Technical Fuel Pressure before cranking 1.9 jtd 2002

[lcf666]

Hi guys, I have an starting issue on my Punto it has the 1.9 jtd 85cv engine.

I think is related to the HP Fuel Pump. I put the key in ON position without starting and I see that I have 1.8 Bar when the fuel pump in the trunk is active and 0 Bar when its stop.

On the Desired Fuel pressure by the ECU the value says 300 Bar but I'm not sure if it is valid whe the engine is off.

I searched all over the forum but couldn't find the value.

So, could someone with a similar engine and multiscan tell me the fuel pressure before cranking of your working engine?

thanks!

 

[Brendan W]

Hi icf666 and welcome.
1.8 bar from the low pressure pump sounds about right. The high pressure pump should increase pressure during cranking. This is a V70 and it's fairly typical

 

[lcf666]

Thanks BrendanW! I also found a work coleague with an Alfa 147 and has the same 1.8 Bar before cranking, wich means I have a leak somewhere. Any ideas for common leak issues?

thanks

 

[s and b]

you would see a leak
maybe pump weak and unable to sustainpressure
is filter blocked? is it frozen? has it collapsed etc

 

[Brendan W]

Thanks BrendanW! I also found a work coleague with an Alfa 147 and has the same 1.8 Bar before cranking, wich means I have a leak somewhere. Any ideas for common leak issues?

thanks

If you are having problems starting especially from cold one of the first things to check is the leak back from the injectors. If one is leaking more than 40 ml/min at idle it can be enough to prevent the rail having enough pressure to start.
After that you might look at cranking speed too low because of low battery, lazy starter motor or high resistance in the starter circuit.
Less likely is high pressure pump failure.
Glow plugs are not really needed if the ambient temperature is above 6-7 C.

 

[judderbar]

If you are having problems starting especially from cold one of the first things to check is the leak back from the injectors..

leak back testing............

https://www.uniteddiesel.co.uk/docs...njectors-checking-back-leakage-1398762965.pdf

 

[lcf666]

Thanks Bendran and Judderbar :worship:! I'm looking where to buy one of those test kits. Btw, I replaced all 4 glow plugs and now I'm getting P0201/202/203/204, I guess its the connector on the injector as the plastic gets old and all dry out, or I touched something wrong

 

[Brendan W]

Four drinks bottles taped together and the hose from a pet shop aquarium supply or pneumatic supply shop. Just make sure the lengths are the same.
What exactly is the problem and did you check the resistance of the plugs ?

 

[maggers]

Out of interest, what's the cranking pressure and how quickly does it get to it? 3 bar is about the average, as stated by your desired pressure.

 

[lcf666]

Hi guys, thanks for you help, quick update: I found that (not sure how) I inverted the cyl3 and cyl4 injector connector. Before I proceed with the leak back testing should I use some injector cleaning additive? any of those any good? any brand to recommend?

 

[Brendan W]

Hi guys, thanks for you help, quick update: I found that (not sure how) I inverted the cyl3 and cyl4 injector connector. Before I proceed with the leak back testing should I use some injector cleaning additive? any of those any good? any brand to recommend?

If you mean you swapped over the 3&4 supply pipes then swap them back and try to start. Are you sure the pipes were swapped, would seem difficult to get them to go on the wrong way. That could be your problem. I wouldn't use any cleaner before a leak test. You are trying to find a smoking gun not make the problem go away before a diagnostic test. Maybe you won't need to do it at all if she fires up OK with the pipes back the right way

 

[lcf666]

If you mean you swapped over the 3&4 supply pipes then swap them back and try to start. Are you sure the pipes were swapped, would seem difficult to get them to go on the wrong way. That could be your problem. I wouldn't use any cleaner before a leak test. You are trying to find a smoking gun not make the problem go away before a diagnostic test. Maybe you won't need to do it at all if she fires up OK with the pipes back the right way

No I meant the connector that goes to the ECU.

Anyway I did the Leak Back test as you suggested and I found Inj Cyl 4 was crazy flowing diesel out.

I'm going to replace it. I have the 1.9 85cv JTD, I'm not sure if I need to code the Class only or the IMA code. Because I don't see the class on the injector.

Attached images.

thanks :worship:

 

[Brendan W]

No I meant the connector that goes to the ECU.

Anyway I did the Leak Back test as you suggested and I found Inj Cyl 4 was crazy flowing diesel out.

I'm going to replace it. I have the 1.9 85cv JTD, I'm not sure if I need to code the Class only or the IMA code. Because I don't see the class on the injector.

Attached images.

thanks :worship:

I don't know about the Fiat set up. Volvo code injectors in three classes 1,2,3. At assembly they are the same class but the ecu can handle up to two injectors from an adjacent class. ie a set of 2s will handle up to two 1s or two 3s. ( 5 cylinders)

 

[lcf666]

Hi guys.. Good news!! After replacing the injector on the Cylinder 4 I have least 1.8Bar before cranking and the engine starts very fast and no white smoke after starting.

Thanks to everyone that helped!