No start on 2005 GMC Suburban - possible TBI signal issue?

[Andrea F]

Our 95 Suburban stopped running in the driveway last week. It does fire if you put a little gas down the throttle body but then dies. We repalced the fuel pump in the gas tank and it's pressurizing the TBI unit but still no start.

We have 12v to each injector but they are not firing when you crank over the motor (no spray pattern). We replaced the fuel pump relay, chacked all the fuses in the dash and under the hood.

Any suggestions? It ran fine before this and quite right as we were replacing the air cleaner element and were putting it back together. Hoping it's something easy.

 

[jaki54321]

First off, in the newer vehicles you are not suppose to put gas down the throttle body because they have a multiple electrical components (it is a dry intake). When you do this, you wet the throttle position sensor and idol mottor that the new vehicles have inside the throttle body (and/or other electrical parts.) So you may have fixed ur issue by replacing the fuel pump relay, but you may have caused more issues by poring the gas in directly.

Run a voltage in the throttle position sensor and read the ohm that comes out ( you have to get a vehicle manual to tell you how many ohm's is correct for your vehicle.)

Goodluck!!!

Source: My husband, mechanic over 16+ yrs.

 

[Joseph V]

u didn't mess up any sensors if you poured the gas into the throttle body it self. so if u did that your still good. sense you already replaced the pump and your getting pressure at the fuel rails my next guess is your pcm is bad. if you had a scanner or noid lights you could be sure that your injectors are good but it goes down down to either your injectors or ur pcm

 

[Joseph V]

u didn't mess up any sensors if you poured the gas into the throttle body it self. so if u did that your still good. sense you already replaced the pump and your getting pressure at the fuel rails my next guess is your pcm is bad. if you had a scanner or noid lights you could be sure that your injectors are good but it goes down down to either your injectors or ur pcm

 

[Joseph V]

u didn't mess up any sensors if you poured the gas into the throttle body it self. so if u did that your still good. sense you already replaced the pump and your getting pressure at the fuel rails my next guess is your pcm is bad. if you had a scanner or noid lights you could be sure that your injectors are good but it goes down down to either your injectors or ur pcm

 

[tech frank]

you may have a bad connection at the feul pump plug ,not having noid lights you really cannot tell if injectors are fireing ,plus the parts are crap anymore there is a good possablity that you may have recived a bad pump itself , if all else fails the ignitoin module could be at fault