Vcious04

iTrader: (16)

Well, I found out today exactly what a map sensor does. I was playing around with the timing settings on the MSD-6010 with my laptop and here's what happended...

Here's the scenerio before my discovery :

I have been full throttle several times on the street, ran at the track about 6 times and had 3 dyno pulls with the same timing table. It seemed to run find and it was hard to tell if it was detonating due to mainly I thought I had the timing correct at a max of 36 deg.

Here's the deal, I was monitoring the live data on my timing tonight while it was running and couldn't figure out that when I would slowly rev to about 2k, then to 3k, then to 4k I was pulling about 44-46 deg of timing.

Well, I had the timing curve set to about 20 deg @ 2000rpm and slowly advancing to about 36 deg by 6500rpm. What I did not know, is I had the map sensor set at 2 bar, but did not relize that it was set to add 6-7 deg of additional timing by certain vacuum/psi. I took it out on the street with the laptop hooked up and nailed it in 3rd about 50mph and sure enough it jumped up to about 44-46 deg of total timing!! I then turned the map sensor function OFF and just ran a mechanical advance that I mapped out.

The coupe still seems to run ok, and pulls really hard now. I can't notice any damage, but what might I have caused and how much power did I lose? Is there a certain test I can perform on my motor to make sure? Is this the reason I put down some low dyno #'s? Thanks guys!

Todd157k

iTrader: (5)

how much kr did you have on your run? if you haven't driven it too much, you can pull a couple plugs. Look for particles down in the valley of the electrode. You can always do a leakdown test to see if you toasted any valves.

Vcious04

iTrader: (16)

I'm not running any knock sensors due to the carb setup. I did pull the plugs after the dyno run and I remember the part that is normally white was light red with dark red spots. No black at all on the plug, just on the threads about 1/4 or so.

Only thing that bothers me is when I am cruising at about 3000rpm it sounds like it misses a little (exhaust note). If I cruise up to about 3500 rpm and let off, it popps out the exhaust a little.

Thanks, I will perform a leak down to make sure.

Todd157k

iTrader: (5)

this sounds like 1 or more burned valves.

Vcious04

iTrader: (16)

Wouldn't a burned valve cause the vehicle to smoke from the exhaust at high rpm's?? Also it sat for about a week and I cranked it up and no smoke, idles fine, pulls hard, no miss a wot.

I know before I installed a x-pipe on my cobra, it would pop alot. Thanks for the info

cantdrv65

iTrader: (3)

You didnt hurt the motor. If You'd melted the electrodes OFF the plugs you might want to be concerned.....otherwise don't sweat it.

Todd157k

iTrader: (5)

It's the "slight miss at low rpm" thing that tends to be a toasted valve. We're only arm chair guessing here. Best thing is to do a leak down. It'll tell ya everything/anything.