IHADAV8.com - Turbo Buick Tech, and Nonsense
Tech Area => General Buick Tech => Topic started by: Just a Six? on April 26 2017, 01:58:18 PM
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Hey Everybody I hope you are all ready for another season with the Hot Rods!
Spring is here & I have an old Gremlin I'm tired of & need some pointers.
I have a Mechanical Boost-Vacuum gauge along with Scanmaster 2.1
They both work great when the under the hood engine temps aren't too hot.
When the engine bay gets hot after some city-highway driving & some quick blasts the Scanmaster Boost readings get all crazy.[size=78%] [/size][/size]It shows 5-10 lbs boost while just cruising along & I think it also shows some Knock when this happens. Vacuum is also Screwy. I'm not sure if the dash Boost Lights go funky? Meanwhile t[size=78%][/size][size=78%][/size]he Mechanical gauge works fine through all this nonsense.[size=78%][/size][size=78%][/size]Once the engine is c[size=78%][/size]ooled down a bit then everything works Normal again?[size=78%]
Again I need to confirm but I think the Scanmaster shows some Knock Retard when this happens yet the Audible Knock Detector didn't go off. The engine never goes over 160* & the Dual fans work properly.
I will hook up the Powerlogger for some readings the next time I go for a drive.
Separate issue l[/size]ast couple years had the Audible Knock sensor chirping when the car was cold at start up & the first 5 mins driving so I unhooked the Engines Knock Sensor last year. [size=78%]
[/size]Any suggestions are Appreciated! [size=78%] :cheers:
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Man I had to reset the Font Size 10x for that post & it's still screwed up?
I can't Cut & Paste here or even Deleting words makes my post come out messed up? :013:
Sentence should read: Once the engine cools down a bit everything works fine again?
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sounds like you need a new Map sensor to me
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Thanks Steve,
I may have a spare in the pile but I forget how it goes, 2 bar is stock & 3 bar for Power Logger of something like that? Can I just plug in the Stock one for testing or will it affect the Scanmaster on Boost setting?
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If you look at it - the glue might have melted out of it. It's possible to fix it.
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You have both in there? Yes 2 bar for the stock gauge to work.
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What chip are you using? Boost isn't used unless you got some kinky setup
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sounds like you need a new Map sensor to me
That's exactly what I was thinking when reading your post. 2 bar is stock and makes the stock dash boost guage work but doesn't read as much boost as a 3 bar will.
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Most of us would like to know what the boost is doing while we are looking at our PL files...and those of us that spray alky would like it to work correctly so we don't lose an engine :)
David, the three bar sensor must be used with the SM or PL to get the right answer above 14 psi. You can select 2 bar sensor in the PL set up and get the correct answers up to 14 psi, I believe, altho I have never tried it.
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Thanks Guys I think my plan will be to look at my existing 3 bar for something obvious but I'll probably just order a new one. I got this one when I installed PL so that's at least 6-7 years ago from what I can recall? Maybe a local will have a spare if I get lucky? If not I'll see what the vendors have for sale. Cheers!
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Dave the chip is an Alky from Turbo Tweak for Power Logger & I think it has AF correction but I've never really gotten that far into it since the car is set at 21 lbs on the adjustable waste gate rod.
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Call Norbs...he may have one. Mike Ricketts may have one to...tho he uses race gas like I do...but his dads GN may have alky for street use...so he may have a spare. Julios alky kit requires a 3 bar map sensor...the old ones from Steve used the 2 bar. Grab a 5.7 112 race chip from Eric...and turn the alky off. I'll come out to Cayuga and put the fukn thing on the back bumper for ya'. Tell him to throw 28 pounds of high gear fuel at it.
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Brad I don't know if I'll make it to Cayuga but I think I found a 3 bar to borrow & if not I'll try Norbs.
It's the ALKY Control from Julio. Maybe today I'll take a look at it to see if anything looks weird?
Only other thing I need to do is pull some fuel from my Cruising RPM's as it smells rich.
I have a Gen 2 but need to refresh my memory on how it works. Never really used it much after I set it up.
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I forgot about the alky bit- being a teetotaler myself
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If you look at it - the glue might have melted out of it. It's possible to fix it.
If I'm thinking straight an absolute sensor has a vacuum chamber reference internally. As long
as that is intact then sealing up any housing leaks should fix it as nocooler says.
Test it in water like a tire.
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A mighty vac and a low resolution air regulator for you compressor would allow you to test it. Just watch it on the powerlogger or scan master
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I suspect the common failure mode is that it leaks and thus become inaccurate rather than just being wrong/bad. Anyone have exposure to a few failures?
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it's a strain gage sensor so it can flake out electronically too. You'll see it like in the output. Most fail by leaking. Apply 20PSI or so and I'll bet you can hear it leaking past the body.
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I'm thinking I'll put back the 2 bar to test when the engine is hot & if it reads normal then the 3 bar is bad.
If the 2 bar also reads bad then I have another issue but I hope it's just the MAP sensor.
I only need to cruise & then get into a couple lbs boost to see if it's good or bad.
I'll try to do it this weekend & let you know what happens?
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be sure to set the pl to two bar
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Good thing you said that Steve as I surely would have overlooked it. Good news is I'm picking up a 3 bar in the morning so hopefully it's an easy diagnosis.
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So I borrowed a known good 3 bar & long story short I couldn't get the engine compartment hot enuf to make it go nuts but it's going to be pretty warm here so maybe this weekend I'll know the problem. I wanted to post final results but don't have them yet.
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maybe it did not go nuts because that fixed the problem! Be optimistic :D
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I sure hope so Steve, but my testing was messed up from a hose I knocked off by accident.
Long weekend here so if the rain stays away the roads will be wide open. :cheers:
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Watch out for the boyz in blue.........t hese long weekends are great revenue generators for the gubment