2000 NB starting issue

Thanks in advance,
First I’m not a newbie here, I think I understand the ALH fairly well, I have 5 of them now.
My latest project is a 2000 5 speed NB that was supposed to be a simple TB and mods......... ended up with a lot more engine damage as first lead to believe .
PO mechanic set the TB wrong and had an incident, replaced the head when valve dropped ( didn’t know about this ) found this out after I didn’t like the way lifters looked.

I pulled the head and found head looked good but piston 1 &2 from tb side to have had an argument with a ball peened hammer and lost.
I did a height check on the pistons and found 1&2 to be below spec compared t 3&4 and the head gasket holes.

Long story short Franko6 got me squared away with a balanced set of pistons, and rods , new crank bearings and connecting rod bearings cap bolts etc.....
Honed cylinders ,new rings .

Engine fired perfectly runs great for that last few months as I get other things done on it, put about 20 miles on car and runs great till,about a month ago.....

Usually I start my cars and either let the idle till warmed up or drive them up and down my street just to get everything moving and up to temp and keep battery charged.
Last month had trouble starting car.......symptoms seemed to be lack of fuel.....cranks several times and finally fired up , then die......did this several times till everything was normal...
Let it sit for awhile and boom , fires right off......even better than my current driver.

Tried starting today and same symptom, fired than died to the point that it killed the battery........
Charged the battery for several hours and attempted it again.
It would start then die as if fuel starved.
When I finally did manage to get it started as soon as I let my foot off the accelerator car died.

I had to keep rpm to 1400 so car wouldn’t die, if cold car died , when warmed no problem with the idle.
Now with engine warmed up it’s as if it never happened.......very confused as not sure fuel related.

It’s not a 109 issue as GP light illuminates at each start attempt.
No codes are showing either.
Timing is slightly advanced.
ASV works as should.


It sometimes seem electrical......sometimes fuel....... very weird.

Sounds like a temp sensor right off. Could be the fuel temp, or the engine temp sensor.
Other thought is timing, however, sensor sounds more appropriate.
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Sometimes fuel sometimes electrical makes me think advance solenoid, which also makes me think temp sensor immediately.

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Timing is set slightly advance, mechanically it’s spot on.
Wouldn’t the fuel temp set a code?
No codes are being thrown.

I've seen crazier things, and from what I know fuel temp may not. I've read quite a few change the fuel temp sensor to fix cold start issues posts.
The great part is they're like $15 if I remember. I know the engine temp sensor doesn't necessarily throw a code.
https://www.idparts.com/fuel-temperature-sensor-a3b4a4-p-1142.html
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And order a seal kit if you want to get ahead of the inevitable fuel leak when you pop that cover off.

I don't know how the temp sensor fails but a MAF will often times read improperly before throwing a code...

Standby for the posts saying that they've worked on 1 trillion and never seen one fail and yours hasn't either...

Do you see your fuel temp when checking timing? Does it ever reach temp or change numerically

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WildChild80 said:

And order a seal kit if you want to get ahead of the inevitable fuel leak when you pop that cover off.

Do you see your fuel temp when checking timing? Does it ever reach temp or change numerically

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Click to expand...

Yes I will have to order another kit .
Need to check withVCDS, currently just had rotator cuff surgery so it will be awhile before I can connect.......unless if one of my kids come home to give me a hand ( no pun intended ).

To rule out temperature sensors, check when engine cold, then with engine hot. A bad sensor will show an out of range type setting. There are several sensors, found here.

csstevej said:

...
Wouldn’t the fuel temp set a code?
...

Click to expand...

Not necessarily. About the only thing the ECU could check on something like that is a sensor shorted or open, and it does that. The other would take a little more programming - check the fuel temp against the ambient air temp right at start up and screaming if the fuel is wildly different than the others. But it would need to also retain the memory of when the car last ran, and therefore would it be OK to be hotter or colder than the current level of the other temp sensors (coolant, ambient air temp).

Otherwise, get out your VCDS and see what the fuel temp is. If it reads way off first thing in the morning when it should be cold (i.e. same as ambient air temp) or very warm in those same conditions, then you'd be able to see for yourself that the sensor information doesn't make sense.

Good luck,

PH

Well was able to hook up VCDS to check fuel temp.
Upon first attempt to start could not connect to engine ecu......also no fault codes either.
Upon turning key car immediately fired then died.
Again no codes.
After several attempts was able to get engine ecu to connect..... engine fuel temp was ambient with no issues...... again car fired and immediately died....... again no codes and it’s not the immoblizer.
Been loosing connection to engine ecu randomly.
Only way car would start was if I pumped the pedal and when it fired keep the eng rpm about 1400 rpm when engine is cold......as soon as it drops below 1400 it dies.......once car is started and kept above 1400 run to warm up as soon as blue cool temp light is out I can let the rpm go to normal and runs great.
i can shut the car off and it fires right up with no issues.
I’ve run full auto,scan and no issues pop up.
When car up,to temp fuel temp is good, nothing erratic , I watched it the whole time engine was running till blue coolant temp light went out.
I’m starting to believe it’s elecrical but for the life of me cannot figure out what.

