Fuel strainer / pump is one of those things I've been meaning to take a look at for several years...

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My Dynaspark is one of the best engineered and built parts I've put onto any car.

But I have the original, you probably are talking about the latest incarnation.

First gen opti for sale cheap:

http://forums.corvetteforum.com/c4-pa ... -ac-delco-unit-200-a.html

I may reach out to him.

I have several other diags to perform, and the guy at Dynaspark said he would test my unit for free. Same with the LTCC box. I want to test harnesses today, remove the LTCC and get it ready for shipment. Same with the Dynaspark. I will ship both out tomorrow. I can then use the down time to replace the rear bearings and ujoints.

I found he had an issue with sensors, about the same time I sent mine in for repair last year. A new supplier promised him gold, and sold him lead... at least that's what he claims.

My only problem... and this is what bugs me... is that it seems to be heat related now. It starts, it runs great, then after about 5 minutes, it falls apart and starts to run poorly.

What I am learning is that not all LSx coils are equal. The LS1 is essentially the first generation coil... each subsequent version is better; more stable, more durable and more predictable. And more expensive. The latest are over $100 EACH. And the worst part? I haven't found an easy way to test them. Sure, if I have a pulse generator and an o-scope, yea, or even a Tech II, but there doesn't seem to be a fixed way of saying "this coil is bad."

As I scan through the C5 and C6 service manuals, I find that coil replacement is based on a process of elimination. Make sure the circuit to the coil is good. Make sure the plug wire is good. Make sure the plug is good. If you are still getting the code (misfire, usually), replace the coil. This, I find, is rather annoying when you don't have the intelligence of OBDII to guide you...

These coils are smart, and as such, you can't test them in the conventional way. They have a built in dwell and are sent a low voltage signal to indicate "charge up" and are then sent another signal that tells them to collapse the field and spark.

whew.

They are durable, tho, and are not common failure points.

In short, I must diagnose this and found out the root cause before I consider the engine swap. I don't feel this is ENGINE related, but something endemic to what makes the car run. Installing a new engine would only migrate the problem. Unless it was opti related, because the new engine is a 96 LT1, with a GenII opti.

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Where is your latest log? This sounds like a bad O2 sensor. No way telling with just a screenshot, I'd need to see the ald file.

You did swap ECMs, didn't you?

I still have the ECM swap to do.

The O2s are NEW. As in 30 days old! I replaced those with the EGR.

I do need a datalog... what I really need is to get rid of this migraine...

Have you seen this for checking coils:

http://www.thetoolwarehouse.net/p-7559-waekon-76562.aspx

I saw a youtube video with that a year ago or longer but can't seem to find it anymore.

I've also seen putting a piece of fuel line between the coil and plug and testing spark strength with a test light. Something to consider.

Matthew

The other trick is to use a timing light... but I have a lead on some used LS1 coils. All I need is one or two good ones and I am in good shape.

LS2 coils seem like the thing to have. But I don't want to spend $800 on coils!

My plan is to get these used coils, then replace a coil and let it sit for a couple of minutes to see if the replacement coil fixes the problem. I see no harm doing this whilst the engine is running. Pull the coil harness, pull the plug wire, plug in the wire, plug in the harness, wait, move down the line.

Andy,
Take a look back at your opening post, and at #49. Before you go and spend the $ on a set of coils, try your plug wires. Swap out the wires from the right side harness. and see what happens. For that matter, you may even have a bad connector inside the cap itself. Just an idea.

Well... I don't have a cap! The LTCC eliminates that for a set of coils. I have checked the coils as best I can, but I am going to take a different approach to my next round of diags.

That will come tomorrow.

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Well paint me green and call me GUMBY! I was trying so hard to type real words, I overlooked the fact that LT1's don't have caps.

Oh, LT1s DO have caps... the stock opti is a conventional distributor at it's heart... but I have this thing called LTCC that bypasses the Opti's high voltage side.

Ever checked the cats?

yeah he did that change out last week i believe

yes. Changed cats. Starts fine, then falls apart after 5 min or so after starting.

