intermittent shudder at idle - carton reward

[Mrmal]

Check your EGR cooler. The EGR valve only opens above 15c IAT and when EGT is over 84c. If there was a slight leak of coolant in the cooler the engine will produce that momentary miss as the EGR opens and the water/vapour is sucked/blown in, blanking plate at the head will still allow any coolant leaking to enter the EGR valve as either steam or water. Saw this in a Hilux that had miss at idle and had some interesting vibrations, they did a full EGR delete (took the cooler off completely) and when they did the delete the miss went away. Only thing they could put it down to was a small leak in the cooler.

Easy to test - fit a full blank plate to the EGR valve and not the head. You will get a P0400 code but if the shudder goes away you may have a leak in the cooler.

[Talktheroo]

x2, and becoming more common.



The Roo.

[Mrmal]

When they finally sort out the full blank set up on the EGR - I reckon that cooler will make an awesome camp shower heater......... clean the egr out, a couple of tigged nipples and pump water through it..... 87 degree shower water..... nice

[keleher]

Check your EGR cooler. The EGR valve only opens above 15c IAT and when EGT is over 84c. If there was a slight leak of coolant in the cooler the engine will produce that momentary miss as the EGR opens and the water/vapour is sucked/blown in, blanking plate at the head will still allow any coolant leaking to enter the EGR valve as either steam or water. Saw this in a Hilux that had miss at idle and had some interesting vibrations, they did a full EGR delete (took the cooler off completely) and when they did the delete the miss went away. Only thing they could put it down to was a small leak in the cooler.

Easy to test - fit a full blank plate to the EGR valve and not the head. You will get a P0400 code but if the shudder goes away you may have a leak in the cooler.

No worries will give it a go. I had the egr off a few weeks ago to clean it again but there wasn't much build up or crusty Ness coolant usually leaves? Would this relate to the brakes in any way? It's only when I have my foot on the brake pedal it happens.
I got the torque app last night and had it on today. The egr was opening and closing like normal but the shudder didn't happen.
I noticed my maf reads .26 with the car off but the workshop manual says it should be .42. It's clean and reads within the ranges its suppose to at idle and 2000 Rev could this be the issue?

[sharp018]

Just an opinion check your timing make sure it's lined up sounds like it's outta time.

[keleher]

Had the timing belt replaced. It's really intermittent. Might happen once every 90 mins of driving time. Sometimes it will do it at 2 sets of lights or give ways but usually one. It wouldn't phase me but it feels like the engine is about to bust through the bonnet. If it was timing it would happen all the time wouldn't it?

[fourby4diesel]

If anyone can solve this I will have a carton of cold ones delivered to your door as it is doing my head in and cost me a fair bit to not solve it. Car has a very intermittent shudder like a D.D.D....D.D.D....at idle where the whole cab gets a jolt through it but I can't seem to make it happen when I have it plugged into techstream or at various mechanics or diesel specialists so they tell me she runs great. Some details:

- It started a few months ago and a swear the shudder is getting more intense
- It only happens while stationary and my foot is on the brake, if i take my foot off the brake it subsides and if i tap the accelerator or let the clutch pinch slightly it goes away. I have tested all vacuum lines and brake booster with a vacuum gun and no leaks.
- Revs don't drop
- It mostly happens after coming off the freeway but has done it in start stop heavy traffic
- It only happens when at operating temp and been driven for at least 20 mins or so
- It doesn't do it in cool weather (<15 °C) but seems to happen more frequently the warmer it is.
- No codes
- All readings in techsteam are in spec but I cant get it to play up while connected
- Injectors are all under +/-1
- Runs great when moving, no power loss
- No smoke or knock

Things I've done to no avail:
SCV
Timing belt
fuel and air filter
fuel leak test
cleaned maf
cleaned egr again
engine mounts
Serpentine belt, pulleys, tensioner
harmonic balance
alternator

Anyone got any ideas?

Some vehicle details please?
Year? Klm's?

[keleher]

2010 just hit 140k manual diesel

[Mrmal]

Check your EGR cooler. The EGR valve only opens above 15c IAT and when EGT is over 84c. If there was a slight leak of coolant in the cooler the engine will produce that momentary miss as the EGR opens and the water/vapour is sucked/blown in, blanking plate at the head will still allow any coolant leaking to enter the EGR valve as either steam or water. Saw this in a Hilux that had miss at idle and had some interesting vibrations, they did a full EGR delete (took the cooler off completely) and when they did the delete the miss went away. Only thing they could put it down to was a small leak in the cooler.

