Hello all,
I am a 19997 Trans Am, it has 60,000 kms on it. Barely drive the car. In the last couple years things are going on it.

In the last year I replaced the ICM, Crank Sensor, Fuel Relay, Fuel filter, Coil, and fuel pump. This summer I start the car and it just stalls while idling (that only happened when the coil went). It would start right back up. I noticed the oil pressure gauge wasn’t moving at an idle. The car would run, then stall, sometimes cranking before fire up. The last time it started all of a sudden the oil pressure gauge started moving again. Then all of a sudden it won’t start, just crank over. I checked the coil, seems good. I changed out the ICM, and it started. So I put everything away and then go to start and just cranks no start.


I haven't had a chance (or really a want) to check for spark, or fuel pressure yet. I am just getting frustrated and uninterested in getting to it. I’ve had this car since 1997, and never had any issues, now it seems like every time I go to start it I am afraid that it won’t start or that I can’t go for a ride because it won’t last.

I have talked to some people (In Windsor, Ontario) and the mechanics here don’t have the experience or the want to even look at the car (especially LT1).

I am losing my love of my Trans Am and the want to drive it.

 

I have come to an understanding with myself over my Trans Am WS6 that she is a financial commitment, especially to keep her driving as a daily driver and to drive her through New York State winters where we use salt on the roads which is a catalyst for rust! Fortunately I have Carwell to go to for yearly oil based "Rust Cop" treatments. The car is going to need a full tear-down, media-blast and repaint, and some cosmetic upgrades and some of my own spins on the styling that pay homage to the Third Gen F-body and 5.7L LT1 Corvette.

With this said, you are going to be forced to perform your own diagnosis on the LT1 as I have been forced to do and with enough investigation you will narrow down what is wrong with the engine. I am going to take a shot from the hip and guess that your problem may be the optispark distributor, assuming you have had moisture build-up from the car sitting and not being driven which may have now corroded the interior components. If it is the optispark then you will have a royal pain of a time finding a mechanics shop willing to perform this service since changing these distributors is a nightmare to say the least, but not nearly as bad as needing to remove intake manifolds to get to spark plugs on some newer engines from different make cars these days.

I will also guess that you may even have a worn out EGR valve if the diaphragm dried out over time and is now no longer functioning. I hope that is the case for you, something simple to fix! I had to replace my EGR valve after replacing my optispark and further diagnosing start-up problems after eliminating the spark problems.

SOMETHING ELSE, are you using ethanol blended gasoline? If so, have you stored the car with fuel stabilizer?! Another problem might be that you have gunked up fuel in your fuel system and perhaps this can be causing some problems?! I hope not because this job will require professional know-how assuming you don't have such knowledge.

Right now these are the likely culprits that come to my mind and I hope other members chime in to offer their thoughts to help you out. I know the 5.7L LT1 is regarded as the odd-ball "red-headed child" of the SBC family and when replaced by the LS family of engines. However, this engine is pretty damn reliable and for me, I have spent so much time learning about it that I refuse to put an LS engine in my Trans Am WS6 and I have had my car since 2007. I love my Trans Am and she is my hobby and an extension of me. If you love your Trans Am, don't give up on it when she likely requires some kind of fix that will be worth it to keep her driving and in your life. Okay?

 

I appreciate the response, I will try and find the issue. I have put premium fuel in the car and fuel stabilizer in the winter, as well as adding fuel injector cleaner at least once a year. I know the opti is known to go. I have watched many video's on them. Doesn't look terrible to change, just a pain. Then what one to buy? There is a ton of buy this one don't buy this one so there is that challenge. I love the car, just finding myself more and more not wanting to get it running. These last few years have just been working on it more than driving it. Of course when I start it up in the winter to run it always starts, just in the summer it doesn't.
I will look at your suggestions and try and figure out what the issue now is, again thank you.

