need a little help trying to hunt down my problem, got a truck for cheap (but very clean and good looking) and it acted like it was just a fuel pump, guy said truck drove parked it and would not start(crank but no start), changed the fuel pump. and still did not work. we put fuel in the carb and it would start and run.

now what we did
towed it to my house, found the plug on the pump was not plugged in right (came right off), pluged it back in and the pump is now alive,
but
in the process fouled up the plugs. changed coil, cap, and rotor before finding this out. then changed plugs
it would start but will not stay running..... checked ECM for code and nothing.
now wont start unless at full throttle, can keep running if i hold a little on the gas peddle.

i was thinking IAC or map.... but don't want to keep replacing parts that could be good(also in Alaska with out a garage and it is 20 degrees F out).
any help would be great

i also notice the throttle blade look to be all the way closed when nothing on the the throttle, is that normal for a TBI.

the plan was for this to be my sons first truck and he just need to fix the pump...

 

First you should verify fuel pressure and leak down even with a new pump.

George

 

do you have a link to show us the past way to do that, the one I seen was to do it at the fuel filter. is that the correct place.

 

https://blazerforum.com/forum/2nd-ge...eakdown-88305/

you start at the Schrader fitting on top of the engine. If you fail there then you need to repeat the test at the fuel filter output. Make sure to also do the leak down part of the test.

George

 

Les caught my mistake here, this is a 90' TBI motor so ignore that gen 2 FP sticky. You should have 8-10 psi at the TB


George

 

so took some time and had to order a test kit as the one the Autopart store had was bad..... when we tested today we got 8 PSI when trying to start, but if you just put it in run and let the pump prime it would never read over 0..... after hitting 8 PSI, once we stopped trying to start it, it would drop to 0 PSI in less then 2 seconds. any ideas what we are looking at here.....

thanks