What next ?

[HOTSIX]

Well guys...I still have no start on my rebuilt motor.

Checked SES light - bulb was removed - put back in and I get code 12 over and over. No other codes flash (after having rolled it over a few times). I have checked and double checked the Cam sensor and crank sensor - all set corrrectly. I have spark and gas but no start. Compression is good - its a rebuilt motor. I also checked all the grounds as well. The coil and module are brand new - so are the crank and cam sensors.

I get 1 extra RPM light on my gauge when I roll it over - does this mean the crank sensor is working ? What would you guys try next ? ECM bad ?

Help.... TIA

 

[Men in Black]

I had the same thing when my motor was brand new. It turned out that it was too rich and it washed the rings, hence no compression. We pulled all the plugs, put some oil in each cylinder, rolled it over a few times, replaced the plugs, and it started. Do a compression test.

 

[REDS HOT AIR]

has it tried to start?

if it is flooded (plugs wet) then prop open the trottle and let er air out for a few and try cranking it with the pedal to the floor that should tell the computer to cut back fuel but keep it to the floor till it starts to start or the computer will start loading it down with more fuel that it wont be able to burn off

this method is called clear flood..

 

[IRaceAV6]

camshaft sensor set correctly?

Crank sensor set correctly?

I had a problem with getting my car running after it's rebuild. The expert is our moderator... he walked me thru all the tests.
It ended up being the crank interupter wheel. $95 through GM. Somehow the wheel's fins got tweaked in the 18 months the car sat in pieces. (the first time)

 

[cool 84]

Fuel spark and compression, you have everything needed to make it run as long as it's occuring at the right time. If all else fails pull the front cover off and make sure the cam is degreed correctly. I had it way off one time (I still have no idea how I did it) and it still had good compression, it just wouldn't start but the plugs were turning black. You might want to do a compression check even though it's a new motor. I forgot to change the chip when I switched to 009s and flooded it and washed the rings. If you upgraded inectors, check the chip.

Has it popped or kicked back, or smoked, or made any signs of starting?

 

[HOTSIX]

Thanks for the replies guy - really getting frustrated here....

It hasnt even made an attempt to start when I roll it over. It just seems to roll over and over.

How will I know if the cam is degreed correctly ? Isnt there a mark on the chain and the cam or something like that to tell me...? What do I look for....I have the Lunati 200/200 cam...does this make any difference ???


I RaceAV6 - what happened to your interupter wheel ? Were the fins damaged ? Mine are not - I checked um out today. I have quadruple checked the cam and crank sensors...all set correctly.

I will do as REDS suggested and try it with pedal wide open....and also try a compression test to see what that says...

Why do none of you think its the ECM...I noticed nobody mentioned that....the service manual has a no start trouble diagnosis chart in it and it says maybe a bad PROM or ECM according to my symptoms...got that from Chad's site...heres the link:

www.geocities.com/rad87gn/tech/aldl2.jpg

I have SES light on with key to "ON" and also code 12 when ALDL is grounded....the chart suggests faulty ECM or PROM...what you guys think ????

 

[cool 84]

You ECM sounds fine. It's supposed to have a code 12 and the SES light is supposed to be on with the key on engine off. I'm starting to think it is mechanical. I would think that if your getting fuel AND spark something would have to happen (pop, backfire, some sign of life) unless there's no compression.

If you decide to check the cam timing, it depends on the timing set you have. On most aftermarkets you have a dot on the cam gear and a 0 mark with a dot on a tooth on the crank gear. I forget about the stock set but I'm sure it's obvious, probably a matter of lining up the dots on the gears.

 

[HOTSIX]

Thanks COOL 84

I guess my next bet is to pull the front of the damn engine off and have a look. I really dont want to do this and I dont possibly know how the (good) engine shop could have messed that simple task up.

I hope you are right....dont know where else to turn now.

