My AHU no start

ludowrx974

Member
Joined
Jan 11, 2009
Location
reunion island
TDI
seat cupra TDI
hello !! my car no want start. The engine only start whit cleaner, if i turn off it's impossible start. I have already check:


- vagcom no code

- relay 109 it's ok

- Pump selenoid it's ok 12v on

- I tested a new pump (engine always no start)


- I tested all injector (engine always no start)


Sorry for my english !


 

Mozambiquer

Vendor , w/Business number
Joined
Mar 21, 2015
Location
Versailles Missouri
TDI
1998 VW Jetta TDI. 1982 VW Rabbit pickup, 2001 VW Jetta TDI, 2005 VW Passat wagon TDI X3, 2001 VW golf TDI, 1980 VW rabbit pickup,
Have you checked timing? How about compression? Both of those could cause issues.

Sent from my S60 using Tapatalk
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
We mean physically checking timing marks. Not what's in vcds. Also there is no timing adjustment in vcds. Its manual.

There is a good thread here on no start.

You should not have a pump. Ahu only has IP. No in tank pump. So your getting fuel at each injector ?
Sounds like your wire harness is suspect. Check ALL of the wires in the cord to the ip. White wire especially. Typical for them to brake.
 

ludowrx974

Member
Joined
Jan 11, 2009
Location
reunion island
TDI
seat cupra TDI
We mean physically checking timing marks.
yes i used timing marks and use tool specific engine.


yes there are not pump in tank. and i have good fuel at each injector when the engine start.

when the egine start with cleaner i eliminate:


-The immoblizer
-ECU
-CKS sensor
 

garciapiano

Veteran Member
Joined
Feb 12, 2018
Location
Southern California
TDI
1997 Jetta TDI (1Z)
A car that only starts with starter fluid would indicate an issue with fuel delivery. Crank no start condition usually indicates an issue with the shutoff solenoid and potentially the pump electric controls themselves.. In my car, crank no start was related to a bad ignition switch. I restored proper starting with bypassing the alarm module immobilizer, replacing the ignition switch and replacing relay 109.

Usually an issue with a connection to the shutoff solenoid will result in a code, so the fact that you are getting no codes leads me to think there is something else that is not triggering that solenoid to open.
 
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Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
You can have fuel delivery but not enough.
Check the wires on the harness. This is a growing issue now.
 

ludowrx974

Member
Joined
Jan 11, 2009
Location
reunion island
TDI
seat cupra TDI
i have already check on the harness just wire:


-shutoff selenoide. there are 12v and i even removed the piston small inside

-CKS sensor 1,2k ohm about
 
Last edited:

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
So it's a shot in the dark but check the connections at the 109 relay. I have a mk3 ahu like yours and I some times have to wiggle the 109 to start but once started it will run but needs to wiggle again to start. Not sure why but the relay is good but the connection at the block is worn out . Also had a very similar issue with the smaller ip harness wire connection. Pull it apart and make sure its clean.
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
hello !! my car no want start. The engine only start whit cleaner, if i turn off it's impossible start. I have already check:


- vagcom no code

- relay 109 it's ok

- Pump selenoid it's ok 12v on

- I tested a new pump (engine always no start)


- I tested all injector (engine always no start)


Sorry for my english !


What happened before your engine quit running?

When was last time you replaced the fuel filter?

Is this 110 hp tdi?


Steve
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Ok, so you have a new fuel filter installed recently?

Does your car have the immobilizer? What year is your Cupra?

Steve
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
You can jump the security immobilizer behind the dash driver side door dise vent.
 

ludowrx974

Member
Joined
Jan 11, 2009
Location
reunion island
TDI
seat cupra TDI
You can jump the security immobilizer behind the dash driver side door dise vent.

I don't have immobilizer at least I can't find it. may be the european car because not this type immobilizer.
on the other hand I more or less find the breakdown either it is ignition switch or connector.When i move the wire the engine start and sometines no start.
Somebody have a schematic ignition so that I can find the fault precisely.




 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
All makes came with one. It's not under the steering colum. Lile I said. Pull off the side vent its behind that off to the side
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
There has to be that harness and it will be either plugged into a bypass or just hanging there with the bypass already done.
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
I don't have immobilizer at least I can't find it. may be the european car because not this type immobilizer.
on the other hand I more or less find the breakdown either it is ignition switch or connector.When i move the wire the engine start and sometines no start.
Somebody have a schematic ignition so that I can find the fault precisely.




Ok, are you talking about Leon or Ibiza? I have been assuming you have a Leon? Also what year is your car, it will help to know.

I am beginning to suspect that your ignition swith is bad, especially since you mentioned a wire that would cause it to start and then not to start.

When he says immobilizer he really means convenience module or alarm box. It controls keyless entry and sets off an horn if the car is broken into.

Steve
 
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