BAT B6 A4 1.8T AMB "No Start" (No trigger signal from ECU) Now, who has some ideas?

[MerkurRS]

Hello, AZ! I/we have an interesting issue going on with a friend/customers "build." We're hoping someone here may be able to help us out. Either by "knowing" about an "odd" quirk that may be specific to the AMB (separating it from other 1.8T's and their 'usual' issues) or possibly setting us on a less-than-obvious path that results in us getting this thing out of here, for good, finally..

We have been working on this car trying to get it running after a few other shops were unsuccessful. THEY (meaning at least TWO other, unaffiliated shops/people... Yes, it has been passed around, incomplete, numerous times.. Extra suspect..) built the car and we were only introduced to the car with the expectation of cleaning up a few things, install a larger intercooler & piping, a better exhaust, and a custom tune. However, after correcting and verifying (resistances/ohms/etc.) all of the necessary connections/sensors, the engine still will not fire up.

Back story: it's a built 1.8T AMB (06A block) with an AEB head and the adjustable cam tensioner has been retained.
When we got the car, the camshaft timing was off, the tensioner (by Gates) was broken, which we replaced with a genuine OE unit, and we had an "implausible signal" from the camshaft sensor. There was metallic particulate in the oil, as well as quite a bit of fuel and a LOT of what we can only hope was excess assembly grease. The smart coil harness was severely corroded, so we replaced that portion of the harness. All of the wires are in the correct pin positions and we have again verified the integrity of the connections. Two of the large relays next to the ECU were rusted (as well as the relay connection "seat") and were replaced. Again, we corrected the wiring issues. We also replaced the crankshaft sensor and wiring. We have tried several camshaft sensors (swapped from running cars), replaced plugs, coils, and even the ECU, twice. We even attempted to use a stand-alone Ignitron ECU without any useful feedback. The Ignitron software is showing plausible signals across the board.. Yes, plausible signals. Yet, still no "trigger" being sent from the ECU to the coils.

After doing all of this, we have made progress! The coils now have power (still no signal though), and the initial "camshaft implausible signal" is gone. The VAGCOM scan (below) shows nothing that would prevent the car from firing, but we still have no coil signal and the car refuses to fire up. Ok, yesterday afternoon, we did get the car to "tumble" a bit on starter fluid (fuel pump fuse pulled to prevent flooding). It "wanted" to fire up, just once. That's the closest we personally have gotten this far.

What else could/would prevent the coils from getting a signal?
This appears to be a stumbling block we cannot get past.
Any help is greatly appreciated.

Address 01: Engine Labels: 06B-909-518-AMB.lbl
Control Module Part Number: 8E0 909 518 BC HW: 8E0 909 018 A
Component and/or Version: 1.8L R4/5VT G 0010
Software Coding: 0016751
Work Shop Code: WSC 87119 806 641192
VCID: 72EB0E846E7C5601C5-5122
8 Faults Found:

18034 - Powertrain Data Bus
P1626 - 004 - Missing Message from TCU
18320 - Pressure Sensor for Brake Boost (G294)
P1912 - 001 - Short to Plus
17834 - EVAP Purge Valve (N80)
P1426 - 004 - Open Circuit
17526 - Oxygen (Lambda) Sensor Heating; B1 S2
P1118 - 004 - Open Circuit
17837 - Circuit for Brake Vacuum Pump
P1429 - 004 - Open Circuit
17840 - Secondary Air Injection Solenoid Valve (N112)
P1432 - 004 - Open Circuit
17695 - Boost Pressure Control Valve (N249)
P1287 - 004 - Open Circuit
16486 - Mass Air Flow Sensor (G70)
P0102 - 002 - Signal too Low

[Mike Tries]

Did you upload your tune before replacing all of those sensors and doing all of the no-start troubleshooting? If so, did you later try running it on a stock tune? Have you tried swapping in a known-good ECU?

