Member Since: 22 May 2019
Location: Norfolk
Posts: 305
Compressor air inlet
I replaced my hitachi compressor roughly 18months ago, now have the 'pressure does not decrease when venting gallery' error again i have replaced the electrical valve with a known good one but still randomly get the fault, just wondering if theres any value in investigating where the exhaust pipe work leads to im guessing the air inlet pipe work? anyone ever found this fault and pipe work are related? or am in completely the wrong area!
28th Mar 2022 7:33 am
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 5044
No, wrong direction I would say as this area very rarely if ever gives a problem unless a pipe has been crushed. Exactly what dtc's are you getting?
It sounds like your exhaust valve is sticky/faulty or bad plug connection.yµ (idµ - eAµ) ψ=mψ
28th Mar 2022 1:06 pm
Andyyav
Member Since: 22 May 2019
Location: Norfolk
Posts: 305
I’ll get a screen shot next time it faults it’s only one fault wording along the lines of pressure does not decrease when venting, it comes up randomly, I’ll give the plug a check but guess I’ll end up with another compressor
28th Mar 2022 7:10 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 5044
What make of compressor did you fit 18 months ago?
Was it a genuine Hitachi or an aftermarket make like Dunlop, or something worse from yonder east?yµ (idµ - eAµ) ψ=mψ
28th Mar 2022 8:00 pm
Andyyav
Member Since: 22 May 2019
Location: Norfolk
Posts: 305
It was genuine hitachi trying to think where I got it from,
28th Mar 2022 8:32 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 5044
Unlikely to be much wrong with that after such a short period, see what codes you get next time and post them here. yµ (idµ - eAµ) ψ=mψ
28th Mar 2022 9:01 pm
Andyyav
Member Since: 22 May 2019
Location: Norfolk
Posts: 305
Fault came in last night, going between the yellow and red 30mph max warning, cleared with the tool.
2nd Apr 2022 9:10 am
Admirable
Member Since: 19 Jul 2015
Location: Fife
Posts: 1039
I'm sure I've posted this before as it's a common fault.
2nd Apr 2022 9:37 am
Andyyav
Member Since: 22 May 2019
Location: Norfolk
Posts: 305
Nice info! I wonder if-
Air suspension exhaust silencer blocked/restricted
Air suspension exhaust pipe
blocked/damaged
Are related to the pipe work I pictured above?
Are there any implications with running the compressor with the pipe work ‘bypassed’?
Don’t want to get another compressor to find it’s that pipe work at fault, I’ll get under it later to see if there’s any visible damage
2nd Apr 2022 9:58 am
garrycol
Member Since: 06 Dec 2010
Location: Canberra
Posts: 1130
Well just disconnect the inlet pipe and the exhaust pipe from the compressor and see if you have the same issue - too easy.
2nd Apr 2022 10:16 am
Andyyav
Member Since: 22 May 2019
Location: Norfolk
Posts: 305
It’s intermittent so I’ll have to leave it disconnected for while, guess I can shield the openings somehow I’ll see what I can come up with
2nd Apr 2022 10:31 am
garrycol
Member Since: 06 Dec 2010
Location: Canberra
Posts: 1130
The exhaust does not need any shielding - mine has been off for about 12 months and no issues - you can hear everything that goes on with the compressor. You will not need to remove the inlet side to work out if your exhaust piping is blocked - so just disconnect the exhaust.
Remember there is an exhaust valve in the compressor that is closed most of the time and when it is opened pressurised air is escaping so nothing can get into the compressor.
Dont over think things - it is a simple test - if the exhaust line was blocked you would have the problem all the time and you dont so not a blocked exhaust line.
2nd Apr 2022 12:29 pm
Andyyav
Member Since: 22 May 2019
Location: Norfolk
Posts: 305
Not knowing the construction or flow process of the pipe work I wondered if maybe something was breaking down after 12yrs / 140k causing the intermittent fault, had some time after ‘flushing’’ the power steering fluid out so gave it an external once over for what it was worth and all looks ‘ok’, could hear air escaping from around the compressor air drier (soapy water test inconclusive) so think it’s time for another new compressor. Maybe I’ll go AMK this time 🤔
2nd Apr 2022 9:08 pm
garrycol
Member Since: 06 Dec 2010
Location: Canberra
Posts: 1130
The AMK is not a better compressor, it is just a different compressor. If you have leaks around the desiccant chamber then you need a new aluminium cap as the plastic ones do get small splits.
I would buy a rebuild kit for the Hitachi that includes an aluminium cap and also get a new exhaust valve and housing and your Hitachi will last for many years to come.
Garry
3rd Apr 2022 2:19 am
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 5044
The age of either compressor is a significant factor as to overall health, especially if it's beyond 6 years service and been subject to improper maintenance or none at all!
The Hitachi compressors are easily refurbished with both accessible component availability and ease of rebuild. The AMK unit does not lend itself as easily to refurbishment, but it does tend to have a greater life span than the Hitachi if it has been serviced correctly.
They are both quality components and well made, but having personally repaired or replaced dozens of them, the AMK is the better compressor....By far!!yµ (idµ - eAµ) ψ=mψ
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