You said fuel temp, did you check the engine temp reading and did it match?

The reason I am curious about the temp sensor is that you have to give it fuel to keep it running. Makes me think it's not feeling for a cold start and it's just getting cold enough to need it.

I'm not saying it's not electrical, just looking at what I expect to happen. That being said my ecu died not to long ago and it was temp related. I never had issues connecting to it with VCDS, however, it's possible.

The old no start, you probably looked already though
http://forums.tdiclub.com/showthread.php?t=199398

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That's a good point, if it don't know it's cold...have you unplugged your temp sensor and tried to start?

So there are 2 sides of the temp sensor as I understand it...one for the gauge and one for the ECU.

At this point you gotta start with a methodical process and prove good parts and go from there, it's weird that you have intermittent connection issues though...now I've talked myself in a circle...

Could a crank sensor be this temp sensitive?

I might have 1 I could send you, it's probably good, from the Carnage found in the block, I'd say it worked...

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Anything is possible with a temperature dependent intermittent issue. Crank sensor doesn't seem as plausible, though you never know.

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eddieleephd said:

Anything is possible with a temperature dependent intermittent issue. Crank sensor doesn't seem as plausible, though you never know.

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Amen to that, the second you "know" it couldn't do "that" it seems to silently laugh at you.

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eddieleephd said:

You said fuel temp, did you check the engine temp reading and did it match.

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Click to expand...

Yes the engine temp read ambient then slowly climbed to 90C steadily.

WildChild80 said:

That's a good point, if it don't know it's cold...have you unplugged your temp sensor and tried to start?

So there are 2 sides of the temp sensor as I understand it...one for the gauge and one for the ECU.


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Click to expand...

I realize that it’s a dual sensor, fairly certain is a new one, not to say it cannot be bad. I will attempt to disconnect it tomorrow and see.

Again what throws me is it fires right up.........then immediately dies......

csstevej said:

I realize that it’s a dual sensor, fairly certain is a new one, not to say it cannot be bad. I will attempt to disconnect it tomorrow and see.



Again what throws me is it fires right up.........then immediately dies......

Click to expand...

If it's a new one was it an OEM and not aftermarket, I've never had to deal with either but some have had issues with the aftermarket ones.



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The other thought I get is the MAF sensor. If it's reading too much air, it wouldn't fuel as much either. Process of elimination, rule each out.

Immediately sounds like an IMMO however that would leave a code.
Next thought was fuel so what depicts fuel quantity. What is your IQ?
Finally we have air, is there an ASV partially open, or a Miss reading? I would check the position of the ASV and try unplugging the MAF.

Electrical issues aren't usually do consistent, unless they're temperature dependent. Then I would start looking at advance solenoid and other sensors. Also cam and crank sensors which I haven't mentioned because it does fire right up then die.

https://forums.tdiclub.com/showthread.php?t=238141

Intermittent and temperature dependent issues are most difficult to diagnose so good luck.

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Couple things come to mind:

Fuel starvation issues, which would generally work themselves out once the engine was started and running. Loss of fuel prime goes away once the engine is started, not likely to make it run, then die. Once it is started and running, even if for a couple seconds, it will stay running. So I do not think that is the problem at least on the side of fuel to the pump. The pump itself could still be a problem. You can do a simple test, crack one of the delivery pipes loose at one of the injectors and crank the engine. It should "spit" fuel out, a few inches at least. Just crack the line loose, union turned maybe two times, but the line still on the injector.

Next thing is, the ignition switch. Specifically, the connector shell where it plugs into the switch. On the NBs, for whatever reason, these can get a poor connection and draw too much current over that connection and melt the connector shell. You may have good "run" contact while cranking sometimes, but lose it when the key is released, or somewhere inbetween. Easy enough thing to check, pull the steering column clamshell covers off and have a look at the connector. Look for any burnt wires or if the shell is loose on the switch, unplug it and look on the inside at the terminals. If anything is bad, you'll need to make a new pigtail to repair it and splice it in.

Oil hammer , I’ve checked the ignition switch no defects noted.
Car immediately fires as soon as ignition is turned then dies, I’ve even wiggled the crap out while starting with no ill,effects.

Again it seems temp related, as soon as blue coolant temp light goes off the rpms can go to Normal.
Anything different and below 1400rpm instant shut down.

I’m throughly stumped.

Have you unplugged the MAF and tried to start it?
You said the temp sensors checked good through VCDS.
One of the basic resets is to pull the battery terminals and touch them together for 5 seconds to discharge remaining charge in the electronics.

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No I didn’t disconnect the MAF.
I have an egr delete and it’s tuned out with a Malone stage 3 tune.
There is a fixed valve in the fields that is constant on VCDS.