Tomorrow I will dig into it.

it sure sounds like a coil/coils breaking down once they get hot or a connection to them that has a problem .i feel for you. you have the patience of a saint.i would be going totally nutso by now

does it run fine in Open loop and then like crap in closed loop?

so when it runs like crap, if it sits for a bit on a restart how does it run?

great ? jeff.

great ? jeff.

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I don't think it starts to fail soon enough for that switch to occur. When I run the data log, I will find out more.

Excellent question... And since I plan on swapping ECUs here shortly, we will learn more.

I have something... The LTCC has a fault light, just have to remove the cover and monitor.

It kicked a code:

Wrong number of Hi-Resolution pulses counted during a High Lo-Resolution pulse or Low Lo-Resolution Pulse.

I have an email into LTCC to find out what this really means.

I ran a data log... but the damned thing didn't save. I don't get this software at times. The UI is goofy at best. And I don't know what I did wrong that wouldn't save the data.

Whatever the case, I will wait for LTCC to respond. I suspect the Dynaspark is the fault.

Ok... thought: I don't know what the ECM is expecting as far as data from the Opti. Hence, as long as it is sending data, it is happy. The time a code is tripped is when no data comes across.

I need to read the Opti code diags to determine if I am right or not. But it does make an element of sense.

I was right. The code is set with a LACK of data, not too much.

It will set an H16 if it gets too many hi-res counts, meaning, it didn't get any low res counts.

H36 is set the same way.

To use the words of the Helm Manual: "...can prevent the voltage from pulsing to the ECM". As long as something is going there, it's ok with it.

You always figure it out in the end...Im watching this thread closely. :D

The promised data log would be helpful
Wouldn't the opti be bad right from the get go or at least when restarted hot?

I wish I had the data log... I did something wrong and it didn't save. Damnit.

I will generate another one later today.

It's acting like an electronic component is overheating. I have been in contact with LTCC, and he thinks that the misfires caused timing chain slap. Ok... I will buy that, 180k, all bets are off.

I am in the process of figuring out this mess.

According to the diags for the C5, there are no "tests" one can perform on the coil. They tell you to test plugs, wires and harness, and if none of those are at fault, replace the coil.

I got my new coils Saturday from EFIConnection.com

They had the best price, hands down. These are real GM LS2 coils. One major difference, the pin for the plug wire is seriously deep inside the coil. I will be curious about how the plug wires I will be making will go! Should be interesting.

three coils and one plug wire... that's the diag so far.

I will have the car running tomorrow, but, what I have figured out so far:

* 1 coil has a chunk taken out of an edge, near the epoxy blob.

* 2 coils have loose plates in the transformer bar thing. The plates are coming apart and are loose from each other.

* 1 plug wire, #8, came off... now, it felt tight before, so I wonder if it was something I just left loose after my last round of diags? or is the wire failing? I have new MSDs ready to assemble.

Tomorrow morning, I am going to put a charger on the car and then after breakfast, give it a go. More updates as I get to them!

Installed the new coils... ran the engine for 30+ minutes. No break downs, not misses, not failure. I fired up the AC and also put it into gear whislt running and fookRan very well.

next up, reassemble and test drive.

That is good to hear Andy.

I will know more tomorrow, but this feels real good! I think I nailed it... sure hope so... getting tired of doing everything three times!

Excellent! What ever happened from the diagnosis from LTCC? Or did you not send the unit it?

I wanted to test the coils first. I had no reason to believe the LTCC was the cause. I was more suspecting the Dynaspark, and until this has driven a few miles, I will still be suspecting the dynaspark. If it passes tomorrows short drive test, then we shall go for a longer drive on Saturday.

If it passes that, I will start to feel better about things.

Been following this thread for a while - it sounds like you nailed it Andy - good luck with the test drive!

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I did a short drive yesterday... and it ran fine, but I wasn't quite ready to accept victory... YET.

Today is my standing Saturday morning breakfast down at the pier with friends. From my house to the pier and back is 25 miles, or near abouts.