I'm wondering if you uploaded your tune (which was somehow corrupted/broken), and then you went and fixed the issue that was broken when the car showed up. Like... it showed up and "A" was broken, and the order you went in was to break "B" as well, and then fix "A".

- - - Updated - - -

Also, do you really have six Passat W8s?

[EuroxS4]

Does the tach move when cranking? IF not change the crank position sensor and call it a day. Also if this vehicle is a manual I would recommend recoding the ecm to a manual trans.

[MerkurRS]

Did you upload your tune before replacing all of those sensors and doing all of the no-start troubleshooting? If so, did you later try running it on a stock tune? Have you tried swapping in a known-good ECU?

I'm wondering if you uploaded your tune (which was somehow corrupted/broken), and then you went and fixed the issue that was broken when the car showed up. Like... it showed up and "A" was broken, and the order you went in was to break "B" as well, and then fix "A".

- - - Updated - - -

Also, do you really have six Passat W8s?

Thanks for taking the time to reply. We have tried a few ECU's including the Ignitron, which is new. The OE ECU has IMMO delete and a mild tune. Using that one, the car "tumbled" (tried to start up using starting fluid) and is the closest we got.
As for the W8's, I updated my profile, we recently sold two, a 2004 Reflex Silver 6-speed sedan and 2003 auto sedan. We still have four others; 2004 6-speed Variant, 2004 6-speed sedan, 2003 auto Variant, 2002 auto Variant. We have another Passat Unicorn: a 2004 1.8T 4-Motion 5-speed Variant.

[MerkurRS]

Does the tach move when cranking? IF not change the crank position sensor and call it a day. Also if this vehicle is a manual I would recommend recoding the ecm to a manual trans.

Thank for taking the time to respond :)

We have replaced the crank sensor a few times, checked for wiring integrity, OHM's, etc. Yes, the tach does move when cranking. UGHHHHHH.

[grayjay]

Bent valves?

[Protection]

Do you have an oscilloscope at the shop? If not, it is really worth the $$ to get one—even a cheap one for $200. You can check the signal from the crank position sensor, cam signal, you can even check timing with a two channel scope by doing a cam/crank correlation waveform and comparing it with a known good. You can also see if you are getting a signal at the coils. I know you can do a lot of this with a DMM, but a scope makes it so much easier to capture and interpret.

I’m only a hobbyist, but using an oscilloscope has saved me hours of chasing down problems on vehicles.

Have you verified the car is sending a crank position signal?


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[Protection]

I see you posted you have tach movement so not likely CPS.


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[EuroxS4]

Have you verified spark, fuel? timing ? It needs al l3 to start should be cut and dry. If using AEB head make sure you swap over cam trigger wheel from AMB as well as sensor. Otherwise no bueno.

[kwilson]

We have another Passat Unicorn: a 2004 1.8T 4-Motion 5-speed Variant.

Hmm. I had one of those here in CO for a brief time several years ago. By any chance, black with a vin ending in 8202?

[MerkurRS]

Hmm. I had one of those here in CO for a brief time several years ago. By any chance, black with a vin ending in 8202?

No, it's not that car. We picked this up last summer in Pennsylvania and is Silverstone Gray & Gray "leatherette" interior. It's in pretty good shape despite 200,000 miles and being an East Coast car. It runs very well, especially with a custom tune my husband wrote for the car

[Militant-Grunt]

Hello, AZ! I/we have an interesting issue going on with a friend/customers "build." We're hoping someone here may be able to help us out. Either by "knowing" about an "odd" quirk that may be specific to the AMB (separating it from other 1.8T's and their 'usual' issues) or possibly setting us on a less-than-obvious path that results in us getting this thing out of here, for good, finally..

