Sudden loss of revs when stopping? 1HZ 100 Series

[mike_nofx]

Hey all, got a little problem with my 100 series. 1HZ with turbo

When stopping (eg pulling up to a set of lights or stop sign etc) Just before coming to a complete stop, for a split second the engines revs will die right off. It sounds like it may stall, but it only happes for about half a second or less. After that the engine will idle normally.

This has only started happening in the last 2 weeks or so. The problem doesnt happen all the time, at first it happened once every 2-3 days, and gradually started happening more often. Now it happens maybe once every 4-5 stops.

All other driving seems normal. It idles fine, it will cruise along fine, and it doesnt feel like there is any loss of power.

Any ideas?

Thanks
Mike

[SIMMO84]

Maybe vacume? does a light come on the dash when it happens? im kinda thinkin if it looses vacume and the air con idle up comes off the revs will drop. try starting the car and hold your foot down on the brake pedal ( the booster could be leaking) hope it makes sence

[5lefi60]

Hey man being diesel i am thinking more like fuel restriction some pumps have a small filter in side the inlet to the pump not sure on the cruiser but it may pay to check the filters ne way and it is the cheepest place to start just my thoughts cheers

[SIMMO84]

only does it when he is stopping if he had loss of power i would think fuel could even be an electrical problem.

[80's_delirious]

Maybe vacume? does a light come on the dash when it happens? im kinda thinkin if it looses vacume and the air con idle up comes off the revs will drop. try starting the car and hold your foot down on the brake pedal ( the booster could be leaking) hope it makes sence

diesels dont produce vaccum in the same way petrols do, diesel have no throttle in the intake and run a seperate vaccum pump for brakes etc

Id say fuel problem but not sure what

[SIMMO84]

Maybe vacume? does a light come on the dash when it happens? im kinda thinkin if it looses vacume and the air con idle up comes off the revs will drop. try starting the car and hold your foot down on the brake pedal ( the booster could be leaking) hope it makes sence

diesels dont produce vaccum in the same way petrols do, diesel have no throttle in the intake and run a seperate vaccum pump for brakes etc

Id say fuel problem but not sure what

thats why i said air con idle up

[Hidatid]

possibly air in fuel system

[SIMMO84]

possibly air in fuel system

that was my next question how much fuel in the tank?

[mike_nofx]

Thanks for the replies and ideas. I will check it out.

Fuel filter was replaced 13,000km ago.
There is 1/3 of a tank left in main tank (one in use at the moment) and sub is full. Neither have been run dry.

Come to think of it, its only really happened on this batch of fuel. Could bad fuel cause this problem?

Took it for a short spin this arvo, and it didnt do it once. So its definately an intermittent problem.

I'll check my manual when i get a chance on how to bleed fuel system and i'll do that anyway. (never done it before)

Thanks again
Mike

[BENOLUX]

i have to agree with Hidatid, check for air. mine did the same thing the other month, was driving along nicely then it went down to 300rpm and was on the brink of stall then it stalled in peak hour traffic. i got it started and drove it to sidewalk on 300rpm.
i turned the manual idle up up, lux has one and then about 30 seconds later it must have got fuel and it revved right up and was fine after that, fuel filter was only about 4000 old and i do loose pressure on hills sometimes so makes me think there is a air leak, so just check for air as well.

[5lefi60]

like i said there is a small filter/screen in the inlet to the pump and if it starves the pump at low eng speed it will cause it to starve the transfer pump there for airating the fuel and lowering the transfer pressure it manages the fuel pump timing and amount of fuel delivered as the pump operates it will cause it to stumble and lower the rpm as it caint deliver the amount of fuel required for the engine idle speed it may operate normal at engine speed as it is higher and can draw it through the filter/screen just some thing that aint hard 2 check call ya local diesel pump center and ask it your model is fited with this small filter/screen at the pump inlet or in a banjo fitting in a line cheers

[Chucky]

Does it only happen when the AC is on?

The 1HZ has a sensor that shuts down the ac when the water temp hits a cetain temp.
Maybe a earth could cause this.

[Dzltec]

There is no filter in the inlet of this pump. Does it slowly die down or just stop at the low revs and come up? Air in system may be the biggest culprit. Any other loads on the engine besides a/c? How many kms on the vehicle. If you have a sub tank, does it do it on that?




Andy

[mike_nofx]

It happens just before the vehicle stops, Just as i put the clutch in to stop (but while still rolling)

Its very quick. Like i was saying when the revs drop out, its only 0.5 of a second probaby even less before its back up and idling fine.

I guess it kind of feels like for that 0.5 of a sec, the ignition key is turned off and immediately back on. Probably best way to describe it.


It still doesnt do it every single time i stop. Happens with AC on or off. With AC on it feels like it happens more often, could be coincidence. (I havent done enough 'testing' yet!) And no other loads bar AC.

Yet to see if Sub Tank makes a difference, but why should it? Could air be in the main tank system but not the sub?

195,000km on it.

Still havent had a chance to try bleed air from fuel system. Is it a simple procedure?

Thanks for all the help, really do appreciate it.

Mike

[SIMMO84]

You wont achive anything by bleeding it now. if it starts there is no air in there. Rotary pumps are good at bleeding themselves.

[oldmate]

You wont achive anything by bleeding it now. if it starts there is no air in there. Rotary pumps are good at bleeding themselves.

true. there isn't any bleeding system on a 1hz. the pump basically recirculates fuel from the tank effectively bleeding it. You only need to prime it with the pump on top of the filter when you've disconnected a fuel line somewhere there.

[oldmate]

Thanks for the replies and ideas. I will check it out.

Fuel filter was replaced 13,000km ago.
There is 1/3 of a tank left in main tank (one in use at the moment) and sub is full. Neither have been run dry.

Come to think of it, its only really happened on this batch of fuel. Could bad fuel cause this problem?

Took it for a short spin this arvo, and it didnt do it once. So its definately an intermittent problem.

I'll check my manual when i get a chance on how to bleed fuel system and i'll do that anyway. (never done it before)

Thanks again
Mike

what does the engine normally idle at? should be around 650. You should change the filter too, that could very well be the problem