm check that oil making sure you don't have a lot of gas in it.

Mikes67

Definitely, of course I just changed it right before I put the injectors in.

Pro Stock John

iTrader: (34)

How the dipstick smell?