THIS LOW RPM ENGINE STALLING SAGA POSSIBLY SORTED

[benm]

Well I had the earth wire grounded and also a kill switch installed for $100 ($80 for the kill switch and $20 to ground the wire) . Ran perfectly for about 24hrs and then it started happening again.

Did a bit more research on here and heaps of people mentioned cleaning the AAC can fix the problem so I bought some electrical cleaner from DSE to attack that job (also the AFM). Took 1 look at how to remove the AAC and released I need a better set of tools so thought i'd try something easier and clean the AFM but couldn't work out how to remove the air scoop (has 2 weird plugs on it that I haven't worked out how to remove whilst upside down and no view of them).

Took 1 look at my K&N panel filter to realise that it was black instead of red so I repleaced it with just a generic panel filter that I got with the airbox and it hasn't missed a single beat in a week. It idles spot on, doesn't 'dip' when I brake/clutch it's absolutely perfect (although I was definitely down on power at WSID on saturday).

So I think my problem may have been a dirty K&N Panel filter choking the system. I'll get some stuff to clean it properly and throw it back in and see how everything goes.

[Craved]

there's a point, i havent cleaned my pod in a long time might give that a go! hopefully you've got it sorted for yourself! how'd you go at wsid?

think my issue would be caused by the crack in my exhaust manifold.. but i'll definately be cleaning my pod now!!

wierd plugs plugs on the scoop?? you shouldn't need to remove the scoop.. just take the top of the box off, undo the 4 nuts, then unto the hose clamp from the other side of the afm.. and it should come out... thats from memory, took my airbox out a couple of years ago!!!

[Craved]

which wire was the earth by the way?? did you happen to see?

[benm]

Nah didn't have a look, could probably work it out just by looking at it. I didn't even think it could have been my air filter choking it all. I just thought if it was really dirty that I wouldn't get as much power. I'm sure it is something that many people would over look just because it is so obvious.

WSID was a shocker, it was my last chance at drag racing for awhile (working night shift now) so I thought i'd go for a run on the last saturday event just for sh1ts n giggles. No traction, standard air filter and could only run on 7psi (12psi was cutting at about 4,500rpm, not sure if it was the factory boost cut or not coz i've 'never' had that issue before).

Yeah I could prolly remove the AFM without removing the scoop but it would have been a tight squeeze getting to the clamp for the AFM hose so I didn't bother. I will take another look at it tomorrow when I change my front brake pads.

[dangerous_daveo]

Well after doing a few things to my car the other day I think its partly fuel pressure.

I put a mallpasie on it, and it worked fine, sounded better at idle, never droped at all, absoultly perfect, took it off, bang problem was back.

[Craved]

there's something else for us try! thanks for the info dangerous_daveo!

[jonnyboy]

hello all

yes i had this problem as well basically on take off idle would drop and then raise or sometimes if u put foot down a bit it would stall as not enough current running to fuel pump to push more fuel thru. anyway you could here when engine is idling on 600rpm the fuel pump gets quiter and if you just tap the accelerator you can here it wine again, which means that when dropping to idle the fuel pump would be running lower pressue which means the stalls

if i read this earlier it would of saved me being ripped of a fuel pump! anyway have a nice new bosch now. 400 dollars later!.

could of spent to 400 on something else!!!.

regards

jonny.

[Doctor 30]

Mine DR30 does it with the RB20DET. Thanks for the tip.

[Grey skys]

have any of you guys had a problem with stalling and the engine cutting out in all sorts of driving conditions, not just at low rpm? This is the problem that I had. I say had because I think that I might have fixed it. I cleaned all of the electrical plugs in the engine bay, cleaned the air filter had the voltage tested on the battery,altenator and fuel pump,leads and spark plugs were all good and gapped and firing fine. My mechanic even used my car as a daily driver for about 3 weeks, but Murpheys law would tell you that nothing happened when he had it.

For about 8 months nothing happened, no stalling,power cuts or jerking and about 3 weeks ago it all came back with a vengence.

Every time I drove my car it would stall and have huge power cuts when drivingat speeds of 30km/h to 110km/h.

Then I remembered something that the guy that installed my alarm and turbo timer told me, that my computer wiring had been hacked in Japan. Not all of it only a few wires.

I thougt to myself it cant hurt to take a look..... And there it was 2 wires joined together with no tape around them. Alittle test started the car and touched the wires together and the car stopped. Start her up again the same thing.

So I soldered the wires up and taped them up and not a single problem for about 2 weeks.

It might be related to your problems so I thought it was worth the mention:)

cheers Jon

[Craved]

thanks for the input Jon, where abouts was the cut in the wiring? so we can also have a look!

[Grey skys]

It was cut at the loom on the computer

[Craved]

cheers! mine is ok.. had the ECU out recently

[B-Man]

Add me to the list now that I have gone from Microtech LT12 to PFC & AFM......

