Hello everyone

Rover 220 coupe turbo 94 T series

when accelerating revs drop and then recover.

if revved high >2000 rpm and then allowed to fall revs drop and car nearly stalls, sometimes does stall.

car runs OK at idle

have tried the stepper motor reset advised on this forum (ignition to 2, 5 presses of throttle) stepper motor makes whirring sound, doesn't solve problem.

have noticed the stepper motor makes the whirring sound every time i turn the ignition back to 0, is this normal?

have checked the black tube running from the inlet manifold to ecu (map sensor) as advised on the forum and there was no blockage in the tube

also noticed a third spare nipple next to the map sensor tube on the inlet manifold this was open and sucking air in, is this correct? other nipple had a hose on it.

any suggestions for the next step in diagnosis much appreciated.

Lee

Lee wrote:also noticed a third spare nipple next to the map sensor tube on the inlet manifold this was open and sucking air in, is this correct? other nipple had a hose on it.

any suggestions for the next step in diagnosis much appreciated.

Lee

Just had a look on my GSi Turbo, and there is a blanking tube/cap covering the third nipple on the inlet manifold, so I wouldn't mind betting that the excess air getting in is the cause of your problem. It would interfere with the airflow and pressure sensing to the ECU.

Try blanking yours off (could do a temp job with screenwash tube and a bolt?) and see if that cures the problem.

Rimmer Bros have the correct part in stock: http://www.rimmerbros.co.uk/Item--i-GRID002421 (item 15) at a bank-breaking cost of 66p, although I don't know how much their P+P might be?

HTH


Paul

Lee wrote:Hello everyone

Rover 220 coupe turbo 94 T series

when accelerating revs drop and then recover.

if revved high >2000 rpm and then allowed to fall revs drop and car nearly stalls, sometimes does stall.

car runs OK at idle

have tried the stepper motor reset advised on this forum (ignition to 2, 5 presses of throttle) stepper motor makes whirring sound, doesn't solve problem.

have noticed the stepper motor makes the whirring sound every time i turn the ignition back to 0, is this normal?

have checked the black tube running from the inlet manifold to ecu (map sensor) as advised on the forum and there was no blockage in the tube

also noticed a third spare nipple next to the map sensor tube on the inlet manifold this was open and sucking air in, is this correct? other nipple had a hose on it.

any suggestions for the next step in diagnosis much appreciated.

Lee

No definatly not normal and will give running issues. From memory there are 3 nipples at this point. One blank (used by many people for a boost gauge), one running to the ECU, and I think the 3rd runs to the carbon cannister but I'd have to check that to be sure. The "joiners" on these lines commonly split too so check these too. Any air leaks into the manifold will screw up the idle and be a boost leak under boost conditions.

Fix the air leak and see if that cures the fault. Otherwise you may need to clean the air-bypass on the throttle body as this also commonly gets clogged causing poor idle control and throttle pickup.

Thank you for the help Paul and E_T_V, its much appreciated.

Have blanked off the third nipple, this resulted in the car running worse and the hesitation on the throttle being more pronounced with the car more or less stalling every time i let the revs drop.

have taken throttle body off and given a clean especially the air bypass. car runs a bit better at idle but still has the hesitation and stalling problem.

disconnected the map sensor tube from the inlet manifold to the ECU and the car does not hesitate or stall when letting the revs drop, it doesn't idle too well but the hesitation problem is not there at all. the revs do drop a bit below normal idle to about 600rpm but it hasn't stalled with the map sensor tube disconnected.

have already cleaned the tube and was nothing in there.

is there any way to reset the map sensor?