Fuel Pressure Pump FB15 Automatic

[Deepal Priyanga]

Hi guys,

My car was having this acceleration issue recently and show it to a mechanic and got the fuel pump (the one inside the petrol tank) replaced by mechanic two week ago. Actually he checked the fuel pressure and there was no pressure at all when switch is on only jumped it to 25 knots after engine started. when engine stops pressure came down at no time. Mechanic told that even after engine shut down it should keep the pressure. With that conclusion he changed the fuel pressure pump. However replaced one was a TAIWAN made. After that I drive the around 1000 km with several long trips.

Last week I drive to Kandy and again the same issue came and car was not moving at all at the middle of Kandy Town. Engine was not accelerating when I paddle. However I found a mechanic there and managed to drive back. He told that TAIWAN petrol pump is not reliable.

Since the  I was driving the car and I felt car was not ruining smoothly as earlier. Hence I show the car to the mechanic who replaced the petrol pump two weeks back. He tune up the engine replacing spark plugs, cleaning injectors and all. After that he check the petrol pressure again. It was zero when switch is on. went up to 30 knots after engine starts. back to zero in no time after engine stops. Mechanic is telling i got to replace the petrol pump again with  genuine one. 

Now I am thinking of what option I have. Car is not running well and engine starting is also a bit lazy. I have to give little gas to start the engine. (can all these be due to not enough petrol pressure? can it be something else)

Please share if you have any this kind of experience and hope mechanical experts can assist me.

Thank you.

 

 

 

[Rumesh88]

Your car is on "fail safe mode" I believe. When it goes to this mode the fuel pump runs only when the engine is started. Do you have a CEL (Check Engine Light) indication on the dash? First make sure the CEL indication is actually working. Our makabasses have a habit of bypassing CEL to hide faults they cannot trace or repair. I am pretty sure that is the case with your car. Get the car scanned, note all stored fault codes and get them attended and car cleared of all fault codes first. Then get the CEL indication to work. I don't think your original pump was faulty.

Edited April 24, 2017 by Rumesh88

[Deepal Priyanga]

Thanks for the response.

CEL is on when switch is on and disappear after engine starts. That's normal, right?

[Rumesh88]

10 minutes ago, Deepal Priyanga said:

Thanks for the response.

CEL is on when switch is on and disappear after engine starts. That's normal, right?

No that is NOT normal if the makabass has done the bypass properly. Usually they disconnect it from the original wiring and wire it parallel with the oil pressure alarm. Then you get the visual effect you described but it will not indicate a fault when one occurs in the system. If you want to test it, while the engine is running ask your mechanic to disconnect a sensor like IAT, MAF, TPS or cam position sensor - whatever sensor easily accessible and safely removable - and see if you get the indication. I am sure that you would not get the indication in your case suggesting a bypass of CEL.

[Deepal Priyanga]

will do that,

So, you are suggesting issue may not be with the fuel pump and my original fuel pump might have worked properly.

 

[Rumesh88]

4 minutes ago, Deepal Priyanga said:

will do that,

So, you are suggesting issue may not be with the fuel pump and my original fuel pump might have worked properly.

 

Yes precisely. Some one must have already bypassed CEL indication when the ECU detected some other issue and went into fail safe mode. Since the CEL indication did not pop up mechanics went on a wild goose chase. However, in spite of all that if you got the car scanned you would have seen the real fault code. 

[Deepal Priyanga]

6 minutes ago, Rumesh88 said:

Yes precisely. Some one must have already bypassed CEL indication when the ECU detected some other issue and went into fail safe mode. Since the CEL indication did not pop up mechanics went on a wild goose chase. However, in spite of all that if you got the car scanned you would have seen the real fault code. 

I told the mechanic to scanned the car. That guy told it is not necessary as CEL was not indicating. Even he told that such scan would not find issue with petrol pressure.

i would get done what you have advised,

just curious, why do I experience misfire, loss in power then, if it is not fuel pressure what t could be ?

