What year LB9

I acquired a 1982 Chevy Truck for cheap and is really good shape. Anyway it has a LB9 TPI in it but since its a transplant I don't know what year its from. I gather it is at least a 1988 since it has a serpentine belt drive and alternator on the drivers side. I suppose it could be a L89 but was told it was a 305. Without taking it apart enough to see some casting numbers how can I tell what year it is?

It was cheap for a reason. The owner put in / took out some fancy alarm-remote start and started having problem to the point it will not start at all now. There is good spark and the engine fires if "PRIMED" (fuel sprayed into intake) but it looks like the injectors are not pulsing. The fuel pump does not come on at all but I jumpered it to run just to get fuel pressure up but still wont fire. I'm sure its a wiring problem someplace or the ECM is bad. Still trouble shooting.

Its what one gets buying something like this but at $1000 with a good straight body and two sets of new wheels & tires it was too good of deal. I could part it out and make triple. Or rip off the TPI and go carb. Got a good 600 holly just need an intake and there cheap. $25 at swap meet I'd guess. I would like to fix it correctly though.

I do know it did run pretty good at one point. I blame the alarm/remote start and them not knowing what they were doing but maybe its something different. Its the only lead I have for now. The alarm has been removed and I'm trying to get it back to the correct wiring. It does look like a new wiring harness was installed when the engine swap was done. The original engine was a 305 TBI

Any help / ideas?
Thanks
Doug  

most TPI computers are equipped with a VATS system...  where resistance from the key allows the ECM to fire the fuel injectors...    did the installation include a ALDL connector.. so you can check codes or look at live data stream with a proper scan tool...

how about a part number and broadcast code from the ECM/ pcm...

oh TPI motors and most others.... the fuel pump is controlled by 2 things...   the 2 or 3 wire oil pressure switch   one wire is usually unswitched but fused power... the other wire goes to the fuel pump... if it is a 3 wire switch.. the center wire goes to the gauge..  that fuel pump power circuit is in parallel with the fuel pump relay...   so the fuel pump relay is controlled by the computer.. when the ecm sees power come on from the key.. it cycles the fuel pump relay on for 2 seconds. this primes the fuel system..  the ecm also commands the fuel pump relay on while the engine is cranking..  there is a crank signal wire from the ignition switch to the ecm...

if the VATS system is giving you problems .. it will set a code 48 or 58??? but only for 4 minutes..

i hope that you have an OHM meter.... i will see if i can find some links to various TPI wiring diagrams..


here is the wiring diagram for the 86 TPI camaro motors.. there is not a lot of differences up through 91 or 92..

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/09/91/6f/large/0900c1528009916f.gif  

Thanks for your reply. I think it does have VATS as there is a wire labeled that. After a bit more work the fuel pump does come on for a couple seconds when the key it turned on but the injectors do not pulse. There is a OBD1 connector but I need to solve a couple more things I guess. I get no "chech engine" light at all and shorting A-B on the ODB1 connector yealds NO codes and it should be at least a 12. Just a matter of tracing wires with the ohm meter until I find it. I'm using the wiring diagram for a 1988 firebird TPI since I was told its from a firebird/ formula but I don't know what year.

It looks like they just added an engine wiring harness as the fusebox and rest of the wiring is from the truck.

I'll get the ECM part number and post it. Also I'll look into everything else you talked about. I only have a few hours a week to work on it so it is slow going.

Thank you  

OK, Had some time to mess with it. The ECM has the following numbers on it.
I think its a 1989 engine or later since it has a serpentine belt

Number- 7-7730  DC code 0304GD

It appears to be a remanufactured unit. It Also has a HyperTech label on it. Thats all the info.

I read in another forum that the VATS shuts down the fuel injectors (thats whats happening to me). There is a wire labeled VATS that comes out of the ECM that used to go to the aftermarket alarm modual labeled VATS. Now it goes no place.If I can find were it is supposed to go or how I can hook it up I bet my problem is solved.

I'll try to find a wiring diagram for the ECM / Harness to see where the (BLUE) VATS wire is supposed to goto.

Thank you
Doug  

Problem solved.........Seems the idiot that wired it up hooked up the VATS modual incorrectly and had it labeled wrong., that through me off. Once the 555 timer (VATS BYPASS MOD) was correctly installed it runs fine.

I'm a software engineer and know about the hardware side also. These VATS moduals are such a rippoff. Seen them on the internet up to $200. If someone wants I can build them for $20.00 beard board and $30 with a potted enclosure. I'll need orders of 100+ to get to that price. They would have a jumper to select between 30-50 hz and be a true 50% duty cycle unlike the junk Dakota one I have. See www.redforksoftware.com or email info@redforksoftware.com

Thank you all  

i bypass the vats system  with under 10 bucks worth of stuff from radio shack... but it requires having the key that actually worked the car to OHM ... there are 15 different values.. and the ECM locks out if the wrong value is used for 4 minutes...  

waynep7122

Thank you very much. Yes the VATS bypass parts are cheap. I used a PIC micro-controller $0.65 so I can program many different outputs and its about the same price as a 555 timer but much more flexible and accurate with less parts on the circuit board.

now on to the rest of the problems....making progress. I think I'm 90% done. I found many bad wiring junctions which I cut out the 'crimp' connectors and soldered the wires then heat shrink the joints. fixed a vacuum leak here and there and replaced the fuel regulator. seems to start and run. Torn it apart again to clean up the wiring, ensure all vacuum lines are good ect...........hope to try it in a day or so.

Thank you
Doug  

radio shack     spliced into the car side of the vats harness under the steering column   ORANGE color.. not yellow... yellow is air bags..   using a small european style terminal block... on the first and second terminals or second and third...  first and third won't work...   match the resistance to the value measured on the original key pellet...  radio shack also sells the european style terminal block...

10K-Ohm 15-Turn Cermet Potentiometer/Trimmer

Model: 271-343  |  Catalog #: 271-343

Vary the resistance in your circuit with this 10K multi-turn PC trimmer. Rated 3/4-Watts and include...

if your key value is less than 1K ohm....  they also have the  same item in a 1K ohm rating..



does not work for 98 up.... or keys without resistor pellets... PK1 , PK2 , PK3 stamped on the shanks..  

this was a lot simpler. Since there is no key with a resistor, its an 82 truck I just needed to output a 30hz square pulse to the VATS into the ECM. A $0.65 PIC microprocessor and a 5v regulator $0.15, is all thats needed. Two parts, well you need a circuit board another $0.50 and some wire.

Since I have the tools to program the pic microcontrollers its not a big deal. No resistors (well one but not for timing its to protect the PIC), caps, 555 times or other drifting parts. A perfect 30 or 50hz square wave.

If someone needs any pic firmware like this, or anything else, contact me at info@redforksoftware.com

Doug  

Just want to give a big thanks to Wayne for all his help. It would have taken much longer if not for his help

Doug