 

Just as long as you have added fuel stabilizer then you should be fine. Personally, I try to buy pure gasoline whenever I can simply because I had two fuel pumps go bad over five years and the shops told me it was gunk in the tank and I drive my car year round! I have not had any issues with ethanol-free gasoline and I am even treating the fuel with fuel system cleaner just to keep my engine as clean as I can. There is a website pure-gas.org that lists all current gas stations in the United States and Canada that offer ethanol-free gasoline. Around here most sell 90 octane but I did find one that sells 91 octane and the added octane level did make a difference in my engine performance and idle and the station is a top-tier detergent gasoline brand so all the better!

Though the optispark is the prime suspect for many issues with our cars, it is not always the problem! As I stated before I discovered my EGR valve was bad after testing spark from my optispark. Which, just to state it, a simple check of the optispark is to use an inline spark tester, hooking up the one boot to, for example, the #1 spark plug on the driver side and connecting the spark plug wire to the male connector of the inline spark tester. While in a dark garage or at night, have someone crank or start the engine and if you see electricity shooting through the clear viewing panel of the spark tester then the optispark is at least sending spark to the plugs. However, if the camshaft sensor inside of the optispark went bad, then this would be a likely reason for starting problems since the computer needs the crankshaft position sensor and the camshaft position sensor to run the engine. When playing a guessing game and throwing money at the problem, often-times you just buy a new optispark when you have tried everything else.

What do you buy? I recently bought a Petris Enterprises Optispark. This company deals with Corvette Performance and even supplies parts for Chevrolet Peformance if I remember their website correctly. The owner swears by his modifications to the optispark and if you request it, he can give you a red/black two-tone cap which is otherwise color-coded for the spline-drive optisparks of the 92-94 LT1 whereas our "pin-drive" optisparks are given a solid black cap which is no different than a remanufactured brand opti. So, to ensure I feel like I am getting something special that looks like an MSD opti, I requested the two-tone red/black cap. These optisparks are EXPENSIVE with a factory GM/Delco price tag but my car certainly has a better crisp idle than it did before on a NAPA optispark I was using before that went bad because of the water pump timing cover seal slowly leaking oil into the optispark over time. Also you get brand new vacuum lines with a metal filter which he recommends checking every 3-years. A general rule of thumb is that you want either an original Mitsubishi sensor or one of equal or better quality since our PCMs were designed to work with such sensors and anything else has compatibility and quality issues! Petris Enterprises supposedly uses a brand of sensor equal or superior to the Mitsubishi sensor! You also get a standard one year warranty or can purchase an extended three year warranty. I bought the extended warranty and so far no problems!

I should also mention, as I mention to others on posts that bring up which optispark to buy or what to do to keep them from getting fluids in them, just coat the exposed seams with dielectric grease which is the same electrical moisture protection for electrical plug connections on automobiles. This trick was suggested by a member on LS1 tech whose name I have long forgotten but should exist on an old post of mine. If you ever need to change your water pump and end up dripping some coolant on the optispark, the dielectric grease coating will be sure to protect it from that coolant working it's way past the internal rubber seals.

I am glad I could help with my suggestions. I will keep on supporting you, don't give up on your car! My Trans Am took a long time to get running proper between many bad mechanic's shops and aftermarket parts I put on her that took away from daily driving performance. However, my girl is improving and the drive is more enjoyable as I finally restore her to where she used to be and keep up on strict maintenance. Working on these cars and doing what work we can on them is a bonding experience. I seriously doubt I can have that experience with a brand new Camaro which, even then, the looks of that car are like a brick trying to look curvy compared to an F-body that was designed to have curves and modeled to be sexy! Don't give up on your car! I know I would have regretted it if I gave up early on and sold my Trans Am way back when...

 

I'm a little puzzled by the purpose of this thread. If you're “not wanting to get it running”, “frustrated and uninterested”, and don’t “really (have) a want” to do any sort of diagnostics, what are you asking for? Any approach, without some serious diagnostics, is going to turn into a costly game of parts replacement roulette. Nothing wrong with posting your true feelings, if that's what you want, but it was unclear to me what response you were looking for.

And to clarify - the PCM does not need the crankshaft position (CKP) sensor to run the engine. The CKP sensor was added in OBD-2, strictly for misfire detection. The PCM derives a pseudo-crank position from the low resolution, variable pulse length slots on the inner circle of the optical shutter wheel in the Opti.