 

Edited April 24, 2017 by Deepal Priyanga

[Rumesh88]

7 minutes ago, Deepal Priyanga said:

I told the mechanic to scanned the car. That guy told it is not necessary as CEL was not indicating. Even he told that such scan would not find issue with petrol pump.

Would you expect better analytical skills from an average mechanic? Obviously his analysis was based on wrong presumptions. Even now he may try to fool you if you go back to him. Better get the car scanned by someone else and stored codes noted.

[Deepal Priyanga]

Hi

On 4/24/2017 at 2:56 PM, Rumesh88 said:

Would you expect better analytical skills from an average mechanic? Obviously his analysis was based on wrong presumptions. Even now he may try to fool you if you go back to him. Better get the car scanned by someone else and stored codes noted.

HI,

just to let you know that i got the issue fixed. Issue was with the petrol filter and git it changed now starting issue is fixed. now car start without any issue.

However there is this knock(not a noise, but a shock) while driving. As long as I keep the foot on accelerator car runs smoothly, but when I release the foot to reduce speed, car gets this knock(one time shock). Then again when I keep foot on pedal car start to gain speed after a one time shock.  Any idea why this might be ?    

[The Stig]

3 hours ago, Deepal Priyanga said:

Hi

HI,

just to let you know that i got the issue fixed. Issue was with the petrol filter and git it changed now starting issue is fixed. now car start without any issue.

However there is this knock(not a noise, but a shock) while driving. As long as I keep the foot on accelerator car runs smoothly, but when I release the foot to reduce speed, car gets this knock(one time shock). Then again when I keep foot on pedal car start to gain speed after a one time shock.  Any idea why this might be ?    

During the tune up did you clean the throttle body, iacv and EGR?

Sounds like an issue with your idle air control. It could also be the tps and maf, clean them both and see. 

[Rumesh88]

3 hours ago, Deepal Priyanga said:

Hi

HI,

just to let you know that i got the issue fixed. Issue was with the petrol filter and git it changed now starting issue is fixed. now car start without any issue.

However there is this knock(not a noise, but a shock) while driving. As long as I keep the foot on accelerator car runs smoothly, but when I release the foot to reduce speed, car gets this knock(one time shock). Then again when I keep foot on pedal car start to gain speed after a one time shock.  Any idea why this might be ?    

How is your CEL indication? Does it really indicate a fault when there is one?

Subject to your CEL is working the knock can be either due to a worn out TPS sensor or wrong throttle adjustment. Does it happen on cold start and when the engine revs are high? or only when the engine is warm? 

[Deepal Priyanga]

2 hours ago, The Stig said:

During the tune up did you clean the throttle body, iacv and EGR?

Sounds like an issue with your idle air control. It could also be the tps and maf, clean them both and see. 

Throttle body clean up done. I don't have much idea about the IACV and EGR

However MAF & TPS both clean while diagnosing the issue of hesitance in engine start.

P.S. Injector filters also replaced when petrol filter was replaced as those were clogged.

Edited May 30, 2017 by Deepal Priyanga
Adding futher details

[Deepal Priyanga]

1 hour ago, Rumesh88 said:

How is your CEL indication? Does it really indicate a fault when there is one?

Subject to your CEL is working the knock can be either due to a worn out TPS sensor or wrong throttle adjustment. Does it happen on cold start and when the engine revs are high? or only when the engine is warm? 

according to the person who scanned the Car told that CEL indication is working fine.

Actually I noticed that this happens only after car is driven a few of miles. I checked this several times. It always happens after I drive about 2 miles.

[Rumesh88]

1 hour ago, Deepal Priyanga said:

according to the person who scanned the Car told that CEL indication is working fine.

Actually I noticed that this happens only after car is driven a few of miles. I checked this several times. It always happens after I drive about 2 miles.

 Solutions for a similar case discussed in this thread http://forum.autolanka.com/topic/15899-rpm-drop-and-intermittent-jerky-feeling-of-engine-at-idle-and-low-cruising-rpm/#comment-300029 

 

[Kisal]

Mr deepal can you give me your contact number..mage vehicle eket oya problem eka tiyenawa

[SenakaGW]

Do you have Housing for Nissan FB15 Petrol Pump - Old Model