It's damn annoying - and looks like there is no clear fix to this issue - looks like it depends.,

* AAC

* Fuel pump ground

* AFM

* BOV

* Tune

* etc

Hmmmmmmm

[Steve]

Well my car is idling fine - I found a few culprits.

Vacuum leaks - the main one was the PCV valve - blocked it off

AFM - the mesh does serve a purpose. I ended up getting a strainer from the warehouse for $2.50, cut the mesh to size. This stops air reverting back up the AFM and playing havoc with the signal.

Lastly, and this was the hardest to find - the ECU plug. I noticed that the idle only seemed erratic, intermittantly when the car was cold. By using the sensor check on the power fc hand controller I noticed slight fluctuations of about 0.15Vmax on the AFM - initially I thought it was the CAI, but when a friend asked to borrow my hand controller I checked the plug and it was sitting out slightly on one side by a couple of mm when I gave it a push. Bingo idle perfect ALL the time. Enrico Palazzo had a problem with this a while back, kept coming up with afm fault codes and the car wouldnt idle right - turned out to be his ecu plug too.

Anyway B-man, use the sensor check, make sure everything is set where it should be ie, voltages in range. Good luck.

[the phantom]

I also had an issue with the ECU plug with an intermittant connection to the AAC pin no less!!.

Another thing...I have tested two different Power FC's with a CRO and had a look at the AAC waveform in comparison to the standard ECU. Quite suprisingly, the PFC idle control strategy on throttle lift off is INFERIOR to the standard ECU....

Standard ECU: When you open the throttle, the AAC valve opens in unison. When you release suddenly, the AAC valve SLOWLY closes back towards the idle target value.

POWER FC: same except when you release the throttle, the AAC valve closes to the idle target value INSTANTLY. This obviously causes a much larger reversion effect as the turbo cant repond instantly to changes due to its inherent rotational inertia, a situation made worse with bigger turbos. Suddenly the now excess air has nowhere to go except out the AFM. Contrast that with the stock ECU which allows an additional bleed path through the throttle, thus reducing the impact.

My solution: Install a dashpot on the throttle linkage to slowly close the throttle when you lift off. This has been extremely effective, to the point that I can say my issues are solved. Whats more, the dashpot only cost $5 from the local UPullIt. An veritable automotive nirvana when you're on the prowl for some odd tidbit and want to take your time to look around for something suitable from different manufacturers. My dashpot came out of a Mazda 121....

[B-Man]

Phantom - I read most of your thread on SDU and am amazed at your knowledge. Cheers

What is a dashpot ???

[the phantom]

Hey B-Man,

A dashpot is a mechanical damping device like a shock absorber. The type I mean here usually resembles a vacuum diaphragm, with a rod comming out the end. The rod is free to move out one way, but when you try to push it back in, it resists. Its pretty much like a 90/10 shock except its more like 100/0. The idea is to position the unit so some part of the throttle linkage pushes against the rod just before throttle closure. When you lift off the throttle, the linkage hits the rod, stopping the throttle from instantly hitting the stop screw, and only allowing it to slowly creap towards closed over maybe a couple of seconds....just long enough for the reversion to have subsided.

[B-Man]

Cool - thanks, I get the drift now - Your's was off a Mazda 121 - OK, I'll be going hunting soon -

I guess this the exact same thing as what I am doing now anyway - just letting the reves come down with engine in gear - then slowly taling my foot off the clutch......

Right - off to wreckers to find a dashpot...........

[The Dan]

Many seem to have problems with stalling and aftermarket bov's. Particularly on 33's it seems? Mine does it on occasion since installing a new bov. Doesnt bother me too much, once a week i can put up with.  

Perhaps boostmeister had more chronic issues. Many thanks for the tip though!

Red17

This might be attributed to the fact that you are dispelling air that has been measured from the AFM thus car runs rich but less air per fuel ratio. Plus AAC valve is doey and engine drops out. I'm gonna try the earth thing. Can't hurt and sounds like it makes sense.

[Oosh]

:D

Well, I had to take my balls in my hands and do it myself. After I regained the strength in my arms I got to work.

Cut the black wire and earthed it out under one of the screws holding down the metal plate with the arrow on top.

Started car and idle was still a little up and down after I gassing car while it was in neutral.

Took it for a real thrashing on a private road, a REAL thrashing, then drove it around off boost for 10-15mins and came home.

Purrs like a kitten, idle steady. Now I'm going out to give the AAC valve a carby cleaner shower and wave goodbye to this embarrasing problem hopefully forever.!

Just did the same, immediately better on idle, but the car wasn't 100% cold so the real test will be when i get home and start her up tonight!

Will keep you all posted... oh i apparently have newish Denso pump (haven't checked) so hopefully running it 100% wont kill it.