This started about 2 weeks ago. It seems to only happen when the motor is all warmed up. It also seems to only happen between about 2500-4000 RPM. And it is loud! Sounds like a gun going off.

The Check engine light came on AFTER the problem started one day when the car was on the verge of dying and I was pressing on the gas/letting on and off the clutch trying to save it.

My car has I/H/E/MSD 6al ignition and that is pretty much it. So it should run better than stock. I have no idea what the problem is. I just had the 100k, $900 service done to it by the dealer 4 months ago.

ANy help would be GREATLY appreciated.

-Edward

 

missfire? smell any gas? disable the MDS see if it helps

 

No, no, no... You said the CEL light came on, then first step, what code are you pulling up?

fs

 

Yo, jump the service clip. See what code your pulling.

 

...
Backfiring is cuased by exsest presure in your exhaust, clean your cat/race pipe. What happens is exhaust gas gets trapped and fills the chamber as the valves are closing, cuasing for a gap when spark is thrown out the exhaust valves before full combustion. This will cuase a cell.

See if that helps any.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by filthy_shovel &raquo;</TD></TR><TR><TD CLASS="quote">No, no, no... You said the CEL light came on, then first step, what code are you pulling up?

fs</TD></TR></TABLE>

yes. me stupid in morning today.

 

mine did that similar thing, didnt back fire too bad but jus everynow and then, and it about died the way ur describing, checked my code, it was a 7, tps sensor on the throttle body

 

OK, There was no code when I did the servic clip thing. It just turned off the check engine light.

I went for a drive and it is still back firing and losing power.

What are other possible causes?

I'll check my timing tonight. Could the valves be not adjusted correctly, or be out of spec? If so, how do I adjust my valves?

Any help is GREATLY appreciated.

-Edward

 

sounds like the 6al is going bad. swap back to stock ignition for a while and see if the problem disappears and if it does, pop the 6al back on and see if it comes back which it probably will.

i had this problem with an accel setup that went bad.

 

At first glance, i doubt the valves...

Backfires and loss of power can be caused by alot of things...

First, visually inspect the wires for obvious signs of damage (burned or cracked insulation, chaffing, contact with the exhaust manifold, loose plug boots or terminals, etc.).

If the wires pass a quick visual inspection, start the engine, then look and listen for arcing while the engine idles. A snapping or cracking noise would tell you secondary voltage is finding a shortcut to ground. Observing the engine in the dark may help you see where the voltage is leaking. Any fireworks that are visible along the length of the cables or at the plug boots, coil tower or distributor terminals would tell you one or more wires need replaced.

If the above checks out, then you need to look at possible sensors and such even if you did not trip any codes:

check crankshaft position sensor: test sensor using multimeter - if voltage out when car is at 2000rpm, then should be fine.

check O2 sensor: test sensor using multimeter - when your car is at operating temperature (very important), check voltage coming out. SHould be between .3 and .6 volts

Is the PCV valve sucking air?

Could be a bad coil?

Do you hear hissing under the hood - possible vaccum leak

How is your idle hot and cold?

Does it just backfire through the exhaust?

Does it only do this under load, or in neutral at 2000rpm?

Any smoke coming out the exhaust when you lose power?


fs

 

...
are you running a cat, or race pipe. take it off, clean it. done.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MoogenToad &raquo;</TD></TR><TR><TD CLASS="quote">...
are you running a cat, or race pipe. take it off, clean it. done.</TD></TR></TABLE>

& how excatly do you clean the cat out?