18 replies to this topic

[rajenkins]

Hi,

I've been catching up with maintenance over the weekend; the thermostat was on its way out, rattly swirl plates in the manifold, EGR valve errors etc.

 

Having done those and thoroughly cleaned the oil separator plate & PCV valve, I got it all back together yesterday evening - and it won't run properly.

 

 

It won't start without giving it some extra throttle and its running almost in bursts or hunting. Most of the time it won't tick over, it just cuts out.

The one time I get it to tick over for a while, the idle was hunting like a old diesel with a sick governor...

 

I've just pulled the plugs to see of there is any obvious sign of certain cylinders missing. They are all very black and sooty, it looks like it's been running on crude oil never mind petrol.

(There was quite a bit of oil in the manifold though, so I'm thinking the PCV valve may have been acting up for some time & that could be partially responsible).

 

 

The battery was disconnected for several days the first time, I've also disconnected it again overnight and shorted the leads for a while before reconnecting it, in case it was some corrupt data retained in the ECU. No difference.

 

Looking at diagnostic info, there are no faults of any type stored.

 

 

Is there any one sensor fault / connection that would cause this type of problem? 

 

 

ANY ideas at all appreciated, I'm getting desperate and my customers are going to be getting upset soon, I'm supposed to be repairing machines!

 

Thanks,

Robert.

 

[paul05149]

Need to check all Electrical connections that have been disturbed are sound and any components that have gaskets are airtight for a start. PCV hose all connected OK and Knock sensor on engine block is still Ok.
Need to go back to basics to fault find this as you have played with quite a few different parts getting amongst it.

Paul m.

[FRANZ]

Is your TMAP sensor connected up?

[rajenkins]

Hi,

after looking through the possible symptoms for different sensors etc. I thought it could be a fault in the TMAP sensor.

Just replaced that - no change.

 

With it trying to tick over, I've tried removing the oil filler cap to make sure the PCV valve was not letting air through, it had no effect. Removing a small vacuum pipe from the inlet manifold also had no effect.

 

Pulling out the large brake servo vacuum pipe allows it to tickover smoothly! I think that rules out an air leak as the cause of the problem, but I'm out of ideas as to a possible cause.

 

I can't see any problems with any connectors but there is no easy way to tell if there is a faulty connection or cracked wire somewhere.

 

 

Paul m - do you know what the symptoms of a bad or disconnected knock sensor would be? Is that not something that would produce a fault code?

 

Thanks, Robert.

[tomskys]

if you took the swirl plates and metal rod out,did you seal the holes up where the rod comes out of??? if not will run like crap.also leave the 4 gasketts in the manifold.

Edited by tomskys, 30 May 2019 - 06:20 AM.

[tomskys]

make sure you have connected this hose or again will run like crap.https://www.justansw...oes-vacuum.html

[rajenkins]

Hi,

Yes, the actuator hole is bunged with a 8mm caphead screw (picked as the seal fits the thread and the head is too big to pull through) totally sealed and plugged with silicone gasket.

 

The swirl plate shells are back in place, with new gaskets. [Note the web page link in my sig].

 

 

I did not seal the internal drillings between the inlet ports, as after looking through a lot of other peoples posts on here the consensus appears to be that it has no effect.

 

I have three vacuum pipes on mine (and one spare, capped, takeoff point which looks to match the location in your link), for the swirl plate solenoid valve, brake servo and to a valve at the rear of the engine - the purge valve?.

 

 

As mentioned in my previous post, the problem is excess fuel, not excess air - removing the brake servo pipe and allowing extra air in smooths out the tickover.

 

I've just taken a short video of it trying to tickover, link here: 

 

The "sucking" noise is from the air bypass port in the throttle body, feeding the idle control valve as it's trying to stabilise the speed. 

 

 

It's getting to the point where the only thing I can think of is broken wire at a connector, from moving things around while extracting and replacing the manifold - though something totally stupid like a missed connector is always possible!

[tomskys]

have you doubled checked thar the pvc pipe behind the manifold has not come off??or come off the back of the manifold??make sure all connectors are back where they came off and that you havnt mixed them up, possible

[tomskys]

this sounds exactly like  yours.https://www.youtube....h?v=MsvQhqGCfag

Edited by tomskys, 30 May 2019 - 11:02 AM.

[FRANZ]

Excess fuel means the injector opening time is longer and this is due to the sensors measuring the air in the inlet manifold. As you know an engine is just an air pump when it is being cranked on the starter. If there was no fuel there would only be air moving. Sensors are TMAP already proved satisfatory, throttle position sensor is that closing properly? Can it be checked for resistance? The signal from the sensors go to the ECU and injector opening timing is based on this. But then again you say removing the brake servo pipe smooths out the tickover. Fuel and air must be more evenly matched then it is a tricky one.