brillomaster Posted August 20, 2014 Share Posted August 20, 2014 I think its normal, when you're coasting down hill in gear a modern fuel injection engine will be using zero fuel, and simply be using gravity and the wheels rotating to keep the crank turning. I'd imagine when you then accelerate down hill, the engine needs to wake up so to speak and start injecting fuel again - I think its this hesitation that you can feel - and I think the jolt is often exaggerated by being in a lowish gear. Quote Link to comment Share on other sites More sharing options...
cmck13 Posted August 20, 2014 Share Posted August 20, 2014 Least said soonest mended. Quote Link to comment Share on other sites More sharing options...
StevoD Posted August 20, 2014 Share Posted August 20, 2014 95 or 98 octane fuel? 1 Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted August 20, 2014 Share Posted August 20, 2014 What i suspect that your noticing is as already explained when the throttle is shut for a pre determined amount of time the fuel injectors are also off, IE not supplying fuel, but its also depends on RPM and because you going down hill the RPMs will rise beyond the the threshold with the road speed and kick in again, and i suspect thats what your experiencing. Quote Link to comment Share on other sites More sharing options...
Ekona Posted August 20, 2014 Share Posted August 20, 2014 Daft question time, please don't take these to heart as I'm genuinely interested and think I may have been a bit harsh in the first place after your last post OP! 1. Is this your first car? 2. Is this your first petrol car? 3. How many years have you been driving for? 4. Do you drive any other vehicles regularly? Quote Link to comment Share on other sites More sharing options...
Grundy Posted August 20, 2014 Share Posted August 20, 2014 No need to feel harsh Dan, I apologised on behalf of everyone at the start of the thread for moments like these I got your back! 1 Quote Link to comment Share on other sites More sharing options...
theheff Posted August 20, 2014 Share Posted August 20, 2014 If you have read something in the manual would it be something to do with the cruise control and adjusting the speed by the button? Just a thought. And also, these forums are for finding stuff out and educating yourself on stuff you don't understand. Better to ask a question than try and blag it, the internet is full of people that do that. Not everybody was born a mechanic with a Haynes manual stuck up their arse. And as far as I know there are different techniques that could be considered engine breaking, not answering your question though as I can't see why these would be in the manual 1st is down shifting into a lower gear, lower gear will use the engines lower momentum and cause the car to slow. Rev matching would be advised in this case to prevent as much wear on the clutch. 2nd, is to just come off the throttle and the engine, along with gravity and other opposing forces will slow the car, gear and speed obviously affect the deceleration. Useful on motorways with speed cameras etc. Covered as acceleration sense in road craft. 1 Quote Link to comment Share on other sites More sharing options...
SiriusProjects Posted August 20, 2014 Author Share Posted August 20, 2014 Some answers to previous queries. StevoD - I never put ordinary unleaded in my car. I'd only do that if I was low on fuel and couldn't find a garage nearby that did 98 or equivalent. Ekona - The zed is not my first car and all my previous cars have been petrol driven. Been driving since 1990 and no I don't drive any other vehicles. The zed is different to previous cars I have owned in that I've never owned a car where you can plug a device into it which allows you to analyse and alter settings in the ECU (I don't mess with the settings myself by the way, in case your wondering). I've never had a car dyno'd until I got the zed either. In truth I've never been able to afford anything like a zed before in my whole life. It sounds pretty self deprecating, but I wouldn't say I'm a great driver either. I don't mind admitting it. I wish I knew more about the mechanical side and I so wish I could drive it far better than I do. 2 Quote Link to comment Share on other sites More sharing options...
Ekona Posted August 20, 2014 Share Posted August 20, 2014 That's cool, it's just bizarre that you've never noticed engine braking before. Either that, or there is a genuine issue with your car. Quote Link to comment Share on other sites More sharing options...
Stu_2424 Posted August 20, 2014 Share Posted August 20, 2014 I need to thank the participants of this thread for making me laugh in the middle of a restaurant! I now look like a crazy person laughing at his lamb.... Quote Link to comment Share on other sites More sharing options...
docwra Posted August 21, 2014 Share Posted August 21, 2014 Hmmm, the one thing that springs to mind is that the 350 is rather unsubtle when it "makes itself" idle - Im talking about when you let the revs drop down under 1K and the car sorts itself out to stop it stalling. Most cars Ive driven you dont notice this happening but in the Zed you can actually feel the car lurch a little as it cuts in, maybe its that youre feeling? 2 Quote Link to comment Share on other sites More sharing options...
