I have problem with Golf mk3 1.9 TDI 1Z '94 engine ECU . So I need help from someone to tell me can I replace ECU from 1.9 TDI 1Z but '96 ? I need to know difference between that 2 ECU-s , because my engine has problem with starting up. Every time I start the engine longer than usual and it runs smooth till it gets to the normal operating temperature , then when I drive it between 2500 and 3000 rpm it just looses power just like it goes in safe mode, but it doesen't have any faults. Engine injection timing is good I checked that first. I checked fuel distribution that is also ok. I don't know where or what to look so I need help.
Golf mk3 ECU problem
- Thread starter Mixa90
- Start date
iluvmydiesels
Veteran Member
looking at your problem, mixa, i dont know if thats an original motor to that car, for one each ecm will be marked look for commonality in the first 2 letters, could be JY, its been sometime since i ve looked up the ecm. or ecu markings.
id point out a common problem is the vacuum lines/hoses. these are at least 10 maybe 11, or 12, one is a short one inside the ecm, so you have to open it up. that means unhooking battery and getting ecm/ecu out of windshield well, when putting back in, i dont know exact procedure, for one battery unhooked(-), two there maybe another step to reattaching electrical connection to ecm, ask. so replace all vacuum lines and see, i took mine to my shop, for one to make sure it put back in right order, was about $200 for me, not too cheap, but well worth it. start with that. you need a couple of hose sizes to do this.
id point out a common problem is the vacuum lines/hoses. these are at least 10 maybe 11, or 12, one is a short one inside the ecm, so you have to open it up. that means unhooking battery and getting ecm/ecu out of windshield well, when putting back in, i dont know exact procedure, for one battery unhooked(-), two there maybe another step to reattaching electrical connection to ecm, ask. so replace all vacuum lines and see, i took mine to my shop, for one to make sure it put back in right order, was about $200 for me, not too cheap, but well worth it. start with that. you need a couple of hose sizes to do this.
Thank you for your help. All numbers are match except the ove wich is beneath production year. And the difference is in 4-th letter mine original ecm is 28SD3287 and new one is 28SA3287 production date is 17.4. '97
Bosch numbers are match , except last 2 letters old one is QQ new one is GG but I think it is not problem because my engine won't start if ecu is not from tdi 1z ahu or alh , I am not sure for ALH engine fuel pump , maybe problem is in that , because my pump is from '94 and ecu is from '96 ... I will try to do what you told me , but I am sure that all vacuum hoses are good. I will look the one in ecm.
Bosch numbers are match , except last 2 letters old one is QQ new one is GG but I think it is not problem because my engine won't start if ecu is not from tdi 1z ahu or alh , I am not sure for ALH engine fuel pump , maybe problem is in that , because my pump is from '94 and ecu is from '96 ... I will try to do what you told me , but I am sure that all vacuum hoses are good. I will look the one in ecm.
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iluvmydiesels
Veteran Member
i cannt say for sure about long cranking to get started, however bad vacuum lines will cause a 'limp mode' with no-lo power. there should be at least 10. 1 will come off pipe coming off intercooler to intake, 1 will be inside ecm, 1 will come off vacuum pump, there will be about 8 or so, for a stock set-up there are 2 vacuum 'banks/connections', each has like 4 vac connections, (each)with an electronic plug connected, they are on passenger side fender, 1 near air box, the other should be close, by shock tower(if a stock/factory set-up). replacing -all- vac lines assures this part of a problem is solved. mark both sides of vac lines for positioning before taking off lines.
It takes more than 30 seconds to start. All vacuum lines are good , checked it twice. It has 3 lines near Airbox , 1 goes to intake manifold before turbo , second is wastegate , third goes on turbine high pressure side . It has 3 more hoses for EGR valve 1 is on vacuum pump , second on airbox and third on EGR actuator. And one hose is from intake manifold to ECM
iluvmydiesels
Veteran Member
so i take it you have VCDS?
-no codes, hummm
so 1 do you have air in your fuel inlet line, the clear line?
new fuel filter? when you change out a fuel filter prime it first, new and good air filter?
from what you say its not definite that the ecm/ecu is bad, but if you want to switch the other one in, i suppose you can just try. different letter(the 2 letters) codes marking an ecm can tell you what, and/or where the ecm if from, cali for one, canada, for another, then again i dont get much from the east coast, NA. in the search section put in ecm, i would say codes as that would be what comes up for CEL codes, but look for those letter markings as i mentioned, in the forum, there may be a list of where and when ecm-s are good. call VW and ask or look online.
the other thing, im not 100% sure otherwise, you disconnect -neg at battery, and can try the other ecm and see what results you get, as long as the wire connector fits, i use electronic spray, a little clean up, (check pins, on both sides), hook up other ecm and youd have to check to be sure if after your just ready to re-connect battery. do you have the shop manual, there may be it in there; procedure.
