400E no fuel pumps prime intermittent

[ap961145]

Hello to all of you,

As i have tried to fix it the LH module by changing capacitors and it works but only occasionaly.
So when I turn the key to contact the pumps don’t start. When I check voltage in the fuel pump relay I get arround 7-8 volts. If I manualy short relay pumps work I can start the car and it works good. After arround 30-60 seconds, the relay works normally even if I try to start the car normaly.
But occasionaly the starting is just fine. Sometimes like today I put key to contact and no proming, but after 5 minutes I hear the pumps priming. And after the car works great.

Any Idea what to check?
Checked the contact wire which supplies power to base module is ok.
Base module fuses are ok.

Looks like there is not enough power going to LH module by the looks of it.

Any idea will help.

Alen

 

[gsxr]

Replace the LH module with a good used one. There may be something else wrong inside besides the old capacitors.

 

[ap961145]

Ok. Already bought the same WOT and its shipped via usps from states. Hope this will be ok.

Funny today it worked through the day but when the prime should take 2 seconds it would prime continuously. Without stopping prior the cranking. Starts normaly and drives well.

 

[ap961145]

Just to do a followup.
Checked the pressure on the rail and star pressure on the mark. When removin vacuum from FPR gone up to 4,1 bar.
Whe car was turn off in 5 minutes residual pressure went to 0 bar.
So today bought ne bosch FPR A0000781889 and the car starts like new.
It even feels little quicker.
thanks for you assistance.

Alen

 

[gerryvz]

Just to do a followup.
Checked the pressure on the rail and star pressure on the mark. When removin vacuum from FPR gone up to 4,1 bar.
Whe car was turn off in 5 minutes residual pressure went to 0 bar.
So today bought ne bosch FPR A0000781889 and the car starts like new.
It even feels little quicker.
thanks for you assistance.

Alen

Everything is still OK with your fix of a new fuel pressure regulator?

 

[ap961145]

Yes. It starts fine now.

 

[ap961145]

But sill would like to buy a spare LH module

 

[gsxr]

But sill would like to buy a spare LH module

Search eBay but make sure the seller accepts returns, in case the used module is DOA. Are you located in USA?

 

[ap961145]

nope. i am in Europe.
Croatia.