Engine stalls after restart when warm

[scootchu]

I searched the threads and didn't see anyone with this exact problem so forgive me if I just didn't use the right search words.

I have an 03 P5 and a problem that started at the end of the Summer has continued. The car will start normally when cold and that goes for when the temps outside are in the 20's. It idles okay. The problem happens when I have driven say 45 minutes, turn the car off, and then go to start it again soon after. I
t starts and then the idle dives and usually stalls. If I start it and the outside temps are warm it happens more frequently. If I start it and hold the idle at about 1500 for 10-20 seconds usually the engine will idle normally.

It isn't always a constant, but when the temp outside is warmer it happens a lot more.

Is this an EGR or MAF problem? I get no codes at al, in fact I went through DMV inspection and it stalled on the inspector and he was checking the computer for any codes and it was clear.

Any advice would be apreciated.

 

[delguini]

I'm not claiming to know the answer by any means at all, but i do know on my 92 Prelude it was the main relay that wasn't working. I had the exact same symptoms are you are having. I would drive 30 mins, then stall the car on a hill. It would take over 2 or 3 minutes to start her back up again.

No idea if that's the case with your car, or if something like this even happens to protege's, but it's a possibility.

 

[scootchu]

I'm not claiming to know the answer by any means at all, but i do know on my 92 Prelude it was the main relay that wasn't working. I had the exact same symptoms are you are having. I would drive 30 mins, then stall the car on a hill. It would take over 2 or 3 minutes to start her back up again.

No idea if that's the case with your car, or if something like this even happens to protege's, but it's a possibility.

I should clarify; It never stalls when running. It will stall after I stop the engine and then try to restart. It will fire right back up and then stall. If I start it and hold the RPM's around 1500 it will settle back to a normal idle... most of the time. The hotter the weather, the more predictable it is. The colder, the less the chance of stalling.

 

[ho bag]

Could be the PRC solenoid.

 

[scootchu]

Interesting. After doing a search it kinda makes sense. I read this over at the RX-7 forum:
"Mazda, in their infinite wisdom, put an actuator inline of the vacuum hose going to the fuel pressure regulator. When under hood temperature reaches a certain level during a warm restart the actuator cuts off vacuum going to the FPR which raises the fuel pressure at least 10 psi. I had the same exact problem with my FD, and sure enough every time it would do it I would see the elevated fuel pressure on my Defi gauge....as soon as the pressure went back to normal the idle would too. The best part of all this is that I think Mazda worked this control feature into the ECU to help warm starting! I hope this helps."

I think I will bypass the PRC and see if that solves the problem. Thanks!

 

[ho bag]

Ya i know it was a bad decision on Mazda's part. I left it on the P5 but took it off my mx3.

 

[scootchu]

After I went to my car after work I popped the hood and bypassed the PRC Solenoid, going directly to the FPR and it started cold like normal so I figured at least it didn't change that.

I did drive home and made a stop on the way. I restarted the car and it ran and idled like normal, but it was in the high 30's out. The real test will be when the temps are in the 50's or even higher. I am keeping my fingers crossed and if it does happen again at least I will be able to rule out the PRC.

Thanks for the lead. It saved me much aggravation.

 

[ho bag]

Hopefully it resolves your issue.

 

[scootchu]

I thought it did, but nope. Cleaned the MAF sensor and that seemed to help, but it will still stall once before it runs normally. Maybe its the EGR too. It has been too cold to work on it outside so it will have to wait a little bit.

 

[STP2307]

My '03 P5 does the same thing except it never actually stalls. The revs just dip extremely low and then return to normal idle. I have'nt noticed a corelation with outside temperature either. Let me know if you resolve your issue.

 

[gsmooth]

mine does this too and i have too hold the rpms over 1000 until it idles normally

i'm thinking its the cold air intake that messes around with the sensors....if I take off too early my CEL comes on, so I gotta wait 5 or 6 minutes especially when its really cold.

its only stalled once or twice...if I dont give it gas it will dip down really really really low (and most likely stall all the time!)

 

[GhostMercury]

my car does this exact thing and i can't find the ******* reason for it. my car has done it for like a year, i think it is the intake mani i put on, but now that you say you have the same problem, i dont think its the manifold anymore.

 

[scootchu]

Still trying to figure this one out. If the outside air temps are in the 30's or lower I have no problem whatsoever. When idling it's a wee bit bumpy, but not like it's missing. If the outside temps go into the high 40's, 50's or higher the car will start normally when cold, but if I should drive to a store, come back out 10 mins later the car will start and immediately drop RPM's and stall. I have to drive with both feet to get out of the parking lot. Sometimes it returns to normal quickly and sometimes it takes a few miles and like a switch it idles where is should.

So the question is what affect does warm outside air have on what sensors?
I am going to clean the MAF again and install a new filter. This is killing me.

 

[fourthmeal]

Most common cause of this problem is the known issue of a bad EGR valve. There is an informational bulletin about it by Mazda. Also, though rare, the timing belt may have slipped a tooth. This would cause a similar problem.

 

[scootchu]

Most common cause of this problem is the known issue of a bad EGR valve. There is an informational bulletin about it by Mazda. Also, though rare, the timing belt may have slipped a tooth. This would cause a similar problem.

I read every post in the cleaning the EGR valve thread and I am beginning to think it's the IAC. Someone posted the exact symptoms. I need to get a tamper proof torx T-25 socket to get it off and clean it. I tried to start the car yesterday with it disconnected and got exactly the same problem. It would start and die.

I seafoamed yesterday, cleaned the MAF, and installed a new air filter. Was too cold and windy to tackle the EGR. This weekend new plugs and one or both of the valves.

I know it has to be something very simple. Both the EGR and IAC make sense.

 

[fourthmeal]

sometimes a replacement EGR might be the case instead of cleaning it.

 

[scootchu]

I cleaned the IAC and (fingers crossed) the problem went away. I will see today. Temps are supposed to be warm.

 

[scootchu]

I cleaned the IAC and (fingers crossed) the problem went away. I will see today. Temps are supposed to be warm.

Man I think it's fixed. Warm restarts were no problem and the temps were in the high 40's. I think I will clean the EGR tomorrow.

 

[GhostMercury]

what did you clean to fix the problem????

 

[scootchu]

what did you clean to fix the problem????

I cleaned the IAC valve as mentioned in the EGR HOW-TO. The carbon build up was pretty bad.