LT1CST

Ok I think I know where the problems is but I need your imput to make sure my theory is right and how to fix it.

APPLICATION:
94 LT1 rebuilt to 385 stroker 224/236 XE cam. High Compression pistons, Ported heads. Stock Fuel system, stock injectors, brand new fuel pressure regulator and fuel filter.

ADDED PARTS:
About two months while building my car, I ran over to the junk yard and found a donor camaro and obtained the following parts.
4L60E trans
PCM
Vented Opti
MAF.
and some other goodies.

THE PROBLEM.
Car will not start!! I go to crank the motor and it cranks and cranks with very little often times wanting to fire but no start at all.

My Diagnosis.
SPARK:
First thing I did was check for spark. I pulled out the number one spark plug wire and placed a spark plug on top of the intake manifold. Started the car and I saw a blue spark coming from the plug which tells me that the opti spark is working. Next I wanted to verify that the coil was working so I pulled the plug wire off of the opti. Placed it on the intake and started the car and saw a spark coming that end. So at this point im telling myself that I have plenty of spark.

FUEL: Before all of this occured I thought I didnt have any gas. I put gas in it and checked the fuel pressure. I placed the gauge on the shrader valve, turn the key on and the gauge went up like it should. So this tells me that fuel is getting to the rails.
NOW FOR THE INTERESTING finding,
After being confused on this whole thing I pulled out the number one spark PLUG checked to see if there was any fuel on the plug and I smelled NO FUEL at all, Which tells me that the injectors are aren't working.
CAN SOMEONE PLEASE CONFIRM MY FINDINGS???.
The only thing that I can think of is that the PCM that I purchased is has not been programed yet for my car however I dont see why it still would not start. The only mod that I have is a cam. ALSO. the opti spark that I pulled off the DONOR car had an VENTED opti. Which tells me its possibly a 95 because I think they were standard on the 95 LT1. So if my opti is from a 95 then that means my PCM is from a 95. Please HELP!!!
Chris

LT1CST

I just ran a Carfax off the donor car and the PCM and other goodies are from a 94 camaro. Just like mine. Buddy of mine was thinking maybe the pinouts are different from a 95. But I dont have to worry about that because I have a 94 allready.
Chris

95Blackhawk

Fuel, air, spark. We can assume air is not an issue.

I would check to make sure you are getting a 12 V signal going to the injectors while someone is cranking. Another thing, put a little starter fluid in the TB.

Come back when you have diagnosed this and then we can get into more details on the spark side. There are a few things to look at there.

LT1CST

Will do. Ill get on it first thing in the morning.
Chris

LT1CST

Update!!
I borrowed a noid light from a buddy of mine to check out the injectors. While starting the motor the noid light was flashing. Which tells me that the injectors are working. I ran a test light on the injector fuse. I got power to those as well. CAR STILL WONT FIRE UP!!!!. I thought maybe my valves were too tight. I backed them off after finding out that they were too tight. Still same result. NO FIRE!!. Blackhawk I tried putting a cap of gas in the Throttle Body and the car did nothing. I pulled out the number 1 spark plug again to check to see if it had fuel. And im not sure if it didnt or not but it seem like there was still no fuel on the plugs. IM OFFICIALLY LOST!!!!!
Chris

FryedClutch

a couple things ive had happen that caused similar things
1st are you 100% sure the opti isnt off a tooth or two?
i managed to install my vented opti with the cam dowel in the wrong slot (near impossible but im good like that) and the injectors and spark plugs were not firing at the correct times
put the opti on correctly and fired up like nothing

did you check to see that ALL the injectors are firing?

hope this helps i figured mistakes might do someone else some good

LT1CST

Are you referring to that small groove like dowal pin on the back of the opti that fits in the cam gear? If so I believe there is only one place for that pin to go. Otherwise the opti will not fit. I believe there is only one way that opti can go on. But I could be wrong LOL. Anyway I did not check all the injector pulses but I verified clynder 1 & 3. Ok Now here comes the most retarted question of them all. PLEASE DONT LAUGH AT ME.
I twisted off my gas cap and a large amount of air came out. Does that mean I have no FUEL? (I SAID DONT LAUGH)
LOL
Chris

FryedClutch

yeah i havent dealt with the older optis much but i do believe it can be forced on the wrong way
all that the air coming out of th tank means is it is holding pressure which is good

95Blackhawk

I would spray starter fluid while someone cranks. Let the fluid more evenly flow through the plenum.

After that, I would check to confirm the opti was installed correctly. You can install them incorrectly if you haven't done it a time or two.

I feel for you. It sucks not knowing what is the culprit. I too had a similar problem and took me 2 weeks to find the issue while the car sat. Don't worry your problem is not the problem I had.

pizzi-man

Just a thought. Isn't the dowel pin in the cam shorter on a 94 non vented opti then on the 95.

T/A lt1

Also just because your getting pulse to the injectors doesn't mean the injectors are firing, if they have been sitting up for awhile they could be locked up or maybe double check firing order wires and opti ?

Nostang 96z

Also, check to make sure your engine has compression. I ran into this problem on a friends 408 and the pushrods were a little too long causing a zero compression issue due to the vales not cloasing all the way and the car would backfire a little through the exhaust but not start. The pushrods were changed and the car fired right up.

If you take off the intake elbow it should smell of gas fumes if the injectors are providing fuel. You can also feel them pulsing with your hands.

LT1CST

Well I double checked the opti last night and the hook ups to make sure the wires are hooked up right, And they are. The only thing that I can think of is on the passenger side opti hook ups. I have the wires routed underneath the motor mount and their wrapped around the front part of the opti near the tension pully. So almost all of them are somewhat at a 90 degree. NOt sure that means anything but I thought I would point that hout. The dowel pin on the back of this opti is the same exact length as my old one. I placed them side by side. By removing the a spark plug wire and placing a spark plug on the end of it and firing it with seeing blue spark lead me to believe that the the opti was functioning properly and I was getting enough spark. Now I asked the question about the gas tank. From my experience everytime ive opened the gas cap and pressure comes out I always thought I was out of gas. But maybe not because I turned the key on and the gas gauge reads half. But the car is on jack stands too so im not sure if im getting an accurate reading.,

LT1CST

No stang. A friend of mine thought that maybe my valves were too tight. As far as the pushrods they are the stock ones. However I have switched to the comp cam full roller rocker 1.6. NOw I was backing the valves off after bumping the motor a couple time and I herd a little back fireing. Also it felt like it wanted to start too. I just think im out of gas. How do you unlock injectors?
Chris

Nostang 96z

If you milled the heads on the 383 or decked the block your pushrods could be a little too long. If you have access to a compression gauge then hook it up and see if there is any cranking compression. Or another easy way is to take the spark plug out and push your thumb over the hole while having someone crank the engine. If you feel a lot of air coming out then you can assume your pushrod length is OK.