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St185 std boost gauge goes to full boost on ignition. http://www.gt4dc.co.uk/forum/viewtopic.php?f=2&t=7679 |
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Author: | Diceman [ Wed Nov 30, 2016 8:25 pm ] |
Post subject: | St185 std boost gauge goes to full boost on ignition. |
A bit of a wierd one this. Suddenly the boost gauge in the instrument cluster goes up to full boost on turn of ignition key and stays there. Anyone had this before? I suspect it is just a an instrument cluster issue as the car runs and doesnt fuel cut! Battery voltage was low and I've seen instrument oddities before due to alternator issues so maybe linked? |
Author: | Sirius [ Wed Nov 30, 2016 10:12 pm ] |
Post subject: | Re: St185 std boost gauge goes to full boost on ignition. |
I have heard of this before and it being alternator related. Might be time for a trip to Burghfield. |
Author: | Nibbles [ Wed Nov 30, 2016 11:19 pm ] |
Post subject: | Re: St185 std boost gauge goes to full boost on ignition. |
I've had the boost gauge go erratic on my 205, sometimes indicating full boost as above, sometimes working correctly. Again, engine operation was fine so not a sensor issue. Check the alternator voltage with a multimeter to see if that's the problem. I suspect it's more likely a poor connection or gauge problem, maybe the instrument cluster earth. |
Author: | Diceman [ Wed Nov 30, 2016 11:25 pm ] |
Post subject: | Re: St185 std boost gauge goes to full boost on ignition. |
Alternator appears to be outputting a steady voltage of around 13.8V. The problem seems to have gone again now after a bit more charge and startup again after a couple of hours. Maybe it didn't like the jump pack? This has kind of coincided with a start of sporadic speedo failure (then it gets better again!) so I will pull instrument cluster and check as well. |
Author: | emicen [ Thu Dec 01, 2016 6:00 pm ] |
Post subject: | Re: St185 std boost gauge goes to full boost on ignition. |
Subscribing in case there are any eureka moments in this thread My ST205's OEM boost gauge is still inverse reading. |
Author: | Nibbles [ Thu Dec 01, 2016 8:13 pm ] |
Post subject: | Re: St185 std boost gauge goes to full boost on ignition. |
I never bothered sorting my 205, though I suspect the gauge itself as all other things work ok. |
Author: | audiodjmp77 [ Thu Dec 01, 2016 8:15 pm ] |
Post subject: | Re: St185 std boost gauge goes to full boost on ignition. |
Just a thought. Could there be some form of capacitance, that if the battery is very depleted, cause false readings ? Emicen, could you have a connector the wrong way round ? I am ready to be shot to bits, as said before I am just thinking Hopefully it all sorts out the faults Sent from my Nexus 9 using Tapatalk |
Author: | Diceman [ Thu Dec 01, 2016 10:45 pm ] |
Post subject: | Re: St185 std boost gauge goes to full boost on ignition. |
As I understand it the MAP sensor has a 5V feed from ECU and returns a voltage between 0-5V with circa 4.2V being around 17psi and low voltage being vacuum. As such if you stuck 5V up the dash boost gauge it would think it had "mega-boost" so is possible if somebody has been ahem fiddling with wires. I guess there are other cocked-up scenarios that would cause a similar issue but you'd have to get a multi-meter on the dash cluster to measure the voltages. If the ECU was seeing the same voltage it would fuel cut unless sombody had installed a fuel cut defender. My theory is that it must be an issue dash cluster end or an anomaly with low battery. |
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