Audiofight

My car is starting to **** me off again.

Last October it flooded majorly on me and I had to really work at it for almost 3 hours before getting it running again. After that, I had to floor it whenever starting it warm. But, it always started relatively quick.

During the summer it quit doing it....but today, when it was raining and like 40F, it flooded 3 times on me.

The last time in the middle of the parking lot with traffic moving. I had to push it into a spot.

The car will idle fine, doesn't smell like gas when running and has absolutely no problems starting when cold (like first start in the morning or after sitting a couple hours). Only has trouble starting when the engine has been warmed up to temp.

So, I ran across the "Hot Start Assist System". What composes this system (part wise) and is there any way to diagnose if it is failing.

1987RX7guy

iTrader: (3)

I have only heard of the cold start assist.(crap anyhow)

I don't think I have ever seen or heard of the hot start assist.

Audiofight

Yeah, I finally got the FSM up and running and am looking for my answer as I type this

Hot Start Assist page 4A-80

TheMysteriousCarlosX

Tell me more. Sounds like what I'm dealing with.

Audiofight

I am beginning to see where the problem may be located.........

The "Rat's Nest" seems to be where the selonoids are located that are involved. Hopefully I can find some time during daylight hours to work on this.....would love to save some money and avoid going to the mechanic on this one

1987RX7guy

iTrader: (3)

Maybe the reason I never heard of it is because I run bare block IE no rats nest.

BlackRx7

its one of the sileniods you removed :p, you just need to make sure you supply the vaccum line on the 2ndary fuel rail with a good vaccum source.

NZConvertible

The two parts of the Hot Start Assist System are the solenoid that cuts vacuum to the FPR to increase fuel pressure and the Air Supply Valve which increases idle speed. The ECU activates these for a short time whenever both the coolant and air temps are high, indicating the engine is heatsoaked from sitting for a while after shutdown.

This heatsoak can cause the fuel in the rails to boil (vapour lock), which causes hard starting and poor idling on hot engines. The increased fuel pressure and increased idle speed fix this problem long enough for fuel flow to cool the rails down.

If you've removed the vac rack and all the solenoids you can't really complain about hot-start problems, since you've removed the system Mazda put there to cure the problem. You can however reinstall the FPR solenoid on it's own quite easily.

Audiofight

See.....

I DO have the rat's nest and I am thinking that either one of these selonoids is defective or else I may have a vacuum leak. All I know is that I have saved that section of the FSM and am going to drive back to my father's shop across state this evening to try and fix it once and for all.

Wish me luck!

NZConvertible

Oops, dunno why I though you'd removed it...

RotaryRevn

Audiofight

Well. Good news and some not-so-good news.

I stopped to my local Autozone store and they had a blue silicone hose kit (17' total, 4/6/10mm hose) for only $15.99. So I bought it with the intent to dress up my engine bay along with trying to fix the problem.

Being that the solenoid valves are vacuum driven, I figured replacing the old brittle vacuum lines would be a good thing.

The car still starts kinda hard while hot, but still easy than before. I don't have to floor it now, just crank it for a bit first. Cold, still starts like a champ.

But, the side-effect to replacing the hoses is a nice power increase. My car used to really start pulling hard after 4k when the 6-ports opened up. Now, much more power in the lower end (2-3.5k) and is perfectly smooth when the 6-ports open up. You can't feel it at all.

So, back to the drawing board on fixing my car, but I do have a dressed up engine bay and more power.

All in all,

I WIN

RotaryRevn

I have similar problems with my car. I think I will do the same with the new hoses. Beats trying to track down the leak.

Audiofight

Yeah, that's what I figured. Hell, for $15.99 at Autozone you get all the hoses you need and it dresses up your car too.

I will warn ya though, I didn't replace a couple of them b/c they are a pain to get to w/o removing major components. 90% of them are accessable w/o any real effort. Those are the ones I replaced.

RotaryRevn

Ok, I saw the kit but didn't get it yet. Do you actually use the bigger sizes too like 6mm and 10mm. Also, how come I can't seem to find metric size hozes that aren't in that kit? I tried pep boys, and autozone and the only ones were in that kit. I just thought that was strange. Wouldn't all Jap cars require metric hoses?

HAILERS

Just FYI for NZ......the n/a cars don't have a Air Supply Valve. And make sure your air intake temp sensor on the dynamic chamber , is plugged in and making the connection to the ECU.

Audiofight

You would think that all imports use Metric hoses, but the standard sized hoses are all so close that you can use them interchangably.

I bought the kit b/c it offered specifically Metric size hoses and b/c it dresses up the engine bay.

I did use all 3 sizes (4/6/10mm) when doing this. You will actually run out of 4mm before finishing it totally but you will have left over 6 and 10 mm hoses. Be careful not to mistake a vacuum line for a cooling line. There are some that look like 10mm vacuum lines run near the top of the intake manifold near a 10mm vacuum.

RotaryRevn

sounds good, thanks for the info

Fingers

Sorry to dig this up from the dead, but i suspect my FPR solenoid as being defective too as i'm experiencing these EXACT symptoms. I don't really want to pay to replace it, as I'll be gutting the emissions anyway... and i plan on keeping the fpr solenoid... so are there any other solenoids that will be removed with the rack that I Can replace the FPR one with?

HAILERS

Anyone of them that has the filter on the opposite end of the valve from the two prong electrical connector. Thta means the Switching (grey), Relief(blue), FPR(orange). You don't want to use the EGR (YELLOW) or the Twin-Scroll (green).

The FPR (orange) passes vacuum from the manifold to the FPR itself ninety nine point nine percent of the time. The only time it does not is during hot start , for fifty seconds, where it gives the fpr atmospheric pressure (causes a higher fuel rail pressure).

Saku

OK I just parked my car for winter. And I was having the exact same problem with my TII(would flood often when hot, but awesome when cold) I recently replaced my hoses with the hose techniques kit, and that didn't help. There is one original vacuum line right behind the engine(in between engine and firewall), but it is not connected to anything.....would anyone know where this might go? Sorry I don't have a pic, but if anyone did I would be able to show you it.