A4 B7 Starting Issue

[donovanj]

I have been reading through here about various starting issues, but many seem like they are fuel delivery and ignition coil related... but unless I am misunderstanding I think my issue is different.

This is my sons car. It is a 2005.5 A4 2.0 FSI FWD. We have owned it for about 10 months and to this point it has been reliable for a car with 150K miles. Last week it just started a "no crank" issue that seemed to be intermittent. I thought it was a bad starter because initially it was clicking but not turning over. Pulled the starter, had it tested, and all was fine. Put in a new starter because I didn't want to jack with this again in 6 months, or so I thought...

After that didn't fix the problem we were switching in another battery I had and noticed that the (+) cable that goes directly to the starter looked damaged and as soon as we removed it from the battery it completely broke off at the crimp! I thought we found the true source of the issue.. we rigged it up with a screw together battery connector I had in the garage and the thing fired up immediately, and again 2-3 more times before my son went out with his friends for the evening. now we just need to get a fresh replacement for that cable to complete our temporary fix.

Well not so. Now we are back to an intermittent "no crank". When the starter does crank it fires up immediately and runs great. As soon as we stop the car it won't start again for another 20-30 minutes, but eventually cranks and starts. This has happened consistently for the last 4 days. No rhyme or reason when it works. Outside of fixing the starter cable with the proper connection here are the following things I have read about but am not sure whether they are worth trying:

- Fuel Filter (Not sure how old mine is so thinking it should be changed anyway)
- Ignition Switch
- Various Sensor (fuel, crank position, etc)

Looking for some suggestions on what is worth trying for a "no crank" situation. Most of the posts seem to be more related to a "crank but no start" condition, and some really odd situations with other Audi models.

Other things of note:
- Good cam follower (had a new one, but the one in it was in like new condition so the previous owner seemed to do some maintenance)
- Tried two different batteries and jump starting doesn't help either
- Not throwing any codes

At this point I am just and . Thanks in advance for any guidance.

Also.. For starter removal/install... I am going to do a more detailed post with pics, but I found an easy way (well easier than I have seen posted or videoed) to remove and install the starter. The YouTube video is the worst where the guy recommends removing the wiring harness first and then removing the exhaust to get the back bolt. My procedure is to remove the (1) Remove the bottom Allen bolt; (2) Remove the top bolt (17mm) that goes through the back by removing the passenger wheel and using one of those 90 degree extension adapters to a cordless drill with a socket adapter (very useful $19 tool at Home Depot); (3) with the starter pulled away from the engine, remove the 10mm and 14 mm bolts holding on the wiring harness. I can literally remove the starter in < 20 minutes . The reinstall is about the same (first the wiring harness, then the lower bolt, and finish with the upper bolt) but is completely dependent on getting the lower bolt threaded. I found the lower bolt the easiest to align so that is why I did it first on the reinstall. One day I hope to meet an Audi engineer and find out the purpose in using an Allen, 10mm, 14mm, and 17mm on the 4 connections for the starter?

[vce1232000]

Check the main chassis ground

[donovanj]

How does this car ground. I am more familiar with classic car wiring (I have a 66 mustang I rewired myself). It grounds to the body, body to engine, etc. The only ground to chassis I see is the one directly from the battery to the body right near the battery. Is there another ground? Bad grounds generally cause really crazy stuff like this so I agree but am just still a noob with this car :)

[vce1232000]

i would @ the ground wire from the battery to the ground. Check with meter to make sure it has good continuity.

[SlvrArrw]

I agree , older cars can typically have grounding issues. I would replace ground to battery cable and also run some 12 gauge grounds to the body and engine.

Sent from my SAMSUNG-SM-G935A using Tapatalk

[Rulty]

I would also check N75 valve, I believe that when these fail they can cause no cank issues. Although it is typically right after you fill up.

[donovanj]

We replaced the N75 valve about 8 months ago. We started getting a CEL for it shortly after we purchased the car.

