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boost readings vs altitude

3046 Views 19 Replies 4 Participants Last post by  Dr. Mike
Ok guys... I know that altitude impacts boost readings. I am just over 6,000 feet here in good old Colorado Springs.
When I turn the key, I get .8 bar and at idle I see .4. Pulling in 2nd gear I can see 1.4 and in third. I am lucky to see 1.6 at max.
Is there a conversion for altitude? I know at sea level you should see 1.0 during ignition on.
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Buy a real boost gauge. ... stion.html" onclick=";return false;

Post number 5 explains it pretty well.
It's on my list. Along with a vent mount.

yodasfro said:
Buy a real boost gauge.
This is the math I wanted. Thanks!

rogermoz said:" onclick=";return false;" onclick=";return false;

Post number 5 explains it pretty well.
I pulled a vent out of my parts car to cut a hole in for my gauge, want me to do up a second one for you?
Sounds like a plan. I pick up my boost gauge tomorrow.

paradox11235 said:
I pulled a vent out of my parts car to cut a hole in for my gauge, want me to do up a second one for you?
real boost gauge acquired.
ah the plot thickens....
The car is exhibiting intermittent poor performance. Drives fine at first then on decel and at idle the factory boost gauge drops to .2 and the car becomes a dog.
When I restart car, key in the gauge starts out at .7 rather than .8 and if I wait til OK disappears on the dash it will eventually go to .8.
I am hooking up the real boost gauge today, checking ECU for fault codes and I will be building a boost cap like the one in sjm. My plan is to follow the sjm procedure, by plugging up the intake hose and then removing the oil cap and pinching the off the breather hose. Anything else to watch? Most of my intake hoses are and out of the intercooler. I did order a silicone throttle body inlet hose from 034 as mine appears to be original as has some slight cracking. I figued I will just replace it as it will eventually get worse. If all of this fails, I will look at the wastegate. I am thinking boost leak that manifests through harder driving...
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Pretty sure this is the culprit


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You want to clamp off your ecu line and block off the breather pipe from the maf to turbo hose also remove the old cap. You don't need to block off the intake you won't catch any of the leaks there then.
Now I am getting fuel cutoff symptoms like before. With key on I am reading .9 and when I pull hard (WOT) the fuel cut off symptoms from earlier this year have reappeared.
My attempt to pull codes was unsuccessful. I followed the procedure in SJM and got nothing. I am going to try to attach some blade connectors to the wire and see if I can get better contact. I have a CEL on the car when I turn on the key, so I should not need the light bulb. Everything is pointing to a boost leak at this point yes? I am waiting on a compressor to properly boost test the system. The creation of the cap was easy...just took some digging at ACE. My gut is telling me that the hose I took a picture of is leaking.
All you need is a paper clip with the car running bridge the connectors like so for 5-10 sec then remove the paper clip do it again to move to the next blink code.
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Still getting nothing, granted I just noticed my cel does not always come on when I key on the car.


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When you jumper the connectors the CEL should illuminate and stay on until you remove your wire then it will start blinking. You are doing this with engine running correct? Try giggling the key in the time it doesn't come on maybe you needs a new ign. switch?
When I jumper them, I get illumination like you suggest. I am doing this with the engine running. Goood question though.
Cutoff symptoms are consistent now. Anytime I go to WOT she cuts out. I am getting an air tank this weekend to look for leaks. I will also clean the MAF as SJM suggest that that can cause these symptoms.
Air tank arrives today. Still waiting on 034 silicone hose. Fed Ex did not deliver on Saturday....
Hopefully I will have this resolved today.
Resolved issue for now. I cleaned a VERY dirty MAF and replaced a few very shoddy vacuum hoses as well as a slight leak on the diverter valve.
Did not take the time to play professor science and determine the exact cause, but fixed all of the issues and after warming the car up buried the throttle multiple times with no adverse reactions.
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