rwcjnr

Need help. I've owned my Mazda since '84 and have 335,000 miles on it. I recently had Mazda put a motor in it (8K or so ago/1-2 yrs ago). The injectors have been cleaned and they do not leak. They spray within 1% of each other. I recently replaced all intake related gaskets, checked air flow sensor, H2O temp sensor, throttle sensor, idle/fast idle, and mix potentiometer. All check out OK. Fuel pressure is good and tank supply and return are clear. Trouble is it won't start after it's been shut off for 30 min's or more even when it cools off. The colder it gets, the worse it is. I have to use the plug unfouling method to get it cranked but when it does run, it runs great, like new. There are no vacuum leaks that I can tell and all throttle valves seem to be adjusted properly. It just seems overly rich at cold startup. Plugs get soaked. I'm assuming compression is good. My 150K motor started better than this. Could this be O2 sensor?? Not enough spark? Too little air? What else should I check or do? Running out of ideas. I gotta get this baby on the road again.

Thanks in advance.

zookeeper

I dunno. Sounds like it's flooding for sure, though. Check this site out http://www.rx7.com/tech/index.html and select "13b - common starting problems". It has a good discussion about flooding causes and unflooding procedures.

And... welcome to the board.

rwcjnr

Thanks zookeeper. This problem is a tough one. Just seems that initial burst of fuel is a little too much for it to handle. I'll keep searching and asking. I'm considering getting control of the fuel pump and seeing if I can regulate it initially to get it started. I've read about those delays but don't know if they apply here.

LongDuck

Just to get the facts straight, you have 8k miles on the new engine, and you're seeing these problems?

When the dealer did the engine swap, did they do anything else, i.e., replace any intake system parts, perform tune-up, etc. that would affect this?

What you may notice is that there is a thermowax pellet at the rear (passenger side) of the throttle body which accounts for cold starting. This is where the heater hose (1/4") from back of water pump sends hot water once the engine is warm to tell the thermowax pellet to melt and stop holding the throttle bores closed during cold starts. By keeping the secondary throttle bores closed longer, it creates a rich fuel mixture during cold starts, which allows for better warm up and better compression/combustion until the engine heats up.

Also, something to look into is that the SE's were equipped with injection of 90/10 antifreeze during sub-zero starts. If you live in a very cold part of the world, check that you have adequate 90/10 (antifreeze to water ratio) mixture in your sub zero tank, underneath the windshield washer tank on the passenger firewall. This tank supplies pumped (check connections and operation) 90/10 mix to the lower intake manifold, where there is a temperature valve mounted to the top of the lower intake manifolding. This can only be seen by removal of the upper intake manifold, and looks like a solenoid valve, but metal. This valve is temperature sensitive and when cold, combined with the air-intake temperature reading from the RE-EGI switch (drivers side, under the BCAV), will turn on the pump for the 90/10 mix to flow. This is injected into the intermediate housing and helps the side and corner seals to better provide compression during VERY cold conditions.

Check these 2 things and report back. I've been amazed with the level of knowledge on these boards, and know that someone out there has experienced this problem. There are a lot of SE owners here.

Also, I'm truly amazed that you got 327,000 mi out of your original engine - I hope I'm that lucky and I'm only at 163k mi. HTH,

MosesX605

Did the SE's have that wonky 90/10 antifreeze injection? I thought only 12A's had that. Has anyone here noticed a difference with the system disabled?

zookeeper

Yeah, they got it. Mine never seemed to use any fluid (ever) and I really didn't know what it did or was supposed to do. Anyway, one day I looked and it was, like, MT. Turns out the bottle is cracked. I've never fixed it and haven't ever noticed anything different. BUT... I don't live in a sub-zero climate. So I guess I wouldn't miss it anyway.

Since rwcjnr lives in Austin, I don't think sub-zero starting is his problem either.

RWCJNR, the one thing I can tell you is - don't even touch the accelerator when you go to start it. Nor the clutch, nor the brakes! Just make sure it's in neutral and turn the crank. I've learned that with my 84 SE when it's acting up. As soon as it starts, goose it a little and then let it idle. Not sure why the brake and clutch pedals affect it, but they sure do when my idle's acting wonky. CC switches, probably.

