cold idle and mpg

Don't know about the cold idle situation.

We are getting about 37 mpg in our year 2000 1.6 NB over here in the UK. I guess our Imperial Gallons are a bit larger than US ones but that seems about normal for ordinary road use. ( It does depend a lot on the roads though, I know I get a lot more MPG in France where generally the hills are less steep and the bends are less sharp, hence a lot less braking, gear changing and acceleration. )

Regards Chris

The message

from peter contains these words:

Mileage of any Mazda seems heavily dependent on how it's driven; kids with Mazda3s often get only 20, while our 3 sees 30-31 in mixed use and up to 35 on trips (if we can hold the speed down to 70).

20 isn't that surprising for a supercharged Miata, if the extra power is used as a matter of habit, especially if the car hasn't been custom tuned using an aftermarket timing control. Even if you keep your foot out of it, the S/C will still cost 1 mpg or so just to spin the pulley. Plus, if it keeps stalling it's obviously not running properly.

Spend some time in the Forced Induction forum at miata.net. Someone there will have the solution for you.

In a separate email directly to peter, I sent him a jpg image (pretty large file size but easy to read) of page from Haynes repair manual regarding miata Intake Air Temperature (IAT) sensor which is part of the mass air flow sensor. These cars should get better mileage than 20mpg even when supercharged. I get 28ish highway and city with an automatic transmission. The IAT may be the problem but I would first clean the throttle body using spray cleaner ($4) and consider replacing your ignition wires ($40). OEM type ignition wires seem to last not more than 2 years on miatas before they degrade badly. If you intending to keep the car, Nology wires are seriously and noticably better but also cost $125-$175. I like mine that I bought several years ago. Unfortunately there is only one idle adjuster. The cold idle is computer controlled based on the IAT sensor. Regrettably, the mass air flow sensor is pretty expensive ($222 to $895 at RockAuto.com), so let's hope that is not the problem.

Brian

"peter" wrote in message news: snipped-for-privacy@k26g2000vbp.googlegroups.com... hi,

i drove my wife's 95 with an eaton s/c to get gas today and it kept stalling on me. i know i could just adj the normal idle but i wonder if there is a cold idle or other winter adjustment?

aslo, the car with a recently rebuilt drive train seems to be gertting ~20 mpg...that seems a tad low, what do you guys get?

thanks, peter

The MAS might benefit from cleaning, too. An over-oiled foam air filter element (the Achilles heel of the Eaton system) can contaminate the hot wire.

Be sure to use a cleaner that specifies that it is compatible with sensors (about $6), not carb or FI cleaner. I need to clean the MAS sensor wire in my 2001 Toyota Corolla twice per year to avoid error messages. It also has a K&N type filter that is cleaned and oiled (and maybe over-oiled).

Brian

The MAS might benefit from cleaning, too. An over-oiled foam air filter element (the Achilles heel of the Eaton system) can contaminate the hot wire.

I have never cleaned the MAS sensor wire on either the Miata that I drive or the Camry that I also care for. In fact, I have never cleaned it on any car.

There are lots of arguments as to the advantages and disadvantages of a K&N style versus a paper filter.

If the K&N were clearly superior in filtration, yet was also the cause of fouling the sensor wire, I would probably still go with the paper one just to avoid getting in there twice a year for a MAS sensor wire clean-up.

As it is, there is a lot of evidence that the paper filter is better to use, or at least as good, so there is no contest for me.

I did run the JR CAI with the oiled foam filter for about 2 years and never had a problem with it, (the filter that is, the actual JR CAI unit was a poorly-made nightmare). Same with the oiled foam air filter unit I have on my turbo, neither have ever passed enough oil through to become a problem.

Still, if my turbo would take a paper air filter I would use it and just replace it very frequently.

XS11E, that makes a re-starting of the dreaded oil thread and the K&N filter versus paper filter thread in the same month. Should I go into hiding? ;-)

Pat

I've already taken out the contract, the guys will find you where ever you go!

I was surprised that the price, usually a hit is pretty expensive but they said, "Oh, that guy, we'll do it for $10.00!"

You mean, aside from the appalling amount of dirt it passed? The first time I removed my JR filter element for cleaning, I found a disgusting pile of crud in the bottom of the airbox. Then, when I cleaned it out, I could see the cracks around the mounting surface for the aluminum MAS adapter. Out came the JR, back went the OEM. All it really did was make a silly "blub-blub" noise at idle, anyway.

Hey, hey, you snipped that at the wrong place, the LAST thing I am going to do is to endorse that POS product. As far as I am concerned, it is not far from the Vornado in lameness, and I am ashamed to have shelled out $200.00 and then installed on my car, even if it was 10 years ago.

Hell, the Vornado probably will not damage the engine the way that Jackson Racing's Cold Air Induction has done to thousands of Miatas.

Let Jackson Breaking sue me, it is truly squeezing a turnip and they know that this product is a turd. :-)

What I wrote in the previous post was this, please note the parentheses.

"I did run the JR CAI with the oiled foam filter for about 2 years and never had a problem with it, (the filter that is, the actual JR CAI unit was a poorly-made nightmare)."

I hate the JR CAI, absolutely hate it. The thing developed cracks on the bottom where I could not see them. When I took the air filter off and saw a pecan tree twig that was at least 1/16" of an inch across underneath the filter, I could only shake my head and wonder how many small particles had dusted the engine.

Jackson Breaking Products is what I routinely call them now. I have seen about 7 or 8 of those JR CAI's close-up, and every one of them that was over a year old had cracks in it.

If I am looking at a Miata to buy and it has a JR CAI, that is a huge downside as the engine has probably been dusted, the filter over-oiled, or both. Most likely a JR CAI will be a deal-breaker since there are endless models to choose from out there. It would also make me need to find a new intake immediately, though I would just order up a Randall unit. Still more noise change than anything with the Randall CAI, but at least it is not destructive to the engine and I can see if cracks starts to appear in the carbon fiber air tube.

I really wonder about the person who designed the JR CAI And thought that you could mount a plastic air filter box on top of the radiator, and towards the hotter side of the engine without having trouble with it becoming brittle and cracking.

I sold my used JR CAI and felt really bad about it, but the buyer could not wait to get it home to damage his engine with it too.JR XAI SUCKS!

Pat

Now that just hurts.......That price seems to slip down all the time.

Pat

Make that, the JR CAI sucks! Also, that was endless used Miata models to choose from. The 1990 - 2003, (or so), Miata is so cheap and plentiful that is only makes sense to find a good one with only the "good" mods, if any.

Pat

The Randall tube is on the dirty side of the filter anyway. Mine is a rather loose fit, and isn't stressed enough to crack. In hot weather (>80F) it lets me run 89 octane at 14BTDC with no pinging, whereas I used to need 91 in summer. IOW, it doesn't really add any power, but it helps prevent loss of power in hot weather. If that makes any sense.

In my opinion, the Randall unit is superior in every way to the Jackson Breaking Unit, except for the need to cut into the firewall with the Randall, which is no big deal to me.

I am pretty sure that Jackson Racing hired an engineer from GM to help design that cold air intake. (that was just for you, Tim). ;-)

Pat

Nah, Lucas. The original plans called for Whitworth fasteners. The oil leaks were tolerable, but they fired him after an argument over cloth insulation for the MAS wiring.

LOL! :-)

Pat

You crazy mugs!

cd

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