NEED TBI HELP

[jeremytkoontz]

OK, GOT A NEW TRUCK.... I UNDERSTAND THAT IT'S NOT A S-10 BUT THE SAME RULES APPLY.... 1993 2WD SILVERADO 5.7, TBI...



SO, TRUCK HAS BEEN SITTING APPROXIMATLY 2 YEARS GIVE OR TAKE... GOT IT RUNNING TODAY BUT IT WON'T STAY RUNNING...



IT'S NOT GETTING FUEL TO THE ENGINE.... FUEL PUMP IS GOOD, TOOK OUT THE FUEL FILTER AND TURNED ON THE KEY, GOT LOTS OF FUEL COMING OUT WITH KEY ON... PUT IN A RUBBER HOSE IN PLACE OF THE FUEL FILTER BECAUSE I THOUGHT MAYBE IT WAS CLOGGED... TRUCK WILL RUN IF I POUR GAS IN THE TROTTLE BODY OR IF I SPRAY IT WITH STARTING FLUID BUT THEN IT DIES... WILL NOT STAY RUNNING ON IT'S OWN... THE FUEL INJECTORS ARE NOT SPRAYING FUEL.... ANY THOUGHTS OR SUGGESTIONS WOULD BE VERY HELPFULL.

[riotpolice75]

when you first turn the key on on a TBI motor the injectors will spray for about a second then stop. when you turn the key to start the injectors will alternate between left and right firing. i believe they fire 4 times per revolution. so when starting you can see it clearly. make sure theyre doing that before you say the motor isnt getting fuel. either get someone else to turn the key or rig a jumper wire up to the starter so you can do it yourself remotely.



if you dont see the injectors firing at all then disconnect the connectors off the injectors. youll have 4 wires. the solid red wire and the solid white wire are the 12V constant to each injector. get two wires, run one to the battery and to the hot side on the injector. take the other wire and run it from the other side of the injector to ground. with the key on the injector should spray as long as you leave it hooked up like that. as soon as you ground it youll hear it click.



if the motor has been sitting that long then make sure you give your vacuum lines a good once over. especially the MAP sensor. another thing to check is that you dont have rust in the injectors. both have happened to me. if you jump the injectors with the key on and nothing comes out then chances are theyre rusted up.



it is a 350 right?







smith

[chris1972]

get a noid light see if the injectors working ..it will flash when cranking if its is working .if it is flashing.then it the ignittion modules in the distributor...the module control the pulsing of the injectors..chris

[chris1972]

on the injectors wire two goes to 10 amp fuse same fuse for the computer ..the other wire goes to the computer..

[jeremytkoontz]

ok, replaced the injectors.... still having basically the same problem... fuel will dribble out of the injectors but it won't stay running on it's own... fuel pressure seems to be fine.... I hot wired one of the injectors, started the truck, it ran for about 3 minutes or so, then the injector that I hot wired blew up.... so, now I'm thinking that it is a problem with whatever controls the pulse to the injectors.... is it correct that the ignition control module does this???

[Melonhead]

Jeremy, this may sound dumb. Did you check the fuel filter to see if it's clogged? pull the filter and connect a hose to the inlet side. Put the hose end in a bucket and have someone turn the key to on. If the pump is good the fuel will come out like there is no tomorrow. If all is good, try the same thing with the filter attached and to the bucket.

[jeremytkoontz]

took the filter off yesterday, it was clogged, put a rubber hose in place of the filter.... getting plenty of fuel to the tbi unit, just won't come out of the injectors right.

[Melonhead]

You thing maybe trash in the line to the injectors? http://www.s10v8.com/images/smilies/icon_confused.gif

[jeremytkoontz]

nope, I took the trottle body off today, replaced all the gaskets when I replaced the injectors and I have fuel coming out of the lines up to the throttle body.... when I had it all apart, I cleaned the trottle body out really good and blew all the fuel passages out with my compressor.