And MAF delete tune or not, the MAF should not cause this. The engine would still start and run with the MAF unplugged.

Temp sensors (intake air, fuel, and coolant) should also not prohibit the engine from starting and running. There is very little the ALH "needs" to run. It needs a signal from the crank sensor, the quantity adjuster in the pump needs to work at least enough to make idle, and the stop solenoid on the top of t he pump needs to be energized. I do not even think the lift sensor needs to work for the engine to at least start.

So let's go back to the basic fuel delivery, since that is at its heart still a purely mechanical process, aside from the stop solenoid.

You should be able to attach a test light to the top of that solenoid. Depending on what you have, this may require a helper, since the engine will normally shake a lot during cranking, but you need to see if 12v remains on that solenoid the entire time the engine is cranking. We can assume the ground side is OK, because if the starter is cranking the engine normally, that will be the biggest draw, and the starter is bolted to the transmission, which is bolted to the engine, and the pump is bolted to the bracket which is also bolted to the engine... so we can assume the solenoid's ground is good.

If you have 12v there, that never goes away so long as the key is ON or the engine is cranking, then we go back to cracking those delivery pipes loose and see if you get an actual delivery of fuel.

You may just have a tooefed pump. I have seen it before, they get some poor fuel over time and the suction pump gets trashed and it just cannot keep the actual injection pump primed. Your problem, from you original description, sounded like it first manifested as a long crank time and then became this. If everything else checks out, the only thing left is the pump itself (this of course assumed the engine proper is healthy, which it probably is).

And of course (you may have already done this) make sure the fuel is indeed diesel and not some mystery mix of gasoline and who-knows-what.

csstevej said:

Oil hammer , I’ve checked the ignition switch no defects noted.
Car immediately fires as soon as ignition is turned then dies, I’ve even wiggled the crap out while starting with no ill,effects.

Again it seems temp related, as soon as blue coolant temp light goes off the rpms can go to Normal.
Anything different and below 1400rpm instant shut down.

I’m throughly stumped.

Click to expand...

Lets try a funny one.
With the car in neutral, step on the clutch, start the car but do not release the key from the crank position.
Let the clutch up to disengage the starter.
See if it keeps running.

I'm thinking something in the ignition switch is not making a connection or something internal is loose.

My car was an auto to manual swap and I never put the clutch switch in so that idea will not work.
Appreciate the advice though.

I took apart the steering column and inspected the wires and the switch assy as OH stated, no defects noted.
I just got a test light today and will do as OH suggested and make sure the power is constantly on the fuel shutoff valve while cranking.

I’m leaning towards the ECU cutting fuel off. As stated before if I can start it and stay above 1400 rpm it’s fine, if it drops below that while the blue coolant light is on it’s as if someone flipped a switch and shuts off , if the blue coolant temp light is off it will,idle perfectly.
You can’t shut the car off and restart 10 times in a row with no issues

I still think it's worth leaving the MAF unplugged at least once to be sure it's no a culprit. Sure it shouldn't cause it, but, it shouldn't be doing this in the first place, and it's a free quick check.

When normal operation ceases, oddities arise.

Honestly think if it was the shut off solenoid it wouldn't run either way.
As you say it's consistently starting, and it will run as long as you give it fuel.
Oilhammer said the MAF wouldn't keep it from starting, and he's correct. However, it is starting and shutting down. This is the issue.

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Steve, I’ve been watching to see what your solution is. Not that I have a similar problem but as these cars age weird things crop up, so you never know when I might.

Ok so had a chance to mess with car today before rains came in again.

I place a test light on the fuel cutoff solenoid.

Test light connected, key to on lamp illuminates for about 10 seconds than goes out ( car not started)

Test light connected key turned to start light illuminates car fires then immediately dies , light stays on.

Test light connected key turned on no light, cycled key several times light finally comes on ( (suspect ignition switch , but appears good ) turn key to start car fires but need to keep rpms above 1400 till blue coolant temp goes out ( I let rpms drop,below 1400 car immediately dies but lamp stays lit.

Test light connected, key turned to,start , light illuminates, car fires right up , keep rpms above 1400 till blue light out, let rpms go to normal and all is well.
Car starts next several attempt normally.......

That is really strange.

Is the engine smoking or shaking or nailing or anything while it is able to be kept running at 1400 RPM?

You may have answered this already, but in the scan tool data, when it cranks but will not start, can you see the engine RPM during cranking? Should be around 250+ or so I think.

Still haven't sold me on the 109, or the MAF. While I conceed the MAF will likely not change it, why not rule it out.
Ignition switch is possible, intermittent light says it could be a wire, or relay.
Still not convinced it's not a ground issue with the fuel pump or ECU, the QA, or the advance solenoid. All these need to be looked at and tested, preferably ruled out.
Do you have a spare 109 to change it out? Have all the grounds under the dash and in the rain tray been cleaned?
I honestly think you might have two things complicating things. The first being involved with fueling and the other an intermittent electrical.

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