Engine feels rough when driven hard-not all the time though

[purple-rado 0]

hi guys,

 

Yet another problem with my Rado. I have noticed lately that when driving the car hard Ie. revving the engine to 6.5 - 7k revs, the engine feels quite rough and the acceleration is noticeabley slower than normal along with a tapping noise (probably pinking). However, this problem is not all the time as sometimes the engine revs up to 7k smoothley and quickly without too much of that supsected pinking noise.

 

Any ideas.

 

Many thanx

[purple-rado 0]

Oh by the way the rado is a 1.8 16valve.

 

thanx

[dr_mat 0]

Pinking only usually occurs in mid-range, under load. High revs doesn't *usually* see pinking.

But if you think it *might* be pinking, it's worth trying some different fuel. Most people swear by Optimax. Stick a tankfull in and see if you're still getting a problem.

Can't hurt...

[Kevin Bacon 5]

Pinking only usually occurs in mid-range, under load. High revs doesn't *usually* see pinking.

But if you think it *might* be pinking, it's worth trying some different fuel. Most people swear by Optimax. Stick a tankfull in and see if you're still getting a problem.

Can't hurt...

 

The problem with high speed pinking is you can't hear it over the wind/road/engine noise. It does definitely happen though as my 16V was put on the rollers with the same complaint and it showed huge troughs in the power curve at 5,600 to 6000 rpm. Pinking!

 

Mat is quite right in suggesting a higher octain fuel, so try that first.

 

If not that you may have worn plugs (16Vs are quite fussy with these), broken down HT Leads, again, common on the 16V causing a very slight misfire or the injector seals could be leaking, which surprise surprise, is also a 16V achilles heel. All are cheap (except the leads) and easy to fix.

 

You might also want to consider the warm up regulator mod to supply more fuel at high rpms. You'll need to speak to stealth about that as it is a very precise procedure.

 

Kev

[purple-rado 0]

thanx for the help guys,

 

just to add, i do use super unleaded from BP all the time and as mentioned this problem occurs only sometimes. In addition when i start the car when engine is warm it does idle lumpy for a while until i blitz the accerator a few times to clear it out. Dont know if this is connected with the problem.

[Beetlebug_2001 0]

I have the exact same problem with my car, seems rough between 6-7k as if the engines shaking about all over but fine up to 6k dont bother me cos i dont like to take my car upto the red line, i somtimes have a funny idle on start up also but clears up when the engione warms up guessing its just the choke or summit, i dont use hi octane fuel very often because the nerarest shell garage is a good 10 mile away, cant remembver what my manual says the C should be using in the 1.8 16v i belive its 85 RON and BPs super unleaded is only 80 Ron or summit dunno if trying shell optimax which is 85 RON will make much of a difference?, i used to put shell optimax in my old beetle before i got my C and it made it go like s**t off a stick ;)

[Andi 2,147,483,647]

:?:

Standard UK unleaded is 95 RON, BP Super is 97 RON (can be 98 - depends on area) and Shell Optimax is 98 RON.

[Beetlebug_2001 0]

yeah thats what i meant couldnt remember what the RON's where, but but yeah remember now 95 RON standard unleaded, 97 RON Super unleaded by BP and some other garages and Optimax from shell 98 RON (great stuff) anyone ever heard and tried some stuff called Nitrox power hot shot, £7.99 ish from halfords ect and its an octane booster gives u a 10% bhp increase and cleans the engine of carbon deposits, says can be used as an octane booster for drag meets ect even if its been used before, for the purpose of cleaning the engine, sounds like good stuff ill buy some next week and let you all know what its like if no ones tried the stuff yet.

[Kevin Bacon 5]

yeah thats what i meant couldnt remember what the RON's where, but but yeah remember now 95 RON standard unleaded, 97 RON Super unleaded by BP and some other garages and Optimax from shell 98 RON (great stuff) anyone ever heard and tried some stuff called Nitrox power hot shot, £7.99 ish from halfords ect and its an octane booster gives u a 10% bhp increase and cleans the engine of carbon deposits, says can be used as an octane booster for drag meets ect even if its been used before, for the purpose of cleaning the engine, sounds like good stuff ill buy some next week and let you all know what its like if no ones tried the stuff yet.

 

Millers CVL (competition valve lubricant) is good stuff. I used to use it on the Evo car magazine meets in my 16V Turbo. It takes Optimax up to 101 ocatane aswell as lubing the valves and upper cylinders.

 

Kev

[Bruno 4]

it does idle lumpy for a while until i blitz the accerator a few times to clear it out

 

Thats oil on the pistons if its really happening when its warm. Best option is that your oil's too thin. Make sure its thicker or the same as 10w40.

 

Check the oil levels as well and oil colour. If its dark and sooty get it replaced and then see what happens next. If it soots up quickly, check the compression.