-no codes, hummm
so 1 do you have air in your fuel inlet line, the clear line?
new fuel filter? when you change out a fuel filter prime it first, new and good air filter?
from what you say its not definite that the ecm/ecu is bad, but if you want to switch the other one in, i suppose you can just try. different letter(the 2 letters) codes marking an ecm can tell you what, and/or where the ecm if from, cali for one, canada, for another, then again i dont get much from the east coast, NA. in the search section put in ecm, i would say codes as that would be what comes up for CEL codes, but look for those letter markings as i mentioned, in the forum, there may be a list of where and when ecm-s are good. call VW and ask or look online.
the other thing, im not 100% sure otherwise, you disconnect -neg at battery, and can try the other ecm and see what results you get, as long as the wire connector fits, i use electronic spray, a little clean up, (check pins, on both sides), hook up other ecm and youd have to check to be sure if after your just ready to re-connect battery. do you have the shop manual, there may be it in there; procedure.
I have VCDS and it says no fault codes. I have 2 ECU-s , 1 is from VW Golf mk3 1.9 TDI 1Z '94 year and other is also MK3 Golf same engine but '96 year . I think that my '94 year ECU is faulty , so I can change it to '96 ECU but when I do that I have problems with cranking , it is cranking 30 sec or more sometimes , it goes good but then problem is when it comes to normal operating temp. it somehow goes in some kind of limp mode but doesen't record any fault . When i stop engine and start up again it goes normal for some time and then it repeats limp mode thing.
The '96 year ECU had an immobiliser protection but I got that removed by my friend who works in car service near by. Just to mention when I run car with '96 ECU it has idle rpm about 900 rpm and with '94 it is around 840rpm.
The '96 year ECU had an immobiliser protection but I got that removed by my friend who works in car service near by. Just to mention when I run car with '96 ECU it has idle rpm about 900 rpm and with '94 it is around 840rpm.
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Steve Addy
Top Post Dawg
My approach would be to take the two part numbers for these ECU's (the VW part numbers) and search online for evidence that they are interchangeable with each other. You can do it via online VW parts suppliers like Ellis VW or even the older online ETKA too.
That's how I would start with this.
Steve
iluvmydiesels
Veteran Member
^#1&2?
Steve Addy
Top Post Dawg
I found the problem. Problem is in coolant sensor , when I disconnected it engine starts without problems and goes well on '96 ECU . Next thing is to find the right sensor. It is not black with yelow ring , because I bought that one and it is not working , so I disconnected it... Anyone who knows wich sensor goes please let me know . Thank you all for your help .
Steve Addy
Top Post Dawg
That seems rather odd, but are you sure that the replacement yellow ring sensor you bought isn't bad? That would be my first guess. Can you replace it with another of the same and see what that does?
It seems odd that they would change the sensor specs like that but I suppose. There might be another, I know that there is also a blue ring sensor and a brown one as well. Which is the one you need, if you actually need a different one, is unknown to me.
Steve
iluvmydiesels
Veteran Member
which coolant sensor are we talking about. in my mk3 i have 2 sensors one in the flange that comes out of the (front) of the head, and the same hose has a sensor, this is the hose that goes to the top of the radiator. cannt think off hand of another coolant sensor. although isnt the rad fan controlled by sensor in bottom of rad. the sensor in front head flange i think is a 4-connector/pin, is it for A/C control? im not sure off the top of my head. the sensor in rad hose i think is 2-connector/pin. either should be fairly easy to find.
i dont know if you want to order from US, but for a part like this, autohausaz should be an easy place to order from.
i dont know if you want to order from US, but for a part like this, autohausaz should be an easy place to order from.
@Iluvmydiesels Coolant temperature sensor from front of head , someone calls that temperature sender.
@Steve Addy I don't know , because I bought new one , and the old one worked on my '94 ECU , that I am confused , because on every parts catalog it says black/yelow or black/green difference is only in manufacturer black/green is from SWAG , black/yelow is from BERU , TOPRAN and FEBI...
@Steve Addy I don't know , because I bought new one , and the old one worked on my '94 ECU , that I am confused , because on every parts catalog it says black/yelow or black/green difference is only in manufacturer black/green is from SWAG , black/yelow is from BERU , TOPRAN and FEBI...