P reg 1997 4.6 v8 gems

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Davidosik

Davidosik

Member
Posts
18
Location
West bromwich
Just a quick question with the rocker covers am them ment to both breath as my one side ain't doing nothing since I had rocker covet gaskets changed the left side which I count as the no oil cap side .....i have a issue of over revving since changing cover gaskets it' had new breather pipes new idle control valve even been and had a diagnosis off the lynx and he reakons it' a air leak but I can' find where even with soapy water
 
Last edited:
There are two breathers, one for each rocker cover as illustrated....
(photo from the mez.co.uk site - arrows by me!!)
P38_GEMS_Breathers.jpg
 
Try the throttle cable. This should be slack. Play with it whilst it's overreving. The throttle pot should tell the ecu the throttle is closed bringing into play the idle valve. If it's not closing or the throttle pot is worn it won't bring the idle valve into play. Reset adaptive values would reset the idle speed ( stepper motor values) it may be as simple as that as my guess is lynx doesn't do that. You need a nano or test book. Are people thinking it's unmetered air entering the system? Not sure what other air leaks are possible. Check the bit of pipe that goes from the fuel pressure regulator to the manifold these can leak vacuum.
 
Am them ment to both breathe as my one side ain't doin nothin. This is crankcase ventilation. It let's fumes that blowby the Piston dissipate. There is an oil catcher but other than that it's just a pipe vented into the intake. If one of those pipes is off I guess it would leak unmetered air into the system but that's easy to check.
If both get blocked the valley gasket balloons out!
Jb
 
I had throttle checked with a gauge don't know what it was called the man who checked was a range rover specialist and he couldn' find no fault and I had adaptive values reset as soon as he reset it it went to over rev and u hear a little suction but I noticed other day the pipe don' vent or suck when off plenum the other side does so would this cause overevving it' ment to be going back to him this week coming ...im just trying to keep my bill down if u know what I mean by eradicating little things I find
 
I'm not expert but it would be easy to check the throttle sensor voltage using diagnostics. I'm suspicious hes not reset adaptive values as I don't think the lynx does that. I may be wrong.
Last time I changed tps it overreved until I reset adaptive values. Just blow down the tube if it's free you'll tell it just goes into the sump. I don't think I can help you further than this as I'm not sure what has and hasn't happened. I guess you were just observing and just took them on what they said. Good luck with it though.
Jb
 
Well he showed me option on there to do it the blokes a specialist who plugged it in ....the revving is doing my nuts in he told me to take plenum back off change idle control valve to old one make sure it' clean and reseal ...im gonna leave it with him he' being phoned tomoz he best fit me in I've been waiting 3 weeks to get in ...all this because I done my rocker covers and clean all the gunk out of there ....
 
Must of reset them then.it can't be anything major TBH. Your biggest problem is finding parts the last throttle sensor I brought was used and from America! It no longer available.
 
Yh the potentiometer I've seen em priced up 150 160 new in America I don' think it' that I hope not I just hope it needs reasealing right fingers crossed
 
They often list stock and don't have the part. I tried for months to buy a new one. A scandi chap brought a new one using the generic part nos from the states a while back. Buyer beware on this.
 
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