My TA stumbles and dies on the highway

[Captainofiron]

So the car in the past has stumbled randomly while cruising at low RPMs on the highway. But it never died till Monday Tuesday and Wednesday.

I was coming home from work on Monday and about 10 miles down the highway, it stumbles, I see the CES light turn on blink, and it dies, so I pull off the road, let the clutch in and the tach drops to zero.

I hit the starter and it turns right on and I drive away, no problems.

then Tuesday

at the same exact exit, the same thing happens the light blinks and it dies, I put in the clutch while still moving and crank the engine, it turns on and I drop the clutch and it dies again, so I put in the clutch and crank it and it turns on and dies, so I downshift to 3rd and dump the clutch and hit the gas and away we go, no problems, then about half a mile down the road it stumbles but doesn't die

Finally on Wednesday,

at the same exit, the CES light blinks, the car stumbles, but doesnt die, I go over the overpass, and it dies
I pull off to the side and let the tach drop to zero, and crank it, and nothing, it doesnt start, but it sounds like it has no ignition, so I sit for about 5 minutes, and it finally starts up, I take off and go to Autozone for them to scan the codes

My CES light has been on for about a year, P0400 (EGR flow code) due to my longtubes and a leak
The kid at AZ plugs in the scanner, and pulls off a P1371 code, which is a low signal from the crank position sensor, but in reality it means there is an optispark problem

I have the MSD opti, and talked to them, and they want me to take it in for them to rebuild it. fortunately they are based in El Paso, which is about a 40 mile drive for me.


Im still really curious about why the car only would stumble and die on the way (in the afternoon) home when:

• It was cooler (~40 F) here in the mornings, vs ~70 F in the afternoon
• I was driving faster ~75-80mph in the mornings vs 65mph (cruise control) in the afternoon

There has to be some sort of correlation.

I took a video of when it died this time, from the time I turned the car on to when it died was about 13 minutes.
the engine temp was slightly below the 1/4 hash mark on the temp gauge

[Lightfoot]

I would say it's definately engine temp related, from the consistant timing of the problem.
Could be the crank position sensor has just reached it's age limit. Is it the OEM sensor?

What year Firebird?

[Captainofiron]

I wish it was the crank sensor.
Its a 97

Unfortunately, the 1371 on the LT1 means the optical sensor inside the optisuck isnt getting proper low resolution readings.

[Sirrotica]

I know condensation was a problem in optijunk units it could be condensation related. Although I though in the later units they had that fixed, something to be aware of though. I'm wondering if MSD did whatever GM did in their units which I believe was venting the unit to a vacuum source.

I don't know if you're aware of the company that takes a late model multiple coil unit from a cadillac and converts it for LT1 use eliminating the optijunk unit. I was considering that for my 97 T/A before the gas leak that caused the car to catch fire.

[quicksilver97ta]

Thats a tough one. Its not the cps. On these cars it only serves to detect a misfire based on unsteady engine rpms. If its throwing a cps code, that code at least, is not related to the opti.
Still could be alot of things the way it runs and dies. Fuel, air, spark is what you need so think basic. While I would hope throwing codes would give you a clue, right now I dont think it is. Just to get started I would try a couple of different things. First I'd unplug the MAF just to rule that out. It should still run on the speed density tables. I'd also wonder about the ignition control module, I understand when they are failing they will be at their worst when they get hot. Also, you can bench test your coil by reading the ohms, just refer to a chiltons or other reference. Do you have an aftermarket ignition box? Wouldnt hurt to check your fuel pressure if you have access to a gauge, pumps can have the same symptoms.
Let us know. I havnt had to "think like an LT1 car" in some time.

[quicksilver97ta]

I would also check from a reliable source what exactly code 1371 is. Some scanners have better, more accurate definitions than what AZone may have used.

[HO 67 BIRD]

I think on F-bodys the check engine light flashing means you have a missfire.I would also check the coil it my be getting hot,Also like others have suggested check fuel pressure and the ignition module.Good luck .

[Captainofiron]

Originally Posted by Sirrotica

I know condensation was a problem in optijunk units it could be condensation related. Although I though in the later units they had that fixed, something to be aware of though. I'm wondering if MSD did whatever GM did in their units which I believe was venting the unit to a vacuum source.

I don't know if you're aware of the company that takes a late model multiple coil unit from a cadillac and converts it for LT1 use eliminating the optijunk unit. I was considering that for my 97 T/A before the gas leak that caused the car to catch fire.

It is vented via a vacuum port on the bottom of the opti to the intake

I did have a heater hose seeping though, I talked to the MSD tech support guys, and they think its either oil or water inside the opti

as far as chunking the opti, there are 2 companies that come to mind, LTCC and Delteq

but one requires that you retain the optical disk, cant remember which.

Originally Posted by quicksilver97ta

I would also check from a reliable source what exactly code 1371 is. Some scanners have better, more accurate definitions than what AZone may have used.

