Took my car out for a wee spin today decided to give it a bit of a blast to clear out the cobwebs. what with the weather lately its not been easy to give it a good rev to clear things out.
so im out and about, the car\'s all warmed up and i find a nice quite section of dual carriageway. so i accelerate in 2nd, crazy wheelspin, into 3rd still a bit of wheelspin, into 4th and i start accelerating, the cars doing a bit of hestitating while accelerating, i try to rev through it, put my foot on the floor and it hesitates like mad, my cat light on the dash flashes a couple of times and my power fc shows a highest knock level of 115. my foot was barely on the accelerator for a second while this happened.
now the car runs really rough, like its chugging along, when its at low revs it sounds like a subaru. i managed to get it to my mates which was closest after it happened to let it cool down. ive just brought it home and it feel worse than when it was warm, the revs wont pick up at all, the cat light is constantly flashing, and the knock levels on the power fc are all over the place.
any ideas?
bob
Have you got a boost gauge mate???
If you have and you have lost a tip, the needle will be bouncing all over at idle!! If this is all OK, you kight be lucky & find it\'s a plug gone bang!!!
Jono
yeah i have a boost guage. i noticed when i was driving it was bobbing up and down, but i cant remember if it did it on idle
may have boost spiked in the cold weather or probably needs new plugs.
Did you check all your vacuum pipes are still on? If you have a loss of boost then you may have blown a pipe off. Or maybe the pipe off the MAF sensor has come off. Always start by checking the simple stuff.
cats usually get hot when unburnt fuel makes its way down the exhaust and burns inside the car, they usually stink too, this unburnt fuel could be caused by a missfire, like its been said check plugs, leads if that dont help then a small electrical fire followed by an insurence claim wound be an idea lol *joke*
i dont think it even reached full boost. think it maxed at 0.77 bar, set up for 0.9 on stock twins running a non seq set up, rats nest all removed. i\'ll try some new plugs and see if it makes a difference. i hope its not cracked a tip although i never got a chance to even rev it hard and it wasnt under any stress for longer than like half a second at the most
bob
yeah also meant to say, although my cat light was coming on i have a straight through, decatted exhaust. dont know if that means anything!?
bob
Sounds to me like you have chipped a seal (tip). happened to me a few times unfortunately.
Does it sound a bit like a tractor on tick over?
And feel like it has very little power on acceleration?
However when at revs in excess of 4k ish, you cant really notice much different in sound/feel etc.
hard to start warm/boost gge fluttering noticeably on idle/car chugging /vibrating all sounds like u have lost a tip or more ime afraid
Quote from: sideshow bobyeah also meant to say, although my cat light was coming on i have a straight through, decatted exhaust. dont know if that means anything!?
bob
the light was coming on as it was detecting the high nock.
unfortunatly it sounds like tips as said. before condemming it get a compression test done to confirm.
hope it all works out mate.
if it is a tip etc, remember to find out why.
in this cold weather a guess would be a spike in boost.
ok thanks guys. i\'ll prob need to wait til the weekend to have a look at it in daylight and i\'ll do some investigating. if it is a cracked tip, how much does it typically cost to have an engine rebuilt?
bob
£3k or thereabouts all depends on what you want to do etc
Right..Sorry to rub salt in the wound (i\'m new to this stuff) but what\'s the moral to this story? I mean, in cold weather & all. Would letting the car tick over for a few minutes at startup
help avoid this kind of upset?
Quote from: LawlerRight..Sorry to rub salt in the wound (i\'m new to this stuff) but what\'s the moral to this story? I mean, in cold weather & all. Would letting the car tick over for a few minutes at startup
help avoid this kind of upset?
Nope. You would get boost creep/spike regardless of how hot or cold the engine was, it\'s the ambient temp outside which determines it, with no sort of boost control. At most you\'d probably end up with a blown water seal boosting on a cold engine.
With proper mapping boost could probably be controlled (according to Pip), but i opted for a boost controller aswell just incase.
duly noted
Sideshow bob - what management are you running? Is it a full exhaust on stock ECU?
Quote from: KevinAt most you\'d probably end up with a blown water seal boosting on a cold engine.
Can you expand on the theory behind this, please?
There was a thread on rx7club on some guy that did testing on these engines and found that boosting on a cold motor caused the water seals to go. Was quite in depth explanation as to why but I cant find the sodding thread now! :(
Quote from: KevinThere was a thread on rx7club on some guy that did testing on these engines and found that boosting on a cold motor caused the water seals to go. Was quite in depth explanation as to why but I cant find the sodding thread now! :(
I can think of ten reasons not to WOT a cold engine but blowing the water seal would not be one of them??? Plus I don\'t think i\'ve ever seen a blown water seal its usaly the Plate Grooves that go down to Stress fractures/Corrosion/Bad wall thickness.
Back on the Question in hand, Do a Curb side comp test, if its running bad enough to feel when driving there will be a noticeable enough Drop in compression to be Audible when you turn it over with a Plug out.
But i would have to agree that it doesn\'t look good, i did a Motor in Much the same way a While ago, The only difference was it ran fine through the rev range until i shifted from second to third and it started missing.
Quote from: GrizzlyI can think of ten reasons not to WOT a cold engine but blowing the water seal would not be one of them???.
I can think of numerous reasons not to WOT any cold engine regardless of wether it\'s rotary or not.
I wish I could find that thread, it was really informative. I\'ll keep searching.
Quote from: SiHSideshow bob - what management are you running? Is it a full exhaust on stock ECU?
Apexi Power FC with commander
I\'ve got my fingers crossed for plugs but i\'ve yet to check. took a long weekend off work to take my mind off some non car related woes lol. but to point out the car was fully warmed up before i went to give it some stick, and my power fc didnt even register as hitting full boost til it started acting up.
however what i was wondering was, when your car does the kinda jittery accelerating is this putting the engine under more stress than usual?