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About LinkBacksNo, just pull it out of the servo and block it with your finger...Originally Posted by whitie
No, just pull it out of the servo and block it with your finger...
When advanced technology fails you need advanced personell using advanced tools and equipment to find advanced solutions... Somehow in either of these matters it keeps going wrong??!?
ive got similar trouble with my cav turbo, revving at 1500 at idle, and the fuelling on my wideband all over the place, ive changed icv twice, changed tps, temp sensor, and checked all the vac hoses numerous times eventually i got it put on tech 2 and that pinpointed the AFM, when i unplug the afm with engine running the engine dosnt even stuuter, makes no difference at all, the car even starts with the afm not plugged in, ive been told this should not happen, im waiting of another afm coming from my mate to see if this cures the problem, Ads
Right, will fit new TPS tomorrow, then try servo pipe block off, then try sealing the TB up! Cheers Vinci
Ads, I fitted a new AFM about 2 years ago. Mine wouldnt start at the time unless the AFM was unplugged!
Hope you get it sorted so I can try something else on mine!
Holy crap, where did all that rust come from.....
so has this engine ever idled ok ? or is the engine new to you and done this ever since you had it running ?
i dont know whether to suggest component failures that are making it idle high, when it didnt used to. or whether to suggest reasons its idling high due to human intervention in the past
need a bit of medical history on it !
Not a bad idea, but the basics of high idling are not that complex. Whether it is component failure or previous human intervention or not.
The first and most simple test is already done, clamping the ICV hose. If this is done right and NO air is allowed through and the engine keeps running there is definitely a leak. Not a speck of doubt. If there is a leak there can still be a component/wiring/ecu failure, but not even worth looking at when there is a leak...
Finding a leak isn't always very easy though, but just a matter of excluding all possibilities starting with the most obvious ones. Some will advise you to spray brake cleaner around the inlet and see if the engine responds to that. This is a useless test though, not worth spoiling any brake cleaner on because it will never really pinpoint the problem to my experience. Easiest is to seal all possible entries one by one....
The ECU is pre programmed for a certain RPM at idle, but will only enter in to this mode when it gets the right information from the TPS. If it doesn't it'll be in a sort of limbo and even though the throttle valve is closed will steer the ICV open pretty far and that can give all sorts of idling speeds, usually very high (2000-3000 ish) Now, even though there is a component failure then still the engine should stop from clamping the ICV hose.
I thought it would be a good idea to make a possibilities list in order of likelyhood of things that can leak on the inlet. Just copy and paste it with any corrections if you feel there are any errors.... Keep in mind that ONLY parts UNDER the throttle valves are suspect, when I was still a complete noob someone has once advised me to replace the SFI box gasket, but this is NOT in the 'system'....
1. Vacume hoses
On the front side of the TB, the two little ones under the big one coming from the cam cover. They can be torn when they become brittle of their age and this is particularly suspect when the problems are not consistent.
2. Hose between ICV and inlet
The hose between the ICV and SFI box is not interesting though, because it's not really in the system.
3. Gas cable
Obviously a prime suspect, if it isn't allowing the TB to return to closed position there is an air leak.
4. Inlet manifold gasket
Because it is a large mating surface and close to the head which is rather hot it is a prime suspect. Also check for loose bolts!!
5. Throttle valve trouble
Some find it overly tempting to temper with this part and especially if you've never seen your engine run as it should there is a great chance of prior malicious human intervention. It is also possible the springs and joints of the parts 'between the gas cable and the throttle valve' are stuck somehow. And always check the adjustment screw as I pointed out earlier on in this thread!! Especially when you can't seem to adjust the TPS far enough to make it click!! Also look at the little valve, I've personally had a TB where this one was filed on and leaking like crazy. Made a constant 1200RPM idle which made me mad finding the cause!!
6. Throttle body gasket
I have never actually used these, I prefer using some Loctite sealant and this always worked fine for me. It is a suspect though, it can tare or bad aftermarket ones can rot away.
7. Brake servo hose and fittings
Yes, the pretty tough plastic hose that goes in to that large drum. I've actually never seen one of these fail, so can't tell you if or how suspect it really is....
8. Injector seals
Although it is unlikely and I've never seen them cause a leak it is a possibility.
9. A crack in the manifold
I'd render it very unlikely since it is rather a bombproof part, but it is a cast item and cracks can never be excluded.
Last edited by Vinci; 29-09-2011 at 06:19. Reason: Pic got removed on hosting site
When advanced technology fails you need advanced personell using advanced tools and equipment to find advanced solutions... Somehow in either of these matters it keeps going wrong??!?
I think it's best to stay non turbo in this thread because they're rather different intake systems, but maybe check all that is mentioned on the parts that are similar....
When advanced technology fails you need advanced personell using advanced tools and equipment to find advanced solutions... Somehow in either of these matters it keeps going wrong??!?
So pissed off, just wrote a massive post including the history of the engine whilst I've had it and my most current findings and apparently by the time I went to click
'Post' I'd logged out!
Holy crap, where did all that rust come from.....
The history just took me 30min to write out, missus has passed out on me!
so I'll skip that and just say:
Engine started fine other day, but found I'd left the throttle cable off after fitting the new TPS!
Refitted cable and revs were back up. Removed c clip from throttle cable today and revs dropped to 1200!
Will remove cable again tomorrow and test but looks like there's some tension there that I couldn't see
when looking at the butterfly and this is causing the TPS to 'click' into open circuit showing open throttle!
Amazing how sensitive this system is... or how ham fisted I am.
Can't remember what throttle cable you are meant to use for the corsa b conversion and which
cable I have actually used!
I feel 'special'...
Holy crap, where did all that rust come from.....
Sjite!! That happened to me a couple of times on fora too, including that missus passing out on me bit...lmao I now only write the elaborate posts in notepad, or copy and save it before pressing any buttons....
Glad you've made some progress on diagnosing the problem, cable is well suspect, especially when it's a redtop converted Corsa, chances are the cable either doesn't fit too well, installed not properly or got bent and doesn't go through smoothly any more. And on top of it the TPS won't click which makes trouble complete...
System sure is sensitive, as it should be because when working well that's what makes it work really well.
When advanced technology fails you need advanced personell using advanced tools and equipment to find advanced solutions... Somehow in either of these matters it keeps going wrong??!?
Done some reading, most use the cable of a calibra or MK2 Astra, but then the inner cable is about an inch too long.
Some:
1. Shorten the inner cable and use a motyorcycle or moped end piece
2. Lengthen the outer cable with some cut in length tubing.
3. Shorten the inner cable at the pedal end and place an end piece there, it is reported to also work with a screw terminal.
When advanced technology fails you need advanced personell using advanced tools and equipment to find advanced solutions... Somehow in either of these matters it keeps going wrong??!?
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