94 Bravada wont start now

[ericn1300]

Originally Posted by thebox_is_here

Well the vin is definitely OBDI. I didn't personally check the fuel pressure but, my gf father checked it against the manual and said it was correct. We havent checked the CPS but we can. The reason I say I am thinking ECU is the Hayes manual says for the model of Bravada I have there is a code 12. I'm ready to throw caution to the wind and try the computer route.

that's a shotgun approach, stop throwing parts at it. as Chris once said to me "do yer daignostics". this is from the repair manual: Code 12 is not a fault code. It is used as a system acknowledgment or handshake code; its presence indicates that the VCM can communicate as requested. Code 12 is used to begin every diagnostic sequence.

the above info remains the same for both the OBDI and OBDII. if it's an ECU (or ECM, VCM, PCM or what ever you want to call it) problem, i'd be surprised. but go ahead and try a new one. you'll have to get an exact match from the recyclers, otherwise it's a dealer only part. a used / reconditioned one will cost you over $300. maybe you can find someone with the same vehicle that will let you borrow one. or you can take your's out (easy to get to) and trot down to the dealer with it. get it read, cleared, tested and reprogrammed with the latest eprom update on their test bed. let us know how it turns out.

[Chris Stewart]

If the truck had Throttle Body Fuel Injection (TBI), the fuel pressure spec is 7.5 to 9 psi....not enough for the Central Point Fuel Injection on ya'lls Bravada which specs 55 to 60 psi. I can't see a motor starting and running then after changing the fuel pump frying the computer unless ya'll had to arc weld the fuel tank back on.

Thanks for the 3.1 motor info Eric.

[ericn1300]

does the 94 bravada have the pass-key security pellet in the ignition key?

[Chris Stewart]

Originally Posted by ericn1300

does the 94 bravada have the pass-key security pellet in the ignition key?

I don't know.

[ericn1300]

well chris, how about your 97?

i think the origional pass-key system system shuts off only the fuel pump if it doesn't see the key pellet and you can crank the engine all you want with no start. the pass-key2 system shuts down both the starter and fuel pump too. the way to tell if you have a problem with the pass-key system is to turn the key to the run position. if the security light flashes you won't be able to start the vehicle, if you get a solid light on you're ok.

i found this out the hard way on my pontiac when i had a no start situation this weekend and did some research. the dealer wanted over $500 + towing to fix it and the local lock shop quoted me $200 to change the ignition switch, but maxwedge posted a bypass that cost less than a dollar in parts and took less than 15 mins in the parking lot to get me going again. thread is here: http://www.automotiveforums.com/vbul...d.php?t=546556

thank you maxwedge and all the other posters that help out here, you've saved me a bundle of cash.

[Chris Stewart]

No, it doesn't have one either but the young'uns '91 Camaro does and it's been a pain in the past. I read there's a fix for it but then there's no antitheft.

[ericn1300]

Originally Posted by Chris Stewart

No, it doesn't have one either but the young'uns '91 Camaro does and it's been a pain in the past. I read there's a fix for it but then there's no antitheft.

yes, that's true, but do the thiefs know there's no anti-theft system still active? sometimes the appeareance of, or knowledge of a theft control system is enough to make them to move on.

anyways, i bought the pontiac for only $1,500. the bypass works for me.

[Chris Stewart]

What do you think of a hidden switch in that circuit with the trick resistors?

[ericn1300]

Originally Posted by Chris Stewart

What do you think of a hidden switch in that circuit with the trick resistors?

thats a great idea. tossing a toggle switch into the circuit would be cheap and easy, or you could even put a key operated switch in. mine kinda is switched since i cut the wires on the ignition side of the connector and soldered it to the leads so that i can unplug it and take it with me or lock it in the glove box when i leave it at the airport.

wonder if i can run a wire over to the stereo and rig a switch to disable it when i remove the stero control panel. kill two birds with one pull, and even the load levler knows how to put the stereo panel back on.

[Chris Stewart]

If the antitheft needs to see 12 volts, the electric antenna circuit, if so equipted, could power it.