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Have a 1996 Buick Riviera with a highly modified L32 engine.
Was racing and the car shut down at the start of 3rd gear (~90ish).
Pulled over and it wouldnt start back up. Towed home and been working to fix it for 3 weeks now.
Symptom: Cranks over, fuel pump primes, injectors do not pulse. Security light comes on for 3 secodns at key on/start and then goes off indicating no security problem.
I have replaced the CKP, PCM, BCM and swapped several parts over so far to no avail.
The PCM i got was out of a 1996 Bonneville and the car started up (did not run right as the OSID on the bonneville is not compatible with the riviera). I flashed over the OSID/Tune from my old PCM (from a harddrive, not the "bad" PCM itself) and the car would not start, just cranks over like before.
I tried a theft module fuel enable bypass and it would not start still. With the VATs wire cut and the bonneville tune uploaded the car will start and then stall after 2 seconds, so it would appear that the VATS its doing its job.
What else can disable the fuel injectors? Or what is different about the bonneville osid/pcm pin out vs the riviera?
I made a hybrid .bin file using the bonneville osid but the tables copied from my riviera tune (trans, fuel, spark, etc). Car still starts and runs.
With the bonneville tune i have a MAF code and the MAF shows no reading on the scan tool so the car is running on the VE fuel tables. Not sure if the MAF is dead or the bonneville tune just references a different wire for MAF reading.
Would the car be able to run on a different program with a bad cam sensor? With the bonneville OSID uploaded the car runs mostly ok and cranks up every time.
But i will try unplugging the cam sensor and see if it still runs.
Thank you for the reply!
I missed where you said the car actually ran on a different program. My apologies. If it ran, it most likely is not the cam position sensor. Won't hurt to verify functionality of it though for any intermittent.
"Only a handful of people in the world can do what we do."
I'd be tempted to stay with the VATS thing, even though the light is leading you to believe there's no security concern. I recently got cooked by a Camaro that wouldn't start. Theft light insisted there was no problem, but it still wasn't seeing the resistor pellet. Which VATS wire did you cut, and what kind of bypass have you attempted? You still have the resistor pellet key?
I bypassed dark blue wire #55 at the PCM connector and put in a 50hz square wave 5v signal to mirror what the vats sends. I need to retry this bypass tho because I used the snap connectors instead of cutting and splicing. Didn't want to ruin my harness if it ended up not being the fix. I have not tried to bypass the key resistor yet.
So I dug up the diagram for the anti theft system on the Riviera, came up with this:
The pin assignment for the VATS fuel enable signal changes between makes... Wondering if the PCM is looking now looking for that signal on the wrong pin now? :huh: This is the only way I can think of to explain how the car would start before the programming change.
Did some testing this weekend and i dont think it is a VATS issue. Yes the Aurora and the Riviera have slightly different pinouts. I have a FSM for the 97 riv and should be mostly the same for the 96. Was just missing the pinout for the bonneville since that is the program the car is trying to run with.
So i have 2 PCMs, 1 with a riviera file flashed, and the other with the bonneville file flashed.
With the bonny pcm in, i installed the fuel enable bypass and the car works as it did before. Swapped pcms and the car wont crank. Swapped back and cut the VATS wire and the car will start and immediately die on the bonny tune as expected because the pcm isnt getting a vats signal.
This tells me that my VATS is working as it should.
I also checked resistance of the keys i have (3) and they are all the same. Then inserted a key and turned the key to ON and checked resistance of the wires coming from the ignition module. Same exact resistance, so this tells me my ignition module is working as it should. Also still do not have any security light on with either pcm attached.
I scanned all parameters i could on the car and saw no readout from the MAF sensor with either pcm connected. I initially thought the P0102 Mas low V code with the bonny pcm was because the pinout was probably different and the pcm wasnt able to see the signal, but not that i see the same static reading with both programs i thought i would check the maf wiring.
Unplugged the maf and checked the yellow signal wire for continuity all the way to the pcm, and it is there.
Pink hot line shows 0.05V which i believe it should be 5-7V. Tried to trace the wire back through the loom as far as i could and its not broken anywhere i could find.
Unplugged the harness from the firewall and checked some of the pink wire pins and the MAF fuse and they all show good voltage (13 at fuse, 9 at harness).
None of the MAF wires ohm out with the harness disconnected so i assume this means none are broken and crossed.
If i read voltage on the pink pin with the ground of the multimeter on a ground terminal i still only see 0.05V.
