I'm not really stuck here just seeing if anyone thinks I may be missing something or has seen this strange no start issue. And I am going to be very descriptive. 1985 Z28 305 TPI. New plugs, wires, coil(ground screw in cap just seem to tighten like I think it should), have strong fire initially, have good fuel pressure.

Okay car cranks but won't start, upon initial tries it will actually almost start sometimes it will but just barely run and stall right out. It seems as the spark is getting weaker after cranking for a bit. I am really thinking I have a ground issue.

It has fuel pressure uncertain of psi I left my guage at work. But it does spray out the front fuel line strong. This car hasn't been driven in over a year the gas smelled putrid so I let a ton spray out and added new gas.

IT has a new ECM, the burnoff module works, do have a code on the brand new ECM a 33 MAF but testing it showed it worked and that was what made me replace the ECM in the first place. Have not done any tests since replacing ECM.

Just trying to see why this thing won't start I am planning on doing some major swapping but wanted it running before I did if I can't I will just start the swap and triple check everything while it is apart.

 

Pull the plugs ;
Wet plugs - no spark .Dry plugs - no fuel ( and maybe no spark )

How good is the battery ; as power is drained from cranking the engine over less power available to make a strong spark

Means little wthout a gauge.
If the pressure is too low , the injectors won't spray correctly

 

If it didn't run after the tune up, you should check to see if the wires were put on correctly...
If it did run after the tune up, but not now you might want to check for a vacuum leak as you could have broke a line during the tune up?

 

Ran after tune up but would occasinally run very rough and spewing black smoke which was diagnosed as tps sensor finally got it right ( had to get a 2nd one 1st died and if I remember right in 6 months). Also change pigtail to TPS and then after a good while the 33 MAF code appeared and it hasnt ran other than using starting fluid (only ran once) since.

 

So do you still have the DTC 33 showing ????

DTC 33 is a fault somewhere in the whole MAF system ( parts and wiring ) ; not just that the MAF unit itself is ( might be ) faulty

 

I have a 33 showing after ECM swap, prior to ECM swap I had it as well. I used ALLDATA diagnosis tree to determine a pin on the ECM was sending voltage to MAF. I am going to do the diagnosis tree again but would a MAF issue really cause a no start?

 

The computer in a car reads the amount of air coming into engine from the mass airflow sensor. If the sensor stops working, the engine can't send right amount of fuel causing problems including sometimes no start situations. There will be someone smarter than me come along shortly but my answer is yes.

 

As I said above , alot more to the circuit than just the MAF or the power to it

Try the method from the factory service manual ( which you should own )
http://www.chevythunder.com/maf_code_33.htm

 

Check the TPS Voltage
TPS voltage is one of the items that triggers a code 33;

Code 33 (mass air signal voltage high) is set when the computer sees a high mass air reading at low engine speeds.
In other words, there appears to be more airflow through the MAF sensor than the engine can physically breathe at a specific throttle and rpm.
and the TPS tells the ECM how far open the throttle is

 

Hmm I will get back on that asap and it makes sense if the car is initially ready to start but then the ECM cuts the fuel back. Thought I had licked this pesky TPS with new one and pigtail but it appears I haven't. Any brand better than another?

 

Thanks vette you pointed me right to it. I will be trying to locate a factory service manual ALLDATA steered me all wrong.

 

As a side note ,
if while cranking over ,the ECM sees the TPS voltage too high ( over a certain % ) ,it will cut off the injectors completely because it " thinks "
you have the throttle open to clear a flooded engine but will not throw a code.

When you read on here of guys having to " pump the gas" on a EFI engine in order to get it to fire, what they are actually doing is cutting off the fuel