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Mazda Engine General \  2.2 idle issues....

2.2 idle issues....

Mazda Engine General Mazda Engine Mazda Tech
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wannahdawg   +1y
89 b2200, 5spd, 150k miles, 2wd. the truck will not idle. it revs up and down without ever holding an idle consitently or it just shuts off. i've only put about 200 miles on the truck since i bought it, and it gets about 21 mpg and has no trouble running down the road, but when you come to a stop or park, etc it won't idle at all or the idle surges up and down. i did a search and tried to clean my egr, still stuck open, so i made a block off plate and plugged the vacuum port. didn't change anything. unhooked the three tubes off the airbox, didn't change anything so i hooked them back up. i checked the timing as the previous owner sold the truck becuase of the idle issue, and he messed with the mixture screw, the idle speed screw, and the timing. i set the timing back to 6 btdc, the mix screw to about 2 turns out (which is what i read on here is close to stock), and i turned the idle speed screw back down some. (it's hard to get it to idle at 800 rpms when i won't hold a steady idle hahaha). i do not want to spend the 250 bucks on a weber since i only paid 250 bucks for the truck. i replaced some of the vacuum lines as well, but i think that was just a waste. i also sprayed some ether around the carb area and it didn't do anything either. i can't understand why it won't idle to save it's life, but it runs fine down the road and gets decent mpg. any help would be much appreciated.
mazdatweaker   +1y
Have you tried replacing the fuel filter?

The other thing that I would check, since it is pretty easy to do, it pull the top of the air filter housing, and while the truck is idling, look down the primary barrel and see it fuel is *kind_ of* blobbing into the intake stream. It may be that the idle mixture circuit has gotten clogged, which will lead to really poor fuel atomization at idle. The jet that controls that has a really small (like .009) inlet port, and yes, they clog.

Since you can access the mixture screw, you can take it out, and try to shoot the hole with carb cleaner and/or air pressure to get it open, but methinks the easier thing will be to pull the carb (four nuts) and the top of the carb (airhorn) and get to it that way if that is the issue. Be aware if you do this that the mixture control solenoid has an o-ring that will probably need to be replaced if you pull the top of the carb off.
wannahdawg   +1y
No i haven't gotten to the fuel filter yet. just got back from a 9 month vacation in afghanistan and been busy, but today is officially my work on my truck day. so i'm going to get a fuel filter and order the carb rebuild kit from auto zone. i don't know how good the rebuild kit is, i've gotten a couple rebuild kits from auto zone and some have had more than enough gaskets and misc hardware, and some of them haven't had enough stuff so i guess we'll see. i will pull the carb tonight if they have the base gasket, if not it's my daily so i need the truck for tomorrow. i also checked all my fuses (i read that on here as well) but all my fuses were good. thanks for the reply, if anybody else has some input as well it would be great.

later,

matt
mazdatweaker   +1y
Personally, i wouldn't waste my money on a carb kit, unless you cut the.gasket taking the airhorn off.

I think you can buy that gasket alone from the dealer. I would look at this picture:



If you notice, there is a slotted screw that covers the jet you need to get to. It's the one directly in-line over the mixture screw. I think it's number six in the picture.

You pull that plug, and then use a GOOD screwdriver to remove the jet. It's brass, so it's really easy to destroy it otherwise.

Once you have that jet out, you will see the end that *probably* needs a wire run through it to open it up.
wannahdawg   +1y
hey thanks man. will try that out when i pull it apart. i found some gasket material out in my garage so i'll use it instead of buying the kit.

later,

matt
mazdatweaker   +1y
If you are careful, the airhorn will come off without tearing the gasket, which will be relly hard to fabricate if it does get cut. But even if it does get cut, it's pretty thick and really does nothing except seal the top of the carb from the entrance of dirt into the carb.

From your original descripton of your issue, there really doesn't seem to be any indication that any other part of your carb needs to be torn down, and unless you want to go to a lot of extra work, if it were me, I would just fix the broken issue, and not get involved anywhere else. . . .but that is just me.
wannahdawg   +1y
okay tweeker....tried some stuff. had a gift card for auto zone and knew i needed some plugs and wires when i bought the truck. so i used my gift card for cap, rotor button, plugs, wires, and a fuel filter. when i changed all of them the truck ran worse. well that's what i thought....i did all the work with the truck on a hill in my backyard. backed the truck up onto level ground and it almost smoothed out. almost doesn't count except in horseshoes and hand grenades though, so it's still idling erratically. so today, i took the carb off and did what you said with the screw. clean as a pin, no dirt or sediment on the jet or in the passage. i don't know i think i'm just going to burn the truck to the ground or sell it. hahaha. the weirdest thing about it is the fact that it does it worse when the motor is cold compared to when i've been driving around town and got the motor up to temp. but the choke works as advertised.
mazdatweaker   +1y
When you had the top of the carburetor off, what did the inside of the float bowl look like in terms of contamination?

Since I wasn't there when you took it apart, from you description, it sounds like you maybe have missed the part I was talking about with regards to the jet.

If memory serves correctly, the jet has a tapered end on it. At the end of the taper, there is a point, which has a hole drilled into the center of it. . . .that is almost impossible to see. . .and almost harder to clean if it has a piece of dirt in it. If i had a picture to post I would. Whatever wire you use must be able to be seen from the other end of the jet to verify a clear passage. . . .otherwise it is a bullet stuck in the bore.

Fuel *blobbing* into the primary intake bore indicates a clogged idle circuit. The blobs are unatomized fuel that causes lean drop out at idle.

It isn't as much of a problem once the engine warms up, due to better fuel evaporation.
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Now that you have it back together, what hapens if, when the truck is idling when hot, you slowly turn the mixture screw in all the way?

If it stalls, how far out from seated is it?

Do you have a multimeter that can measure DWELL.

You may need it.
wannahdawg   +1y
ok, this carb is screwed... took it apart and it had some water in it i guess. every part was corroded, the aluminum has white powder and severe pitting. the steel parts were rusted, the needles were junk, float bowl was half full of gunk etc. the float was broken sitting in the bowl... yeah, this thing was still running somewhat too. either way, i'm getting rid of it and going with a weber. i've seen some people running weber 32/36, 32/34, etc etc.... which one does anybody recommend? not looking for performance really, just a truck that runs and drives to work everyday. and maybe a place to pick one of these bad boys up... webercarbsdirect, etc etc...
wannahdawg   +1y
used weber carbs direct. 259 shipped. got here 2 full days after i ordered it with normal ground shipping. install was straight forwarded. and she drives like a brand new truck. if you got carb issues, then this 32/36 is awesome. highly recommended.

later,

wanna