Glow plug issue ?

[JohnTF]

The glow plug system symptom is that long crank - appears to be from glow plugs not coming on normal length of time for cold starts .
I've many diesels and lots of testing & repairs .
The weather here is between 30 - 50* F .
The long crank is only after sitting typically overnight / or long periods maybe half day + .
Then the glow plug light comes on for only a few seconds , even at around 30*F .
I tried disconnecting the coolant temp sensor and the glow plug comes on for , what I would call normal length of time for cooler temps and starts much easier / normal .
Put in a new sensor / no change , tested the 2 circuits [ 4 pins , figuring 2 circuits ] and the Ohms were 20K & about 19K , so should have measured 1st - and not bought a new sensor
So now my conclusion is that the engine control system does not seem ? to operate correctly with the glow plugs / temp sensor ?
Any ideas ?
So for easy starting , disconnecting sensor - then lights the check-engine-light ;(
Checked the injection timing and it varies between 42 - 43 , later I might move it to a couple degrees above / into the advanced maybe something like 46 - 47 ?

 

[JohnTF]

Not an answer to my own question , just more thinking through , need to find wiring color codes , possible loss of signal to controller - since the glow plug system acts like it is always above coming on temp , thought I saw 40*F & below tells controler to activate glow plugs .

 

[Sauaciden]

Check Coolant Temp Sensor there are two sensors inside that one. One sensor send data to ecu and another one to cluster. It is possible that engine side sensor is reporting higher temp than it actually is. Also check outside temp sensor mounted on front bumper bracket

 

[Mozambiquer]

I'm going to go out on a limb and say that your long crank probably isn't the glow plugs, but something like timing or fuel draining back. Mine doesn't come on for a long time when I start and it's not super cold. That's the point of the coolant temp sensor, if it doesn't need as much, it won't turn on as long. But timing being off could mess with that. If it's overly retarded, you'll have a harder start when it's cool, but being that you said it only does it after sitting a bit, I'd say you probably have a leak that is allowing fuel to bleed back.

 

[JohnTF]

You guys missed a few things - sensor replaced , old one sensor tested ok - timing only retarded 1-2* .
As soon as I disconnect temp sensor - glow plugs come on for longer and starts right away , that wouldn't affect fuel leak / drainback issue .
So seems like it can only be the lack of glow plugs not being turned on . with good sensor ?
Thanks for looking .
Like above , at this time it seems maybe wiring connection to controller , but then it wouldn't respond to disconnecting sensor , so still does not make sense yet ?

 

[Vince Waldon]

Yup, a TDI in good health will start just fine with NO glow plugs at those temperatures.

If it's starting better by fooling the glow plugs into running for 30 seconds first chances are something is going on which a bit of extra heat is covering for.

One example: a bit of timing advance can make a big difference with starts at around the freezing mark.

 

[JohnTF]

It hasn't been warm enough over night to not use glow plugs 40* & under , mostly 30s at night .

This may be 2 issues , the long crack .
And the glow plugs not coming on without disconnecting the sensor .

Disconnecting the sensor just helps the make the long crank go away .

 

[wonneber]

When you shut the car off for the night look at the clear fuel hose attached to the fuel filter.
There should be a bubble at the high point.
In the morning look again before starting it.
Is it longer?
If so the fuel is draining back to the tank and had to be sucked back to pump.

Have you changed the small hoses that run between the injectors?
Also the rubber cap on the last injector?
Could be letting air in also.

 

[JohnTF]

A lot of the lines have been change , including the clear one to watch for bubbles - doggy dew .
Plan on getting new clear fuel line - so I can watch for bubbles .

 

[Tdijarhead]

If you hiave no glow plug code per vcds then your glow plug system is operating fine. I would lean to an air leak as has been mentioned, retarded timing or a dying starter that’s not spinning the engine fast enough, or any combination of these three. When was the last fuel filter change?

