Injectors, no fire !!

[big wheel bob]

Hi, all, new guy here. I am having a problem with a 87 blazer, we just swapped out the tbi 350 for a tbi 454. This thing ran perfect with the 350, now I cant get it to start. There is fuel pressure, and spark at the plugs.I have replaced the ign module, then the whole dist. Also i have changed the computor, still nothing.Checked my grounds, and for pinched wires. Any help would be appreciated.

 

[dave_90_blazer]

check the inj. fuses(1 & 2)
they supply power to the injectors, and the ECM grounds the injectors to fire them

 

[big wheel bob]

I have power to both injectors.

 

[k20]

are the injectors firing? Are they spurting fuel? Have you used a NOID light to see if the injectors are getting an impulse to fire? Is the coolant temp sensor new? (I had a coolant sensor go bad, kept the injectors from firing).

 

[big wheel bob]

The injectors are getting power, i have never heard of the coolant sensor giving this problem.

 

[k20]

its not spurting fuel, but you are gettin spark? THat could be the temp sensor, when mine went bad, it got 'stuck' on a hot temp (210 or so) and when a motor is hot, the computer takes fuel away from it. If it were to get stuck on a cold temp, you would be having a problem w/ it flooding out once it got warm.

 

[rescuekrawler]

on my 87 I had trouble with that! It ended up being the prong on top of the trottle body striaghtin them or replace but I couldn't find new ones. good luck!! let me know how it goes

Tom /forums/images/graemlins/truck.gif /forums/images/graemlins/usaflag.gif

 

[Thunder]

Kind of a long shot. But have you checked the Oil pressure switch?
Is the IAC hooked up right. The 454 and 350 have diferent connectors. Might be getting too much air to start it cold.
Also if the Temp sensor is bad as said above it wont supply enough gas to start it cold.
Will it start if you pour a little gas down the TB?
Do you have a scanner? A scanner would really help to narrow down the problem.

 

[Thunder]

Oh! One more question. When you swapped in the 454 TB Did you also rember to swap the injectors from the 350 TB into the 454 TB. I dont think a 350 ECM will run 454 injectors. I think the drivers or something like that are diferent.

 

[big wheel bob]

Appreciate the help. I will look into bothe of those things this week, i hope.I will let yall know.