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Author: Subject: help finding a fault?
AndyW

posted on 8/8/15 at 09:18 AM Reply With Quote
help finding a fault?

the car starts and runs ok (albeit slower than I expected)

I have a fault code of PO171 which is lean bank 1. I have a new O2 sensor and that's working ok-checked.

Air flow meter has been cleaned along with my air filter

Had new coil pack and leads last year

Not changed spark plugs recently.

Checked timing last night and spot on.

Any other idea's what to check.

I have checked exhaust and can see no signs of leak. I have also checked inlet and can find no signs of air leaks. I have replaced the vacuum hose from inlet to fuel pressure reg and still get fault code after 10 mins driving.

I have done the usual google search but it shows several things. Could this be a case of elimination or does any one have a suggestion.

Going to change my fuel filter this morning as not done so since building and now covered 3.5k miles.

Could it be an injector???

Ta in advance

Andy

[Edited on 8/8/15 by AndyW]

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adithorp

posted on 8/8/15 at 09:47 AM Reply With Quote
First thing should always do basic service checks before searching furtherunless there's something obvious; Plugs+ filters.

What colour are the plugs. If it's an air leak the ECU will be trying to compensate. Exhaust side leak and they'll look rich (mixture ok but extra air in exhaust makes it look lean to ECU so it adds extra fuel). Inlet side and they might look normal. Poor fuel presure/injector and they'll look lean as no amount of compensation will actually increase the fueling.

Re-check for an air leak including the exhaust side (a slight manifold crack will be enough). Also check the PCV valve and brether pipe. For the inlet side spraying carb cleaner around helps but I prefer taking the nozzel off a blow torch, fitting a hose and feeding butane gas around. More precise and less messy. The engine note will change if you find the leak.





"A witty saying proves nothing" Voltaire

http://jpsc.org.uk/forum/

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rusty nuts

posted on 8/8/15 at 10:37 AM Reply With Quote
Unlikely but tight valve clearances will cause a weak mixture but high HCs and still show black plugs. Silver top engines suffered if the wrong grade of oil was used but Blacktop uses shims, might be worth checking? When you say you've checked the timing I suspect you mean cam timing?
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britishtrident

posted on 8/8/15 at 11:08 AM Reply With Quote
What is happening with the fuel trims? and is the engine running closed loup? Are the temperature sensors giving sensible readngs?
There is an excellent YouTube channel Schrodingers Box that has some very good videos on diagnosing lean configuration faults.





[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]

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britishtrident

posted on 8/8/15 at 11:50 AM Reply With Quote
Schrodingers Box Youtube Link





[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]

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mac1ZR

posted on 8/8/15 at 11:57 AM Reply With Quote
Have you got silicone hoses? I had this same fault on a my focus rs. and it turned out to be the hoses moving very slightly as the engine moved on its mountings, and letting slightly varying amounts of air in. Changed to rubber hoses, which sealed better, and no more problems.

[Edited on 123131p://666 by mac1ZR]

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AndyW

posted on 8/8/15 at 12:15 PM Reply With Quote
just pulled the injector rail out and found that injector 3 has the end missing. Its a round brown thing that the other 3 injectors have but this one is missing. Could this be a cause?
Description
Description

its the brown collar on the end that's missing from one injector

Has anyone local to Bedfordshire got a spare 2.0 blacktop injector (that works!) that I could try please.....


[Edited on 8/8/15 by AndyW]

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AndyW

posted on 8/8/15 at 12:53 PM Reply With Quote
Description
Description


missing the end bit......

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AndyW

posted on 8/8/15 at 04:24 PM Reply With Quote
Fuel trims at idle....

Description
Description


Fuel trims at 2500rpm ish......

Description
Description

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rusty nuts

posted on 8/8/15 at 04:31 PM Reply With Quote
Was the engine hot? logs show a cool engine
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AndyW

posted on 8/8/15 at 04:33 PM Reply With Quote
no engine wasn't fully warm as just removed and put back inlet manifold. So just ran it to see fuel trims. Running out of time for tonight but must get this sorted tomorrow.

Any more help appreciated

Cheers

Andy

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AndyW

posted on 9/8/15 at 10:03 AM Reply With Quote
any one have any suggestions as to my injector issue above??
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adithorp

posted on 11/8/15 at 07:32 AM Reply With Quote
Not sure how that would affect the spray pattern but my first concern would be, where's the bit gone?





"A witty saying proves nothing" Voltaire

http://jpsc.org.uk/forum/

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AndyW

posted on 22/8/15 at 04:07 PM Reply With Quote
ok the saga continues. Injectors have had new filters and o rings fitted. New inlet manifold gasket, changed back to my old o2 sensor, still getting PO171 bank 1 too lean

I have a silicon hose between the airflow meter and throttle body, looks ok and does not appear to have any splits. Checked vacuum hose to fuel regulator all ok.

I just been out for another drive after clearing the fault code and it has come back again.

I did notice that my high pressure pump is very noisy and can be heard even when driving along at about 30mph with no roof or doors on.

I'm away for a week now but really want to sort this as not long left until tax runs out and want to get this resolved.

Any further suggestions of what to check etc.

Thanks
Andy

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rusty nuts

posted on 22/8/15 at 06:06 PM Reply With Quote
If the high pressure pump is noisy it might be a good idea to check the fuel pressure and the delivery rate, noisy pumps are often an indicator of pump failing . Check for fuel pipe/hose restrictions as well. Low fuel pressure/delivery rate could well cause the EML light to show a fault
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AndyW

posted on 22/8/15 at 06:43 PM Reply With Quote
I have a Schrader valve on the end of the fuel rail, can I get a fuel pressure gauge to take reading from that??
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britishtrident

posted on 22/8/15 at 07:24 PM Reply With Quote
quote:
Originally posted by AndyW
I have a Schrader valve on the end of the fuel rail, can I get a fuel pressure gauge to take reading from that??


Yes but it is really adviseable to use the proper screw on fitting test gauge.





[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]

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