Hey, I have this problem that when the car is on, the idle seems to want to go under 1000 rpms, when I try to press the gas then the engine sputters then goes up, a few times when the engine was at idle it actually did go under 1000 rpms and just died. I think the fuel system is dirty but I want to see if you guys may know?
Thanks, and sorry for the questions all over, I do have this running with the battery and all.
Alex

 

It would help if you provided some info on the car; Year? Engine type? Miles? Auto/ Manual? Any OBD diagnostic codes showing? Check engine light on? Does cruise control work? Any prior history which might be relevant?

Normal no load engine idle is 700 - 800 rpm. and is pretty solid; even when the A/C compressor cuts in out the surge is minimal and of short duration.

Try first of all making sure that your mechanical throttle linkage is clean and in good working order and the cable linkage, cruise control link and the return spring mounting is secure, and the throttle plate movement is smooth and free.
Next (although this is specific to the 1.8L ZM or FP engine, it's generically applicable to all 1995- 2000 4 cyl. Mazda engines).

Before getting into serious money, I suggest you look very carefully at that ducting between the air filter unit and the engine intake. Unclip the air filter, and don't be hesitant about really moving it around a bit either. The air duct has a habit of getting brittle and splitting apart. What happens is it seals at rest, the engine is then torqued on the mounts as you engage gears, then the movement of the engine opens the split, letting air (which the MAF doesn't "see") into the engine, making the mixture way too lean. Now the engine complains, rocking to and fro on its mounts, making the ducting work like an accordion (with a split bellows), so the whole show just rocks (literally) on the engine mounts. This you can fix with duct tape.
If the duct is OK, then next you get yourself a 2ft. piece of tubing (even garden hose works), and use it like a stethoscope to "earball" your way around all of the plumbing which is connected eventually to either the throttle body or the intake manifold, listening for sneak leaks. (The underside of the hood has a "map" of the vacuum circuits.)

Another common weirdo of the Protege is that bad ignition hickups can throw the ECU for a loop. Get yourself a spray can of contact cleaner (which is good for cleaning the MAF anyway), and remove the two connectors at the front of the coil packs. Give those connectors a really good cleaning with the spray, and clean the dirt off the coil packs while you wait for the contact cleaner to do its job.
While you're at it , disconnect the two connectors on the air filter/MAF assembly, (MAF and Air Temp.) and squirt them too. Then take the tube off the spray can and shoot a good shot down into the MAF itself too.
Now go back to the coils, spray them with WD40 and clean them up well, using an old toothbrush, rag or whatever.
Next, check the condition of your plug harness. If it's old, it will arc onto any metal it gets close to, so make sure all of the wires are 1/4" or so clear of metal and each other, and that the plastic spacers which slide onto the mounting tabs on the engine head, are clean and in good shape too.
Now put the four connectors back where they belong, but connect and disconnect them a few times to ensure good contact.
Start your engine, warm it up, note the idle speed ( should be 700 rpm. and stable to +/- 50 or so) , go for a run and (if you've got it) check out your cruise control.
Now call it end of phase one, and post your data and findings on this thread.

 

Hey, Im going to fast posting things, Ive got some injection cleaner Ive had in the fuel system and it is running much better now, I drove it and its pretty crappy in 3rd with bogging etc, I think its still dirty, when it sputters I looked to the back and could see smoke, so I need to just keep running it, the previous owner let it sit awhile so it needs wearing in again. Now that Im doing this it is staying at about 1000 rpms now. Just to make things clearer, it is a 1990 Mazda Miata manual
Thanks!
Alex

 

What color of smoke? White= coolant, Blue= oil, Black= rich mixture/ ignition misfiring.
Have you had a compression test lately?
What's your oil consumption like? Have you tried yanking the plugs and checking for dryness, color and condition?

 

Hey, the smoke "was" a lightish blue, over the weekend Ive put in new plug wires, sparkplugs, (spark plugs were crap (black ashy) and put in new fuel filter. It doesnt smoke anymore, now the gas when you hit it in too much it will go under the rpms, Im thinking the throttle position sensor, so I bought a maf and throttle sensor, picking them up tomorrow. But since Ive cleaned out the fuel system, I was able to switch gears at about 3000 rpms, otherwise it would go under while driving like if done at 2000, so its still not great but Ill see what happens. I need to replace the oil too. I think that since Ive replaced the plugs, one piston may be knocking with a valve, so I guess its been running on minus one cylinder before replacing the plugs.
Sorry for the "blow up" of info at one time, I just got time for the computer,
Thanks!
Alex

 

Oh, and also, about the battery, I got it charged over the weekend, but when I put it in, a few hours later it didnt work, the starter shorted, but, I looked through the engine with basic checking of the alternator to see if it had a good 12 volts, turned out that when I tapped the altenator with the wires, the altenator swung back and forth, how screwed up! I was able to take its bolt and hook it back onto the bracket and tightened it enough to keep it sturdy and not too tight to strain the belt and what do you know, the battery kept its charge!
Im not sure if this happened with the previous owner or the one before, but that was messed up.

 

Ok, so I installed the mass air flow sensor and throttle positioning sensor, it reacts faster, but it still hesitates when you accelerate, especially in 2nd gear, this does change a little with the ac on though.
Any ideas, I heard it could be a grounding strap, or maybe some vaccuum hoses?

 

That's right, but only partially. You machine pre-dates OBD-II, perhaps OBD-I even, and I don't know if it has a check engine light; if so is or was it on?
Sounds like your wheels need some TLC. Before spending big bucks on sensors and stuff,go to the oldeng post of 04-13-2009, 10:06 PM and run through that routine, check the state of your air filter and clean up and check your throttle linkage as well, since it seems your car has been neglected; then report back.

 

Alright, I was looking at the engine and some clips on the hoses were off, I put them on which I do believe made the acceleration drop even worse. The engine check light wasnt on, just a airbag light that blinks 6 times which I dont care for I do like Christmas lights. Maybe the intake is dirty? I will look at the other posts.

 

Did you check the condition of your air filter? Also worth checking is the PCV located somewhere around the top of the valve cover. It's plugged into a neoprene grommet so you just disconnect the hose, yank out the valve and shake it. If it rattles it's good, if not, replace it (a universal no name brand will do just fine).
You should re-read that post I made 05-12-2009, 11:50 PM, and go through that very methodically and post your findings in a well ordered fashion before jumping all over the place, because tackled methodically you can avoid spending biggish bucks unnecessarily.
You should also check to see if your engine has an EGR valve.
[Just find out if you've got one , don't do anything about it until you've gone through everything I posted previously.]
If it has one, you'll find it underneath the throttle body, and it's a S.O.B. to get at.
It can cause problems when the stem gets gummed up or corroded, but even more likely is that the port coupled to the exhaust plumbing gets totally obstructed by carbon and crud and has to be nearly reamed out to clean it.
Since your plugs were a disaster, if you've got an EGR it's almost certain to need attention, and if it sticks it will have a significant effect on performance.