Fiesta 1.4 engine code SPJC (FIXED)

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Technician
TwoWaves
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Fiesta 1.4 engine code SPJC (FIXED)

Post by Technician » Tue Jun 04, 2019 5:38 pm

Just scratching my head a little with this one. Engine will not start. Compression test using a gauge records 150 psi on each cylinder. There is fuel supply. I am advised the engine back fired into the plastic intake manifold. I used the WPS to establish manifold vacuum thinking that the manifold could have been damaged. There is no manifold depression during cranking to shout about. I used the WPS set on the number two setting not knowing what to expect, so the trace needs expanding to read it. There is only one vacuum take off on the inlet manifold and that is the brake servo hose. There does not seem to be a leak on that hose assembly.

How can the engine generate compression yet have very little manifold depression, especially when I cannot find a leak!
Attachments
190602_Relative CompressionTest Ford Fiesta.pddata
(90.41 KiB) Downloaded 30 times
Ford_Fiesta_2012_Petrol_cranking vacuum test with PCV blanked off.psdata
(422.44 KiB) Downloaded 24 times
Ford_Fiesta_2012_Petrol_Very low cranking manifold pressure recorded.psdata
(935.42 KiB) Downloaded 25 times
Last edited by Technician on Wed Jun 05, 2019 5:49 pm, edited 1 time in total.

liviu2004
TwoWaves
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Re: Fiesta 1.4 engine code SPJC

Post by liviu2004 » Tue Jun 04, 2019 5:55 pm

There is no much depression on starting, to begin with. 200 rpm does not do any. Move away from that. Backfire might indicate wrong timing.
Is there spark? Is there injector valve activity?

Technician
TwoWaves
TwoWaves
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Re: Fiesta 1.4 engine code SPJC

Post by Technician » Tue Jun 04, 2019 6:24 pm

Yes cranking is a tad low at 200 rpm, and yes the valve timing was out. If I understood it correctly when I checked it I thought the pistons 1 and 4 were set past TDC rather than at TDC, hence back fired into the intake manifold. The compressions were checked prior to adjusting the valve timing and nothing was recorded on the gauge for any cylinder, but after adjustment of the timing the compressions now read 150 psi. The engine tried to start afterwards but was very lumpy and then stopped. Truthfully I had not thought about the injectors pintle operation, which might of been damaged when the back fire occurred in the inlet manifold, but then would four injectors all go down at the same time?

What has really thrown me here is the very low manifold depression during cranking.

liviu2004
TwoWaves
TwoWaves
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Location: Netherlands

Re: Fiesta 1.4 engine code SPJC

Post by liviu2004 » Wed Jun 05, 2019 4:48 am

Injector operation needs to be checked so to confirm integrity of the ecm functionality.
If this engine had no compression, valves damage to be suspected?

landroverman1958
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Re: Fiesta 1.4 engine code SPJC

Post by landroverman1958 » Wed Jun 05, 2019 6:00 am

Good morning why not do a cranking in cylinder and get the whole picture,with an ignition sync?Odd you have,nt done one as you have the transducer to carry the test out. :o

Technician
TwoWaves
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Re: Fiesta 1.4 engine code SPJC (FIXED)

Post by Technician » Wed Jun 05, 2019 7:31 am

Thank you gentlemen for your replies they are very much appreciated. I'll be honest when the engine back fired into the intake manifold (plastic) it sounded really bad and much smoke present, I feared the worst. I did the above tests prior to removing the inlet manifold yesterday thinking that very little manifold depression was indicating a serious leak maybe caused by damage. I visually inspected the manifold and piping/hoses to find nothing visually wrong. I decided to rebuild the intake system and think I'll put the scanner on and check injector operation via CTM! What a let down, the software on scanners in most cases I see is rubbish, the people writing the software must have no experience and blindfolds on when they write the software. I could not even do component tests.

Anyway after rebuilding I thought I'll look at cranking live data and see what happens from there, and to my surprise the engine started. The engine runs OK :D

I respect that I have the WPS and did not use it for in-depth diagnosis, but I was respecting Pico and their Pico diagnostics software. I was relying on the results of the relative compression tests and the gauge tests which proved correct. It appears then that valve damage has been avoided on this occasion and serious luck has been in my favour.

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