Bockaaarck Posted August 21, 2014 Share Posted August 21, 2014 SiriusProjects, first of all you were 100% right to post and ask the question / ask for help. If you're not sure if something's normal / wrong how else are you going to find out? The first I would ask is do you know when your Zed was last serviced? If it hasn't been done recently it might be worth getting it serviced. I'm sure you've thought of this already to be fair. I'm no mechanical whizz kid either so I find out a lot by asking these guys questions (some of the answers are on occasion helpful ). In all seriousness it does sound to me that possibly there could be an issue which might be resolved by a good service. However; it's also possible (bearing in mind I'm no mechanic) that there's possibly something air / fuel related which is making your Zed behave a bit 'odd'. I'd start with a good service and then move on from there my friend Quote Link to comment Share on other sites More sharing options...
4RE Leather Posted August 21, 2014 Share Posted August 21, 2014 There isn't actually an engine brake (except for in some trucks/diesel engines) ~ it's just a term used to describe the effect caused when you're off the throttle & the vehicles rolling faster than the engines rpms. Like when you downshift from a higher gear to a lower gear at speed coming to a stop at traffic lights for example. The friction in the drive train/vacuum on the engine basically causes the engine to slow & the vehicle in turn (won't happen when you're not in gear as you're just free wheeling then). Hope I've explained it correctly as that's the way I understand it. Stop showing off you Nurdy Geek !! 2 Quote Link to comment Share on other sites More sharing options...
GMballistic Posted August 21, 2014 Share Posted August 21, 2014 Lol. Quote Link to comment Share on other sites More sharing options...
SiriusProjects Posted August 22, 2014 Author Share Posted August 22, 2014 My zed was fully serviced a few months ago. The hesitation isn't that pronounced and it does only occur when I am going down hill and not applying any acceleration. I have been on google since starting this thread and read up on engine braking and the descriptions on some sites mirror exactly what happens with my zed so I'm thinking it's nothing to worry about. It has been useful asking about it on the forum though. It's good to get other opinions when your not sure about it yourself. Thanks all for your comments. 1 Quote Link to comment Share on other sites More sharing options...
spursmaddave Posted August 22, 2014 Share Posted August 22, 2014 My zed was fully serviced a few months ago. The hesitation isn't that pronounced and it does only occur when I am going down hill and not applying any acceleration. I have been on google since starting this thread and read up on engine braking and the descriptions on some sites mirror exactly what happens with my zed so I'm thinking it's nothing to worry about. It has been useful asking about it on the forum though. It's good to get other opinions when your not sure about it yourself. Thanks all for your comments. As many have said I think the jolt is just the engine sparking back in to life so to speak after you taking your foot off the pedal Quote Link to comment Share on other sites More sharing options...
Rock_Steady Posted August 22, 2014 Share Posted August 22, 2014 (edited) well lets hope it's just paranoia, I've modded a few cars and sometimes you feel an old jolt or hear funny noise and think " what the diddly is that?" your mind and thoughts can run away to horrible places. It might be something the zed does that you've noticed that others haven't. But of course, it's always wise to ask just in case. Edited August 22, 2014 by Rock_Steady Quote Link to comment Share on other sites More sharing options...
Ebized Posted August 22, 2014 Share Posted August 22, 2014 That's cool, it's just bizarre that you've never noticed engine braking before. Either that, or there is a genuine issue with your car. That maybe down to driving style though - use of brakes to slow down (as many do and nothing wrong with it) rather than the gears, but having driven a host of cars in nearly 50 years I have to say all 3 ZEDs that I have owned have such efficient engine braking that does suit my style and why I find them such a joy to drive. Probably stems from my days of youth taking part in Production and Classic Car Trials when the only braking you did was with the engine and handbrake . Diesels and especially the 4 x4 variety with their torque characteristics, are a good example where we know going down a slippery slope you simply rely on a low gear and let the engine do the braking and avoid the brakes altogether and feel the engine doing the slowing - something an off-road experience day would reveal to the full The 370 in fact addresses the issue rasied by the OP very well with the synchro rev (yes I know heel and toe can do the same but hey, I never got it right all the time ), and quite often when you find the the need to upchange, such as natural increase in speed going downhill, the synchro rev will blip the throttle to match the engine to the road speed and nicely smooths the drive. Quote Link to comment Share on other sites More sharing options...
-Bradders- Posted August 22, 2014 Share Posted August 22, 2014 Just to add my 2 pence, mine was doing this if i was going 70 say and let go of everything, it would slow down as if i was braking, it would coast at all. i would say check the calipers as after changing all my brakes it doesn't do this anymore. 1 Quote Link to comment Share on other sites More sharing options...
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