Update, and more info. The car has the 6spd Automatic. Reason I point that out is the starter wiring is different from the manual to the automatic. The automatic has what is called a Starter Interlocking Relay (haven't found this yet), and the manual has a switch on the clutch petal. I have verified that I have a good ground, but have not started looking at the relays yet. This video seems to be related to the issue where they bypass the relay (https://www.youtube.com/watch?v=x4pAKKLvGpQ), but they don't show real clearly what they did to fix it. After reading about relays the issues I am seeing are similar to a relay that is going bad, but who knows... I think that is what I am going to look into tonight. Some of the relays are behind the fuse panel (under the steering column), but it looks like what these guys were dealing with was in the ECU box in the engine bay.

The last thing in line is the Transmission Control Module which seems to have some role, and commonly fails, but it looks like you generally get codes when that thing starts to go bad. The parts to repair/replace that are pretty expensive so I am not even going there.

Thanks for the ideas guys. I will let you know what I figure out when I get this resolved once and for all (hopefully)!

[Theiceman]

if its not even cranking it has nothing to do with followers, fuel pumps valves etc.

Check the relays UNDER the computer in front of the firewall on the drivers side and check your ignition switch.


Edit due to brain fart

[donovanj]

Update.. Here is what I have done so far:

- Replaced the starter (had it out for testing, was good but decided to drop the money so I didn't have to change it later)
- Replaced the battery to starter wiring (This main cable broke at the battery.. replaced with a good used one off eBay. Unfortunately had to basically remove the starter again to replace)
- Checked the fuses (specifically fuse 31 which has caused similar issue for others)
- Replaced the Starter Interlocking Relay under the ECU (the narrow one #395.. note this relay has been superseded by a 646 relay so don't look for a 395... you prob won't find a new one anywere and will get frustrated like I did)
- Tested the ground continuity & quality (both sets... near the battery and down near the front passenger motor mount)
- Switched out with a newer battery I had

After all that I still have the same issue. Luckily this has cost more time than money other than the starter. Last night I noticed something new about the car. The key fobs have good batteries, but periodically the car is also not locking and unlocking (similar to the no crank). I hadn't noticed it because it has mainly sat in the garage unlocked anyway so that doesn't get used. My son mentioned this one time when we were first experiencing issues, but it seemed to work when I tested it so I thought it was a fluke or he did something wrong.

If the fob has a good battery and the doesn't work what would I look at to diagnose? Note: I get the same work/no work with both fobs at the times it doesn't work.

I think I am going to order an ignition switch and just change it out since it is cheap and will probably fail at some point. Any thoughts given the new information?

[Theiceman]

When you changed the starter , that small wire comes from the ignition switch through the relay. I would see if you have 12 on that wire when you turn the key to start. If not I would troubleshoot that



Sent from my iPhone using Audizine

[B7S3wannabi]

Had this same issue three weeks ago with a car that came into the shop. Check the ground cable near the passenger side engine mount. Clean up both ends of where it attaches to the block and chassis and re-secure. You can obviously test this as well when it starts acting up, put the negative lead from a jumper directly to the starter housing and then touch the positive to the signal wire. If it works, its for sure that ground.

[donovanj]

You had me excited about the ground issue. Didn't realize that ground was there but knew there had to be additional grounds. Didn't change the result. That thing was pretty easy to remove but a bit harder to get the through bolt back on the mount. Had to fish the cable in place and hold pressure while trying to thread the bolt with a long extension. Thanks for the idea. Can't check the power at the starter yet till I get a helper home.

Looks like I am down to this power test at the starter or an ignition switch.

Note: updated above with this to have a complete list of what I have done so far.

[Okedokey]

Scan the car. It could be something as simple as a relay.

[Theiceman]

It's easy to check just run a piece of wire from the small wire to a meter , ground the other side of the meter and throw it on your windshield. Get in and watch meter


Sent from my iPhone using Audizine

[donovanj]

I tested with a test light at the starter (thinking you mean the other main wire that routes through the back of the engine to the starter, not the one from the battery)? This was not getting any signal when the key was turned on. This seems to indicate it is something between the key and the wiring to the starter. I started with the ignition switch itself, but this resulted in no real change. I already have another good harness that runs from the ignition (?) to the starter. What I am not sure is exactly where this plugs in at the opposite end? I am clear from the starter to the back side of the engine/transmission, but from there it routes across the engine. I need to get it up on ramps to look at that, but haven't had the opportunity yet. It looks like it grounds to the body at the opposite end because it has a similar connector at the far end to what it has at the starter (i.e. a bolt goes through it).

One other thing from a Haynes manual for the A4 it mentions that the "Automatic transmission not engaged in Park (P) or Neutral (N)". Everything else but the wire I mentioned and this is accounted for. Only problem I have with this is that I generally don't even touch the shifter and it will start up after a few tries. This almost sounds like a Neutral Safety Switch type scenario that would give this exact behavior. My thought is this is highly unlikely, but thought I would see if anyone has seen this as well.

Thanks for all the help thus far.

[Okedokey]

Have you scanned the car mate?

[canadianA4B7]

Relays under the ECU, I just experienced your no start issue myself. I swapped out the other 2 relays not the 395. The last one looking at the Ecu from driver fender closest to you in drivers seat is the start interlock relay iirc. Someone had pointed this out as being the correct 70 A relay to change. I'll try and find a link to the info.

http://www.audizine.com/forum/showth...p/767744-P3073

This was my issues to begin. Lead to more stuff but initially the relays did get it started.

[donovanj]

When you say "Scan" the car what specifically do I need. I have seen people talk about scanning with "VAG-COM". These devices range from like $25 - $800 (https://www.europaparts.com/catalogs...ult/?q=Vag-com). I don't have any of these. I have a good ODBII reader that does ABS as well, but it doesn't show anything reported by the car computer as being a problem. With this not being a long term car I don't think I am going to drop a ton on a scanner that is Audi/VW specific, but I could probably locate and pay someone to do it.

On the Relays. Under the ECU I have 3 relays (1X395 & 2X 614). The 395 relay (now a 646) is supposedly the Starter Interlock Relay. The 614's are related to the cooling fan (I believe the middle of the 3) and the fuel pump (the relay closest to the drivers seat). My fuel pump makes noise when the door opens and when the starter turns it fires right up and runs great. It doesn't appear that there is any issue with fuel delivery. In reading through that thread it sounded like the Fuel Pump relay was bad and the issue was a "Crank/No Start" type issue which is different than mine. If my car cranks it starts every time.

[canadianA4B7]

strange, perhaps my 395 was lose and only pushed it in better while swapping.

Good to know I'll be investigating further on my car now.

[donovanj]

Details of the Scan I had done yesterday:

Chassis Type:8E

Scan: 01 02 03 08 09 0F 11 15 16 17 18 36 37 45 46 55 56 57 65 67

69 75 76 77







-----------------------------------------------------------------

Address 01: Engine Labels: 06F-907-115-AXX.clb

Part No SW: 8E0 910 115 B HW: 8E0907115C

Component: 2.0l R4/4V TFSI 0130

Revision: --H02--- Serial Number:

Coding: 0104010A02070120

Shop #: WSC 25002 444 62679

VCID: 20037383BD04F393FB43629353-8075



2 Faults Found:

012555 - Low Pressure Fuel regulation

P310B - 004 - Fuel Pressure Outside Specification - Intermittent



005634 - Power Supply Terminal 30

P1602 - 002 - Voltage too Low - Intermittent



-----------------------------------------------------------------

Address 02: Auto Trans Labels: 8E-02.lbl

Part No SW: 8E3 910 155 M HW: 01J927156HT

Component: V30 01J 2.0TFSI USA 0020

Revision: 00000009 Serial Number: 00000001113773

Coding: 0000001

Shop #: WSC 06325 000 00000

VCID: 322789CBE3E871031DF7284B7D-8067



No fault codes found.

-----------------------------------------------------------------

Address 03: ABS Brakes Labels: 8E0-910-517.clb

Part No SW: 8E0 910 517 B HW: 8E0614517AT

Component: ESP8 front H04 0180

Revision: 00000000 Serial Number: 00000000000000

Coding: 0004525

Shop #: WSC 06335 000 00000

VCID: 260F659BDF201DA3817FA4DB01-8073



1 Fault Found:

01826 - Sensor for Steering Angle (G85); Supply Voltage Terminal 30

000 - - - Intermittent



-----------------------------------------------------------------

Address 08: Auto HVAC Labels: 8E0-820-043.lbl

Part No SW: 8E0 820 043 AL

Component: A4 Klimaautomat 2731

Coding: 00000

Shop #: WSC 00000 000

VCID: 6B9954AF0442F1CB1E319D1782-5160



No fault codes found.

-----------------------------------------------------------------

Address 09: Cent. Elect. Labels: 8E0-907-279-8EC.lbl

Part No SW: 8E0 907 279 J

Component: int. Lastmodul USA 0303

Coding: 00003

Shop #: WSC 06335 000

VCID: 3935BEE73E9E935BDC3D77BF18-4B00



5 Faults Found:

01498 - Bulb for Parking Lamps; Right (M3)

30-00 - Open or Short to Plus





01499 - Bulb for High-Beams; Right (M32)

30-00 - Open or Short to Plus





00978 - Lamp for Low Beam; Left (M29)

30-00 - Open or Short to Plus





00979 - Lamp for Low Beam; Right (M31)

30-00 - Open or Short to Plus





01497 - Bulb for Blinkers; Front Right (M7)

30-00 - Open or Short to Plus





-----------------------------------------------------------------

Address 15: Airbags Labels: 8E0-959-655-94.lbl

Part No SW: 8E0 959 655 H HW: 8E0959339B

Component: Airbag 9.41 H10 3230

Revision: 91H10323 Serial Number: 0036N0008F3F

Coding: 0032607

Shop #: WSC 06335 000 00000

VCID: 3C3BA7F331ACB773C75B96C3FF-8069



Subsystem 1 - Part No SW: 8E0-910-339-B

Component: BF-Gewichtsens. 02 0070

Serial Number: 6332DRB400B2D199S

Coding: 0032607



Subsystem 2 - Serial Number: 6342DRB40155C894S



Subsystem 3 - Serial Number: 6352ARB40045DE9E+



Subsystem 4 - Serial Number: 6362ARB40045DE36S



Subsystem 5 - Serial Number: 63729RB4004A22E3I



Subsystem 6 - Serial Number: 63829RB4004A200FF



1 Fault Found:

01794 - Control Module - Incorrect Chassis (VIN) Number

000 - - - Intermittent



-----------------------------------------------------------------

Address 16: Steering wheel Labels: 8E0-953-549.lbl

Part No SW: 8E0 953 549 Q

Component: Lenksäulenmodul 0601

Coding: 02041

Shop #: WSC 06335 000

VCID: 41C5D607564ECB9B948DCF1FA0-4B00



No fault codes found.

-----------------------------------------------------------------

Address 17: Instruments Labels: 8E-17.clb

Part No SW: 8E0 920 981 N HW: 8E0920981N

Component: KOMBI+WFS 4 H12 0040

Revision: 0040 Serial Number: 00000000000000

Coding: 0022261

Shop #: WSC 25161 444 84964

VCID: 3833BBE305949A5323336AB32B-5184



No fault codes found.

-----------------------------------------------------------------

Address 46: Central Conv. Labels: 8E0-959-433-MAX.lbl

Part No SW: 8E0 959 433 BT

Component: Komfortgerät T7B 3132

Coding: 11836

Shop #: WSC 06335 000

VCID: 844B9F1389DC9EB37F2BAE2347-4B00



Subsystem 1 - Part No SW: 8E1-959-801-F

Component: Türsteuer.FS BRM 0305



4 Faults Found:

01330 - Central Control Module for Central Convenience (J393)

52-10 - Supply Voltage Too High - Intermittent



00962 - Alarm via. Tilt Sensor

35-00 - -





00955 - Key 1

35-10 - - - Intermittent



00956 - Key 2

35-10 - - - Intermittent



End-------------------------(Elapsed Time: 08:51)--------------------------

Save Done, Go Back

[B7S3wannabi]

Uh oh. Might end up needing an instrument cluster... I forgot we had another B7 a while back that had this issue and it was the immobilizer which is integrated in the instrument cluster.

[donovanj]

So based on the scan I started to look into why the low pressure fuel side would not be in specification. From research it looks like it would have to be one of the following:

- Fuel lines damaged or hard lines crimped... inspected this and didn't see any issues
- Fuel filter clogged... Replaced because it was on my list anyway with it being a used car with 150K miles and no idea how old/clogged it was. ** This was the first thing I have done on this car that was easier than expected!
- Low Pressure Fuel Pump (LPFP) failed or failing... audible inspection from the trunk to verify it was coming on and doing work. No telling from this if it is generating the necessary pressure, but it is definitely coming on and doing something.

After we finished the fuel filter we started it up and it did start on the first crank. We turned it off.. let it sit for a min and started it right up again. Problem solved.. not so fast. We had a few more "no crank" starts, but it did start up a few more times. In general seemed like it was starting more regularly, but still has some issue. Test drive/seat of the pants dyno seemed to indicate that the throttle from a dead stop was noticeably better along with acceleration. This would seem to indicate that there was possibly some restriction in the fuel filter. So here are my thoughts and questions I am hoping someone can validate:

1) If the LPFP isn't producing enough pressure will the ECU keep the car from cranking? Initial thought is no and this is why you get the "Crank/No Start" or "Start and die after a few seconds" scenarios when there isn't proper fuel pressure to the HPFP to run the engine.

2) If the above scenario isn't right.. my car could have a failing LPFP caused by age or excessive workload overcoming a clogged fuel filter. If this was the happening I would expect the car would probably start but either die or have poor performance. When the car is started it is pulling considerably stronger than any other A4 I have driven. I have had people tell me that it seems like the fuel pump, but based on the way it performs I consider it highly unlikely this is an issue.

3) Thinking that the next step is to go back and inspect the wiring between the ignition and the starter.

Overall the fuel filter was worthwhile and needed, but there is still a problem.

[Okedokey]

This is an electrical fault.

Also has the car been in a crash?

01794 - Control Module - Incorrect Chassis (VIN) Number

Read and do this: http://wiki.ross-tech.com/wiki/index..._Data_Learning

[donovanj]

According to CarFax the car has never been in a crash... but that code did seem odd to me as well. Would you get the same code if the ECM was switched out? Maybe a computer tune upgrade or something that was possibly performed at some point?

The link you sent I read but am very confused as to what I would do with it. Looks like something I would do using the VAG-COM device if I owned one (which I don't). What is the base level device I would need to do this type of stuff. I found a descent price on VAG-COM UNI-COM by Ross-Tech (http://www.ross-tech.com/vag-com/old...s/uni-com.html) but not sure if this is going to do anywhere near what the ones that are like $300. I think what I should probably get is this one (https://www.europaparts.com/vcds-vag...b-10-vins.html), and just find a few local guys that need scans and have them pay me a small fee (like the guy across town that I found).

[Okedokey]

According to CarFax the car has never been in a crash... but that code did seem odd to me as well. Would you get the same code if the ECM was switched out? Maybe a computer tune upgrade or something that was possibly performed at some point?

The link you sent I read but am very confused as to what I would do with it. Looks like something I would do using the VAG-COM device if I owned one (which I don't). What is the base level device I would need to do this type of stuff. I found a descent price on VAG-COM UNI-COM by Ross-Tech (http://www.ross-tech.com/vag-com/old...s/uni-com.html) but not sure if this is going to do anywhere near what the ones that are like $300. I think what I should probably get is this one (https://www.europaparts.com/vcds-vag...b-10-vins.html), and just find a few local guys that need scans and have them pay me a small fee (like the guy across town that I found).

Yeah, readapt the airbag with VCDS, clear codes, run all adaptations, rescan

[donovanj]

Ok. I broke down and bought a VAG-COM from Ross-Tech. I will do what you suggest once that arrives. Should be Friday.

One thing I have noticed is that if the battery is disconnected for say 30 minutes that it starts up on the first crank almost every time. This was observed every time we were working on something (thinking we had the fix.. only to determine we didn't), so we started testing the theory last night. This would seem to indicate some module or system that resets or something after a period of time with no power. This doesn't seem to fit a scenario of a bad ground, wiring that is damaged/failing, or fuel pump IMO. In those scenarios disconnecting the battery would seem to have no tangible effect.

