Audi 90 quattro with 2.5 TDI and 6-speed, plan B

[ktownboostn]

Does this engine usually run a supply pump in the tank ? I know most TD's like my golf don't....but when it comes to the TDI most use a in tank pump . Ive seen where they go and it will still run but take forever to fire up and sometimes lack on power.
And are you running a supply pump ?

[BlackBox]

I have the stock one in by-pass mode.
My point is that it should be starting without one.
Even if it's fully up to operational temps I still need the glow plug turned on for 7-9 sec otherwise it cranks and cranks and then the smoke show.
Almost like flooding a gas engine. Not normal.

You're right, once it's up to operating temp, it should fire right away with very little smoke. It sounds like a timing issue to me.

[ktownboostn]

If base timing is set the ECU shouldn't have a problem fine tuning. Pump timing is always worth checking though.
Might want to check compression just to be on the safe side. Any ECTS faults ?

[ralleyquattro]

I am running the stock gas pump with an H connection just before the main filter, stock gas fuel filter has been removed.
The system primed very quickly just before the first startup.
No fault codes. I get 4444.

[BlackBox]

I am running the stock gas pump with an H connection just before the main filter, stock gas fuel filter has been removed.
The system primed very quickly just before the first startup.
No fault codes. I get 4444.

The stock fuel pump might have something to do with it. Do you know if the original T44 this engine was pulled from uses a "lift pump". This is the term for the low pressure electric fuel pumps that some TDIs use. In general, the lift pump should be limited to about 4 PSI. More than that can affect the internal fuel injection pump pressures and timing, and can damage seals. You mentioned earlier that it sounds like the engine is flooded. Because of the lift pump, maybe it is.

On my TD conversion I removed the electric gas pump and fuel pressure accumulator completely. I know others have left their electric pumps in place, but removed some kind of a check valve on the top of them so they could draw through easily, and cut power to them. You could pretty easily drop the fuel lines on the fuel injection pump directly into a jar of diesel to see how this affects its start-up behavior.

[TW]

The tacho is definetly not working properly, the 6 cyl one was reading too low, the 5 cyl one is reading too high, not sure what to try next..

I had good luck with the Dakota Digital interface that connects to the "W" terminal on the alternator so that my Tach for the 5 cylinder diesel would work.

[TW]

I know others have left their electric pumps in place, but removed some kind of a check valve on the top of them so they could draw through easily, and cut power to them. .

I left the electric fuel pump in place, but disconnected the power from it and drilled out the check valve. I can still power it up if I need to prime the system, but the diesel IP has no problem drawing fuel through. I was also lucky that a previous owner had removed the fuel accumulator so that didn't interfere with flow.

[ralleyquattro]

I am running the stock gas pump with an H connection just before the main filter, stock gas fuel filter has been removed.
The system primed very quickly just before the first startup.
No fault codes. I get 4444.

The stock fuel pump might have something to do with it. Do you know if the original T44 this engine was pulled from uses a "lift pump". This is the term for the low pressure electric fuel pumps that some TDIs use. In general, the lift pump should be limited to about 4 PSI. More than that can affect the internal fuel injection pump pressures and timing, and can damage seals. You mentioned earlier that it sounds like the engine is flooded. Because of the lift pump, maybe it is.

On my TD conversion I removed the electric gas pump and fuel pressure accumulator completely. I know others have left their electric pumps in place, but removed some kind of a check valve on the top of them so they could draw through easily, and cut power to them. You could pretty easily drop the fuel lines on the fuel injection pump directly into a jar of diesel to see how this affects its start-up behavior.

The original typ 44 installation did not use any pumps, straight fit to the filter and then the IP.
I'll try to disable it, it will still be able to suck fuel through the return line, no?
I can also stick the lines in some diesel, that might work even better for testing.

Cheers

[tecknoquatt]

glad I've been an inspiration to at least someone in my life lol =) looks nice Martin

Yep, picked it up this morning.
It was worth the 2 hour drive each way!

Andrew Warner was nice enough to the work on the Rieger RS2 bumper for me. :thanks:

He installed some mesh holders which the bumper does not come with.



He also fixed up one corner that had a chunk missing



Shot some pearl white to match the car



And I liked Technoquattro's bumper so much I also asked Andrew to the same to mine.





I am very impressed with Andrew's work. Bumper looks stunning. Makes the rest of the car look like a POS.

Next I have to make up some brackets to mount this beast on the car, and then install some 993 fogs and turn signals.

Cheers

[ralleyquattro]

I stand corrected, I just pulled the codes after 2 days of driving.
I got three of them.

2211 Reference Injector Sensor (G80)
2244 Fuel Shutoff Valve ((N108) or no fuel
2312 Coolant sensor (G62)

it's late tonight and mosquitos are in force so I'll check out the Coolant sensor tomorrow.
As for te reference injector, no ide how to check that one. I don't have VAGCOM and last time I hooked one up it would not communicate.
This one is is misbehaving just like the '84 when I got her on the road...

Any of you TDI freaks know off the top if there is one single thing that would cause all of those codes?

Cheers

[80qtdi]

I'm still saying the starting is IP timing related. What color is the smoke?

