1994 Corvette:
Hi, I'm a new member and I'm having a problem with my optispark distributor code 16. My MSD optispark failed so I replace it with a RichPorter optispark distributor, yesterday I installed the new opti and it did not work, code 16, so I thought I may have gotten a bad opti distributor, I returned it and got another new Richporter opti, installed it today and it still doesn't work and I'm getting code 16. My question is, is there anything else that could cause a code 16, the wiring is good, grounds are good, have correct voltage to/from ecm. Does anyone know what I might be overlooking or are there some other component tests I could complete or did I probably get another defective opti unit....if I did at all? I'm not sure on how to proceed so, any advice will be appreciated. I attached a short video of the attempted/conditions of no start.

Could the coil, computer, VATS or anything else cause code 16.

The ICM is new.

 

i will say from personal experience the rich porter optis aree junk, only nice thing about them is they come with new opti harness. was it installed on right? not too familiar with obd1 but i believe the spline drive could be put on wrong. Like stated i have gotten chep optis though and the car wouldnt start with them, personal experience with the rich porter opti is that it lasted 1000 miles before the rotor was arcing on the cap causing a misfire.

 

I originally spent the big money $900 bucks on a MSD with 6A box including MSD wires but, it failed well under a 1000 miles, I would guess it was between 500 to 700 miles. I bought the MSD in 2010 but, didn't install it until 2011 and the warranty is over. I heard a lot of bad reviews about MSD so, I didn't do the $150 MSD rebuild and went with a cheaper brand that has lifetime warranty, from my experience, plus from what I hear from others is that if it is a expensive unit or cheap unit they all fail at about the same rate, although I here plenty of people that state they never have any problems....so it's like rolling the dice IMO. I figure I would go with the cheap unit with lifetime warranty and I'm pretty good/quick at changing optis so, no big deal. I would spend the money again if I was sure it would be a good opti, I hear Dynaspark is pretty good but, I don't feel like risking $600 bucks, then figure in the $900 I already spent on the MSD and if the dynaspark fails then I'll end up putting more money on top of that and that seems crazy to me. I'm living the opti curse!! lol

Yea, the harness was installed properly on the 2 new optis, it only plugs in one way and it should be good. As far as the spline drive goes, there is a groove/flat section on both sides of the spline and it only goes in one way, I'm pretty confident that is correct. I traced all the wires back to the ECM and there is no tears/rips that I could find, the harness voltage coming from the ECM is correct....so I'm at a deadend and not sure what to do, did I get another bad opti? it's rare but, I hear the ECM sometimes fails or is it something else i don't know about?? Any advice is appreciated!

Edit: just notice we are running the same cam, P&P head/intake and pretty much the same setup, although i didn't upgrade my injectors yet. Car runs strong....when it runs!

 

Get a Delphi or AC Delco.

 

Yep, everything appears correct, the opti harness plug: a thru d all show the correct volts/ground so, I'm thinking it must be another bad opti, I don''t think it could be anything else, if the volt numbers on the harness are correct, I think I could rule out a bad computer so, gotta be the opti. I'm gonna return the Richporter opti and pay the extra cash and get a AC delco unit. We'll see how it goes after that, if I still get a code 16 then it's a WTF situation...lol. Hope not!

 

i've had horrible experience with cheap optis, bought a gm performance one from summit when they were on sale, so far so good, but ive bought brand new optis from chandler/autozone they seem like same exact unit bought one of each, chandler worked for one startup, and the advance opti didn't even work for one start up, thats when i bought the rich porter opti which lasted for about 1000 miles less then a year on it.

 

Are you a member of the Corvette Forum? Lots of good technical resources there. Also, you might want to Google search "DTC16".

 

Yea, I have been a member LS1 forum and the corvette forum for a few years now. I have been utilizing the search features, google research and GM shop manual but, 1st hand member knowledge (past lessons learned) is always the best IMO. Between all the forums i have been getting some advice.

 

I attached a video of the car starting today along with the fuel pressure drop:


Well, it's getting better but, it also getting worse. I was fiddling around with the car this afternoon and it STARTED and ran nice and smooth!! It needed a some cranking but, it started. When the car started the check engine light went off and while the car was running I used the scanner and checked for codes and the scanner stated "no faults found" but, soon as I shut the car off and scanned it again the code 16 was there, I erased it but, it came back or never went away, I wonder if it is a history code that for some unknown reason won't erase....anyone ever hear of this?? Prior to me starting the car I was messing around with car ground wires, i wiggled a ground wire under the brake booster and the car started, could be coincidence? I'll have to inspect all the grounds tomorrow, I think there are 5 or 8 in the front section of the car....anyone know which wires plugging into the computer are ground wires or a wiring/plug schematic? So, at this point I'm still not sure if it's the opti, grounds or computer but, the plugs/ground wires in the engine harness all read grounded. I'm gonna do my google research and hopefully find the needed info and if anyone wants to give some free advice, I'll appreciate it.

Also, the ASR service light is on, I have to research this, can this effect the motor in any way? My scanner doesn't read these code so, I'll have to grab a scanner for this or try the paper clip technique.

Also, I noticed my fuel pressure wasn't holding when the key was on but, not started. The fuel pressure instantly bled down. This could cause hard starting. The fuel pressure stayed at 45lbs while the car was running with no issues. On a vette the fuel pump is easily accessed, open fuel filler door and remove a couple hoses and bolts and it pops right out. I changed it last year but, I pulled it out today and clamped the return line and the system held the fuel pressure. Any ideas as to where the leak might be??

 

If clamping the return line stopped the pressure drop, your problem there is your regulator. If it still dropped off, the problem would be in the tank. In this case, it is not.

 

Yea, i rebuilt the regulator last year when i installed the new fuel pump, I'll install the OEM regulator to test the pressure bleed down and if it holds I'll rebuild the regulator. Thanks!