Replaced Opti... now bigger issue.

[zraffz]

My car was missing up high in the RPMs and was gutless down low so I did a full tune up. I am 99.9% sure I set the rotor back to the right position but I didn't check to line up the slots on the opti and dowel. All my wires are correctly in place.

I was scratching my head and I just decided to take a look at my MAF. It is descreened, ported, and looks damaged. Maybe when I took it off to change the opti I damaged it?

Would a bad MAF cause the car to crank for about 5 seconds before turning over, have a stumble down low and backfire out the throttle body? When I disconnected the MAF it fired right up, still had that bottom end stumble but when it gets higher in the RPMs it appears to run smooth.

[WildBillyT]

Descreening a MAF can create a whole litany of problems that don't show up as DTCs, etc.

[LTb1ow]

Swap in a working MAF, see if it fixes it.

What did you gap spark plugs at?

[zraffz]

Swap in a working MAF, see if it fixes it.

What did you gap spark plugs at?

Whatever the computer for those plugs said, the plugs are the only thing I haven't changed since changing the opti. (Plugs are two weeks old).

I would have pulled the opti and checked if it's on right by now but everybody is telling me the car won't fire with it being aligned improperly. Any chance it would start and just run like crap with the opti aligned wrong?

[WildBillyT]

I doubt it. Check all of your sensors and hoses again.

Do you have scanning software?

[zraffz]

No scanning software. I'm not throwing a check engine light even with the MAF off (obviously the light has a bad fuse or is non existent).

while taking apart the hoses on the waterpump I noticed the ECT on the bottom of the water pump never got reconnected. Can this be related to my issues?

[WildBillyT]

No scanning software. I'm not throwing a check engine light even with the MAF off (obviously the light has a bad fuse or is non existent).

while taking apart the hoses on the waterpump I noticed the ECT on the bottom of the water pump never got reconnected. Can this be related to my issues?

Certian PCM behaviors are related to coolant temperature. I think that's the one that the PCM uses and is related to hard starting.

[zraffz]

And what exactly is it controlling? Does it have the ability to affect timing? Like I said it is backfiring right out the intake manifold so it is combustion related. I just find it hard to believe if the timing is off 120 degrees that it would start and idle.

[zraffz]

I guess at this point it's rather the opti is defective or installed wrong... only two ways I can see it backfiring if my wires are correct.

[WildBillyT]

And what exactly is it controlling? Does it have the ability to affect timing? Like I said it is backfiring right out the intake manifold so it is combustion related. I just find it hard to believe if the timing is off 120 degrees that it would start and idle.

And this is a 100% brand new opti? Not a cap and rotor job?

I sense an AKM cable and datamaster is in your future.

[zraffz]

Yes new opti. It is really annoying me... if I set it wrong I don't care. If the opti is defective I'll be pretty upset.

[sweetbmxrider]

Your maf isn't used until closed loop is reached. You coolant temp is used though, get that situation fixed. Your check engine light should light on bulb check, when the key is first turned on.

[deadtrend1]

I raced my LT1 with the maf not plugged in (by accident of course).

What all did you touch during this tune up? I would star back at the beginning, make sure the dowell is i. The correct recess for the opti. Hopefully it is so it didnt damage the opti

[zraffz]

okay well I can't explain it. But today I switched out the dead 4 year old battery (died cause this entire time I've had my alternator unhooked while I was removing the smog pump piping). I decided to try firing it up one more time and now it runs perfectly fine... all I did was change the battery.

My only explanation is the battery wasn't providing enough voltage to properly power the coil or computer?

[grazi]

I had the ECT sensor unplugged and it cranked alot and ran crappy for a few minutes but ran fine when it warmed up. It set a code and the SES light went on.

[sweetbmxrider]

Could be a weak alternator and/or the battery was just putting a huge load on the system causing issues. Or your alternator could be bad and you just have a fresh battery :lol: