revs limited to 2,800 rpm in 1993 MX-3 (4 cyl)

Civic driven01 · Post by **Civic driven01** » February 23rd, 2005, 7:12 am

I dont know if anyone here can help, but a friend of mine has an old 1993 MX3 with the 1.6L 5spd. It runs fine except it stumbles when the rpms reach around 2,800 rpms regardless of what gear its in or even if its neautral. Its like theres a rev limiter there but not really. Its like its losing fuel or ignition at that partucluar point in the rpm range. Brandnew cap rotor, plug wires, ecu, map sensor, and distributor have been replaced already. I believe the distributor was replaced with a used one though. no sign of any check engine light. As soon as it stumbles at 2,800 the engine quickly regains and remains running. This problem occurred out of the blue since it has occurred it has been 100% consistent. It seems like an ignition problem of some kind to me, but I'm not a certified mechanic who works on mazdas everyday. Its a beater but its his only mode of transportation and hes a good guy, that I'm trying to help out. thanks in advance.

matt_fulghum · Post by **matt_fulghum** » February 23rd, 2005, 9:31 am

weird..... there's something in the intake manifold called VRIS where it alters the runner length to let in more air, which starts to open around there, I believe, but I doubt that'd be the problem.

Maybe it's a bad oxygen sensor or air flow meter? Is this problem there when he floors it? That'd be a helpful test.

Civic driven01 · Post by **Civic driven01** » February 23rd, 2005, 11:38 am

I just spoke with my friend and its actually 3k rpms where it experiences fuel or ignition cut. I personally think that hes not getting spark once he reaches that rpm level for one reason or another. He experiences this problem regardless of throttle position as well.

johnboi85 · Post by **johnboi85** » February 23rd, 2005, 1:47 pm

it's not called vris. he said it's a 1.6. if it's a sohc, he's got nothing. if he has a dohc, he's got vics. it opens at 5K rpm so it's not relevant in this case.

Civic driven01 · Post by **Civic driven01** » February 23rd, 2005, 1:53 pm

its a sohc

snellgrove · Post by **snellgrove** » February 23rd, 2005, 3:50 pm

hmmm, I have a crazy idea

get it to this weird 'limiter' in 5th.. then chuck it into 3rd, and see what happens ?!

maybe its the ECU being silly at this one RPM, and might be fine once you blast past it with a different gear

if the engine is like totally dead after that RPM and the speed just drops back til your at 3000rpm in 3rd now... no damage done I wouldn't have thought as you wont have gone much over 4.5/5k or something.. engine can definately handle it (unless its limiting you to 3k for some specific reason that I dunno about!)

maybe??!! just an idea.....

Civic driven01 · Post by **Civic driven01** » February 23rd, 2005, 4:41 pm

Theres gotta be someone in here who has experienced this problem before.

jimishadow · Post by **jimishadow** » February 23rd, 2005, 9:48 pm

hows your fuel filter?is your exhaust free flowing,is the cat clogged?

Franko · Post by **Franko** » February 23rd, 2005, 11:56 pm

Id try testing your coil.. Could be the problem.. Also, hows your firing order? I know the car shouldent even run but it has happened in the past.. if you have 2 wires messed up the car will run but might have weird problems.. hence the 2500 rpm limiter

guyaverage · Post by **guyaverage** » February 24th, 2005, 10:21 am

Sounds like an airflow sensor problem.

Franko · Post by **Franko** » February 24th, 2005, 3:25 pm

Ahh! Never thought of that.. Thats definately possible..

mx3TT · Post by **mx3TT** » February 25th, 2005, 5:20 pm

I have basically the same prob in my BP and I cant figure it out. For me, its not the air flow sensor because I have had about 3 in there and its high un likely that they are all bad. If you find an answer let us all know.

P.S. Franko you trying to steel my avatar?

Typhoonk · Post by **Typhoonk** » February 25th, 2005, 10:06 pm

airflow also includes the TPS sensor..........

mx3TT · Post by **mx3TT** » February 25th, 2005, 10:27 pm

Replaced that too.(not jacking your thread man sorry.)

Civic driven01 · Post by **Civic driven01** » February 25th, 2005, 10:39 pm

mx3TT wrote:Replaced that too.(not jacking your thread man sorry.)

Dont apologize, I was actually wondering about that. I appreciate everyones input. I havent had a chance to even look at the car in a while, but rest assured the details I've given you thus far are pretty accurate I know because I've driven the car once before myself. I'll have him bring it by soon so I can maybe study it again. I might learn a few more things along the way.