fuel injection problems

[marvin]

as soon as it turned cold(snow) in slc my nephew has had problems with his fue l system, he has a throttle body injection on his 1993 GMC Yukon, 5.7L, we ran heat and fuel injector cleaner, then we replaced fuel pump, then replaced in line fuel filter, and replaced pressure regulator. we are getting gas to the injectors but it does no come out of injectors. any help after that??????

 

[way2nosty]

as soon as it turned cold(snow) in slc my nephew has had problems with his fue l system, he has a throttle body injection on his 1993 GMC Yukon, 5.7L, we ran heat and fuel injector cleaner, then we replaced fuel pump, then replaced in line fuel filter, and replaced pressure regulator. we are getting gas to the injectors but it does no come out of injectors. any help after that??????

are you getting spark? GM TBI is fired off the spark pulse you may want to check your ECM fuse, also beg borrow steal or build a Noid light and make sure you are getting a injector pulse at the injectors, so you know wheter it is electrical or hydraulic.

 

[marvin]

Not Getting Any Spark To Injectors, Could It Be The Coil, Fuses Are Fine

 

[Klif01]

Huh?

If the injectors aren't firing, the ecm probably isn't getting a signal from somthing else like mass air flow sensor...

 

[way2nosty]

Huh?

If the injectors aren't firing, the ecm probably isn't getting a signal from somthing else like mass air flow sensor...

Gm TBI is pretty simple, in Open Loop Mode it is pretty well the ignition system that sets the timing on the injection. I was talking about Spark to the Sparkplugs, If you don't have either, Have you checked at the ECU in the Passenger side kick panel, see if it's getting power... let me remind you that you need to use a meter because a testlight will f(c% up a computer.

 

[way2nosty]

I've seen a bad ingnition module cause a no spark - no fuel condition.

 

[Devel]

maby water got in the fuel lines and froze

 

[I Lean]

As an easy test, pour a little fuel down the throttle body as you try to start it. I had an issue with my TBI 4.3 back in the day, it wouldn't start at all--but fire it up with fuel as I said, and it'd keep running. Once it fires, the computer sees the signal it's looking for and begins firing the injectors like it's supposed to.

 

[great scott]

I agree with way2nosty, you need to see if you have spark at the ignition coil, if you do you need to check fuel psi and injector pulse/signal. I have a noid light and a good fuel pressure gauge with all the adaptors. Give me a shout if you need em.

 

[Crinco]

Injection

Not Getting Any Spark To Injectors, Could It Be The Coil, Fuses Are Fine

So we are all on the same page, would you please restate this? There should be no spark at the injector, only at the Coil(s) and Plugs. The Computers checks for a spark (tach signal) and uses that to fire the injectors. It doesn't know that the engine is running without the spark signal. Bad coil means no spark= no injector pulse.
So check your engine for spark. If no spark, then fix that and you should have fuel again. If you do have that, go to a parts store and get a cheap noid light. It will tell you if you have a working injection system (sorta). If the injection isn't working then it is likely a power/ground issue or ECU.
Check for spark
Check for injector pulse
Check D.T.C.'s
Check Fuel Pressure
Lastly I don't know if that year had VATs (vehicle Anti-theft) or not, but that will keep it from starting too if the VATs Module has gone bad. My 93 LT1 engine has VAT's, well, had any ways.