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| frankieh |
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Hello fellow ford nutters,
Tonight I put the boot in on my BA xr6T 4spd auto... hard while traveling about 40.kph. the car took off nicely, then after some hard acceleration, it started breaking down badly.. In a very similar manner to the traction control when it kicks in.. so the computer was clearly doing it rather than some engine issue. (I've also just put brand new NGK iridiums gapped to .7 as well, but it was doing it before this too.) So anyway, after it happened, for about 40 seconds the car was breaking down and I was having serious difficulty maintaining 60kph. Then for no apparent reason, it smoothed out again and ran like a dream. Why would the ECU be doing this? It's all bog stock xr6T, I wasn't anywhere near redline as I wasn't hitting it that hard.. I thought maybe overboost protection, but why would I have that issue on a bog stock BA? I suppose I should hook my boost guage up to check, but would that be an issue? Could it be the auto going into limp home mode for a while? I'm not sure what to check. Car runs only BP ultra premium 98. This is the second time it happened.. and by co-incidence, it's the second time I've really put the boot in so I'm a little concerned. can anyone offer some suggestions? I've ordered a bluetooth ODB2 adaptor so I can use my android tablet to check for error codes.. but it isn't here yet, so I'd appreciate any pointers you might have. regards Franki |
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| 123esproc |
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Turbo lag
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| frankieh |
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Turbo lag is waiting for the turbo to spin up enough to provide boost.. it wouldn't happen after boost is already being provided.
Turns out it happens exactly when boost hits 10psi.. so it almost has to be the PCM protection system. I just need to find out why my factory xr6t is hitting 10psi in the first place as it shouldn't be more than 7. I don't mind it being 10psi, but I would prefer it if it couldn't go any higher and if it didn't trigger the overboost protection. |
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| 123esproc |
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I've never even driven a turbo let alone worked on one more boost is good but to much is obviously bad haha can you set or replace the pcm so you can keep your 10psi?
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| frankieh |
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Turns out that the overboost is caused by a broken diaphram in the wastegate actuator. So essentially it isn't working.
I've got a new one.. but it's a mongrel of a job to swap out near as I can tell. Once I have swapped out the Cat converter, and replaced the actuator I'll get a tune in it to suit. Then add JTG and some nispro springs and get a proper tune I guess. |
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| kboot6 |
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usually it would be valve springs causing your problem due to valve float!
upgrade and probably it will stop |
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| kboot6 |
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but yea over boost do that to!!
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| vevapower |
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Valve springs gone soft mate!
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| frankieh |
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vevapower wrote: Valve springs gone soft mate! Since this happens below 4k rpm, the valve springs would have to be complete spaghetti. The breakdown is actually the exact same feeling as the traction control.. so the problem was the over-boost protection which I did not know about originally. It comes on even faster now that my exhaust is free flowing but will hopefully go away completely once the new tune is on. |
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| budgetba |
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I had a similar issue at 10 psi it felt like missing so I replace coils and plugs still no luck someone said if it feels like you're hitting the limiter at 4k rpm its springs turns out it was changed them for some aftermarket ones and it running happily at 13 psi. The springs can't shut due to increased boost pressure not high rpm.
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| frankieh |
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budgetba wrote: I had a similar issue at 10 psi it felt like missing so I replace coils and plugs still no luck someone said if it feels like you're hitting the limiter at 4k rpm its springs turns out it was changed them for some aftermarket ones and it running happily at 13 psi. The springs can't shut due to increased boost pressure not high rpm. yeah, in this case it turns out that it was just the overboost protection. The new tune got rid of that so nothing to worry about. Interesting thing about the overboost is that if you take your foot off for a sec, then put your foot back in (but not quite as much) it comes good again instantly.. but not having it there at all is much better. |
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| Grimketel |
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Question Frankieh, did the check engine light always come on when it did this? Sorta sounds similar to what mines been doing lately when I try to take off at or near WOT.
_________________ enough isn't enough |
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| frankieh |
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Grimketel wrote: Question Frankieh, did the check engine light always come on when it did this? Sorta sounds similar to what mines been doing lately when I try to take off at or near WOT. Nah, in my case it was just over boosting.. the standard tune had been put back on a modded engine.. so it was over boosting. my engine light has never been on with the engine running thankfully. The intake manifolds on these things do have a tendency to leak like a sieve so that is where I'd start since it's easy to check. I wanted to fix mine temporarily back when I got it so I got a can of hylomar and with the engine running sprayed it all around the join to the head, it will get sucked into any leak and seal it... worked a treat... but to test just try it with a can of aerostart or even CRC.. if the revs change when you are spraying, it's probably sucking the flammable stuff though the leak. If it's doing it when you dump your foot in.. it might such a heap of air and the fuel mixture is leaning out.. that is probably causing the PID for the intake, and possibly the PID for the oxy sensor too. (read your other post) And it's possible that the BF computer has noticed the lean out and is causing the protection thing to kick in. (the same cut out that traction control and overboost does.) |
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| Grimketel |
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I spoke to Chris Dalton's automotive here in Geelong, and they advised to start with putting a boost gauge on it and see what is happening under load. Should be able to tell if it is overboosting and hitting the cut or not. Chris seemed to give credit to the notion that the old actuator may well be on the way out, given the age, and extra boost.
He also advised to check manifolds for leaks. So many different causes, just have to go through 1 by 1. Never installed a boost gauge, kinda nervous to try it.
_________________ enough isn't enough |
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| frankieh |
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Grimketel wrote: I spoke to Chris Dalton's automotive here in Geelong, and they advised to start with putting a boost gauge on it and see what is happening under load. Should be able to tell if it is overboosting and hitting the cut or not. Chris seemed to give credit to the notion that the old actuator may well be on the way out, given the age, and extra boost. He also advised to check manifolds for leaks. So many different causes, just have to go through 1 by 1. Never installed a boost gauge, kinda nervous to try it. Firstly you have a custom tune... With higher boost then factory. They would have had to turn off the over boost protection or it would be over boosting every time you gave it a squirt. I know my tune has no over boost anymore. Boost guage is easy.. But if you have an odb2 adaptor you can use torque as a boost guage.. Failing that a boost guage is either mechanical in that the guage has a vacuum hose that goes all the way onto the vacuum tree near where the brake booster hose goes.. Or an electric unit in which case it has a sender unit that connects a hose to the same tree and wires that run to the guage. Either way its easy as.. You won't have any problems mate. |
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