1993 RT/10 randomly wouldn't fire on startup, now dead. Weird!

[chaparralman]

It's been a long time since I posted here my snake bitten friends.

I have run into an issue with my 1993 antenna RT/10 and am at a loss since both it and my 1997 GTS have been super reliable, well loved cars as I even have about 100k miles on my B/W GTS.

The 1993 has been perfect until this season when I brought it out for the first time. Here is the bullet point chronology followed by details I am confident in with the car.

-I put in a new battery
-Factory alarm went off
-I did the quick tap jump of the green with orange stripe alarm wire to ground to reset it (as I have done numerous times before if alarm goes off from low or dead battery).
-Started car
-Drove it home and all was perfect
-Went to drive it the next morning with kiddo, and it would crank, but not fire.
(No smell of fuel from exhaust, zero puffs, no fire at all, fuel pump would prime in on position as normal, but then it wouldn't even do that, I cranked for a couple to 4 seconds at a time numerous times and nothing, not likely a fuel pressure issue, I am familiar with those)
-Opened the hood, looked around, saw nothing odd
-Got back in tried again and it started normally
-Drove it with zero oddities
-Went to coffee shop for an hour
-Same problem, crank but no start (tied probably 6 times, fuel pump did not energize to prime eveytime)
-Then it just fired and ran normally
-Later drove to shop with same issue, but not as many tries before fired
-Got to my shop, went to drive on an errand while doing a clutch in the GTS and the car would crank with NO FIRE AT ALL(fuel pump wasn't energizing to prime in on position as would be normal)
-I pulled off the fuel pump relay and jumped the wires to make the pump run and prime. (It did so fine. would then crank, but no fire. No alarm oddities were evident, nor did it go off)
Pushed car into garage and then realized I only have one Viper friend and don't know anyone that works on these things and I can't plug in and OBD2 (obviously) and there is not much good information on the net about the early cars to trouble shoot or how to completely neutralize the factory alarm (which is dumb anyway)

The car has 35k miles
Properly serviced across the board
Driven in 3 seasons every year, no rain
No weird hack jobs in wiring
New fuel pump and regulator assembly a few years back
Otherwise flawlessly reliable since I got it about 5 years ago.

I'll be darned if I know what's up right now.

PCM?
Alarm is sneaky?
Crank position sensor?
Is it the CIA or Mossad?
Maybe Gavin Newsome?

I'll just say, I don't know, it's my responsibility, no I'm not schlepping it to some shop, and I hope one of you fine gents or possibly good hearted, but insufferable scalawags might help an obnoxious opinionated Viper driving **** out. (yeah that's me)

Thank you for reading, I hope you got a smile.

Casey

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[Viper Specialty]

FP fail to prime = Primary PCM is failing, in nearly every case.
FP Prime, fail to re-prime during cranking and/or no-spark/no-start = Crank/Cam position error and/or bad ICM.

Your situation sounds like situation #1 if I am reading properly. Generally advise full replacement PCM, and Partial Reman ICM assuming I am correct.

Contact me for the run down.

Please note, I am *VERY* short on time, as I will be up north for all of July. I can likely get this diag'd and a module out the door before I leave, but time is rapidly running out, and may require some expedited shipping.

 

[chaparralman]

I just called and left you a VM. I agree with your assessment on #1 of PCM failing as there is in fact a fail to prime when the key it put into the on position.

 

[BoondocSaint]

Casey? Off topic, but you got an update on the 97 race upgrades?

 

[lane_viper]

Good luck with getting 93 going. Been a follower of yours for a few years. Love what you're doing with the 97.

My 96 is approaching 100k so its good to see fellow high milers that still look and run well.

 

[Timothy McManus]

I have the exact same car and a similar problem that Viper Specialty is helping me with.

The viper with only prime the fuel pump twice when you turn the key from off to on. After that you have to either crank the engine over or just wait a while to reset and get 2 more prime cycles.

If there is an issue with the crank or cam sensors this could trick the car into both not starting and not giving you any more prime cycles after cranking as the PCM doesn’t detect the engine turning.

If you always get 2 cycles after waiting a while (10-15 minutes) I would check the cam and crank signals first.

 

[DickDavis]

All I ask is that when it is resolved you'll us know what it was. Getting ready to start putting heavy miles on mine.