NOT A PROBLEM! It ran like a trooper. Strong acceleration, no misfires, nothing. I was expecting to fail as I neared home, it was at its longest run time at the point and hottest.

I may be heading to Irvine mid-week, I will test again on a 40 mile one way trip.

Happy New Year guys.
So far the best news of the year
Andy, what did you do to your car, needing LS coils and still an Opti? Pics would help

Axel - good question; what I have done:

* New EGR - that fixed the initial failure. Literally, every diag failure that could occur, did! Except for dieseling.

* Then it came back... mostly, tho, as a misfire.

* I replaced the fuel pump. Cheap aftermarket fuel pumps are a known problem. I replaced with a Racetronix unit from Lingenfelter. Great customer service; super fast delivery! That helped a bit, but it would still fall apart and start missing after it warmed up.

* When going through the diags, the coils kept coming up as a potential problem. However, there is no test for them. Three years ago, I had a massive failure of the serpentine belt. It took out the original LTCC harness. Tore the living shit out of it is more accurate. At least two (maybe three) coils had bent pins. I didn't know this when I plugged them in and restarted. So two, or three, were charged without proper ground (same pin in all). At this point, it HAD to be spark related. So I ordered new LS2 coils from eficonnection.com. Great deal, OEM part for $225 shipped; all 8 of them!

* I wanted to replace the coils first, if that failed, then out comes the Dynaspark. But so far, the new coils seem to have done it. I have no reason to believe that the LTCC module is to blame. Its reputation has been very good. And it was dry and clean inside. The connectors were good. So with some less than perfect Dynaspark history, I was more inclined to blame that than the LTCC box.

* I still have new MSD wires I need to make, but they are no longer pressing. Sometime after I get the garage organized and sorted will I get those made.

I should have googled first, prior to posting my question.
I was not familiar with LTCC, but here's a good link
http://www.lt1howto.com/articles/coilpack.htm

Watch this:



I literally wrote the manual for the LTCC installation. It's very easy. The problem is not even GM has a diag to test the coil with! What the books says, basically "test the plug, wire, connector to the coil. If all spec out, replace the coil,

Amazing what you can find at youtube. This might help in the future.
http://www.youtube.com/embed/5-wJH-KUFsM

A little late, ironically this came up when your video was finished. Quite interesting this coil stuff.

That was an interesting video... my problem? No OBDII to tell me where to begin! I had to test all 8!

What I did was use a timing light to test each coil out... but I still feel that whatever was wrong with my coil(s) was heat related. As it heated up, it failed.

Off for another test drive.

The test drive was a non-starter. The head light switch failed some weeks back, and I haven't replaced it yet. I will do so tomorrow.

Tonight, the third time is the charm, eh... Pulling in the drive way, it commenced to running like shit again.

Back firing, idle poor, stumbling, you name it.

Tomorrow morning, I am going to make a new set of wires, using MSD this time.

If that doesn't finally fix it, I am going to bet it's a bad dynaspark, but I won't know until I eliminate everything else. I was cautiously optimistic about the coils... and with good reason... but until its all been checked, I can't commit to anything. One at a time, so to speak, because if I don't, then I will never know which finally fixed it.

Wow, frustrating

My plan is simple... new plug wires today... more test driving. I have had issues with wires where the plug ends won't stay on.

And I have heard from my local vendor (who sells all sorts of brands of wires) that Taylor has a tendency to weaken the plug connectors if removed too often. The spring steel bit fails, or weakens.

So I have new MSD wires ready to build.

If the problem returns, then the Dynaspark goes back, Sunday more then likely.

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The Taylors on the racecar come off every 1/2 hour, 3 times a weekend. They do have dielectric on the boots.

Not saying it couldn't happen but......

I donno... it could... and I took their statement with a grain of salt. But... I need to eliminate so that I have a full diag done before I ship off the Dynaspark.

Almost sounds like it goes to crap on the switch from Open to Closed Loop.

What is the status on you O2s?