96 mx3 with 1.8- stock. Strange behavior, need help

Davidgolf321 · Post by **Davidgolf321** » October 10th, 2006, 12:26 am

This is my first post and it concerns a problem that is, at least for me, difficult to describe and find the cause of. I bought a stock 1996 mx3 , 1.8l 5-speed for my son in July this year and until two weeks ago it ran great. Then, when on a short errand, the engine lost power and the rpms started surging. He pulled over and put it in neutral and the revs swung between 300 and 3000 with no power . He was able to limp home and parked the car for a few days until I could look at it. I started it and it started fine but revs would not settle down- going from 300 to 3000, sounding very rough at low revs and normal at the peak, then when the engine started to warm up the revs stabilized at about 1,000 rpm and stayed there until I touched the gas and then it lost power, and the revs started to swing all over the place again. Thinking it could be a fuel supply problem, I replaced the fuel filter (and thermostate while everything was out of the way) but no joy same problem. I have no local Mazda dealer and people I have spoken to have named everything from vacuum leaks, to EGR valves to fuel pump to distributer as cause. I need help and am not a mechanic, so have any of the members of this group experienced these symptoms or heard of them and can anyone suggest a cure?

ariesdude · Post by **ariesdude** » October 10th, 2006, 1:10 am

Any codes? Could be the ignition module in the distributor (a common problem in mx-3).

PATDIESEL · Post by **PATDIESEL** » October 10th, 2006, 1:26 am

Well, the problem is that without knowing more about your diagnostic skills all I can offer is to start with the easiest cheap things and work upward. The symptoms could mean EGR, vacuum leaks or disty problems. Vacuum leaks are generally the easiest to find and are the most common issue when you have a suring idle right upon starting the car. First check the accordian tube that feeds the throttle body. It is common that they dry out and crack. Usually you can jsut run your fingers around each grove and feel for a crack, so that you don't have to take it off. If nothing there, check all the intake fittings starting at the air filter and working back tword the throttle body (TB). Make sure they are snug and not pulled away on the bottom side. If that checks out try squirting some carb cleaner around the intake maniold seal (where it meats the head). If there is a leak there the carb cleaner will get sucked into the engine and the revs will change. Spray in small amounts and in about 3 inch spots at a time so that you know where the leak is. However, I doubt that you'll find a leak at the intake manifold seal since you haven't had the intake manifold off recently.
Next, I'd take the car to Mazda and let them check the disty. You can do it yourself, but need to know a tad about auto electronics and have a multi-meter that can read sign waves. The disty can cause surging, but usually only after the car warms up and if you shut it off after the problem starts it usually won't start back up until the motor cools back down. This is b/c the disty houses several important sensors that will become sensitve to the heat and not function properly. A silly design flaw of Mazda's, but one that we have found a way to fix cheaper and more relaibly than replacing a poor design with the same poor design. More info if you ask...
Lastly, check each and ever vacuum line on the car for a crack, seperated joint or broken attachment point. This can be tedious and I suggest replacing the lines if you check them b/c it will prevent you having to look at them down the road. The hard part about checking the vacuum lines is that you have to make sure to remove ony one end at a time so that you don't get confused. The stock lines are molded shapes, but you can find a way to reroute and secure all of them if you replace them with simple rubber vacuum hoses.
Welcome to the forum, good luck with the car and tell your son to come and visit our site some time.

max kl · Post by **max kl** » October 10th, 2006, 1:41 am

after my second kl swap i experinced a very simalar problem and it took me way to long to find my brake booste supply hose was cracked. causing a large intermintant vac leak . it idles like it has a big cam then surges ar part throttke only running ok during hard acceleration.

pat steering you in the right direction with the vac leaks and or distrubtor

definatly have he fuel pressure checked
and the vaf boot its gota be cracked

Davidgolf321 · Post by **Davidgolf321** » October 10th, 2006, 5:25 am

No codes, sorry for not mentioning that. We will try again to find vacuum leaks and hope its not the distributor.
Thanks

tehbrookzorz · Post by **tehbrookzorz** » October 10th, 2006, 10:31 pm

Is your CEL burnt out? Most of the warning lights should illuminate shortly if you turn the key to the on position before starting the car. If your CEL light does not come on, you may still be getting codes, but just can't see them. Let us know.

