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+---- Thread: Help interpret valve angle and vaccum readings from an E87 (/showthread.php?tid=37797)
Help interpret valve angle and vaccum readings from an E87 - willisodhiambo - 28-07-2018
I have a car that seems to loose power at higher revs over 2000 and occasional hunting idle or jacking at around 3000k. I have run checks and I find two queer things,
1. Intake vaccum is reading a massive 353hPa at idle. From memory it should be around 50hPa or 100hPa. No way it can be half atmospheric pressure. DME has not flagged it but when I run pressure vaccum sensor test, it is flagged as faulty. With ignition off it reads zero as expected. I had a car before with a similar issue and replacement of the sensor did not cure the fault, nor replacement of DME. What else can I check for? I don't see where the huge vaccum is coming from yet car idles OK most of the time.
2. The valve position is quite confusing. Both intake and exhaust seem to erratically shift position from 90degrees to massive figures like 600degrees at idle. It makes no sense. Almost as if the cam position sensors are faulty. But how can both go faulty? And since car fires, they are surely working.
Am I missing something?
I have taken snapshots on diagnosis.
RE: Help interpret valve angle and vaccum readings from an E87 - interested - 28-07-2018
for maybe you have poor timing chain, poor timing altering the inlet vacuum and also the timing values.
check timing chain for slack and for correct alignment, timing.
RE: Help interpret valve angle and vaccum readings from an E87 - willisodhiambo - 30-07-2018
(28-07-2018, 15:51 PM)interested Wrote: for maybe you have poor timing chain, poor timing altering the inlet vacuum and also the timing values.
check timing chain for slack and for correct alignment, timing.
Possible, will be an item to check for sure. I wonder though if incorrect timing should cause the spikes in the valve timing as read from the cam position sensors.