I just wrote down the code, and went home and looked at Shbox's website

those idiots at AZ were trying to sell me the crank position sensor

Originally Posted by quicksilver97ta

Thats a tough one. Its not the cps. On these cars it only serves to detect a misfire based on unsteady engine rpms. If its throwing a cps code, that code at least, is not related to the opti.
Still could be alot of things the way it runs and dies. Fuel, air, spark is what you need so think basic. While I would hope throwing codes would give you a clue, right now I dont think it is. Just to get started I would try a couple of different things. First I'd unplug the MAF just to rule that out. It should still run on the speed density tables. I'd also wonder about the ignition control module, I understand when they are failing they will be at their worst when they get hot. Also, you can bench test your coil by reading the ohms, just refer to a chiltons or other reference. Do you have an aftermarket ignition box? Wouldnt hurt to check your fuel pressure if you have access to a gauge, pumps can have the same symptoms.
Let us know. I havnt had to "think like an LT1 car" in some time.

ill have to check that, I have relocated my coil and icm unit off of the cylinder head for obvious reasons, so I dont think its those, but I will check it out.


Im just really dreading digging into this, I dont want to pull the opti, for it to turn out to be something else


whenever it dies, and I crank it, it doesnt sound right, like its getting flooded, so for sure its something on the ignition side, which at least narrows it down

[Captainofiron]

SO I tore into the WS6 finally, I got the waterpump and balancer off. and I looked and the top of the opti had all this evaporated dexcool and residue coming off of the upper passenger side heater hose, and it magically ran up and forward onto the place where the electrical connector enters the opti housing.

So the MSD techs suspicions were comfirmed

Yesterday I went by MSD and dropped off the opti, the engineer came out and talked to me, really nice people there.

He looked at it and asked what year LT1, and he said, wow this is a first run model, there are lots of updates to the design, and he then told me that they would do these updates for free.

SWEET

So they said probably Friday my opti would be ready for pick up.

[quicksilver97ta]

Originally Posted by Captainofiron

SO I tore into the WS6 finally, I got the waterpump and balancer off. and I looked and the top of the opti had all this evaporated dexcool and residue coming off of the upper passenger side heater hose, and it magically ran up and forward onto the place where the electrical connector enters the opti housing.

So the MSD techs suspicions were comfirmed

Yesterday I went by MSD and dropped off the opti, the engineer came out and talked to me, really nice people there.

He looked at it and asked what year LT1, and he said, wow this is a first run model, there are lots of updates to the design, and he then told me that they would do these updates for free.

SWEET

So they said probably Friday my opti would be ready for pick up.

Excellent!
FWIW I used to power wash my engine before I ever knew about the opti. I never had a problem with it getting water/moisture inside. No doubt I was lucky but if it's sealed as it should be it can resist alot of water. I have lost two due to the rotor screws though, but that didnt happen until I started exceeding the factory red line. I currenetly have a delco opti with an MSD cap and rotor which I think is an excellent combo. Of course it's standard operating proceedure now to lock tight the rotor screws.

[Captainofiron]

Originally Posted by quicksilver97ta

Excellent!
FWIW I used to power wash my engine before I ever knew about the opti. I never had a problem with it getting water/moisture inside. No doubt I was lucky but if it's sealed as it should be it can resist alot of water. I have lost two due to the rotor screws though, but that didnt happen until I started exceeding the factory red line. I currenetly have a delco opti with an MSD cap and rotor which I think is an excellent combo. Of course it's standard operating proceedure now to lock tight the rotor screws.

you know, when I first got the MSD opti I went to the car wash and hit it with the "engine cleaner" power washer, and it was fine

I guess after a while the dexcool just worked its way in.

Im curious what design updates they are talking about

[428RA4]

Could be many things that is causing this issue.

Bad Computer
Bad Crank sensor
Bad plug wire
Bad coil

Throw parts at it until it stops.

[Sirrotica]

That's exactly why I was looking at getting rid of the damn opti system in my 97. It's so damn sensitive to water and the placement of it just begs to get water into it. If not from the water pump and hoses, then from the water blowing through the radiator during times of rain. Leave it to Chevy designers to come up with a winning system design like that. Glad you solved your problem though.

[Captainofiron]

Originally Posted by Sirrotica

That's exactly why I was looking at getting rid of the damn opti system in my 97. It's so damn sensitive to water and the placement of it just begs to get water into it. If not from the water pump and hoses, then from the water blowing through the radiator during times of rain. Leave it to Chevy designers to come up with a winning system design like that. Glad you solved your problem though.

Thanks

and yea I know what you mean, I hate the opti, BUT I did get 4 solid years out of the MSD, and the heater hose problem that caused this was my fault for ignoring it for so long.

[Captainofiron]

I just picked up my opti yesterday from MSD

I am really surprised by their tech support and customer service.

I checked it out, and they replaced EVERYTHING, the only thing left from when I took it in was the aluminum housing/backing plate

I bought this thing in Early 2007, when they first came out, and even MSD told me that it only had a 1 year warranty.

But they fixed it and R&R'ed it for Free.

So hopefully I will have the TA going soon