91 no start cold strange injector problem

[jeeeptech]

I have a 91 blazer which is not starting cold ALl secondary ignition is good Fuel pressure is within specs. This is the twin injector TBI 4.3 It is recieving an injector pulse but will not spray the fuel If you pour a bit of gas in the throttle body it will start up and run. As long as you do not let the engine cool down it will continue to crank and run every time you try it.When the veh is running it has a good spray pattern from both injectors. The only time it fires the injectors during the no start is ocassionaly when you relese the key from the start position for some reason it will fire the injectors ( you can hear and feel them clicking ) but will not spray feul. Have tried a known good pcm from running veh. with no change I am at wits end I would love some advice or a wiring diagram showing how the injection system works. If you have run into this problem please e mail me @ [email protected]..Thanks

[refrigerationdude]

See my other post...check the ignition module in the dist. My '92 acted like this when it failed...except it would not restart warm either w/o using a shot of ether again. BUt once it ran it ran fine. I think the injectors will not fire unless a spark is sensed and possibly when that ign mod first fails it still works when the alternator is pumping out more than 12v but when cranking the voltage is too low and it fails to produce the pulses needed to fire the plugs and injectors. Thats the only reasoning I could put behind the fact it refused to start but if you caught it w/ ether then it ran and stayed running no prob.

[jeeeptech]

Thanks I appreciate it I will try a module mon morning it belongs to a friend of mine who I stuck my foot in my mouth and said Id fix. I worked for Chrysler for over 10 years so they are my specialty ,just dont know much about GMs .

[leadalto]

Originally Posted by jeeeptech

...secondary ignition is good Fuel pressure is within specs. .......If you pour a bit of gas in the throttle body it will start up and run. As long as you do not let the engine cool down it will continue to crank and run every time you try it......... ocassionaly when you relese the key from the start position .......

I have a 93 S-10 Blazer with CMFI Vortec. It used to start occasionally when the key was released. Now it won't start at all unless gas is poured into the air inlet. Have spark at plugs and fuel pump primes to 55-60 psi. When key is turned to Start, fuel pressure drops to 45 psi and does not come back up until key is released. Pulled tuning valve assembly to look for gas leaks. Did not see any signs of "gas washing" or smell gas in the plenum. I'm stumped. What seems obvious is that gas is not getting to the intake manifold. If you fixed the problem, please let me know what you did.

[leadalto]

Originally Posted by leadalto

I have a 93 S-10 Blazer with CMFI Vortec. It used to start occasionally when the key was released. Now it won't start at all unless gas is poured into the air inlet. Have spark at plugs and fuel pump primes to 55-60 psi. When key is turned to Start, fuel pressure drops to 45 psi and does not come back up until key is released. Pulled tuning valve assembly to look for gas leaks. Did not see any signs of "gas washing" or smell gas in the plenum. I'm stumped. What seems obvious is that gas is not getting to the intake manifold. If you fixed the problem, please let me know what you did.

Since this post, I’ve replaced the “spider” and “Nut Kit” which fixed a problem I had with rich mixture, black exhaust and carbon deposits on the driveway, and failing my smog test as a gross polluter.

The gas washing could only be seen after removing the upper intake manifold. It’s also possible that in addition to leakage, the pressure regulator just wasn’t functioning properly in maintaining the proper fuel pressure. Replacing the fuel injection components, however, did not fix the hard starting problem.

Today, I completed replacing my fuel pump. The result, no more hard starting.

When the key is turned to start, pressure does not drop but is maintained at 60 psi and the engine starts right away.