[riotpolice75]

On 2007-10-29 15:20, jeremytkoontz wrote:

ok, replaced the injectors.... still having basically the same problem... fuel will dribble out of the injectors but it won't stay running on it's own... fuel pressure seems to be fine.... I hot wired one of the injectors, started the truck, it ran for about 3 minutes or so, then the injector that I hot wired blew up.... so, now I'm thinking that it is a problem with whatever controls the pulse to the injectors.... is it correct that the ignition control module does this???





when you hot wired the injector did you get a good spray? if you have a multimeter then check the wiring too. you should have a solid 12V going to the injector. do a resistance check on the wires too.







smith

[jeremytkoontz]

gonna try a new fuel pump in the next day or two.... I have a feeling that I'm not getting enough pressure to the tbi unit.... maybe I'll pick up a tester and check it out first.... anyone know what psi I should be getting on this truck???

[mlhj]

If I remember right it sould be between 9-13 psi.

[chris1972]

first take a light tester and check the wires from the injectors.with the same wires to one injecter..one end of tester to each wire ..while whating it see if it flashes while cranking..if not then check the wire from the injecter one has 12v..the other goes to the computer ..sould like to me its the ignition control module ,does control the plos..chris

[jeremytkoontz]

OK, HERE IS THE UPDATE:



REPLACED THE INJECTORS, NO LUCK, REPLACED THE IGNITION CONTROL MODULE, NO LUCK.... NOW I WAS GETTING WORRIED, THOUGHT I MIGHT HAVE A BAD COMPUTER OR WHO KNOWS, I WAS RUNNING OUT OF IDEAS BUT I STILL THOUGHT THAT I HAD A FUEL PRESSURE PROBLEM.... WENT LOOKING FOR A FUEL PRESSURE GUAGE, COULDN'T FIND ONE THAT WORKS WITH THE GM TBI SYSTEM.....



WELL, TONIGHT, I PULLED OFF THE BED OF THE TRUCK (I PREFER TO DO THIS WHEN THERE IS A FULL TANK OF GAS), REMOVED THE FUEL PUMP TO SEE IF MAYBE THERE WAS RUST OR WHATEVER CLOGGING UP THE PUMP OR THE SCREEN..... AND WHAT DID I FIND???





THE LITTLE .50 CENT 1 1/2" RUBBER HOSE THAT CONNECTS THE FUEL PUMP OUTPUT NOZZLE TO THE FEUL SENDING UNIT WAS APPARENTLY DRY ROTTED AND SPLIT ABOUT 3/4 OF IT'S DIAMETER..... SO, I JUST HAPPENED TO HAVE SOME 3/8" FUEL HOSE LAYING AROUND, I PUT THAT ON AND REINSTALLED THE FUEL PUMP...... TRUCK RUNS LIKE A CHAMP:



WOW, HOW IT'S ALWAYS THE LITTLE STUPID CRAP THAT BITES YOU.... NOW THAT I HAVE IT RUNNING, I JUST NEED A NEW TRANSMISSION....LOL.... BUT WHAT CAN YOU EXPECT FROM A FREE EXTENDED CAB TRUCK WITH 120K MILES ON IT....



THANKS FOR ALL YOUR GUYS' HELP ON THIS PROBLEM.

[riotpolice75]

NV3500?







smith

[jeremytkoontz]

I wish it was a nv3500.... i need a 4l60e.

[cloptonw]

check your fuel pump pressure if the dam thing aint getting 60 pound of pressure it wont run trust me i had the same problem

[mlhj]

Since last Saturday I had two cases of that rubber hose on the fuel pump in the tank.



First one is a 95 S10 I am buying from a junk yard I use to work at. The truck has been sitting for over two years so since I have access there to work on the truck during the weekends I pulled off my box to put on a new one I got off a 99 which is a stepside box. The truck would not run right so I decided that most likely the problem was old bad gas so I decided to replace the hole tank and pump and sending unit, filter. After getting the old tank out I took out the old fuel pump and what do u know the rubber hose was dry rotted and had a split in it now it runs like a champ too.



Then on Monday I had to go pick up a old ladies 92 2wd 305 tbi silverado because it didn't have any power at all one thing that shock me the truck only had a little over 28,000 miles well check it for fuel pressure was only getting about 5psi when it calls for 9-13 psi well turns out that stupid hose on the fuel pump was dry rotten too and had a split in the hose too, but at least it had clean gas in it.