94 GMC 4.3 Injection Safari Won't Start

when did it start to play up ?

was it ok before this time?

when it stopped, was you moving at the time, Or staionary.

When it stopped had you hit a speed bump, Pothole, anyone thump the car threw spare ino it etc.

reason for asking some vehicles have an inertia switch to shut fuel off in collision event, But somtimes any large bang will set it off,

On some cars its in the boot near the spare, So you break down with punture, change tyre throw spare into boot and drive of you get a few yards down the road and car stops and wont start, See what i mean ?

I have great fuel presure at the injectors just not able to get the triggers to fire

Do you Get A Spark ?

yes, I can run the engine on starting fliud just fine

lots of questions and some answers

http://wiki.answers.com/Q/FAQ/762-8

If you have good fuel presure at injectors and no trigger and no spark i would suggest Crank Shaft Sensor

And its Location is, Before removing it though try unpluging it then re pluge it.

http://wiki.answers.com/Q/Where_is_the_crank_shaft_position_sensor_on_a_1999_gmc_safari_van

have spark runs fine on starting fliud

how are you measuring fuel presure at injectors ?

when it shoots out the hose port at a high rate of presure I belive it is fine

I have seen engines similar to yours with a defective rotor and the spark went through a shortcut to ground . I believe your fuel pressure is supposed to be in the area of 39 psi. This is difficult to estimate just by looking at the flow. Is it possible that you are getting a weak enough spark that it will fire the ether ,but not gasoline? Check the inside bottom of the rotor, if its got carbon trails there it could be the problem. Could you let us know what you find? Thanks

h

we still are not getting fuel in the cylinder from the injector, I would check spark if there was gas in the cylinder

I have to ask what seems like silly questions as i have never worked on or even seen your make and model.

http://wiki.answers.com/Q/FAQ/770

just to be going on with

get or make a 12 volt test light and connect both wires into plug on injector, When you crank you shoul get a flashing light, this is just to confirm no pulse, now connect one side of test light to ground/ earth of motor and get somone to crank while you see if there is any power to each side of the plug ( i am assuming there is two wires).

if you get flashing light mark the other connection and run a wire from earth to it and reconnect to injector, and see if it will run on one cylinder, if yes the earth is missing to the injector for some reason.

If not i will go back into dark room and do some more thinking

will try that and I am replacing the injector asembly wire set. I was told the wire shorts out inside the injector tray and needs to be replaced as well

How many injectors does your car have?

just in case we fail here.

http://wiki.answers.com/Q/What_should_the_fuel_pump_pressure_be_on_a_97_gmc_jimmy_4.3

I believe the engine in question has what is referred to as CPI, central port injection. There is one injector to feed all 6 cylinders. Will try to help you stop throwing money at a problem by replacing parts unnecessarily. Be patient and give us all the info you can . There are some quite knowledgeable people on this forum and I'm sure someone will come up with an answer to your problem. Thanks

h

I think I have, Followed the repair manual,Started at fuel pump to presure regulator,then to the spider injector, Fuel is to the injector and power is in to the switch and out of the switch. changed ECM for free no luck,changed the distriutor mod for free no luck.I have fuel pouring out with engine turnover to the injector line. still no fuel into the cylinder. I can run the engine on starting fliud al day long. told to change injector wire asembly because wire detererates in the fuel valley over the years. Thats next hope that will open the triggers allowing fuel into the cylinder

I believe there two fuses that influence your fuel injection cycle. One says "Ecm" and the other is "Inj" . Check those 2 fuses and let us know if that doesn't solve your problem of no power to the injector. Don't give up, you have good folks who really want to help you.

h

Let's try a quit and dirty to see if it works. These guys are notorious for poor electrical connections to the fuel pump...I went through three on a Suburban. Try running power to the fuel pump directly to the battery with fresh wiring and see if it fires up. This cleared up the problem on both of my GM rigs. Good luck.

Have you considered a new truck? It IS a '94 after all.... sometimes it is better to just let things pass on than to keep throwing good money (and time, which is money) after bad.

had one...same problem...bought junkyard throttle body... cleaned it up & installed and the truck's still running today.

the pressure regulator inside the throttle body was probably stuck open...

why do auto mechanics charge so much?

because they can!

Remember the days when a mechanic charged so much for just turning a screw. The amount wasn't for turning the screw, but for knowing which screw to turn. Didn't someone say knowledge is power? I guess this was one of the examples.

h

IF IT WAS EASY EVERYONE WOULD BE DOING IT.

TTO DAVE: (1) If it starts on Starter Fluid( Ether) (2) Are Your Injectors spraying.

2 things to Check: Injection Pump Timing & Injectors Spray Pattern. If the Timing is OFF Enough Fuel Is getting there to Late for the Compression to Ignite It. If the Injector/s ONE or More SPRAY PATTERN Is the Problem, the Fuel is far to rich to IGNITE. With all the ITEMS you replaced, Have All Lines Been OFF UNIT, CLEANED & BLOWN OUT WITH HIGH PRESSURE AIR HOSE ? What Type of Water TRAP/ Filter Has your Unit Got( Some ARE MANY THIN PLATES INSIDE A GLASS BULB) THEY MAY LOOK CLEAN & BE PLUGGED JUST INSIDE THE OUTPUT LINE.

Note: Even Though I retired before Your '94 GMC was built, the Basic Principals Still apply. Old Diesel Tech. Carl.