1992 Rodeo TBI problems

[kmathew]

Have a 1992 Rodeo 4X4. Am having a problem between the TBI (Throttle Body Injector unit) fuel injectors and the computer. When the engine is turned over there is no injector pulse from the computer. Have checked wiring harness between the two and it is good. Have 4 wires at the injectors 2 of them are tied togeather about 12 to 14 inches into the wiring harness.The single wire goes all the way back to the computer. Have checed voltage on these wires the 2 that are tied togeather have +12 volts on them as soon as the Key is turned on. The other 2 wires are ground wires and they go all the way back to the computer. I have determined that there is a +12 volts feed from the computer to the injectors all the time. The two ground wires appear to be switched off and on to energize the coils for each injector. This TBI unit has a throttle position sensor on it. My main question is will the computer shut off injector pulses to injectors if the throttle position sensor is bad or not hooked up.

I know the entire drive train of the 1992 rodeo's were all General Motors. Same thing as what was in the chevy S10 pickup.

If it was a Mustang I could fix it. ;pou fo[iqg fejq!!!!!!


Many thanx
Kmathew

[steveb_92rodeo]

Just out of curiosity, if you spray ether down the tb, will the injectors fire after the computer thinks the vehicle has already started? It's not probable, but may be worth a try.

I'm no expert, but I don't think that a failed tps would cause the injectors not to fire.

Do the injectors spray if you connect 12V direct? (I'd try this without turning the engine over. Put it in the run position to pressurize the fuel pump (is the fuel pump priming?) and just check quickly to see if they open up at all).

Steve

[CBM7760]

I'M BETTING ON THE FUEL PUIMP

Originally Posted by kmathew

Have a 1992 Rodeo 4X4. Am having a problem between the TBI (Throttle Body Injector unit) fuel injectors and the computer. When the engine is turned over there is no injector pulse from the computer. Have checked wiring harness between the two and it is good. Have 4 wires at the injectors 2 of them are tied togeather about 12 to 14 inches into the wiring harness.The single wire goes all the way back to the computer. Have checed voltage on these wires the 2 that are tied togeather have +12 volts on them as soon as the Key is turned on. The other 2 wires are ground wires and they go all the way back to the computer. I have determined that there is a +12 volts feed from the computer to the injectors all the time. The two ground wires appear to be switched off and on to energize the coils for each injector. This TBI unit has a throttle position sensor on it. My main question is will the computer shut off injector pulses to injectors if the throttle position sensor is bad or not hooked up.

I know the entire drive train of the 1992 rodeo's were all General Motors. Same thing as what was in the chevy S10 pickup.

If it was a Mustang I could fix it. ;pou fo[iqg fejq!!!!!!


Many thanx
Kmathew

[Silver Fox]

Originally Posted by steveb_92rodeo

Just out of curiosity, if you spray ether down the tb, will the injectors fire after the computer thinks the vehicle has already started? It's not probable, but may be worth a try.

I'm no expert, but I don't think that a failed tps would cause the injectors not to fire.

Do the injectors spray if you connect 12V direct? (I'd try this without turning the engine over. Put it in the run position to pressurize the fuel pump (is the fuel pump priming?) and just check quickly to see if they open up at all).

Steve

No the injectors will not fire if you spray eather and or Gas down the Throttle body. The engine will burn the gas or eather until it is gone.

Yes the injectors will spray if you connect 12 volts directly from the battery, but you must hook up both positive and negative from the battery. It will not fire off of the ground wires going back to the computer,




As far as the fuel pump I have replaced it with a used one which I tested and it works great.


The main question is does the computer stop sending out injector pulses if the throttle position sensor is not hooked up or bad.

Kent Mathew
Dallas, TX

[89t295k]

I too have a problem starting, I wonder if the TPS would make it not start?

Mine only starts if u use starting fluid, then runs great.

changed ecu...did nothing.

Did u ever get it figured out?

[steveb_92rodeo]

I know this is very, very late, however, I was just cleaning up emails and found this.

Over this past winter (Ontario, Canada), I still had the same hard start problems. I took off the breather and watched for quite some time as the vehicle ran.

As I watched, I witnessed excessive water buildup in the TB chambers. At that time, I poured in a bottle of antifreeze, and from the next day on (using af every fillup) I have not had a single problem since.

I always thought that the gas may be freezing, but new that the injectors were firing. After seeing what I did, I came to the conclusion the water in the gas was not freezing...it was simply condensing as the weather got colder causing more water to flow through the lines.

If your vehicle runs fine in warm weather, but not in cold, then this could be your issue.

Regards,

Steve