 

I will and want to have the car running. I'm not going to let it sit and never run. I'm just in a funk over this.

The help is appreciated and will be used to get it up and going. It's just a few years of frustration brewing to the surface.

 

Phoenix'97

Thank you very much for the input. I really appreciate it.
So just that I am clear, when I hook up a spark plug tester, and if I have spark, the Opti is good? I plan on trying that tonight. If that fails then I have to borrow a fuel pressure gauge,
You also mentioned
"SOMETHING ELSE, are you using ethanol blended gasoline? If so, have you stored the car with fuel stabilizer?! Another problem might be that you have gunked up fuel in your fuel system and perhaps this can be causing some problems?! I hope not because this job will require professional know-how assuming you don't have such knowledge."
How would I check if this is the issue? Just if I have spark and fuel pressure, then I assume it would be this? But if it is gunked up would that effect the fuel pressure??

 

The inline spark plug tester only lets you know if your opti is sending spark to the plugs, hence there is no internal corrosion of the contacts OR you don't have a broken rotor! I don't think this is your problem based on what you stated. HOWEVER, if by chance the sensor inside of the optispark is bad, the camshaft position sensor, this is not something you can easily test with the optispark on the engine.

Some common symptoms that the camshaft sensor in your optispark is bad is that the car will not start no matter how many times you crank it over. It replicates fuel system problems so this is where you need to be very careful on narrowing down the problem! Another issue is driving your car and all of a sudden you lose ignition and are coasting down the road, which that happened to me on the expressway and put me in a very dangerous situation. The reason the opti-failed, oil collection in the distributor over time. The same thing happened again a few months later and it was coolant that the maintenance shop spilled on my new optispark I bought from them because they installed the water pump wrong. Suffice it to say I stopped going to them!

So, if the car will not start and you have ruled out any problems with your fuel system, the likely culprit is the optispark even though it is sending spark to the plugs! The computer needs that sensor working to run the engine!


Common symptoms of bad gas in your fuel system will be fuel injector clogging which results in hard starting, stalling, rough idle, and even pinging. If you have stored your car with fuel stabilizer you should be fine, however, one thing concerns me that I forgot about. Did you run the engine for at least fifteen minutes with the fuel stabilizer in a full tank to ensure you run the stabilizer through the whole fuel system and in the injectors for storage?! If not, there is a good chance your injectors may be clogged. A clogged fuel pump would not send any fuel to your injectors and as far as fuel pressure, I don't think you would notice much of a change since the pressure would remain but it is the fuel injectors that are clogged. It is not like your car was sitting for 30 years and you never put fuel stabilizer in the tank like with some horror stories I have heard about!

Check to make sure your fuel system is in working order first before deciding to buy a brand new optispark when nothing may be wrong with it!

 

Checking Opti cam sensor signals with Opti on engine:

4th Gen LT1 F-body Tech Articles

Yes, takes a volt meter, but multi-meters are dirt cheap.

 

#8
Phoenix'97
Injuneer



Thank you I have a bunch of work and research ahead I guess.

 

Put the spark plug tester on. No spark

 

When you turn the key to “START”, and the starter is cranking the engine, does the tach needle move up to 200 to 400 RPM? The PCM gets the RPM signal from the Opti cam position module.

 

No. It didn't move. I tried to upload a video but it wouldn't upload

 

That would indicate the PCM is not receiving the low resolution signal from the Opti. You should confirm using Shoebox's test procedure linked in post #9.

 

Thank you again for the input.
I don't mean to sound ignorant, I have been doing some reading (lots and lots), the PCM usually doesn't go bad on these cars and if they do then it has to be reprogrammed to the VIN for a pacific car?
I know I need to check the Opti with a volt meter, (I am not to versed in this), I am just waiting for a friend to come over when our schedules match up to help me.

So long story short, Injuneer you are thinking it might be the Opti and not the PCM? There is a ton of posts and everyone always points to the opti, I would just like to be as sure as I can before I try and tackle that job and spend the cash.