Very Cold Start
 

O.K. now iv finally got it running. Dont really know what i did to fix it but i got her cranked up last Wed. and boy owe boy did she smoke.

Today's question on a very cold start up lets say right at 0 degrees what would cause the idle to go up and down. Once it's warmed up it's almost perfect. it's jumping about 500 rpm's. Do i need to reset my fast idle cam or is this more of a TPS problem. I know the Tps is off abit but not to bad. Could'nt get a straight reading from my volt meter today. It's Friggen COLD. just thought id ask before i did the usual go out and play with stuff till i get it right method.

85 GSL-SE

if i was u, take the fuel injection system out, and put a weber or holley carb on it

IIRC the 13B has a cold start system that keeps the idle held high to warm the engine up. I think you can bypass it if you put the car in neutral and hold the clutch (maybe it was the brake) while you start it. If you idle smoothly then its an issue with your coldstart system, maybe.

Thats where I'd start, but keep in mind I'm a 12a guy and I may not remeber this information correctly.

Thanks there i will try that in afew minutes and let you know

Get a block heater and plug the car in on nights when projected temps are 5F and below. A block heater costs about $30 and comes with installation instructions that anybody can follow.

Well, on the cold start system you should know that the 'fast idle cam' is actually a mechanical cam on the primary throttle plate that gets reset when you push on the gas pedal just before you start it up. Sequence is as follows (for an EFI-SE):

1) Push gas pedal all the way to the floor, and let off COMPLETELY,
2) Turn key to 'Start' position and crank until running,
3) See that idle speed runs up to about 2500-3000 rpm

A good link for troubleshooting the 84/85 SE EFI system is located here: http://www.nellump.net/peri/epi/firs...gslseIdle.html

This system is not the Very Cold Start system, it's used to push more fuel into the engine and 'choke' the EFI system to help warm up the cats so they'll run cleaner. The other system is completely different, and for Sub-Zero conditions.

Keep reading, if you're interested in that.

The 'Sub-Zero Start Assist' actually pumps a 90/10 mixture of Antifreeze/water into the intake during sub-zero conditions. This mixture is controlled by a vacuum assisted pressure valve that opens during extremely cold weather, combined with a 'washer pump' attached to the Sub-Zer Start Assist tank (over by the cruise control, and below the washer tank). When activated, this system sprays the 90/10 mixture into the lower intake manifold which runs into the intake path and thus, into the housings during engine starting.

Mazda was hoping that the Sub-Zero system would increase cold cranking compression to help start the car, but most users found that it really didn't work all that well, and ripped the system out, capping off the vacuum lines. That's what I've done, because I live in Arizona (the desert). HTH,

Yep iv been all over the fast idle cam afew times. I got the car to stop the fluxing on start up by re-adjusting the TPS. So that problem is gone. Your saying however that when the fast idle cam is engaged i should be in the RPM range of 2500-3000 which mean i need to adjust the adjacent screw out alittle to open my throttle angle abit. That no problem. thanks again LongDuck and others. no need for a block heater i have the car in a redneck heated garage i mean i have a space heater in my garage LMAO...