97 WS6, 123k, car used to crank once, maybe twice and fire everytime... now it cranks over and over and over and over and nothing, turn key back to off, hit it again and it cranks a bit then goes, usually chugs a bit then finally finds it's 'stride' and goes to correct idle. Car feels like it runs fine all through the power band. Changed the coil at the suggestion of a buddy, but that wasn't it. Checked fuel pressure, turn key to on, spikes to 42psi then backs down to 0, but I was told by a couple people this is normal, because it was only priming. To me it should stay steady, and my haynes manual says the same. But both have far more LT1 experience than I do. Car cranks and cranks, then when it starts it jumps to 38psi at idle. I have no driven around yet with the gauge, the hose is super short and I have to find a solution to that. Plugs and wires are under 8k miles old. Fuel filter is pretty recent but I'm going to change it again to be sure. The problem seems to be getting worse everyday. Looking for direction on what it might else it might be. I'm pretty good mechanically, but I'm not any good at diagnosing issues. Replacing parts and what not I can figure out how to do and do it. The car cranks normal, it doesn't sound weak or sluggish.

 

im guessing its ur opti-spark. which i am in the process of changing mine. when it does trys to start but doesnt. unplug one of your spark plug wires and put another spark plug on the wire, then put the spark plug tip on a piece of metal somewhere and try and turn it over, if its not getting spark then its ur opti.

 

I will definitely check that. Still open to ideas people may have. After reading some old threads dug up on here and elsewhere, I'm going to check the fuel pressure regulator tomorrow and see if maybe that went bad. The fuel pump check valve came up in a few places as well. After reading, it's normal for the pressure after priming to bleed off, but going from 42 down to 0 in just a few seconds isn't?

 

No..it is NOT normal for the pressure to go to zero after a few seconds. Could be the check valve in the fuel pump, or leaky injector(r). Not sure if the pressure regulator could cause that or not.

 

In the book you have check the procedure for your fuel system check. If the book says it should stay steady then it should. It primes to start the engine if it primes and loses the pressure its gonna be a hard start.

Turn key on, engine off like 5 to 6 times. Then try to start if it does start right up...my gues would be fuel pump. But you should still do the procedure in your book to rule out the FPR or leaky injector(s).

 

Wouldn't be my guess, at all. His fuel pressure is dropping to "0" immediately after the pump primes. That will cause extended start times. Once it starts, it runs fine. Absolutely nothing there that points to the Opti.

You have to understand that "its the Opti" is not the only possible answer to problems with an LT1.

 

Thanks for the info guys. I got home late from work and don't feel up to messing with it this evening but I am going to check the FPR tomorrow for sure. The key fwd and back 5-6 times doesn't seem to help it start any easier. It's definitely losing the pressure it primes to almost immediately. I'm really hoping it's the FPR, or at least something relatively simple. Not looking forward to doing a fuel pump but if it's that I'm down

 

I gazed into my crystal ball and....I see you changing your fuel pump in the near future.

 

I saw the same thing. After some setbacks(aka other broken stuff), I got the FPR changed out(I hate you GM) and same crap. Next minor thing to try is to see if I somehow have a ridiculously clogged fuel filter but I doubt that's it. Guess I'm going to be spending part of a weekend changing a fuel pump soon, woo... any other last minute thoughts what it might be?

 

Have checked the injectors to make sure there aren't some leakers?

 

Man I thought about that late last night AFTER I had put the fuel rail back together. It makes sense, the way the car will stumble for a few seconds. If one or two(or more) of them were just pissing fuel into the cylinder when they weren't supposed to, it cold cause the car to chug a bit to get going.