OK..

I think i might have found the answer by accident.

I've always felt like the car had 2 differetn problems. With the crane or Stock ignition it felt like the car just couldn't fire under boost.

With the MSD box it felt like it could fire but just something else acted like a brake.

Well yesterday I was cleaning up under the hood and I decided to remove the MSD Dial (boost per PSI) because i'm retarding timing threw the PCM. That dial connects to the MSD box VIA a little weather proof connector. Its been on zero for months now. I also removed the vaccum line (which is shared by the boost gauge and FMU)

I took the car out and ran it twice last night and once today and got no surge what so ever. And the surge wasn't a come and go thing before.. its never not surged or misfired. So it seems like its not a fluke but it might be, it might have fixed it.

I'm thinking that the MSD dial has shorted and that its seeing maybe infinite resistance and retarding the full 3 or 3.5 degrees per PSI. That would bring timing down to almost after top dead center. That would certainly feel like a engine brake.

I'll have no way of checking htis until i get a multimeter. (I'm away from home right now)

OR- the on board map sensor is bad or is leaky and bleeding boost from the vaccum lines on that side and screwing with the FMU.

I think the first case is more reasonable.

Anyhow..

I hate to get excited just yet but serously the past 3 pulls on two different nights have been really smooth and the datalogs are showing wheel spin up into 45 mph which isnt' too bad when your starting in second at 30mph.

 

I got in my car on accident one time and I brushed the **** on my crane retard box down to 0. Once the LED turned on the unit meaning I'm in boost the car fell on it's face violently, like I hit a wall. It would be fine no matter how much throttle but once I got in boost, boom it hits a wall. I finally realized that the **** was on zero, cranked it back up where it originally was and it was fine after that...

So that probably was your problem haha. They should fix that problem, I had no idea MSD would do the same thing.

 

You would have had a lot of timing retard on your logs.

 

An external boost retard box should take timing out without the computer knowing. Someone correct me if I'm wrong, but the BTM should work independently from the ECM. Now, if he had been watching with a timing light when he was at the dyno he probably would have seen it. I'm pretty sure the only thing the logs would show is timing retard if he was experiencing knock, which he wasn't.

And, just about the only thing that could cause such a huge dip in his dyno sheets would be fuel or timing (I don't think valvetrain harmonics would have caused such an enormous drop, but that could have been a partial problem as well). His AFR's looked good and by just looking at his datalogs everything looked peachy... but since the MSD box is wired inline and right before the distributor (Optispark in this case), the retard didn't show up on the computer.

 

yep

i've had it out for a total of 4 days and no surge what so ever.. and it used to do it EVERY time no exceptions.


I should have unplugged that along time ago just to clean everythign up.. I'm doing retard with a 2 bar

 

[QUOTE]Originally posted by ROOSTER93V8
[B]yep

i've had it out for a total of 4 days and no surge what so ever.. and it used to do it EVERY time no exceptions.


What did I tell you I have seen several MSDs be the culprit of problems. I hope you got it right. Love your car again don't you?

 

Is it possible to run the SyTy code on the LT1 speed density ECM? Or do you just hack the stock fuel and timing tables to compensate for the different calibration in the sensor, since 100kpa will show half the voltage on a 2 bar sensor compared to a 1 bar..

 

glad to hear that you might have it fixed

 

That retard box failure might be my fault.. i never mounted it and I was always a bit rough with it.

I found anthor problem yesterday that might have something to do with it.

the alternator power wire (the wire that feeds the battery) had worn thin and grounded.. The wire was freakign hot as heck to the touch.