Z22YH Fuel Issue - P1191-52

AdamantUK

Member
Been getting occasional issues where when I plant my foot and kick down happens, I get a hard hesitation and the car with spanner light come on.

I thought it felt mechanical so expected gearbox but it's now started happening when engine is under load and I request more power (e.g. accelerating up hill on motorway).

Read code and get P1191-52 so found the TIS and run checks other than the low pressure fuel test as I dont have a manometer.

My guess currently is that it's the hp fuel pump at fault, tests run do far are:

Idle
Hp fuel pressure requested: 5000kpa
Hp fuel pressure feedback: 4559kpa

Disconnected 2 wire plug from pressure regulator and feedback is at 0.7V

When revved but stationary, the request and feedback pressures are pretty much the same up to about 5000 revs where if I keep it there for a few seconds then I get

Requested fuel pressure: 8054 kpa
Feedback fuel pressure: 793 kpa

The separation of the two under load makes me think this is likely to be the hp pump membranes failing.

Unless anyone advises otherwise, my next test will be to pop and see a mechanic friend and have him hook a pressure gauge in line with the low pressure feed where it arrives st the hp pump. I'll then monitor the high pressure and rev until it's not delivering what's requested and, if the low pressure side doesnt drop at this point, replace the pump.

Any other thoughts or suggestions for anything I may have missed?
 
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