98 civic lx auto 230000 miles, new plugs, wires ,full distributer, timing belt, water pump, valve adjustment, Iacv, tps, fuel filter, fuel pump, air filter, all oil clean, coolant new and bled, no cel on. So my problem is on startup right before the temp gauge gets to normal operating temp. my car backfires twice. During the backfires the car looses power. This all happened i think after putting on a DC header and a full exaust ,cat ,resignator , muffler by a reputable local shop. I didnt notice it aleast untill a couple months into having it. Could it be the thermostat going out because if I let the car sit while still warm And the temp. Gauge goes down a bit and start it up again, it will do it again right before getting to normal operating temp.It will go away if you let the car warmup until its warm but u can see the idle change right before it gets warm. WTF? Thank in advance!

 

When you say backfire can you describe it? Is it like this?
http://m.youtube.com/index?desktop_uri=%2F&gl=US#/home

Because backfires are usually due to timing (either cam or ignition) issues

 

For some reason the video won't load do you have the name of it? Also the timing is spot on iv checked the mechanical and ignition timing it's spot on and the motor runs great. This only happens on startup right before if gets to normal operating temp, which leads me to think a faulty sensor or valve or the thermostat. How do you do the cel code check with the paper clip ? Can it be done if the light isn't currently on?

 

I am confused...Is it happening at startup or right before you get to operating temp? You keep saying them both but it should take like 10 mins to get to operating temp after starting. So is it backfiring for these 10 mins? Being that your car is obd2 i would use a code scanner to check for CEL.

 

Sorry it's right before it gets to normal operating temp like right before the temp gauge stops rising it backfires twice not very loud and there is a bit of spacing in time between the backfires. During the backfires the car looses power like if I'm on the gas the rpms will drop. This only happens when it's almost on operating temp it never happens when cold or when it is warmed up. I went to 2 vatozones
And they won't check the car with a scanner. One said they aren't allowed to (why the hell do you have a scanner hanging on the wall then?) and the second said they don't have one I'll have to buy one for 200 bucks?

 

Bump anyone? Noones had this problem? Also will the paper clip method work if my cel light isnt currently on? Really irratating issue since its my daily driver for work. Much appreciated guys!

 

Anybdyy

 

Sorry like this? You'll need to check your ignition and cam timing

 

Lol no that backfire is way stronger. I don't think you can even see it out the the tail pipe. It's a very quiet backfire if that's possible. I'll be cruising then the car looses power then backfires softly then power coma back for two seconds then loses power then second soft backfire then accelerates again. It's always twice just like that. It's driving me crazy the only things not new are the thermostat, ect, map, iat ,pcv, fuel injectors, and egr valve. Motor runs **** and ignition and michanical timing perfect ,Anyone????

 

Bump