Problems with my 1.8T ZT
 

Good Evening all, I hope this message finds you well.

Ever since I have owned my ZT, It has always had an unsteady idle no matter what the conditions were. As well as this, it seems to have fairly poor MPG averaging around 24MPG with town driving, I don't know whether that's good or not. As well as this issue, the gearbox seems very stiff and especially in this bad weather, 1st and 2nd take quite some force to get them in, though once the car has warmed up it's manageable but not quite butter smooth on the changes. Anyway, I have tried changing the spark plugs, HT leads and Coil packs to remedy the rough idle, but that hasn't seemed to cure the problem. My only guess would be some sort of air issue, intake manifold maybe or fuel injectors? I have attached a video of the idling showing the rev needle; https://www.youtube.com/watch?v=NUt9hIcou70

Hi,
regarding the idle,mine is exactly the same and always has been in my 12 years of ownership.I questioned it with a Rover specialist when I first got the car and was told it was normal.It has never caused me any issues.Also,I find the 1.8T quite heavy on fuel,particularly around town.It's a big heavy car with a lively engine so to be expected.Although I would expect 26-28 ish.

Mine too has a a lumpy tick-over but pulls like the proverbial train on the open road. I put it down to her age, and to the fact she she is on 215,600 miles.

Yeah, an erratic idle is a "feature" of the 1.8T. What helped mine a little was when Brian checked the stepper motor and found it well out of adjustment. The stepper motor adjusts the idle depending on any load on the engine, lights, aircon etc.

My beast is a 1.8T and I get at least 35mpg, and on a long run get up to 38. I know my driving is with a light foot.

I would suggest that it might be worth checking the ignition coils and the idle valve.

My 2004 1.8T returns 32-34mpg and idles like a Swiss watch. Lumpy idling can be caused (amongst other things as mentioned mentioned) by coolant entering the inlet manifold (cyl 1 and/or 4) but this usually clears once everything's hot. Obviously this means you have to keep topping up the coolant - which hasn't been mentioned (??)


TC

Hi Terry


your's is the first 1.8T I have heard of with a rock steady idle.Mine has always fluctuated but the car itself has always idle'd smoothly not lumpy.


Is your mpg of 32-34 around town?

My 1.8T has a slightly lumpy idle which seems to worsen when the car's warm. Doesn't really bother me as it's not that severe plus is only noticeable when the box is neutral/park.

I get a regular 30mpg from my car across mixed driving conditions. Not amazing but the engine works hard as she's a heavy beast. 24mpg isn't good but probably about right if you're doing purely urban driving and short journeys.

I get 27-28 on urban travel - 30-31 on motorway travel - when i had a failing crank sensor it dropped to 20-22 - try swopping out the crank sensor - when i did it the MPG jumped up to the figures above and while you are at it sheath the crank wiring with heat resistant cable as it is too close to the turbo and heat damage can short the Crank wiring and goose your ECU.

Also a duff crank sensor can cause a rough idle as it send duff info to the ECU -worth considering swopping it out and at the very least discounts that as the cause and if the cause you are sorted.:shrug: