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gusbus86
01-15-2019, 05:54 PM
hello guys, so ive got an issue with my a4 1.8 5speed. when the cars cold start wont start the car will crank, after a few attempts the car will start badly have a fluctuating idle and just shut off. and if its really cold itll start with a misfire & the cel blinks.

🞄 I replaced 4 pin coolant temp sensor still no luck.

🞄 I tried starting it with maf unplugged and it starts and idles a lot smoother but still shuts off.

🞄 Fuel filter is pretty new, pump seems to work.

🞄 battery is still fresh

🞄 I get 3 codes; 18010(only when engine is cold), 17604, & 16518

🞄 I have plugs gaped to .028

heres a vid that visualizes my issue (not my video): https://www.youtube.com/watch?v=aXqRIx14se4

Blazius
01-16-2019, 05:46 AM
Fuel or Spark. You need to hook up a fuel pressure gauge, FPR also probable. Did you take out spark plugs? Coils any issue ?

gusbus86
01-19-2019, 11:37 AM
Fuel or Spark. You need to hook up a fuel pressure gauge, FPR also probable. Did you take out spark plugs? Coils any issue ?

I might add that I noticed sometimes the fuel pump doesn't whine and I dont hear the relay click engage, and sometimes it does. the times where I dont hear the relay click it cranks and doesn't start. when the relay clicks itll start but die right after. it clicks and turns the fuel pump on like 1 every 5 times (aprox). one attempt i tried starting it and the car died and I could hear a rapid clicking from the relays. when I turned the key in its off position it stopped. could the fuel pump fuse or relay be sticking or something?

no issue with coils, I tried the unplug the fuel injector method and all 4 coils tested good.

Blazius
01-19-2019, 03:04 PM
I might add that I noticed sometimes the fuel pump doesn't whine and I dont hear the relay click engage, and sometimes it does. the times where I dont hear the relay click it cranks and doesn't start. when the relay clicks itll start but die right after. it clicks and turns the fuel pump on like 1 every 5 times (aprox). one attempt i tried starting it and the car died and I could hear a rapid clicking from the relays. when I turned the key in its off position it stopped. could the fuel pump fuse or relay be sticking or something?

no issue with coils, I tried the unplug the fuel injector method and all 4 coils tested good.

Take the FP relay out, its under the dash, clean contacts, take off top off see if the switch is working etc.

gusbus86
01-19-2019, 03:35 PM
Take the FP relay out, its under the dash, clean contacts, take off top off see if the switch is working etc.

the switch works, it turns the fuel pump on when I click it

Blazius
01-19-2019, 03:50 PM
the switch works, it turns the fuel pump on when I click it

Aight. Check fuel pressure. Do double prime next time you try to start. Close door, ACC on, for 5 sec, key out for 30 sec, door open, door close, wait 5 sec, acc on

gusbus86
01-19-2019, 04:42 PM
Aight. Check fuel pressure. Do double prime next time you try to start. Close door, ACC on, for 5 sec, key out for 30 sec, door open, door close, wait 5 sec, acc on

what is acc?

Blazius
01-19-2019, 04:46 PM
what is acc?

Ignition on. Not cranking

gusbus86
01-21-2019, 12:46 PM
Ignition on. Not cranking

that didnt change anything. could something with the ecu management be bad? because when I have the key in the on position and I link my scanner i get an error which has never happened.

gusbus86
01-22-2019, 02:00 PM
bump update: I bought a wireless obd2 scanner and I received the following codes and parameters just from having it run and stall in 21F degree weather

- p1237
- p1238
- p1239
- p1240
- p1500
- p0303 (2x)

fuel system: open loop due to insuffiecient engine temperature
short trim fuel: 0%
long term fuel: 0%
timing advance 12degrees
maf flow was like 9g on first start than settled to 4.92g/s
throttle pos 4%
b1s1 voltage : 0.44v
b1s1 short term fuel: 0%
b1s2 voltage: 0.52v
b1s2 short fuel trim: N/A ( could be cause I have a catless downpipe with that sensor spaced)

any ideas?

Blazius
01-22-2019, 03:17 PM
Did you look at the codes?

You have 4 codes and they all say the fuel pump driver / circuit is broke somewhere, also one for injector 4 circuit. Also what year is this car ? One code is related to the throttle pos/actuator sensor too. On DBW it should around 14-17% @ idle. Your MAF is fine.


Also did you even look at the pump ?

gusbus86
01-22-2019, 03:28 PM
Did you look at the codes?

You have 4 codes and they all say the fuel pump driver / circuit is broke somewhere, also one for injector 4 circuit. Also what year is this car ? One code is related to the throttle pos/actuator sensor too. On DBW it should around 14-17% @ idle. Your MAF is fine.


Also did you even look at the pump ?

its a 99.5 post facelift aeb DBW can I clean the sensor with maf cleaner? or should it be replaced? i just repaired the fuel sending unit a couple months ago and I didn't notice anything. is there anything in particular I should be looking for? the pump when it primes still has a pungent whine to it. and could it be the whole pump thats bad?

Blazius
01-22-2019, 03:47 PM
its a 99.5 post facelift aeb DBW can I clean the sensor with maf cleaner? or should it be replaced? i just repaired the fuel sending unit a couple months ago and I didn't notice anything. is there anything in particular I should be looking for? the pump when it primes still has a pungent whine to it. and could it be the whole pump thats bad?

Yes it can. It could be throwing all those codes. I would check if it gets constant uninterrupted power 1st at the connector. with ignition it should be getting around 9V and 12+ at cranking.

Yeah you can clean with MAF cleaner. AEB is DBC tho. Did you switch ECU's or did you swap an AEB into facelift body? DBW means drive - by - wire aka electronic , and DBC is drive by cable the standart cable throttle throttle body.

gusbus86
01-24-2019, 01:47 PM
Yes it can. It could be throwing all those codes. I would check if it gets constant uninterrupted power 1st at the connector. with ignition it should be getting around 9V and 12+ at cranking.

Yeah you can clean with MAF cleaner. AEB is DBC tho. Did you switch ECU's or did you swap an AEB into facelift body? DBW means drive - by - wire aka electronic , and DBC is drive by cable the standart cable throttle throttle body.

my mistake it is dbc. engine was replaced a decade ago by a dealer but thats all I know. I cleaned the TB and I used a multimeeter to check the 4 pin connector at the top of the fuel pump with the meeter set to dcv 20. with the car in the run position I was maxing out at like 1.00 - 1.23v on 1 of the 4 prongs. 1 was 0.00 and the others were like ~0.23. Am I measuring wrong or is something else faulty?

Blazius
01-24-2019, 02:35 PM
Allright now do the same for prong 1 and 4 while somebody is cranking the car.

Wooshy
01-24-2019, 02:44 PM
Could be needing a tb adaptation, that does weird things to the car, mine would stall the call when i touched throttle, when i did tba it fixed that for me atleast

- - - Updated - - -


Could be needing a tb adaptation, that does weird things to the car, mine would stall the call when i touched throttle, when i did tba it fixed that for me atleast

Car...* stupid auto correct..

Blazius
01-24-2019, 02:45 PM
After fuel pump test, do the TBA too because the throttle pos is way too low, it should be around 13%-17% @ idle

Wooshy
01-24-2019, 02:51 PM
After fuel pump test, do the TBA too because the throttle pos is way too low, it should be around 13%-17% @ idle

^^

u will also need vag com if u dont already have one for the tba, i had to borrow one to do mine, was a very easy process

gusbus86
01-24-2019, 04:30 PM
After fuel pump test, do the TBA too because the throttle pos is way too low, it should be around 13%-17% @ idle

Cranking it shows 10-12v I replaced the primary 02 and it ran a lot longer but still died a couple times. I went to start it up after it died and the relay didnt click and didnt prime and kept cranking. tried to start it again the relay clicked and started. the rpms go up and down from 800-1000 and I did notice the throttle cable has a bit of slack in it

gusbus86
01-24-2019, 04:33 PM
^^

u will also need vag com if u dont already have one for the tba, i had to borrow one to do mine, was a very easy process

I dont have vagcom. I think I read somewhere theres a way to do it through the ebay bluetooth obd tools?

Wooshy
01-24-2019, 06:51 PM
not that I know of, I was just out at Va beach a few weeks ago, wish i seen this sooner, i would have brought it and helped you trouble shoot

Blazius
01-24-2019, 10:02 PM
I think your fp relay is broken. Also fix slop if its at throttle body.

nunya
01-25-2019, 11:19 PM
^^

u will also need vag com if u dont already have one for the tba, i had to borrow one to do mine, was a very easy process

You dont need a vag-com to do a TBA on an AEB. Turn the key to accessory (motor off) listen to the TB reset, thats it. Takes maybe a minute, perhaps two.

Blazius
01-25-2019, 11:53 PM
You dont need a vag-com to do a TBA on an AEB. Turn the key to accessory (motor off) listen to the TB reset, thats it. Takes maybe a minute, perhaps two.

AFAIK it doesnt always work. VCDS is the best way dbw or not.

nunya
01-26-2019, 12:03 AM
It does as long as the ABS module hasnt crapped out or something. I know DBC cars pretty well.

gusbus86
01-26-2019, 03:29 PM
i can hear and see in the engine bay the tbp sensor does moves a little. and fluctuates back and forth when the engine is running. I get a low voltage code 18010 only when the cold start stalls. I replaced the battery like 6 months ago myself, maybe it has to be reset somehow cause its a different battery? Im gonna wait on the relay cause my auto shops are charging $40 for it. ebay sells it for like $8-$10. the other day it was about 45-50F outside and it started right up and didn't even shut off. now its 20F and it dies everytime. I measured the battery with the car off it reads 11.8-12.10v and around 14 when running. then SOMETIMES when it stalls itll drop to 8-9v but only sometimes. and when it stalls theres a weird dripping sound coming from the bay. I only hear the injectors squirt sometimes. and when the relay doesnt prime there isnt a click in the engine bay either that I usually hear. the car wont even run now at this point. it just shuts off everytime. I dont know what all that means but somethings still isn't right.