i have a 89 iroc z28 with a no fuel pump, no injector pulse problem. trouble shooting states to check voltage from the dark blue wire from ecm to vats module. i can't locate the vats module. i saw a cruise control module on pass side of car but that is not it. where is it located. a speed shop told me it was inside the ecm and they could eliminate vats by burning my prom. i did remove a security system from the car but the module was not part of it.

 

Much easier to check it at the ECM. The VATs module is buried.

It is pin B6 on the ECM.

Note that VATs won't stop the fuel pump from running. So that is a different issue. If the SES light doesn't turn on with the key-on, engine-off, then check the fuse under the hood. There is a wire that runs from the radiator support junction block to the ECM/fuel pump. There is a fuse in-line near the front of the car.

RBob.

 

Is the starter cranking? I doubt its the VATS as well. Much easier to check the VATS wire at the ECM as stated.

To answer your question though, the VATS module is buried in your dash. Pull the stereo and climate controls out. Look forward almost to the firewall, up and towards the passenger side and you should just see the connector going into the bottom of it and maybe one of the mounting screws. For security reasons you have to tear most of your dash appart to remove it. It screwed to the side of the HVAC chamber. Its about 3x4 inches.

 

thanks, i checked for that wire, where is it suppose to terminate at. the one i saw was connected to hot/red of the positive battery terminal.

 

thanks, you are right it's too much trouble. the engine cranks but the fuel pump and injectors are not energized. the key and the wires ohm out at the correct value for vats. so i'm sure it's not the vats system. but what do the fuel pump an injectors have in common that they won't work. i already replaced the ecm.

 

VATS located by fuse box. need to re do the ecm to tell it not to look for vats or taking the module out will do you no good at all.
when the VATS is not found to be correct it shuts the system down for 4 minutes. no electricity to the system.

 

> but what do the fuel pump an injectors have in common that they won't work.

Common is the ECM and the in-line fuse.

Does the SES light come on with key-on, engine-off?

The fuel pump should run for 2 seconds at key-on, engine-off.

Then a short crank should turn the pump back on.

The injectors also have two fuses for them in the fuse block: INJ1 and INJ2


Another common item is the ignition module. The REF+/REF- signal from it to the ECM tells the ECM to fire the injectors along with turning the fuel pump relay on.

Although, even with a bad ignition module the fuel pump should run for 2 seconds at key-on. Once the ECM sees the REF+/REF- (DRP's) it will then run the fuel pump based on that.

RBob.

 

the ses comes on goes out in two seconds but the fuel pump does not turn on . the inj 1&2 fuses have 12 volts when ignition is in on/start position. i replaced the ignition module also. my question is this inline fuse, it is part of the positive battery cable. if not what is the source of the fuse to ecm, i don't understand why this is located near the radiator or fenderwell area.

 

If you have power at the fuses its not likely the battery cable junction or fusible link. At the ECM there are 2 or 3 pink/black wires that should be hot with key on and an orange one hot all the time.

I would jump power straight to the fuel pump and verify the pump just hasn't gone bad. Have you run the car completely out of gas? The pump will burn up very quickly. If you supply positive power to the tan/white wire going to the fuel pump, you should hear it run. Easiest place to track it down is the pass through behind the rear seat back under the carpet. If it runs you can work forward to the relay mounted on the firewall next to the brake booster.

 

the ses comes on goes out in two seconds

Is this with key-on, engine-off? If so then it is not correct. In this case I'd say that the ECM may be bad.

This in-line fuse is run off of a junction block. Check on the radiator support for this block. What GM did was to run a heavy gauge wire off of this terminal/junction block to the ECM & fuel pump. Inline with this wire is a fuse. It is located in a holder, should be able to find it along with inner side of the passenger fender (under hood).

The purpose of doing the ECM power feed this way is to get a clean source of power. Close tot he battery provides a low impedance source of power.

RBob.

 

o.k. i mistook the security lite for ses. ses never comes on and the lite bulb is good. i can't find that fuse block. the last owner probably ripped it out. i couldn't figure out the coolant fan relay wiring so i install an on/off switch and wired it hot. i checked various wireson the ecm for voltage and a green and a gray wire were hot for 12volts. so i know the ecm is getting power. how i don't know because that fuse holder is gone. now the dark blue from the ecm b6 to the vats is not hot, no volts.

 

i did all you said and the pump turns on, but not by itself with the key. i ohmed the key and wire connector and i have a # 12 and it reads 6000 ohms. so i think vats is o.k. and the key/igntion switch because the engine cranks.

 

Check pins B1 and C16 on the ECM. These are orange wires and are the battery feeds from the inline wire/fuse.

RBob.

 

You initially mentioned that you have no injector pulse, but how do you know that though? Did you confirm this with a noid light? The fuel pump primes for only a second or two with the key on, but will not stay on unless triggered by the ECM. I would check for an injector pulse using a noid light, and if they're pulsing, look towards the injectors themselves, especially if their the stock Multecs. Also, depress the schrader valve for less than a second with your finger, and if it spews, this will confirm that the pump is supplying fuel...

 

If the security light goes off after a second or two once the key is placed in the ON position, then I doubt it's the VATS. I wouldn't bother paying someone to eliminate the system in the chip, you could do it yourself for much less....;

http://www.youtube.com/watch?v=AKfn7J9CeZM

 

i checked the injectors with the noid lite and nothing happens. also no fuel at the valve, only when i hot wire the pump wire direct.

 

.... then it might be the ECM itself. Check your ECM grounds, and if all are good, try to get your hands on a donor ECM to confirm.

 

o.k. i did not get the voltage, so that is the problem. what color wire is this and where does it start from. could i route a new wire and splice to this two orange wires.

 

i did not get the voltage. since i can't find this wire at the fender can i route a new hot wire to the b1-c16 orange wires direct.

 

.... are you talking about the ECM battery feed off of the positive battery cable?

 

thanks for the picture. is that the connector with the 20 amp fuse. i don't have that but i have the red positive cable with a red wire that is not connected. the black with red stripe wire from the alternator is connected to the battery post terminal. i found a double red wire factory splice with one red wire coming out that is hot all the time and not connected. this can't be the ecm power wire with that 20 amp connector because it's already hot. i need to find out where this wire goes because something is not getting power.

 

rbob, it took a long time but i saw that the two orange wires of b1/c16 went to a four orange splice that branch out to four orange wires with one connected to fuel pump relay, maf burnoff, maf power, and some other unit unit i can't figure out. but there is no voltage. i beleive it comes from the fuse box, fuel pump/ignition fuse. i'm going to test that.

 

Find the corresponding wire coming from the ECM, and connect it....