power problem

projectmx316 · Post by **projectmx316** » February 12th, 2006, 12:52 am

Hey all i need a little advise i have a 94 dohc 1.6 and it doesnt have good power untill after 2,500 rpm and it also smells like its running rich when u floor it. By the way its also a auto any adivse would be appreciated thanks

Yoda · Post by **Yoda** » February 12th, 2006, 12:18 pm

When was the last time you have the O2 sensor changed? In theory they should last almost for ever but with the additives in gasoline these days O2 sensors usually need to be changed after 100000km. I make a big difference in power and gas mileage that you never noticed because it degraded over such a long period of time.

ariesdude · Post by **ariesdude** » February 13th, 2006, 3:00 pm

Definitely check the O2 Sensor - But also check the timing belt and other ignition components. I am dealing with something like this - my plugs are getting contsantly fouled with carbon and i cant find why. I have checked everything except the timing belt. If i clean the plugs the car would run great for sometime and then it would be back to rough idle and power loss.

Devilhog · Post by **Devilhog** » February 14th, 2006, 10:43 pm

My Mx3 has a pre cat and a post cat O2 sensor so get both changed forsure. Not sure if all models have 2, but mine is a 96 1.6l dohc.

My mechanic says pre Cat should be changed at 200,000km but my car is sucking so much more gas and im only at 175k so think im getting that replaced asap. Post in mine is brand new and didnt change a thing.

projectmx316 · Post by **projectmx316** » February 15th, 2006, 4:37 pm

the 02 sensor is brand new in it. The cat thats in the header itself is nolonger there cause it was so cogged up it mad it idle hard so i took that out also i have a 2.25 inch exhuast with a brand new cat sitting on it the 2.25 inch exhaust starts at the downpipe then goes into the cat. the motor has 170k on it but it runs good besides the poping out of the exhaust but i dont hear the poping after it goes past 2,500 rpm im pretty sure the timming belt is dead on cause it looks brand new. but could it also streatch enought to have to reset it. And i also have another problem of it smoking when i first start it up in the morning(white smoke) but it has good compresion on all four. Once it starts warming up it goes away. I was told it could be the valve stem seals that could be shot.

Tunes67 · Post by **Tunes67** » February 15th, 2006, 4:47 pm

I was told it could be the valve stem seals that could be shot.

Well I can tell you beyond a shadow of a doubt that your valve seals wont have anything to do with your engine popping. At least not in a direct correlation. I dont know what is causing this.. sounds like more than a few folks have the problem. I will be very interested to find out what the correct solution is. Probably the first thing I would do is get the fuel injectors flow tested.

Tunes67

projectmx316 · Post by **projectmx316** » February 15th, 2006, 4:55 pm

what is flow tested and where can i get that done

Bochek · Post by **Bochek** » February 15th, 2006, 5:23 pm

Frist thing i would do is go get a bottle of fuel injector cleaner and dump it in your tank.

If that doesnt help, TEST both your o2 sensors, dont just replace them,

If that still doesnt help, then let us know

Bochek

Tunes67 · Post by **Tunes67** » February 15th, 2006, 5:44 pm

Flow testing your fuel injectors can usually only be done by a specialty shop. There are two aspects of proper fuel injector operation. Flow and Pattern. Both are checked when you take them in for testing. Flow indicates how much fuel the injector will pass with each initialization. Pattern shows how well the fuel is dispersed or atomized. There are also seals and nozzles inside your injectors that can get clogged or gummed up.. fuel injector cleaners can remove soft particles from your injectors.. but not hard particles. So if you have blockages inside your injector(s) fuel injector cleaner wont always help.. though running a can through each of your next 2 tanks of gas should show some improvement. Hope this helps. I had a set of 4 injectors for my car flow tested and rebuilt for $120 a year ago.

Tunes67

TREVO123 · Post by **TREVO123** » February 16th, 2006, 5:56 pm

Go standard or go home haha

projectmx316 · Post by **projectmx316** » February 21st, 2006, 1:45 pm

i know the o2 sensor is brand new and my car only has one. does anyone know if its cheaper to rebuild the injectors or get new ones. does anyone recomend a special injector cleaner? I tried the lucas one and it seemed to help alittle bit but no a whole bunch. Im also getting a code 8 on my check engine light what does that mean and how can i fix it.

max kl · Post by **max kl** » February 21st, 2006, 6:58 pm

was it poping out the exhaust before the tb was changed? i have personal experince with timing belts being 1 or 2 teeth off it changes the power band alot. like only having top end power or only having low end power i think advanced exhaust cam timing would cause a weak low end power problem and louder exhaust down low.[/img][/quote]

ryanlindenberg · Post by **ryanlindenberg** » February 21st, 2006, 10:04 pm

when i had my stock dohc b6 in my mx it was pretty weak under 3000rpm. when i hit 2500-3000 it felt like an entirely different motor.

anyway, i would say check the plugs. any misfiring? you could also check the temp sending unit for the ECU (not the one for the guage). could be sending an incorrect signal making your car run rich.

well i couldn't find the CEL code for the b6 motor you have but the BP throws a code 8 for the Vane air flow meter.

projectmx316 · Post by **projectmx316** » February 22nd, 2006, 4:27 am

not sure if it was poping before the timming belt was changed. It is a motor out of a salvage car but it runs awsome. And yeah it does feel like a different car above 2.500 to 3,000 rpm it seems to start its power band at 3k i adjusted the timing abit and it helped the poping but i need new plugs in it they are starting to go out. Also my valve seals are shot so it smokes when u first start it in the morning.

projectmx316 · Post by **projectmx316** » February 22nd, 2006, 4:28 am

oh yeah i also have a new one of those temp sending units for the ecu.