H4Inf

I know this is probably normal for a lot of you, but this doesn't seem normal for me. 13B EFI (Microtech) with rats nest removed - very clean and simple setup - details in sig...

Basically when I first start the car.. say even if its not completely cold. The revs sit around 600-700. The idle is set at 1000. Once its warmed up a bit it idles real steady on about 1050.

Something I noticed which may be useful. Say I'm holding revs at 3000, and I let off the throttle, the rpm drops... drops drops.. below 1000. to about 600, nearly dies, then it kicks back up, jumps around a bit. When first starting it, it's possible to stall it doing this. Hold revs around 2000, drop it, rev up again and drop again and its quite easy to stall.

So as I let off the throttle, revs drop, below 1000, to about 600. Here it sounds like its aboiut to die, the lights dim, then usually it jumps back up and is happy.

Just wondering what you guys might think the problem could be,

Thanks in advance!

Paul.

hanman

Possible bad water/coolant temperature sensor?
By the way, what do you mean by an 1982 SA22C? The only SA's were in 79 and 80?

hanman

I just saw that you were in AU. Did they have SA's later there?
Also, I am not familiar with the microtech, but is there any way to adjust for cold starting, to enrichen the mixture?
And, if I remember correctly, the thermowax is what controls the cold weather starting. And it is removed on your car.

Eriks85Rx7

that sounds normal to me , my car does the exact same thing

H4Inf

Hmm I understand this may seem 'normal' to some of you, but you've probably put up with it forever and considered it normal... I'm pretty sure that this shouldn't be the case. With EFI, you should be able to let off the throttle and rpm will drop straight back down to idle and not any lower...

All first gens in Aus were given VIN numbers starting with SA22C.

Just recently I found out I was running with no thermostat, and recycle port was blocked. Since then I have removed the plug from the recycle port and installed a thermostat. I was having similar issues, but not this bad.

I also have this random ticking sort of noise, something rattling around inside something, since having the plug removed and thermostat installed. It happens sporadically. Sometimes I get home and can hear it, it stops after about 20 seconds. Other times can be when I'm driving (after the cars been running for about 6 mins)...

My ECU is very old, handsets are hard comeby, im sure there is a map for coolant temp to adjust fuel % but I can't get to it at this stage..

I have been thinking maybe I should go and buy an all out new Wolf3D Engine management system and be rid of all these bastards of problems...

But yeah, getting back to the main issue, when you let off revs, I really dont think it should drop below the idle point... right? When the TPS is at 0%, I think the ECU is meant to run off the MAP sensor.. or have some idle map.. So dropping from 100% to 0% will mean the map sensor will be reading lower pressure at that stage, so should be providing a fair bit of fuel. Shouldnt be leaning out when I let it off.. maybe going too rich? Argh.

Any other ideas ? :P I'm not sure this ones gonna be a quick fix..

Eriks85Rx7

oh my bad i forgot u have EFI, i got a carb...

H4Inf

Another detail which perhaps makes this whole situation make more sense...

When I push on the throttle there is like a 1 second lag before the revs come up... I'm not sure if this has anything to do with the rate I push the throttle at. Maybe when it hits the end of the TPS, it revs up...

H4Inf

b u m p

This problem is now happening all the time... not just at night with the lights on.

MAIN PROBLEM: Let off the accelerator from high rpm, revs drop below idle, the battery gauge drops down, then it all shoots back up again.

Microtech EFI. Thermostat now installed. Dynotuned properly twice to make sure.

It does this when its warmed up and cold.. although when its cold its more likely to stall when you let off the revs.

Could it be a weak battery? should the battery gauge drop when the car nearly stalls? it drops to about 9 or 10 from 13...

Any ideas would be top! Cheers

anthrax

The SA designatin was carried through the Asia-Pacicifc market for the life of the 1st Gen IIRC


The Change in North America has something to do with VIN number Standardization in the late 70's early 80's

nothingbutrotor

I have no clue what the problem is, but I have the EXACT same problems. I have that ticking noise, which I found was actually a spark, arcing from my ignition coil tower. If I have my headlights on, it idles really shotty and rough, even without them on, sometimes it just surges constantly. When I start it thre revs shoot up then drop back down almost to nothing, then perk back up.

SF@Rx7

clean the air control valve

jpre

I don't know anything about anything, but I've been trying to do some reading:

http://members.ij.net/mrmazda/gslseidle.html

"PROBLEM #8: When coming to a stop, the idle drops significantly below 800 rpm and then comes back up. Sometimes, the car stalls near the very end of the warm-up cycle if the air conditioning compressor is engaged.

This one is relatively rare, but a devil to find if you don't know what to look for. Due to wear or misadjustment, the throttle plates are closing too far. The EGI system compensates by fiddling with the BAC valve. This works pretty well most of the time, but every once in awhile the BAC system is not quick enough to catch it and the idle drops like a rock. Then it comes back up. To verify that you have this condition, try turning the Air Adjust Screw. If the throttles are not letting much air pass, turning the Air Adjust Screw (which comes before the throttle plates) won't have much of an effect on idle speed. Also, if you disable the BAC system (by disconnecting the electrical connection for the Vent Solenoid Valve and the Vacuum Solenoid Valve) the car will hardly idle at all. The Standard Procedure for Adjusting Idle will also not have much of an effect.
To adjust the throttle stop screw, first take note of it's current position. The object is to turn the throttle stop screw inward an eight of a turn each time--propping the throttle plates open more and more. When you get a linear response from the Air Adjust Screw, you are probably in the right place. The Standard Procedure for Adjusting Idle will also work properly. You will need to use it since changing the resting point for the throttles will put your TPS out of adjustment."