TwistedOne

I noticed that my 7 smokes at start up pr after sitting 8 hours. Smoke goes away pretty quick and runs good.. No smoke while driving or anything..

Also has a little miss when first cranked then smooths out nicley.. Again this is only on a cold start up. Turn key on, pumps runs tap gas twice and cranks on the second turn...

Anything I should look for? Or is this a normal thing... I love these cars more and more every day

DivinDriver

iTrader: (15)

Does it smell like oil smoke, fuel smoke, or anti-freeze smoke?

TwistedOne

More fuel than anything...

Kentetsu

Fuel leaking down into the motor after shutdown? Pull the air cleaner off and check it out. Also, see what the fuel level is in the bowls, see if it changes as the car sits a while.


Perfect_circle had this issue, but worse, so bad he could barely get it started. After a run at an autocross, we pulled the air cleaner and watched the carb fill right up with fuel.

I believe it turned out to be either the return line restrictor was in backwards, or the float bowl solenoid had issues.

Good luck.



.

TwistedOne

That makes since.. Every now and then after I cut the car off and it sits for about 5-10 seconds it will give a little pop in the exhaust. Always smells a bit like fuel..

Local shop here wants $300 to rebuild the carb.. I think I will toss it and go with a carter first... I hate to get away from it being original though...

mazdaverx713b

iTrader: (91)

rebuild the carb yourself and save the money. you'll learn a lot doing it and its an easy job. heck the carb rebuild kits are only $20!

also remember that some smoke on startup is normal. the engines use an oil metering pump which injects oil into the combustion chamber to cool the engine and for lubrication purpopses. as long as there are no driveability issues, fuel mileage is good and the smoke goes away i wouldnt worry about it.

TwistedOne

It clears right up after starting, car runs and drives good.. I think i am going to change the fuel filter as I don't know what the PO did...

I ran a bottle of fuel cleaner through it already.. Maybe time for a set of new plugs and filter.. Just put a new air filter init.. Thanks for th eheads up..

Kentetsu

Yeah, rebuild the carb yourself if needed. But so far I see no indication of needing a rebuild.

This is probably caused by some component on, or related to, the carb, but is not likely to be an internal carb problem...

TwistedOne

I need to try and figure this out.. The wife does not want to ride in it when it smokes on startup... I guess she is a little to worried about what others think.. Not me though...

mazdaverx713b

iTrader: (91)

i will take a pic of my 7 today on a cold start and post the pic of the smoke for you and show you what i feel is normal. as long as the smoke goes away then i wouldnt worry about it. changing the fuel filter, plugs (use NGK) and wires (use NGK) is an excellent idea!

DivinDriver

iTrader: (15)

I've been fighting this for a while, too; Ican actually see the float bowl levels drop after shutdown. Sorry I don't have a resolution to offer yet, but I'm diving into the carb again this weekend. I'm also going to blow out my return and vent lines, and change the hosing back by the tank.

With mine, it seems to take about 20 minutes to start, is worst after a few hours, but if left to sit long enough, will minimize (as fuel evaps out the tailpipe, no doubt). It's enough smoke to be embarrassing, at it's worst, and has made for a couple hard starts.

mazdaverx713b

iTrader: (91)

here are a couple pics of my 85 GS with an SE's 13B. 57K miles on the engine and freshly rebuilt injectors new plugs, wires, cap, rotor, fuel filter, air filter, and fresh Castrol GTX 20W50 oil change. smoke clears in just a few seconds and it only smokes on cold start. no worries here:

TwistedOne

I can say I have a cloud behind my car.. but it goes away quickly.... Yours is very small compared to mine..

mazdaverx713b

iTrader: (91)

i couldn't catch it in its cloud state, lol. i was jacking around with the camera because the settings were not right for the lighting and when i got it set (approx 5 seconds) thats all it had left..

DivinDriver

iTrader: (15)

I can scare neighbors with mine sometimes. Looks like the garage caught fire. Other times it'll start cleanly.

TwistedOne

Well I have owned it for a month now and never took it over 3400roms.. Tolday a Honda hatch thought he could pass me and stay in front of me on the interstate.. Once this thing got past the 4500 mark it sraeted running good..

Even Idels better no.. I stretched it legs 3 or 4 times today...

Thanks for all the help guys.. I am off to call a football game in the rain.. Whoo Hoo..

Kentetsu

Trying to think of other potential causes....

I heard about a line that runs to the charcoal canister, has a restriction consisting of a small orifice.
When clogged, causes this situation.

Not sure about tank venting, but there's a couple of valves and thingys back there.
Can't remember, most of mine are long gone.

That's all I can think of right now, besides what I mentioned above (float bowl vent
and return line restrictor reversed).

LongDuck

Float valves and seats being worn is the obvious answer. A carb rebuild will fix that.

What happens is that the fuel pressure can overpower the float valves and prevent them from seating which allows fuel to overfill the bowls. Once the bowls are full, the Mikuni design allows the fuel to run down the throttle bores, which I suppose is better than squirting it down the side of the engine. Unfortunately, this leads to extreme rich conditions, and blue/grey smoke out the back. This would usually manifest itself beyond just cold starts, however.

My SE, if left to sit for long periods, is know for 'smoke-screening' the neighborhood, and I just make sure not to sit there waiting for it to warm up on cold mornings. You can't see through it, and it's enough that cars have to slow down behind me.

Seems to get better during warmer months, though, and hell, it's all part of the 1st Gen experience. Welcome to the club!

PercentSevenC

Just making sure: it's not just condensation steam, is it?

TwistedOne

No it is not steam on my car... I will try and get a picture of it today.. I have to get the wife to come out and take one...

80's old school

iTrader: (7)

Here is a short video of my 1980 on Cold Start.... This is usually the worse it gets...

Yeah it smokes....yeah it uses oil but it sure runs good and is not worth rebuilding yet...

http://s378.photobucket.com/albums/o...t=P1040138.flv

Twilightoptics

iTrader: (1)

Mine smokes a little on startup too. Looks like the old Chevy Salute. I figure it's residual oil from the OMP lines that drip down and all burn at once at startup.

No worries.


Just premix without a cat and burn all the time! :O)

TwistedOne

that is how mine looks in the video

80's old school

iTrader: (7)

How many miles do you get per quart???? I just drive mine....it runs too good!!!

mazdaverx713b

iTrader: (91)

after looking at the video 80's old school had posted, i would say that the smoke coming from his car is very normal and nothing to be concerned about.