rwcjnr

I can tell by your responses that we're all on the same page. Thanks. I also may have underestimated how many miles are on this engine. I got the motor replaced around 288K. I guessed at the 335K number. I looked last night and it's only at 315K. That makes 27K on the reman'd motor. I messed up in my original post...the 8K was supposed to be 18K. That still doesn't sound too excessive. I'm sure Mazda checked the OMP and lines (they were replaced) so I'm assuming it's had plenty of housing lubrication. Is it possible that I've lost significant compression in 27K miles? It did sit up for a while, but as well as I remember, when it's warm outside, it starts ok. It's only about 40-50 degrees F here in Austin so I wouldn't say the sub-z starting would even come into play. I have disabled and dismantled that system anyway. The BAC has been replaced lately and does seem to work for idle up (turn steering wheel and turn on AC). What else is it for? Hot start assist? Is it possible that I'm going the wrong way on this and it's really too lean to crank initially? Then when it doesn't crank it floods and I have to dry it out and it finally cranks. I can tell you that when cold, the BAC is allowing air through that bypass tube. It seems unrestricted. Is this how it should work? What's the vacuum side of that thing for? The electric side I think is for the idle up. They did replace quite a bit on the intake. All the gaskets, of course. I just got done replacing all that stuff, too, when I had the injectors cleaned. All their gromets and orings. ACV gasket, intake/motor gasket, intake/dyn.chamber gasket, aux port gaskets, check valve inside ACV, (ACV replaced recently). I freed up the aux ports so they'd work right but don't think they're involved in starting. New Oil Metering check valves. Is O2 involved when cold? When I drove it out of the Mazda garage, it was running fine and would start (I think it was summertime). If it wouldn't have started the next morning, I would have taken it back to them. Also, when trying to crank it my foot is off the gas and the car is in neutral. Thanks for the brainstorming. We'll figure it out.

LongDuck

I'm in Phoenix, AZ - desert heat out here causes more problems than cold temperatures ever would. We never see lows lower than about 30-35 degrees (F). My
Sub-zero tank has been empty the whole time I've owned the car. Just recently, I capped off the sub-zero solenoid on the intake manifold and pulled out all the plumbing - no use for it.

rwcjnr

I've been searching the forum for a few days now and have seen a couple of posts dealing with a "not hot enough spark" which causes cold start problems. How much experience does anyone have with this claim? Do ignition coils either work or not work? Is it possible that mine have enough power to run but not enough to start? My cap/rotor/wires all look good and I think they're pretty new. I've heard the 12A Denso plug is hotter than the NGK 14's and 15's and will work in the 13B. Any input? Thanks. Also, has anyone ever found anything conclusive by checking voltages at the computer?

2GSLSE

iTrader: (6)

#14's&15's???? the gslse uses #9's but if you want hotter plugs the 12a uses #8's
I would check out the ignition system first but it sounds like you have checked most obvious things already

diabolical1

iTrader: (3)

just read through the thread and i was going to suggest going to a hotter plug. what type of driving do you do most often, city or highway? also, how new are your cap and rotor?

i would suggest trying some 8-range plugs, and if it still floods with those, then go to 7-range. however, if you do a lot of highway or high-RPM driving, then you'd probably want to stick with the 8's. i don't know how 7's would react to that sort of constant use - maybe someone here has more experience with them.

i have an SE engine in my '84, and ever since it started to get cold here, i've had it flood out on me twice. so i've been experimenting with plugs recently.

i recently switched from the standard type plugs to B_EV type. i'm using 8's, but i'm ordering some 7's and 9's when i get a little cash together. i don't know if they work well with your stock EFI (i have a Dell'Orto on mine) but thus far, i'm pleased - but it's still early.

hope you figure it out.
1

MyRxBad

I have an SE as well and I used to get the odd flooding on restart.
It's happens ramdomly when the car is shut off before it is properly warmed up. My solution to the problem was to install a 12v switch wired to the fuel pump, so I can shut off the fuel pump while cranking and as soon as the car fiires up I flip the pump back on.

But in the meantime check out your ignition side of things.

rwcjnr

My mistake on the 14s and 15s. Don't know what I was thinking about. I've been back and forth with the 8s and the 9s when it was starting properly but not since it's been hosed up. Never tried the 7s. Can I get those at Mazda? Right now I have a set of 8s and a set of 9s but both have been flooded out at least a dozen times. They may be shot by now?? I was thinking about getting that less expensive Denso plug for the 12A just for troubleshooting purposes so I don't screw up another set of NGKs (AutoZone doesn't stock a Denso or other for the 13B). What is a B_EV type plug? The cap and the rotor aren't new as far as age goes but as far as engine miles they are almost new. Are coils either good or bad or could they be halfway good, as in enough power to run the thing but not enough power to start? I think I have replaced one coil and the other is original (18 yrs). I do get spark on all wires. Thx.

rwcjnr

It's fixed ! and I wanted to follow up on the problem resolution. Fact is, I'm not sure how I fixed it. The one thing I did do is change the oil. Apparently it was gas washed and causing compression problems. After changing the oil it cranked right up and has done so ever since. That's the only thing I can attribute the fix to. Thanks to all who offered their input.