 

[WFO]

swingin in the dark here...

first a couple of abstract questions...

do you have adjustable rockers?

are you running stock pushrods?

does you motor go "ruh-ruh-ruh",or "wheeeeee" when you crank it over?(like my sound effects guys?hehehe)


the reason i ask is if your valves aren't closing,nothing's gonna happen...


later,sean

 

[cool 84]

Check your compression first. Also, are your plugs changing color? It took me a week to get my current motor running. I was very sick and half asleep the day I installed the cam and had the timing way off, far enough to smack the valves.

You can pull the driver's side valvecover off and pull the #1 spark plug out to get a guess if the timing is off. Rotate the motor clockwise and watch the rockers on #1. On one up stroke of the piston, as it is getting near TDC the exhaust rocker should be open and starting to close as it hits TDC. On the next up stroke of the piston both valves shold be closed. This is far from accurate but it will tell you if the cam timing is WAY off or not.

 

[HOTSIX]

I dont know if I have adj. rockers or not. I am assuming the shop rebuilt the motor to orig. spec. so whatever was in it before is prob in it now. I gotta check on that. I have replaced the old pushrods with new stock pushrods.

WFO - it goes ruh-ruh-ruh. Sounds pretty normal when it rolls over.

TIA guys !!!

 

[REDS HOT AIR]

DIG VERY BIG HOLE IN BACK YARD
neibors will think your putting in a pool

PUSH CAR IN BIG HOLE
and cover it up
neibors will then think your a total nutcase...

 

[Matthew Stuart]

You did jumper across to check your voltage when setting the distributor for proper timing....it is a pain if you are not aware..let me know I'll dig out the specifics...can't remember the jumper points off hand....!!!

 

[WFO]

Originally posted by HOTSIX
.

WFO - it goes ruh-ruh-ruh. Sounds pretty normal when it rolls over.

TIA guys !!!

ok,cool.i had a sbc that went "weeeee" once,the valves were adjusted too tight,they never closed!


i'd now take a serious look at your cam timing.


later,sean

 

[HOTSIX]

REDS - I dug the hole...took me all day...but the neighbours saw me push the car in it and now I got a crowd of people around my house !!! I tried your pedal to the floor test...still had no luck....not even a sputter !

I tried the plugs again today...got spark and gas on all 6 cyl....looks like real good strong spark too...(plugs tried outta cyls to be sure). Didnt do compression test yet...thats next on agenda but its a new motor....how could it not have good compression?? Maybe rings washed...?

What do I expect is good and bad compression numbers???

 

[cool 84]

I don't remember the exact specs but I think around 120-130psi is good, maybe a little higher. I'm sure someone else on here knows for sure. I've noticed that it takes around 90 psi for a cylinder to fire.

 

[3point8]

no start

Just a long shot, but is there an antitheft device involved?
Good luck with it
Peter

 

[HOTSIX]

Compression test

Thanks for the suggestion Peter. No anti-theft device here.

Today I did a compression test and got 120 psi.

Then I was checking the injectors (again) to see if I was in fact getting gas - while removiing an injector plug I broke it.....1 step backwards, and two more steps backwards...gettin pissed now. Wayyyy passed frustrated.

 

[cool 84]

You should be able to smell fuel on the plugs if it's there.

 

[IRaceAV6]

I RaceAV6 - what happened to your interupter wheel ? Were the fins damaged ? Mine are not - I checked um out today. I have quadruple checked the cam and crank sensors...all set correctly.

They weren't bent visibly... but got tweaked just enough to never allow a signal to be picked up.

Have you pulled a wire... installed a spark plug into it and ensured you have good spark?

The next step is to adjust the camshaft sensor slightly in one direction... crank start it.... see if it catches... nope... adjust it a couple more degrees... if after doing this 20 degrees in one direction... start the other way.

I have set my motor with the Caspers camshaft sensor tool and still had to manually adjust the thing slightly to get it to start.

You can pull a plug and smell or taste fuel on it... yeah I have stuck a sparkplug in my mouth more than once It ain't going to give ya kidney damage.

If you have compression... you are probably set on correct timing chain sequence... but you may have your camshaft sensor installed 180 degrees out too.... and that is what I'm hedging my bet on in your case.

Hope this helps