We have been working on this car trying to get it running after a few other shops were unsuccessful. THEY (meaning at least TWO other, unaffiliated shops/people... Yes, it has been passed around, incomplete, numerous times.. Extra suspect..) built the car and we were only introduced to the car with the expectation of cleaning up a few things, install a larger intercooler & piping, a better exhaust, and a custom tune. However, after correcting and verifying (resistances/ohms/etc.) all of the necessary connections/sensors, the engine still will not fire up.

Back story: it's a built 1.8T AMB (06A block) with an AEB head and the adjustable cam tensioner has been retained.
When we got the car, the camshaft timing was off, the tensioner (by Gates) was broken, which we replaced with a genuine OE unit, and we had an "implausible signal" from the camshaft sensor. There was metallic particulate in the oil, as well as quite a bit of fuel and a LOT of what we can only hope was excess assembly grease. The smart coil harness was severely corroded, so we replaced that portion of the harness. All of the wires are in the correct pin positions and we have again verified the integrity of the connections. Two of the large relays next to the ECU were rusted (as well as the relay connection "seat") and were replaced. Again, we corrected the wiring issues. We also replaced the crankshaft sensor and wiring. We have tried several camshaft sensors (swapped from running cars), replaced plugs, coils, and even the ECU, twice. We even attempted to use a stand-alone Ignitron ECU without any useful feedback. The Ignitron software is showing plausible signals across the board.. Yes, plausible signals. Yet, still no "trigger" being sent from the ECU to the coils.

After doing all of this, we have made progress! The coils now have power (still no signal though), and the initial "camshaft implausible signal" is gone. The VAGCOM scan (below) shows nothing that would prevent the car from firing, but we still have no coil signal and the car refuses to fire up. Ok, yesterday afternoon, we did get the car to "tumble" a bit on starter fluid (fuel pump fuse pulled to prevent flooding). It "wanted" to fire up, just once. That's the closest we personally have gotten this far.

What else could/would prevent the coils from getting a signal?
This appears to be a stumbling block we cannot get past.
Any help is greatly appreciated.

Address 01: Engine Labels: 06B-909-518-AMB.lbl
Control Module Part Number: 8E0 909 518 BC HW: 8E0 909 018 A
Component and/or Version: 1.8L R4/5VT G 0010
Software Coding: 0016751
Work Shop Code: WSC 87119 806 641192
VCID: 72EB0E846E7C5601C5-5122
8 Faults Found:

18034 - Powertrain Data Bus
P1626 - 004 - Missing Message from TCU
18320 - Pressure Sensor for Brake Boost (G294)
P1912 - 001 - Short to Plus
17834 - EVAP Purge Valve (N80)
P1426 - 004 - Open Circuit
17526 - Oxygen (Lambda) Sensor Heating; B1 S2
P1118 - 004 - Open Circuit
17837 - Circuit for Brake Vacuum Pump
P1429 - 004 - Open Circuit
17840 - Secondary Air Injection Solenoid Valve (N112)
P1432 - 004 - Open Circuit
17695 - Boost Pressure Control Valve (N249)
P1287 - 004 - Open Circuit
16486 - Mass Air Flow Sensor (G70)
P0102 - 002 - Signal too Low

CEL illuminated? Did you physically check the crank trigger wheel and the cam trigger ring? Did you try overlaying the harness from crank position sensor to ecu, as well as from the cam position sensor to ecu? Do a leak down and compression test. If everything with the motor is fine, it sounds like you have something that is not being energized. I would really go through the wiring diagram and check.

[MerkurRS]

FOUND the problem!!!
It turns out the coil repair harness we used (we have successfully purchased this from the same seller in the past) has a bad batch of harnesses. They were pinned wrong at the coils, the trigger had to be swap the from Pin#2 to Pin#3.

[EuroxS4]

FOUND the problem!!!
It turns out the coil repair harness we used (we have successfully purchased this from the same seller in the past) has a bad batch of harnesses. They were pinned wrong at the coils, the trigger had to be swap the from Pin#2 to Pin#3.

This is why I always use a factory repair kit from VW. Glad you got her sorted out.