Separate issue that has recently in the past day or so surfaced is the IAC sometimes goes crazy and maxes out. Which means im sitting at 1500rpm in D at "idle" and 3k+ if i drop it into N. IAC will read 120. Turn car off and back on and the IAC will level out back at 5-10 and idle returns to normal. bad ground in the harness? The IAC and MAF wires are close to each other.
What next? Do i just order a new wire harness? FSM isnt really helpful in telling where that pink wire goes. Or should i be looking at the ground wire instead?
Last edit: 7 years 1 month ago by Riviera96. Reason: added IAC problem
Ran a direct hard line to the MAF from a +12v elsewhere in the harness. MAF works now but the car still will not run on the correct program.
CEL is off but i have a pending code for rich condition. LTFT is constantly at -15 to -19 at idle, cruse and WOT. maybe because of the tune/program, or may be another symptom. Also only see 6lbs of boost but with my current setup/pulley i should be 13-14lbs. Guessing the bypass is not operating with this tune and its staying open.
When i plug up the correct program the CEL does not light up during key on for confirmation that it checks ok. Does with the bonneville tune though so i know the bulb is good. All other lights come on and go off as normal with both tunes.
I have ordered a replacement wire harness and a replacement key switch. Really hoping this fixes it.
The MAF wire had shorted somewhere between the IP fuse block and the firewall connector, not on the engine harness side. Cant locate where it broke though.
Still have not been able to fix this car.
To recap, i have 2 working PCMs. With either of them, if i upload a bonneville L36 file (wrong file for this car) it will crank every time and run. Has been getting me back and fourth to work for months now like this. No misfire, no CEL, but doesnt run 100% right because the file isnt right so fueling/timing/etc is off.
If i upload any of the correct riviera files the car will not start, just cranks. Last i checked there was no pulse at any of the injectors. Car will start with starter fluid and fuel pump primes.
I have replaced the ckp sensor (cheap autozone one), ignition switch, coils and ICM (had spares), VATS fuel enable bypass (removed when it didnt fix it), and the BCM. I also had to rewire the MAF because something caused the 12v wire to break at the firewall. No other wires appear damaged. MAF works fine now after rewire.
One other thing to note, when i upload a riviera file the CEL doesnt come on with key on like it should when doing the initial check. It does with the other file, so its not the bulb. What could cause this? Dont say bad PCM, as it does this with both PCMs.
What am i missing here? cam sensor or ckp sensor sending a bad signal and the L36 file doesnt see it but the L67 file does? The cars have the same sensors...
Thank you for the reply. Which signal wire are you referring to?
I did a VATS fuel bypass (wire #55 dk blue) and it did not allow the car to start still. With that wire unhooked and the L36 pcm/program the car would start and then die as expected with the VATS fuel wire not sending signal to PCM/ECU. This leads me to believe the anti-theft device is working correctly.
I don't remember but it seemed like something else was different as well . What exactly is going on it runs on doner ECM but not when correct file is flashed? I think the new file probably is looking for some different pins I think the easiest thing to do is match the original fried ECM part numbers and flash correct file and you wouldn't have to modify wiring otherwise you need a pinout for both ecu and correct the pins that are wrong which can be done but would take some doing and even then it still may not work right . Custom race stuff isn't my (or probably anyone else) specialty. All I can really help you with is wiring diagrams for both ECM and you will have to repin it to match function but where you could come into a problem is if the doner ecu uses different signal type . I've ran into that when changing engines with slightly different years ...
Both ECUs i have are the correct ECUs for this car. The only difference is what program i flash to them. Both ECUs work with a N/A L36 file uploaded (bonneville or park ave from 1996) but the car will not run with the L67 riviera file. The other files are not correct for this car (wrong OSID), and to be quite honest i dont know how its able to run so well with the wrong OSID uploaded. GM must not have changed the tables around too much between makes.
The wiring for the car has not been modified nor has there ever been a aftermarket alarm. The motor is modified but runs perfectly fine. No sensors have been changed and the pins on the ECU have not been tampered with in any way from OEM. I would not consider the car custom race modified.
If you have a ECU pin out from a N/A L36 bonneville from 1996, and one for a L67 riviera i could compare to see what is different.
Rewiring to match the ECU is not going to fix my issue as the software will still not correctly transmit data to my riviera dash cluster, etc.
Also if anyone has a OSID 16238447 .bin file i can try to upload that, seriously doubt all 3 different riv files i have are corrupt, but its one more thing i can try.
Which VATS wire did you cut, and what kind of bypass have you attempted? You still have the resistor pellet key? 
