D3 Start issues with a twist (maybe??)

[swiftnets]

Hi everyone,

We have a Diesel D3 that isn't starting the first time it is turned over (most of the time) but will start on perhaps the 3rd or 4th try, then runs fine.

Occasionally it will start first go.

Background in the last few weeks is that our local mechanic replaced the oil pump for an oil leak. They are not specialists but did work with assistance from one of the independents here in Adelaide.

I get no faults on the Gap tool, appears to show plenty of fuel pressure while cranking and once it starts it runs really well.

One thing to note is that it wasn't immediately after the Mechanic visit, the starting issue appeared a day or so after. It started fine that morning and then after a site visit it just didn't start.

I initially thought it might be the FOB not deactivating the immobilizer, but both the sets of keys are experiencing the issue and I have been advised that wouldn't be the case. I wondered if it was fuel, perhaps the low pressure pump, but then once running it is fine and the pressure looks good.

Given it is a Diesel, it has oxygen and compression, the only variable is fuel. The local mechanic had another look at it yesterday and I asked him about the injectors, he confirmed they appeared to be getting pulses so I expect they would be injecting.

One of the team at TRS was not really able to suggest anything, he hadn't heard of it happening before. Just wondering if anyone has a suggestion as to what would impact this and how I would test and resolve it?

As an aside, can anyone tell me where on the coolant tank the level should be, I haven't been able to find a definite answer in my searches.

Thanks all
Michael
Adelaide

[josh.huber]

I would start by testing the glowplugs

[josh.huber]

I've never seen a D3 tank, but the D4 has two lines that mark the cold and hot levels

[LuckyLes]

Hi,
I'd be checking glow plugs first up. Check that one or more hasn't been un plugged or the loom damaged somehow.
Good luck
LuckyLes

[swiftnets]

Issue occurs 10 minutes after turning off the engine, doesn't matter if it is cold or hot.

Not sure if the glow plugs would affect that would they?

[Porker]

Have you checked all of your fuel line connections as it may be leaking fuel or sucking in a small amount of air into the system and it has to re-prime the fuel system.

[josh.huber]

Crank angle sensor can cause that.. No fault code either

[swiftnets]

Crank angle sensor can cause that.. No fault code either

Where is the Crank Angle Sensor located?

Is it near where the flywheel would be secured while replacing the oil pump?

[Eric SDV6SE]

I'd be taking it to a diesel fuel injection specialist and getting them to do a leak down test of the injectors, you'll probably find that whilst they are getting pulses, they are probably reaching the limits of their flow range ( I.e they are wearing out). Reason for poor starting is that they cannot atomise the fuel enough to create combustion. As you said, you have o2cand pressure, so fuel being the only variable, and if pressure from thr lp and hp pump is good, it has to be on the fuel rail, and most likely injectors. The pcv in the fuel rail can stick too, but that usually gives a code, so I'm leaning toward your injectors being the culprit. If they are, best bet is to replace all 6, don't forget you'll need new fuel connection pipes and crush washers too, usually provided with the new injectors.

[Graeme]

Where is the Crank Angle Sensor located?

Is it near where the flywheel would be secured while replacing the oil pump?
It's located on the left side on the TDV6.

Crank angle sensors can deteriorate with age. Monitor its live values as the engine is cranked to see the stability or otherwise of the signal produced.

[DiscoJeffster]

It’s called a crank position sensor on our engines (CPS) and yes, they’re temp sensitive and can cause these issues. It’s a ***** to change with access behind the turbo and drive shafts. It a a four hour job to get to, but doable without body or engine removal. I had mine done and all my weird start issues were solved.

[josh.huber]

I'd be taking it to a diesel fuel injection specialist and getting them to do a leak down test of the injectors, you'll probably find that whilst they are getting pulses, they are probably reaching the limits of their flow range ( I.e they are wearing out). Reason for poor starting is that they cannot atomise the fuel enough to create combustion. As you said, you have o2cand pressure, so fuel being the only variable, and if pressure from thr lp and hp pump is good, it has to be on the fuel rail, and most likely injectors. The pcv in the fuel rail can stick too, but that usually gives a code, so I'm leaning toward your injectors being the culprit. If they are, best bet is to replace all 6, don't forget you'll need new fuel connection pipes and crush washers too, usually provided with the new injectors.

To be that bad you would have low rail pressure while cranking.

Engine Starting
During starting, the fuel rail pressure must be at least 150 bar. Should the pressure be below this figure, the injectors will
not operate, resulting in the vehicle not starting

Which is about 2200psi before it'll fire injectors.

If they were not atomising the fuel you would have white smoke aswell

[swiftnets]

It's located on the left side on the TDV6.

Crank angle sensors can deteriorate with age. Monitor its live values as the engine is cranked to see the stability or otherwise of the signal produced.

Thanks for your comments everyone.

Is the live value visible through a Gap tool? I had a quick look this morning and couldn't see it listed.

[swiftnets]

To be that bad you would have low rail pressure while cranking.

Engine Starting
During starting, the fuel rail pressure must be at least 150 bar. Should the pressure be below this figure, the injectors will
not operate, resulting in the vehicle not starting

Which is about 2200psi before it'll fire injectors.