[scottmandu]

So... here is a vid of a startup using bypassed glow plug relay.
There is a strange noise I've heard before but don't know what it is... sounds like a bearing ?!?
Have a listen. Sounds like a rooster in the morning, sort of a sick one.


Link to video

That rooster noise is a dry starter bendix.

I wonder if the transporter starter will fit. Otherwise I have to go to Europe for a replacement...

Bosch has a replacement I don't recall the number but I got a 2.2 KW from a 5 cylinder for my 2.6 beast.

[ralleyquattro]

I'm still saying the starting is IP timing related. What color is the smoke?

I've advanced the pump with no difference, the smoke is blue.

Cheers

[ralleyquattro]

Checked the coolant temp sensor this morning, it's fine as is the wiring to the ECU.
Needle sensor is also fine, proper 90-110Ohm resistance and wiring is fine as well.
The shutoff valve clicks like it should.

Turned the pump back to where it's supposed to be i.e. approx 4-5 degrees retard.
Cleared the codes and took it for a small drive.

No codes and runs a bit smoother, but same starting issue and same level of power, so not much change there.

Really need to hook it up to VAGCOM, I've looked at Ross-Tech website and they call thes Difficult cars.

"Difficult" older cars

Include those with 1991-1994 Audi TDI engines which run the diagnostic protocols at 240 (yes, two hundred forty) bits per second"

How do we connect to it then? We have proper software and original Ross-tech cables.

Thanks

[80qtdi]

By chance do you have any fuel leaks from the Injection pump? I doubt it, but it could cause some starting issues. It also seems wierd to me that with the gp relay bypassed it will start right up. Have you tried to have the glow plugs disconnected and bypass the harness to see if perhaps it's an electrical issue?

I have heard when an injection pump is stored for a long period of time it can cause some internal problems with Algae growing and clogging different orifaces in the pump.

Good luck with everything, wish I were closer.

[ralleyquattro]

I discovered that Glow Plugs will not even turn on if it's above 6 Celcius (43F)
So... why does it start right away with glow plugs on even though it should without them?

No problem... hope to have it hooked up to VAGCOM soon, seeing the measuring blocks will tell us a lot about what is going on there.
I have also yet to check compression as well.

Cheers

[80qtdi]

I'm wondering if it's some kind of electrical difference between the relay panel that is causing something funny to go on. That's why I want you to disconnect the glowplugs and energize the relay to see if it will start right away without excessive cranking.

[ralleyquattro]

I tried that and it still needs lots of cranking to start with lots of blue/white smoke following the eventual rough start.

I also unplugged the coolant sensor as per workshop manual to mimic very cold engine and sure enough the ECU turned the glow plugs on as it should, so I know that system is working perfectly fine.

[80qtdi]

Hopefully for you the compression isn't too low. It's kind of seeming as such, if the compression is too low it doesn't heat up the air sufficiently to auto ignite the diesel when it's injected into the bowl of the piston.

Check the compression, if it's good (between 400-500 psi and even), I would find a set of Nozzles and change them out. If the injectors weren't atomizing the fuel enough it could cause the symptoms you are describing.

I also just thought of something, how did you purge the fuel system? Did the tank have any old gas in it?

[ralleyquattro]

I emptied the tank as much as I could with the stock pump i.e. run till dry, so there could have been some gas still left in there.
Then I filled it right up to the top with diesel. I filled the system, lines, filter and pump using the stock gas pump, made sure everything was full before startup.

Went for another test drive and now that the pump is back to the original place the ECU is happy and giving me 4444.

On a related note I figured out what my steering noise was... the bloody subframe was loose, and I mean few threads to go loose... doh!
Tightened up the subframe and the noise from the steering is gone, but I have anoher issue, now the oil pan is hitting the subframe, remember I lowered the engine a bit to help with the hood closing issue? So back to plan C and lowered the subframe 1/4" using spacers. All is well and no noises from the front end... happy happy.

Only issue now is the starting, so I'll check the compression and still will try to get VAGCOM on it to see what the measuring blocks show up.

Cheers

[quattro87]

:woowoo: Always progress on this project. nice

[ktownboostn]

Ya it's sounding like compression... I know on the 1.6/1.9 that I have it starts like a bag of shit on cold starts because of the head swap lowering compression ratio below 19:1.

Id say rings might be stuck or are just bad. Sounds like it needs lots of time to crank to build up the heat for ignition. Dp you have lots of blow-by or excessive oil in the intake system ?

[80qtdi]

I'm still not ruling out the possibility of a little too much Gasoline in the Diesel lowering the cetane rating of the fuel. If your second tank of Diesel doesn't improve the starting I would start thinking about compression (or just do a compression test). If it is the rings sticking, I have had some luck putting some brake fluid in the cylinders and letting it sit in there to loosen them and absorb any water that may still be embedded in the components. Just make sure to leave the glow plugs out before cranking it to clear the fluid out.

[ralleyquattro]

There is very little blow by, I have it venting to the atmosphere right now and you can hardly see it.
I took one of the con rod bearings out while back to see the shape of the engine and it looked really good so I don't think there is a lot of wear on the engine.
It also came from a trusted source and he had it in his daily driver with no starting issues.

Attachment ( 27529 ) : DSC00098.JPG

[80qtdi]

Those bearings look really good, I bet you're right and the compression is great inside. I'm betting on it being fuel related now for sure... :wink: