HottLS1Z

iTrader: (5)

MY 98 Z wont start, car had been sitting for a while but started up fine then died like 15 min later, fuel pump kept shutting off then after about 5-10 min it would start again. (I just put a walbro 255 in it 4 months ago). Also the relays in the fuse box sounded like they were goin a lil nuts lept clicking well now I decide to finally see about getting this taken care of and the damn thing wont start so I switced out the relays under the hood and tried another fuel pump, even tried my other set of keys nothing relays arent making the noise they usually do, pump not kicking on all...connections are tight. even double checked all the wiring on the pump itself. Only other thing I noticed is I have a hypertech programmer for the car I wanted to scan for any codes so I went to check and it kept saying "turn key to run position" even though it was in the run position, usually when you do that it goes to the next screen........could this be a problem with wiring in the colom maybe? Maybe a wire came loose or something in there thats why the programmer thinks the key isnt turned to "Run position" and the pump aint kickin on? The chime still comes on and all the lights on the dash come on though so I'm lost, The motor does crank just no fuel I can hear the pump clear as day I know 100% thats why it wont start just FYI to keep from getting off topic. Anyone have any answers??

HottLS1Z

iTrader: (5)

just incase anyone is wondering its just a bolt on car A-4 and has over 160K on it if it matters. Also checked all the fuses forgot to mention that.

01WS6/tamu

iTrader: (37)

Time for a fuel pump.

HottLS1Z

iTrader: (5)

For the people that are going to reply make sure to read the WHOLE thing I wrote, IE: here I already replaced the pump and tried that already! Not to be ignorant but I need some answers fast if possible not ideas I said I already did.

jmm98LS1

iTrader: (28)

Sounds to me like there's a problem with your ignition switch or the wiring going to it.

alamantia

iTrader: (10)

does the pump at least energize for 2-3 seconds when you first click the key on? If youhold a test light on the relay and have someone turn the key the test light should come on for a few seconds.

01WS6/tamu

iTrader: (37)

I did a cliff notes and missed that point. Jack the car up disconnect the electrical connector to the pump. Take a test light and put it on the gray wire and have someone turn on the key. The gray wire should have 12v for a few seconds and then go out. Then have them try and crank it and see if it lights. If it does then check the ground wire heavier gauge black wire for a good ground. If that all checks fine the new fuel pump is junk. Have had that happen more than once. Even with gm if that is what you replaced it with. Check to see if the service engine soon light comes on when you turn on the key. IF it does the ignition switch is fine. Grab a scanner and energize the fuel pump relay and go from there if the above diagnostics fail.

HottLS1Z

iTrader: (5)

nope sure doesnt, not anymore always used too though

HottLS1Z

iTrader: (5)

ok...Tonight checked the voltage, getting power to the relay under the hood but not to the grey wire by the pump. Pulled the pump assembly out tonight and hot wired it to a battery, pump kicks on so its not the pump. Turned the key to the run position no SES light lights up. Also the relay under the hood was also getting about 12V even with the key off Anyone have any more info on the whole deal with the ign switch mentioned earlier or any other suggestions?

HottLS1Z

iTrader: (5)

Also If the ign switch is bad why would the dash lights come on (minus the SES light) and the car still tries to crank over? If the ign switch was bad the car wouldnt crank would it?

HottLS1Z

iTrader: (5)

anyone???

01WS6/tamu

iTrader: (37)

No SES and no fuel pump sounds like the pcm is not getting power. In the fuel pump relay there is one wire that is hot all of the time this is the wire that bridges over and powers the fuel pump when the relay closes. Check all of the fuses in the under hood power center with a test light, then with a multimeter to see how much voltage is present with the key on. Check the pcm a, b, eng sen, and others those are all I can remeber off of the top of my head. If those have no power or low voltage then pull the Pcm ignition power relay and jumper pin 87,and 30 this will supply power directly to all of the above circuits. If the pcm and fuel pump comes on then it is either a defective relay or a problem in the ign circuit that closes the relay to energize all of the components.

HottLS1Z

iTrader: (5)

So tonight we wired up a switch for the pump and got the pump goin, car still wont start, have no spark, so I guess next is try the pcm.....cars outside and its been 2X degrees all week at night when I get a chance to work on it after work, with snow and ice everywhere any other suggestions incase thats not it?
Thanks

01WS6/tamu

iTrader: (37)

I am betting money on the ign relay that I mentioned earlier. Take a few minutes and go back and read it a little closer in the post before this one. It is a different relay than the fuel pump relay. No spark and no ses screams that the coils and pcm are not getting power. To confirm this suspicion check to see if there is power on the pink wire at the coil main connector and check the pink wire at any one of the fuel injectors.

HottLS1Z

iTrader: (5)

Well, got ir running, the computer wasnt getting power ran a hot wire to it with a switch so if the switch is on the car starts, if you shut the car off with the ignition it stays running! gotta kill the power to the computer for the car to shut off, any ideas why the pcm would not be getting power?

01WS6/tamu

iTrader: (37)

the ignition power relay is more than likely where you will find the problem. pins 85,86 need power and ground to operate the coil in the relay. Pin 30 is constant 12 V and Pin 87 is the output from the relay to the PCM and all associated circuits.

HottLS1Z

iTrader: (5)

All of the relays are working properly and getting power but the pcm isn't I'm thinking bad wire or ground somewhere but where is the question...

01WS6/tamu

iTrader: (37)

Ok turn the key on and tell us if you have 12V at the coils and injectors on the pink wires respectively without any jumper wires installed and the ign relay installed. Lets see if we can isolate it to a bad splice pak or something like that.

HottLS1Z

iTrader: (5)

ok I we can try that but dont think ill be able to do that until this weekend unless plans change, this weeks gonna be a busy one, but on a side note I mentioned that switch we ran to get power to the pcm...well today the car decided it will start and run fine and shut off just by using the key with the switch off....like nothings wrong so it would appear whatever the problem it gone for now, not sure how to track this now that its not acting up...