 

[JesseALH]

The glow plug system symptom is that long crank - appears to be from glow plugs not coming on normal length of time for cold starts .
I've many diesels and lots of testing & repairs .
The weather here is between 30 - 50* F .
The long crank is only after sitting typically overnight / or long periods maybe half day + .
Then the glow plug light comes on for only a few seconds , even at around 30*F .
I tried disconnecting the coolant temp sensor and the glow plug comes on for , what I would call normal length of time for cooler temps and starts much easier / normal .
Put in a new sensor / no change , tested the 2 circuits [ 4 pins , figuring 2 circuits ] and the Ohms were 20K & about 19K , so should have measured 1st - and not bought a new sensor
So now my conclusion is that the engine control system does not seem ? to operate correctly with the glow plugs / temp sensor ?
Any ideas ?
So for easy starting , disconnecting sensor - then lights the check-engine-light ;(
Checked the injection timing and it varies between 42 - 43 , later I might move it to a couple degrees above / into the advanced maybe something like 46 - 47 ?

Did you ever figure out why your glow plugs were not coming on? or find any problems? thx Jesse

 

[JohnTF]

Well I did adjust the timing , a little high about 62* , and the temps were too warm for glow plugs , and with fuel lines replaced with typical black rubber vs. the one clear to watch for bubbles .
Now the temps are back down to a range where glow plugs operate , the car starts faster .
Changing the timing made a big difference , but still a slightly long starts , ruff idle for a minute or so , with blue-gray smoke .
So my conclusion at this time is that there is still an issue , and I have a couple of needed adjustments done , but still need to find any remaining issues .
Without having a shop / garage & lost a lot of tools in a fire , progress is slow as a result .
And with winter coming up and this being a CA car / no rust , plan is to park for the winter - before they start salting the roads .

 

[Diesel Fumes]

For how long does the car smoke after it starts? I'm having the same issues and have no luck. It's good fun finding the issues though

 

[JohnTF]

" ruff idle for a minute or so , with blue-gray smoke "
The smoke part is less than the ruff idle - just a few seconds .

 

[Diesel Fumes]

Yea that amount of smoke is not a concern. Air can get in through various seals in the injection pump if I recall correctly. It's a rabbit hole.

Does the car have a frost heater/zero start? Probably not if it's a Cali car. But worth asking. If it does try plugging that in and let coolant get warm and try starting. If it starts well with warm coolant but also after having sit for a long period of time, perhaps it isn't an air in fuel system problem.

If you're not going to drive the car much, if at all, in the winter then maybe it's not going to cause you any issues?

 

[JohnTF]

I found a NIB but 2nd frost / engine heater , but haven't installed yet , part of the reason is that it was for a manual , I have an AT , but also bought most of the parts for a MT swap .
Have not found info on what the difference is , seems to me that either would install to the same connections lower oil filter and side of head ?
Most of my many decades of diesel truck , car , heavy equipment & cold starting is solved more by battery heaters , unless very cold - not so much in MN the last few decades , but AK need both & more .
The previous owner chased this issue , apparently gave up before selling to me , lots of hoses replaced , fuel pump seal kit - just one or two of the seals used , replaced injectors - got old ones with car not sure which ones were installed [ I suspect original ] .
I may get a battery-blanket , but like with my other cars / trucks - I watch for the overnight temps and if getting close to 0* F or colder , just bring the battery inside to keep warm , one of these days I may get the battery-blanket , before the fire [ lost $250,000 tools & stuff ] a had at least a couple on hand .
I would be more on top of this issue if many problems did not make this more of an issue - not having a shop / lift , tools , disability - on the job injuries , lack of income , dang where to stop

 

[Diesel Fumes]

The Automatics have an extra coolant hose I think. I don't really know the difference. I have an 5 speed swapped alh with a zerostart. It broke so I installed one from a manual. It worked but it's a tighter fit. They both have one hose in and one hose out. But they also made a few different versions over the years.

As for cold starts in the winter. I've always had my cars plugged in and that solves most issues since a warm engine will obviously start easier than one with cold oil, coolant etc. I did have a long crank problem that seemed to go away when I changed the fuel filter (and both O-rings On the t fitting). I could be wrong, but long cranks and hard starting sounds like air in fuel system.. Not sure what else could cause it. Especially if it starts quickly if the engine was running like 5 minutes previous or something.