i just rebuilt the top end going back to tpi from carb and the only piece i dont have is the air coupler so the maf isnt hooked up to the TB and im pretty sure everythings set correct and it tries to start but wont. is this because the maf isnt hooked up or will it run anyways even if it is sloppy?

 

The ECM has programming that is used for failed sensors. This is the CAL-PAK. That is Calibration Package that is loaded into the ECM to use as back-up when the electronics suffer a sensor failure so the engine can still run. Its a wide spectrum program since the ecm is not getting real time data from everything...

heres the deal...the engine has to run for a few seconds for the ECM to 'see' that there is a problem. Without a signal from the MAF the thing is going to be reluctant to produce the appropriate fuel/air adjustments to start up...so its a catch 22 situation...until it runs it cannot "set" itself to LHM and run off of the stored program. It does not want to start because there is something not right with the data coming in....

You have to make damn sure everything else is right. Good fuel pressure, timing is close, spark is good. Then, its just a matter of will. Keep trying. Get some wet gas into the plenum to help get the first few stumbling revolutions and then it might try to keep going. A fresh assembly is going to be harder to start up first time and missing the MAF...going to be even tougher. Once it starts and runs, the SES will illuminate and it will be in the back up mode and you are good to go...it sill stay there until something changes. You can TRY doing the GM paper clip in the ALCL as if you were reading codes, and try to start up. That is supposed to be how to set the "diagnostic" mode in these ECMs. I am not sure how much difference the diagnostic and LHm is, but it may get it to lite up the 1st time then its ok. I ran mine for weeks without a MAF when I just did not have time to mess with it...not good for it but it will work.

 

im trying hard ive got fuel and air for sure. and i got the engine to 6 degrees before when i set the dizzy so i advanced it some. but yes its being VERY reluctant.

 

Apparently it should.
Running with the MAF disconnected is one of the tests for a faulty MAF sensor
See
http://www.chevythunder.com/maf_code_34.htm

Would be advisable to pull the codes as suggested.
http://www.corvettephotographs.com/c4vettes/codes.htm

You may have other problems with the swap you don't know about that are causing the no start cond.

 

grrr. its so close im pretty sure the timings almost dead on and i can turn the dizzy enough for it to "kind of start" but not run.

 

Sounds like you r getting close to vroom vroom. I feel you should have the MAF but make sure no air leaks cause your idle will frreak out. With MAF you will need to do the idle setup which is
http://www.digitalcorvettes.com/foru...ad.php?t=58873
If you have come this far may as well finish the deal

 

There is more to getting a EFI to run than getting the timing near enough like on a carb engine

 

well everything is new. entire fuel system all sensors and gaskets. so im just trying to pinpoint

 

Refer post # 4

A simple power / ground / wiring problem will take out a sensor circuit

 

i have a scanner but how do i check codes without getting the car to run?

 

ive never had a ses or ce light on even with everything disconnected when the carb was on, this was while the ecu was plugged in

 

Does the SES light bulb work at all ?
The SES light should come on with the Ign and go off after the engine starts



Once again post # 4 has a link to detailed instructions for pulling the codes by jumpering the ALDL terminals and just turning the Ign on.
No start required

 

does the ses display on the center console? because that had stopped working one day after i tinkered in the fuse panel

 

When the panel did work the only lights that showed would be hatch ajar and the brake light

 

So your SES light is currently not working ..................

Rather explains your " ive never had a ses or ce light on " comment doesn't it ?

 

I didn't know where it was located. Sorry about that.

 

I had the same problem in my '86. The distributor rotor had skipped (i put it back wrong) back by one tooth.

 

Been there. Done that. Got the same symptoms -- it would "almost run".

Note that you can set the timing while cranking. The engine doesn't have to be running.

 

I got it it won't take any acceleration or it'll die and I can coax it to get gas then it backfires. But arp east it runs haha

 

Sounds like a timing issue to me; without the maf the car should run just fine (albeit not to high level of performance). The above post mentioning unplugging a suspect maf is dead on. That is the easiest way to tell and it always amazes people who bring a car in that is struggling to run and we pop the connector loose and it smooths out and runs well. Of course the next question usually is ok cool, so do I really need that??? lol Just my .02