Easy to test - fit a full blank plate to the EGR valve and not the head. You will get a P0400 code but if the shudder goes away you may have a leak in the cooler.

No worries will give it a go. I had the egr off a few weeks ago to clean it again but there wasn't much build up or crusty Ness coolant usually leaves? Would this relate to the brakes in any way? It's only when I have my foot on the brake pedal it happens.
I got the torque app last night and had it on today. The egr was opening and closing like normal but the shudder didn't happen.
I noticed my maf reads .26 with the car off but the workshop manual says it should be .42. It's clean and reads within the ranges its suppose to at idle and 2000 Rev could this be the issue?

A small coolant leak into the EGR stream is likely to vaporise at the EGT temp so you may not see it. You have me stumped

[fourby4diesel]

2010 just hit 140k manual diesel

It's always very difficult to do a remote diagnostic. It can be hard when the vehicle is in front of you.

My idea, Injectors.

[keleher]

Fairly certain it's an intermittent short now that only happens when the engine bay heats up enough. It's linked to the brake switch some how and making the engine go spastic. now to track the bloody thing down

[sharp018]

yeah if it was timing it would be knocking even if its a slight bit out is enough to make car shake

But now you said after 90 minutes and the engine bay being hot

Are you getting any codes come up? Not all codes make a light on your dash

[keleher]

Used tech stream and there was an error for a short in one of the speed sensors. Since I fixed that 2 weeks ago it shuddered violently once the following day and now when it happens it is extremly faint and doesn't happen as often. Not sure if it was related or because it has been colder lately.

[keleher]

Well it is definitely related to ambient/engine bay temp. It was a bit warmer yesterday and sure enough as I got off the highway it happened (about 25 mins at 100km/h) and the cab was shuddering again. I put my front bash plate back on also and this seemed to make it worse/occur at every stop light or intersection after I got off the freeway and when it was warm the car seemed to vibrate more (ramhead on snorkel shaking a lot). It is slightly different now, before it was in pulses now it is a constant shudder after it starts and is there with or without my foot on the brake pedal so now I’m not sure they are linked now. This morning though it ran smooth as without shuddering and the ramhead on snorkel didn’t shake around. With torque app
EGR Commanded
Engine Coolant Temperature
Engine RPM
Fuel Rail Pressure
Intake Air Temperature
Intake Manifold Pressure
Mass Air Flow Rate
Voltage
Don’t fluctuate and are the same as when it is running smoothly. I tested the camshaft and crankshaft sensors and they are within spec. Anyone recommend anything else to check? It feels like something is coming out of balance, could it be the cooling fan? All the pulleys, belts, harmonic balance and tensioners are new. I have ordered an EGR delete to see what that does.

[Mrmal]

Harmonic balancer is about all I can think at this point. Being at idle maybe higher up the revs it runs straight - can you get a dial indicator onto it? I know you have replaced it.

The only thing is - what are your intake and manifold charge temps like - fluctuating readings here affect injection timing and volume. One should be around ambient and the other should be a lot higher.

Mal

[keleher]

Harmonic balancer is about all I can think at this point. Being at idle maybe higher up the revs it runs straight - can you get a dial indicator onto it? I know you have replaced it.

The only thing is - what are your intake and manifold charge temps like - fluctuating readings here affect injection timing and volume. One should be around ambient and the other should be a lot higher.

Mal

Looking at the Harmonic balance when it happens it looks like it isn't bouncing around or moving at all but ill see what I can do about getting a dial on it.
The torque app only does intake temp which matches ambient but I’ll try get it to play up when I have it plugged techstream to get the intercooler temp and see what that is doing.

[hippo]

as mention before, check harmonic balance bolt and pin might be lose. happen to me with a broken pin which created all sort of strange idle issue.

[keleher]

as mention before, check harmonic balance bolt and pin might be lose. happen to me with a broken pin which created all sort of strange idle issue.

what pin do you mean bud? The key?
will check out the bolt tonight

[hippo]

inside the balance. sorry key or rectangle shaft that mount between the balancer and crank shaft.

[keleher]

inside the balance. sorry key or rectangle shaft that mount between the balancer and crank shaft.

cheers bud, what happened with yours did the key snap? and what was it doing?
Had a look last night and the bolt seems tight but will need something to hold the pully to get the bolt off and check the key.