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Problems at the dyno :(

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Old 09-18-2009, 12:18 AM
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Default Problems at the dyno :(

Hey guys, I have a front mount 76mm "ebay" kit that i just got tuned with a 2-bar SD tune. i have the wastegate spring at 11psi. basically i had a few exhaust leaks, so the turbo wasnt spooling up and the 02 sensors werent reading right. it was also overheating because the fan wiring was messed up and i had a little air bubble in the coolant, so we did an open loop tune and it made 505rwhp, i was pretty excited. dyno guy drove it on the street and everything seemed ok.

i got in the car and drove it away, and it started to overheat again, so i pulled over and ate some dinner, came back out, topped off the coolant and got on the freeway.

once i got on the freeway, i couldnt go WOT. it would get to like 4k rpms and just bog out. I thought it was just my exhaust leaks so i wasnt too concerned

basically i fixed the fans and exhaust leaks, and every once-in-a-while i can go WOT but most of the time it still bogs out anywhere past 3/4 throttle. i called the tuner and im bringing it back in but he thinks it is a physical prob, not the tune. anyone have any advice for me? im a noob at the whole FI thing so any help would be AWESOME. oh and btw, this was all a birthday present to myself, and i can hardly drive it now so im extra bummed
Old 09-18-2009, 01:42 AM
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Start checking the common things for a new install: Burned wires, hoses or tubing popped off (hot side, cold side, boost control, MAP, etc.), fuses, look at your plugs, check all connections, etc.

Not to be rude but it sounds like you had a lot of stuff that should have been found before dyno day...

Also, my advice for your FI education, buy, read and understand Corky Bell's book "Maximum Boost". It will save you money, time and inconvenience down the road.

Jim
Old 09-18-2009, 06:45 AM
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Sorry to hear about your misfortune, no one wants that to happen on a dyno day, but a lot of us deal with it. I agree with the above, but I also think some of it can be in the tune your load changes more when driving than it does on the dyno and there may still be some "holes" in the tuning that need correcting at certain rpm and load levels to account for the boost, do you have a wideband? what happens when it bogs down, go real rich or lean? Also it could be pulling a lot of timing if the car is overheating or the IAT's are really up there, which shouldnt be a prob on the interstate.
Old 09-19-2009, 12:50 AM
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yeah i know i should have fixed them before, but i couldnt. I am running a 2 bar SD tune so i wasnt ever able to boost it before the dyno tune, all i could really do is let it idle to check for oil leaks.. so anyways i dont see how this could be anything but the tune. Ive checked everything. im going back in the morning so ill post up how it turns out.
Old 09-19-2009, 02:31 AM
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80% of the FI problem cars I have worked on (about 15) have had one or more wiring problems. A common one is a burned wire that looks good from the top, or two wires that have melted together and are shorted but look OK from the top. Also vacuum tubing is susceptible to melting if it touches something hot and can leave a hard-to-find hole that messes up boost control or MAP function.

I try to wrap my fingers around each wire and follow it end to end to check it by feel.

Hope it works out tomorrow.

Jim




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