94 GS runs like a 30 year old dirt bike

MX-SLICK · Post by **MX-SLICK** » October 23rd, 2006, 6:02 pm

well, my GS started running like crap the other day. After the biggest pain in the A$$ was over trying to change the plugs, I got all of them changed (they were BAD) and I also changed the wires. Car ran great for 2 days. Just today, it started doing it AGAIN...It sputters and looses power at low rpm's and it sounds awfull with my exhaust on it...I pulled off all the wires and put them back on making sure they were tight but still nothing. Plugs I got were NGK BKR6E-11 (what the manual calls for) but for some reason the person before me had BKR5E's in it (1 step hotter)....I thaught it could be a bad plug, but I pulled them out and tested them all with my plug tester..all fire OK, and i put on a set of wires off my buddies mx3 just to see if i got a dud wire..but it still ran likr crap. Local garage says he cant do a codescan on it for whatever reason (he has like 500 different readers but not the one for this car) There is NO engine light on (asside from the charge light ocasionaly but 95% of the time voltge is a steady 14 and even when the light comes on it only flickers down to 12.9 and never any lower)...Im starting to think fuel pump or even fuel filter but why would changing the plugs and wires make it run like new for 2 days??? this car is on a personal mission to frusterate me!...

PS>>how hard is it to change the altenator on a GS? it looks damn hard!

Tunes67 · Post by **Tunes67** » October 23rd, 2006, 6:31 pm

Its actually fairly easy to change the alternator on the GS.. after you remove the Radiator. Its a bit involved.. but its not rocket science. Have you tried pulling CEL codes to see if you have any errors stored in the ECU? Sounds to me like a coil or ignitor issue. But it also sounds like the voltage regulator built into the Alternator is going bad as well. And one could definately have led to the other.

First thing I would do is pull codes to see if the ECU can tell you whats gone wrong. For whatever reason though.. it wont report a faulty coil. There are test procedures in the online shop manual on how to test it to see if its good or bad though. Keep in mind both the distributor assembly and the alternator are both made for mazda by mitsubishi.. so the likelyhood that one or both are bad is pretty high. Especially if both are OEM parts.

After checking codes.. replace or rebuild the Alternator.. then I would try the HEI modification rather than replacing the distributor assembly.. far cheaper and a more reliable solution if done correctly.

Tunes67

Vanished · Post by **Vanished** » October 23rd, 2006, 6:36 pm

Tunes67 wrote:Its actually fairly easy to change the alternator on the GS.. after you remove the Radiator.

Tunes67

yeah..its hard if you don't. I did it with the rad still in. fun time

Tunes67 · Post by **Tunes67** » October 23rd, 2006, 6:41 pm

LOL I bet you remove the radiator next time though

Tunes67

max kl · Post by **max kl** » October 23rd, 2006, 7:51 pm

change the plugs again. go cheap. if car run great and fades in a few days like before i bet you plugs are fouling. this would also explain why the prevous plugs were hotter. hotter plugs do not foul as easly.

if you notise a white or shiney residue than you are burning oil.

flat black would be fuel fouled
green orcracked electrodes would be coolant

Jay72 · Post by **Jay72** » October 24th, 2006, 4:32 am

max kl wrote:if you notise a white or shiney residue than you are burning oil.

I was under the impression that our engines like to burn a little more oil than other engines so, I'm assuming excessive oil?

jschrauwen · Post by **jschrauwen** » October 24th, 2006, 10:36 am

I would look into Tune's suggestion of having the alt corrected since it's a sure thing that it won't go away or get better over time. I'm leaning towards the plug fouling scheme also since the same problem returned a short time after the plug/wire change. Hopefully you haven't swapped in some bad plug wires for some other bad plug wires - long shot. There's nothing wrong with doing a fuel filter change especially if it hasn't been done in the last 2 years or you're not aware of the last time it was changed. What's the condition of the rotor inside the disty? What's the condition of the contacts inside the disty cap? I make it a habit to clean the contacts of both the rotor and disty cap at least twice a year and I can definitely notice a performance difference when I do. Is the air filter clean? How old is the battery and did you have it tested also? Ask the previous owner why the hotter plugs were installed since it's obvious that it wasn't your doing. I'm also assuming that this is a fairly new car to you since this is your first crack at changing the plugs. Try a few of the previously mentioned suggestions and post back your results for other members to benefit. BTW, this is not an uncommon problem and you may find similar problems with tangable results posted by other members.

MX-SLICK · Post by **MX-SLICK** » October 24th, 2006, 8:47 pm

well, ive had the car for about 2 years. I did not change the plugs because i have had some horror stories of my own removing plugs from an mx6 that were in there for a few years...that and the car ran fine. Car does smoke a bit @ startup... but it clears up after about 10 seconds and does not smoke any more. Uses an annual litre of oil i'd say every 2-3 weeks (wich is not real bad cuz it does drive every day)....The plugs were not dirty or oily when i took them out again...i cleaned them anyway (and as i stated all the plugs fire 100 % on my little plug tester machine ) I swapped out the new wires that I baught for a set of my buddies mx-3 that were working on his (thinking i may have got a dud wire) but still no luck. The altenator issue has to be adressed, but since the first time I seen the voltage light i purchased a voltage guage and installed it in my car. On the very rare ocasion the light does come on, the voltage drops "slightly" from 14.1 to about 13.5 on average...and as i said it only comes on once in a blue moon....like say once every 2 weeks for about 10 seconds...

max kl · Post by **max kl** » October 24th, 2006, 9:04 pm

i will ship you a new set if you will install them so we can see if the plugs are an issue. realy cleaning them is not enuph. replace them its the varable you changed before. you gota try again to no for shure.

you may have a cracked plug and they have not run long enuph to produce a carbon track you can see.

what spark tester are you refering to? it produces a high voltage to see a spark?

MX-SLICK · Post by **MX-SLICK** » October 25th, 2006, 3:48 am

max kl wrote:i will ship you a new set if you will install them so we can see if the plugs are an issue. realy cleaning them is not enuph. replace them its the varable you changed before. you gota try again to no for shure.

you may have a cracked plug and they have not run long enuph to produce a carbon track you can see.

what spark tester are you refering to? it produces a high voltage to see a spark?

correct....its an older machine i got years ago...It simply drives a distributor and all the plugs are screwed into a metal plate...just looking i can see all plugs are firing consistantly and the spark is nice and bright.

max kl · Post by **max kl** » October 25th, 2006, 8:22 am

but the v reqiredto jump the gap outside of the chamber is alot lower. the hight kvs reqired to run may not be firing at the tim and missfiring.