Just to brace yourself; I'm not saying it is the distributor, but it is a possibility.

I had very similar conditions earlier this year wherein the car would surge like that until warm, and then the problem would go away. Many people thought that it was possible to be the distributor but not as likely because usually the distributor problem only starts once the car starts getting warm.

I changed my whole disty and the problem went away, but mine was still under warranty after replacing a previous bad disty.

If you check all your intake and vacuum lines and can still find no leak, post back and one of us can reference you to the cheaper method of fixing the ignition module problem that seems to plague our cars.

Davidgolf321 · Post by **Davidgolf321** » October 16th, 2006, 11:05 am

Well, I checked for air and vacuum leaks and no joy. Discovered that the CEL is not working - where to go from here? Been told it could be distributor and a new one is around $900. Local garages cannot plug their computers into the Mazda dianostic plug, lots of fun.
Someone mented a less expesive way to repair / replace distributer, would like to check that out. I am still checking around locally but these are not common cars around here.
Thanks

Davidgolf321 · Post by **Davidgolf321** » October 16th, 2006, 11:05 am

Well, I checked for air and vacuum leaks and no joy. Discovered that the CEL is not working - where to go from here? Been told it could be distributor and a new one is around $900. Local garages cannot plug their computers into the Mazda dianostic plug, lots of fun.
Someone mented a less expesive way to repair / replace distributer, would like to check that out. I am still checking around locally but these are not common cars around here.
Thanks

twoie · Post by **twoie** » October 16th, 2006, 11:57 am

look under the FAQ section of the v6 forum. There is a mod for ignition module. My car was doing similar things and this mod fixed it for under $20.

twoie

MX3ak · Post by **MX3ak** » October 16th, 2006, 6:12 pm

Are you from Europe?

To pull the codes, jump TEN and GND and put a Led between FEN and B+.

That pulled the codes on mine.

max kl · Post by **max kl** » October 16th, 2006, 8:34 pm

i bet you engine light bulb is blown. just pull the instrument cluser and replace the bulb on the back or swap it for the seatbelt light or sumthn.

Davidgolf321 · Post by **Davidgolf321** » October 17th, 2006, 2:46 pm

Can you point me to a "how to" section on how to take dash and instrument cluster apart? I have been looking and that section is missing from the on line manual and seach hasn't found anything yet.
Thanks

max kl · Post by **max kl** » October 17th, 2006, 9:50 pm

well tou gota remove the gauge cover if you look up from the gauges you can see 2 of the screws and 2 more are exposed when you lower the tilt wheel all the way. they are easer to get to if you remove the stering column covers. i belive te are 2 more under the lower dash cover undr the steering colunm.
once the cover is out of the way you will see 4 screw around the perimeter of the cluster remove them and puul cluster to you so you can unplug the ellectrical connections on the back of the cluster.

dukem2 · Post by **dukem2** » October 17th, 2006, 10:38 pm

try air temp sensor that controls fuel/air ratio. after spending 600 bucks at the local shop and getting frustated and limping the car for a year, a 28 dollar part fixed the problem. man i was pissed but also very happy casue i could drive it normally again.

Davidgolf321 · Post by **Davidgolf321** » October 18th, 2006, 1:56 pm

Well, I got the CEL to work- thanks for the how to. Tried to read it but... when engine is running, CEL flashes. Tried to read codes using jumper, TEN and ground in diagnostics connector, but CEL stays on continuously, no flashing. Does this mean a "Hard Failure"? If so, what does that mean? Does it mean I have to take it to a Dealer to get the codes, if any read?
Thanks
Puzzled