sluggish start

[projectmx]

I advanced the timing a tad by turning the distributor just a little. I also added a civic intake and tightened the wire on the throttle body and now for the first couple minutes of driving the car starts good then at about 2000 rpms it suddenly gets sluggish then goes faster again.... any idea what causes that?

[perhapsadingo8yerbaby]

One thing that can cause power loss is ignition timing that was mistakenly adjusted for a more retarded spark instead of advanced. You end up with too-late combustion where the combusting flame-front is chasing the piston as it recedes down it's bore and the combustion chamber size is expanding. Are you sure of the direction of adjustment? You used a timing light right?

<small>[ August 21, 2004, 09:03 AM: Message edited by: perhapsadingo8yerbaby ]</small>

[projectmx]

wouldn't the sluggish loss of power persist if i had retarded it instead of advanced it? the sluggishness is from like 2 grand to 3 grand and only for the first few minutes of driving then its much faster than before i did the modification. And no i didn't use a light. I had a mechanic help me and he tweaked it by sound... he had it too far at first and we moved it back past where the pinging stopped to be safe.

[luis castro]

could be a vacuum hose or something that is supposed to go plugged into the intake pipe. try that if not the it's the maf sensor

[projectmx]

there are only three hoses from the intake.. the one under the throttle bodie which is connected to the intake already... the one on the valve cover which has a breather filter and the "vacuum" hose which was never attached since i bought it.. that one only works during cold weather from what i've been told

[MX3-Freak]

Originally posted by mazda78:
I advanced the timing a tad by turning the distributor just a little. I also added a civic intake and tightened the wire on the throttle body and now for the first couple minutes of driving the car starts good then at about 2000 rpms it suddenly gets sluggish then goes faster again.... any idea what causes that?

Put that throttle body wire back where it was. That is not meant to be the airflow adjuster...It could fix your problem.

[projectmx]

the wire we simply took up the slack on... do that on the proteges also... that shouldn't have caused it.

[Typhoonk]

I was told once by an old Mazda Mechanic that the timing is done automatically through the ECU (on the 4cyclinder mx-3's). So if the distributor is moved it will cause damage no matter which way you turn it.

I say put the distributor back the way it was, and see if that's what it was. If not then keep trying......

as always Good luck and let us know what happens

---------------------------
PS I just found this on the MX-3 site. It's called Z-Man's Tech Tips

http://www.mx-3.com/people/zoranc/zmantech.cfm

<small>[ August 22, 2004, 10:24 PM: Message edited by: Typhoonk ]</small>

[projectmx]

so waht about cam gears that are adjustable? doesn't that affect timing? should we not buy those?

[LongJohn]

Originally posted by mazda78:
so waht about cam gears that are adjustable? doesn't that affect timing? should we not buy those?

That is a different kind of timing. There is ignition timing (how far off are you from top dead center when the spark fires) and valve timing (where do the valves open and close relative to top dead center).

I don't have anything to say about whether either adjustment is good or bad.

[projectmx]

so which item changes which timing?

[perhapsadingo8yerbaby]

Rotating the distributor adjusts the ignition timing like you described in your original post. I'd stay away for now from making any change to valve timing adjustment. You have a prob now w/sluggish accelleration that wasn't there before make the following changes right?

-Civic air intake
-Took up slack on the throttle cable
-Advanced ignition timing

You also mention that your EGR line to the intake has never been connected.

So you need a backout plan to isolate the cause. Try putting your ign. timing back. If that helps (even if it doesn't), also connect the EGR hose to the intake. You wanna be sure the EGR is functioning properly before doing the timing advance mod on the 1.6 DOHC. When opening the throttle, the EGR should open just as fast as the throttle. As you accellerate rpms, the EGR's purpose is to feed a vacuum regulated increasing flow of exhaust gases to the intake manifold, which helps keep cylinder temps lower than they otherwise would be, which helps control engine knock from early detonation.

Advancing the ign. timing too much can also cause engine knock as you saw earlier, so your mech backed off the timing adjustment. btw, to get anything meaningful from the timing advance mod, your MX requires the higher 93 octane fuel to perform correctly. Best to run a tank thru and try the ign. advance mod on the 2nd tank of the stuff. 93 fuel resists detonation and has a longer burn rate than lower octane regular fuel. Forgot to ask before if you were already doing that.

[projectmx]

which of the three hoses is the egr? the one off the valve cover? the one from the bottom of the throttle botty? or the tiny one coming from behind the engine?


.... oh i'm not using 93 octane... not sure who around here even caries that.. highest we have is 91... i haven't had the sluggishness in about a day or so now....

<small>[ August 23, 2004, 08:05 PM: Message edited by: mazda78 ]</small>

[perhapsadingo8yerbaby]

The EGR hose is the tiny one. If you were to trace it back, you'll see where it routes around the engine to the EGR valve. On a 1.6 DOHC stock setup that tiny hose connects to the side of the air intake box. Not sure what connection point you'd have available on the Civic air intake.

Didn't realize that 93 octane was unavailable in your area. I'm in MD near Wash. D.C. Our regular-grade gas is 87 octane, mid-grade is 89 and premium-grade is 92 or 93 depending where ya buy it. In any case, the higher the octane ya use the less likely the engine will knock as the timing is advanced. I advanced mine last year and have run with 93 since then.

[projectmx]

what exactly does the egr valve do? i was under the impression it opens when the engine bay is cold bringing warmer air into the intake..... we tested it while the car was running and felt no air coming in or out of the tube... does thatmean the egr valve is broken? and if so since it has been for probably well over two months is that doing damage to the engine?