Once the scanner arrives I will get some fresh scan information.

[Theiceman]

That voltage too high error. Has your alternator been checked ? What's at the battery terminals when it starts ? You maybe spiking a module if your regulator is toast.
Sorry if I repeated anything. Did not read whole thread.


Sent from my iPhone using Audizine

[smunson87]

Did you ever figure this out I have hear it's the relays under the Ecu. I am having the same problem my car has 80k on it.


Sent from my iPhone using Audizine

[donovanj]

Nope. The posts are as recent as yesterday. I wish I was done. There are 3 relays under the ECU (info above as to what is what). Your car is getting intermittent "no crank" (i.e. you turn the key and nothing other than the fuel pumps running)?

I will pull the alternator tonight and have it tested. I will probably test the voltage at the back of the alternator prior to removing it. I hadn't thought of it being an issue because the battery is definitely charging. I hadn't thought about the regulator possibly being bad and it producing too much power! I have put 2 alternators in each my current and last to daily car (honda and ford) but my issues were always low voltage output.

Thanks for the idea. Should have already tested that due to the ease of the test.

[A4B7Avant]

If the system voltage is too high, then the regulator is bad.

[donovanj]

Unfortunately the alternator tested out fine. It is putting out 14.1 volts. I really wanted it to be the cause so I had it tested twice with the same results. Back to the drawing board. Hopefully the VAG-COM shows up today. On the bright side that alternator is about the easiest one I have seen to change out. Did the reinstall this morning in about 15 minutes.

[donovanj]

Yeah, readapt the airbag with VCDS, clear codes, run all adaptations, rescan

So I have made no progress on this issue. I have some fresh scans with my VAG-COM now, but the only difference is mine has the Freeze Frame info for the fault codes that were not in the one I had done using a different VAG-COM.

Just to be clear on your suggestion. I would clear all codes, run all of the Air Bag specific adaptations, and then rescan. I am asking because I don't see anything that will run all adaptations. It looks like there are 8-10 airbag related ones to run. Sorry I am new to this software so it may be a dumb question.

One other thing that might be of note. Since the fuel pressure was showing low from the LPFP I was looking at the fuel rail pressure and with the key in the on position it is at 4.5 bar. I want to do a test at idle with the car up to temp, but it has not wanted to start in the limited time I have tried this week. Not sure if this is going to go up at idle (short of the heat creating more pressure), but I was reading that this should be closer to 5 bar. I couldn't figure out where to get the info on the duty cycle for the pump but I know it can be retrieved using VCDS.

[Chris@EPL]

I had a failing LPFP for about 6 years and when I replaced it the LPFP it was laying on its side with hose unplugged and the level arms were off of it and it still started and ran fine except when the tank was low and took a right hand turn sharp. Doubt the LPFP is keeping it from starting. Fill it with gas and see.

[donovanj]

I can't imaging the LPFP is keeping it from even cranking (let alone starting), but I am new to these cars. I would expect the LPFP failing causes a "Crank/No Start" or a "Start and run for a few seconds then stall" type scenarios. It has about a half tank of gas in it already.

[B7S3wannabi]

The fuel system will NOT cause a no crank no start issue. It's an electrical issue within the starting system.

[Okedokey]

What voltage is on the battery. test with car off, then what does it drop to when you crank.

[donovanj]

It is going from just over 12.9 V off the car to 12.5-12.6 when cranking.

[Okedokey]

Disconnect battery for 15 minutes, reconnect and scan. Clear codes and try to start. Either way, rescan and post results. Do it in this order.

[EvolutionArmory]

Dupe

[EvolutionArmory]

I would also check N75 valve, I believe that when these fail they can cause no cank issues. Although it is typically right after you fill up.

What does the wastegate actuator valve have to do with fuel fill ups? Do you mean N80 valve?

To the OP, have you tried disconnecting the battery and connecting the positive and negative cables together for an hour or so? This resets ECU's and can cure a ton of random issues.

I would give it a try if you haven't already. Connect the battery after the reset, clear any fault codes and do a throttle body alignment.