My car has been stalling lately during warm-up and always in the same manner (it's completely reproducible). Here are the cases when it happens, note that it only happens when the car is in neutral and during the first 5 minutes after start-up (car still has AWS):

1) If the car is at a stop and I rev it to about 3k rpms (in neutral) and then take my foot off the gas and let the rpms fall, the tach goes to zero and the car dies.
2) If I am driving in first gear and at about 3k rpms and I shift into neutral, the rpms go to zero and she dies.
3) 5 minutes or so after start-up, there are no probems

This is all independent of if the clutch is engaged or not or if the A/C is on (I never use it) or anything... I would think it has to do with the AWS since it's only during warm-up, but I don't know. Any Ideas?

Thanks.

-Matt

 

My car does #1-2 before and it was a boost leak, its fine now after I fixed it. good luck!

 

Can you elaborate on this? How would a boost leak cause this?

 

I have a similair problem I think it has something to do with fuel maybe the FPR or something.

 

That's interesting... I have suspected that my FPR is not working correctly for a while b/c I have some small hot start problems (low idle, idle hunting, etc...).

Any rational for why it may be from the FPR?

 

light weight flywheel?

 

I think it would be happenng after the car is warmed-up if it was from the flywheel.

 

Well if you have problems hot starting then your FPR may not be connected at all. This is what happened to me when mine wasnt connected. Starting was fine, cold idle was high, but hot idle was dieing and hot starts were near impossible. My want to check your map sensor just incase (possible crack in the hose).

 

the fpr solenoid will cut the vac signal to the fpr during hot starts to stop vapor lock with high puel press. the fuel temp sensor must be ok also. how is the idle when warm? and it never stalls out warm? only cold? and the aws works normally? the iac may not be allowing enough air in when cold to keep it idleing

 

My car does this exact thing but I but I have my AWS removed. I usually keep my foot right next to the gas pedal so when it drops I just floor the gas and it pops right back up to normal rpms and is fine. The wierd thing is... even with the AWS disconnected it still tries to rev up like when the system was still connected, thats when it stalls... as soon as the rpms start falling after reving up.

 

1) Idle is fine when warm... 800 rpms, 850 w/ electrical load.

2) Nope, never a problem when the car is warmed up (once the idle drops to normal). I could rev it to 5k if I wanted and it will drop to normal idle right away.

3) Actually, i'm not too sure if the aws is working normally ... It's sensitive to ambient air temps. For instance, on a cold day (less than 50 deg F), the car idles at around 2300 - 2400 rpms for two minutes or so, then drops to about 1000 rpms for 3 or 4 minutes, then down to the normal 800/850. On a hot day (more than 80 deg F) the car idles at 1000 rpms for about 3 minutes, then drops to 800/850. If the it's b/w 50 and 80 degrees out it idles around 1800 rpms for about two minutes, then 1000 rpms for 3 minutes or so, then to normal idle. It's always been this way for the 2 years that I have had the car, so I never thought much of it, as long as after a few minutes the idle went to 800/850. Is it normal for the aws to be so temperature sensitive? Also this problem always occurs during the aws period.

 

that's exactly it... interesting that you have the aws removed. Does the problem go away once the car is warmed up?

 

I see you have a PowerFC.

Go to the "water temp" screen under settings.

See the +50 and +80 sections? Increase both values (4 total) 2 increments upwards.

 

Thanks clayne, I'll give it a try . What exactly will this do, or what is it correcting?

 

I have the same thing happening with my stock. Its in he shop now. I dont know if you guys have emissions where you live but I do and what it might be is that your car is running too rich. I will post more as they tell me

 

Correction, change +30 and +50, leave +80 alone for now.

Water Temp -> Fuel Enrichment biasing.

Incremementing by 2 for each is not dangerous. Especially when we're only changing +30 and +50.

I've done it on my own car as well to fix the "mid-warmup" fall to 0 crap.

Manually you can blip the throttle right around 1200 rpm as it falls to get around it.

Page 31:
http://www.scuderiaciriani.com/rx7/power_FC_manual.pdf

 

maybe O2 sensor -they work funny when motor is cold if they are fouled up--mine was ,my symptoms were i smelled gas cold or warmed up andi got crappy gas milage--20 us dollars for universal one 130dollars for mazda brand.

 

Yeah, thats what my mechanic thinks it might be. But I still need to address why Im running so rich, any ideas?
My thoughts:
A.) Dirty injectors or
B.) Low compression on the front rotor

 

what do you mean both values

+30 2 increments up on low laod and 2 increments up on high load

+50 2 increments up on low laod and 2 increments up on high load
is that how....

 

Yes.

 

is this setting to high

+30 low is 1.31 high is 1.29

+50 low is 1.10 high is 1.09

that is the setting on my power fc , I just checked

 

my +30 high load is up by 8 increments

my +50 high load is also up by 8 increments

 

I hate it that I have to wait about 8 minutes until it is fully warmed up to be able to drive it without dying

 

I've got extra fuel for the warm up maps but still had issues with stalling. I adjusted the throttle linkage dashpot all the way in to slow the throttle plates as they approach the closed position, also upped the f/c rpm settings to bring the injectors back online sooner as rpms drop. Works!

 

what exactly did you set them to?