If they were not atomising the fuel you would have white smoke aswell

Thanks Josh,

If the pressure is too low, will the ECU not signal the injectors or do the injectors have the smarts to refuse?

I want to clarify as our mechanic advised he was seeing pulsing to the injectors.

Michael

[Graeme]

The Gap tool can show live values for the crankshaft position sensor.
The injectors don't have any smarts so seeing pulses means that they should be opening.

[josh.huber]

Thanks Josh,

If the pressure is too low, will the ECU not signal the injectors or do the injectors have the smarts to refuse?

I want to clarify as our mechanic advised he was seeing pulsing to the injectors.

Michael

Hey mate, as graham said if the ECU doesn't see enough pressure it won't signal the injectors. But if it isn't seeing crank position it also won't. It would be best to get a decent Auto eject to scope the crank position sensor. Especially if it plays up all the time. Doesn't have to be an LR expert. You can buy the manuals with the diagrams off this website. And they are a bargain.

[swiftnets]

The Gap tool can show live values for the crankshaft position sensor.
The injectors don't have any smarts so seeing pulses means that they should be opening.

I must be missing something, or my app is. I have looked through the complete list of live values and can't see one that says what I understand to be Crankshaft Position Sensor.

Thanks again for all the suggestions.

[Graeme]

Graph live values, engine, engine rpm, which is taken from the crankshaft position sensor. The rpm should increase in a couple of steps from turning over prior to firing, then the first fire increases the revs substantially then proper idle revs. Any dips or zero moments indicates a faulty sensor.

[josh.huber]

Be good to graph it against the rail pressure too

[josh.huber]

Be good to graph it against the rail pressure too

https://uploads.tapatalk-cdn.com/20220715/b0156bf56c81f14e5b6a2eff64bd0ed7.jpg

This was a hot start. I'll do a cold start later, but at least you should see engine speed before rail pressure

[swiftnets]

Graph live values, engine, engine rpm, which is taken from the crankshaft position sensor. The rpm should increase in a couple of steps from turning over prior to firing, then the first fire increases the revs substantially then proper idle revs. Any dips or zero moments indicates a faulty sensor.

:ohyes: huh, yeah. That makes perfect sense now ..... [bighmmm]

Yep, I regularly have engine RPM showing, where else would that value come from, I'll setup graphing next start.



Be good to graph it against the rail pressure too

Great suggestion, thank you.

[BradC]

I'll setup graphing next start.

As I found when chasing another issue, graph or display as few variables as possible when you are looking for short events. The more you have subscribed, the slower the update rate.

[Iherbst87]

Just another thought completely away from injectors etc. Maybe ask the mechanic who did the pump and belt if he removed the starter to lock the flywheel, or if he eyeballed it to line up the hole above the starter, then ask him if it is possible to recheck the timing marks once it is all lined up. These can be a pain if the timing is out, as with all cars. I have had many cars where they will run start fine when cold, but not when hot.

Also another question, when did you get fuel before or after the pump was done?

[swiftnets]

Hi team,

So I have 4 start processes on the logs and most of them do show the RPM intermittantly dropping to 0 along the way.

I take it from this discussion, that would suggest the sensor is either going or the connection is having issues?

I'm going to work on uploading the graphs some time today.

Thanks again, looks like I have some work to do [bighmmm]

Michael

[Graeme]

The sensors eventually fail, usually slowly getting worse so it's time to replace it. At least you now have proof rather than replacing it on a hunch or chasing other dead leads.

[DiscoJeffster]

I feel vindicated! Sorry to hear. Mine cost nearly a grand to get replaced as it’s a ***** to get to and they also found a split CV boot along the way that’s included in that cost.

[swiftnets]

Here are some of the log graphs

179852

179853

Sometimes it doesn't show the drop in the start sequences, I guess that happens too quickly then?

179854

Anyhow, other than access and time, does this job need any specialised tools?

Michael

[DiscoJeffster]

Not that I recall when I was looking to do mine. Mine was on the 3L but much the same. Access is from the LHS wheel arch with an access point in the bell housing. A lot of things in the way though to get to it so a bit of work involved.

[Graeme]

The sensor must be very close to not working at all!

Sorry, I can't advise on the required tools.

[loanrangie]

We replaced the sensor on my dads ML350 and it was the easiest job ever. Drove onto his ramp , bent a small shield out of the way, undid the 2 torx bolts, remove and replace, bolts done up and shield bent back - done in less than 5 mins.

[swiftnets]

Hi friendly forum peeps,

So, after a few weeks of struggling to start, I had the kids camping in Tailem Bend for their Pedal Prix event at the Bend Motor Sport Park.

Long story short, it properly stopped and wouldn't start at all. RAA was a big help getting the car and camper trailer home (I knew I upgraded our membership for a reason) and after another review by the mechanic who replaced the oil pump we sent the car to Triumph Rover Spares.

As well as performing the EGR blank and tune they advised the issue was the valve timing was out!!!

Anyway, the Disco now runs beautifully, but I have no tax return left.

Thanks for your responses.

Michael

[Eric SDV6SE]

You got a tax return??