93cutty Posted October 6, 2008 Report Share Posted October 6, 2008 I was kidding about the shutting off on hills. But there have been times that I have put it in neutral down hills and it did save gas but the clunk upoun shifting back in gear stopped me from doing that again. If you want to save gas buy a geo. Quote Link to comment Share on other sites More sharing options...
Crazy K Posted October 6, 2008 Report Share Posted October 6, 2008 FYI for those who care... in a Grand Prix at least, this whole Fuel Cutoff On Decel thing will only happen when you are well over 55mph and will never happen below 55mph. Example, I run up fast to 100mph then let off and coast down, as soon as I let off it cuts off all fuel (wideband in dash showing no fuel) and it does not add fuel back in unless you hit the brakes, tap the gas, or fall below 55mph. It scared me at first since it is very noticeable in my car, you can feel it happen and hear it in the exhaust and see it in the dash. thats what I have thought. in the 95 cutty which I plugged in a 95 gtp dic, when I was going downhill and coasting between 60-80 mph... the instant mpg would go all the way up to 99.... and then flip to ZERO. I always wondered if this was due to the fuel trim being so lopw that the dic/dtad stream number was rounding to cause the dic to divide by a number rounded to zero... or if there was no actual fuel delivered. I also nearly blew a 3.1 mpfi motor. it blew a hose and went red hot. (thought I blew the headgasket) I flicked the key off and let the car coast down from 70 mph... trying to maximize the distance I got. I turn the key on, and the engine would snap back to life (without using the starter) because I left the gearshift in drive. I guess the transmission was turning the engine the entire time?!? I drove 30-40 miles by powering up the engine for 20second sprints to get up to speed... without ever engaging the starter.... Quote Link to comment Share on other sites More sharing options...
j_mezz Posted October 6, 2008 Report Share Posted October 6, 2008 Does this add up to - if you had a big enough hill you could 'push start' an automatic? Quote Link to comment Share on other sites More sharing options...
oldscsc Posted October 6, 2008 Report Share Posted October 6, 2008 Does this add up to - if you had a big enough hill you could 'push start' an automatic? I don't see how, there's no clutch to pop Quote Link to comment Share on other sites More sharing options...
Breakdown Posted October 6, 2008 Report Share Posted October 6, 2008 I should also mention. Anyone ever tried punching a car when it's going down a hill? There's not much of a reaction on the highway, or is that just me. Usually I can get a decent jolt out of a car when dropping the hammer when cruising at 65-75 MPH. Quote Link to comment Share on other sites More sharing options...
Breakdown Posted October 6, 2008 Report Share Posted October 6, 2008 Does this add up to - if you had a big enough hill you could 'push start' an automatic? I don't see how, there's no clutch to pop I was more thinking jump start. I've never rolled a car down a hill with the hood open & engine off though, I really don't think it would work. Definitely not "push start." Quote Link to comment Share on other sites More sharing options...
LuckoftheGTP Posted October 6, 2008 Author Report Share Posted October 6, 2008 Hey Got my car back..... The berring in one of the pullies was shot and the timing belt was chewed up. Trany is fine Thank you all for your input. Quote Link to comment Share on other sites More sharing options...
Crazy K Posted October 7, 2008 Report Share Posted October 7, 2008 Does this add up to - if you had a big enough hill you could 'push start' an automatic? I don't see how, there's no clutch to pop if a car had a secondary transmission pump driven by the output shaft... you could place the car in a drive gear and once the car goes fast enough, enough road force would transmit through the transmission to turn the crank. with the key on... you get a bang and go! but ours don't have a pump. I know of none that does. in my case... I had a slush box 230,000 mile engine, probably since i was in drive with ignition off, the engine was still coupled with the wheels and was turning fast enough even with the key off to provide the transmission fluid volume and pressure necessary to keep the engine and tires coupled. this was a 4T60... which wouldn't give two shits about the ignition on or off.... so the same would might not have occurred with an E tranny. I was really surprised that it happened that way but I took advantage to keep a dying car going. Quote Link to comment Share on other sites More sharing options...
Brian P Posted October 7, 2008 Report Share Posted October 7, 2008 Does this add up to - if you had a big enough hill you could 'push start' an automatic? I don't see how, there's no clutch to pop if a car had a secondary tranmission pump driven by the output shaft... you could place the car in a drive gear and once the car goes fast enough, enough road force would transmit through the transmission to turn the crank. with the key on... you get a bang and go! but ours don't have a pump. I know of none that does. in my case... I had a slush box 230,000 mile engine, probably since i was in drive with ignition off, the engine was still coupled with the wheels and was turning fast enough even with the key off to provide the transmission fluid volume and pressure necessary to keep the engine and tires coupled. this was a 4T60... which wouldn't give two shits about the ignition on or off.... so the same would not have occurred with an E tranny. I was really surprised that it happened that way but I took advantage to keep a dying car going. My '90 Olds had the exact same feature. Quote Link to comment Share on other sites More sharing options...
Crazy K Posted October 7, 2008 Report Share Posted October 7, 2008 it was completely unexpected. IIRC the 4t60 doesn't have an output driven pump, does it???? Quote Link to comment Share on other sites More sharing options...
Brian P Posted October 7, 2008 Report Share Posted October 7, 2008 I don't know what the difference is internally that would cause that, honestly. Quote Link to comment Share on other sites More sharing options...
Crazy K Posted October 7, 2008 Report Share Posted October 7, 2008 hey.... any way to determine RPMs when going down the road with the ignition flipped off? (besides driving with the hood off to see if the belt is turning) Quote Link to comment Share on other sites More sharing options...
Brian P Posted October 7, 2008 Report Share Posted October 7, 2008 I don't think the engine is spinning when the ignition is off, otherwise there'd be the feeling "engine braking" going on. You'd hear it too especially if you have a loud exhaust. Quote Link to comment Share on other sites More sharing options...
IRONDOG442 Posted October 7, 2008 Report Share Posted October 7, 2008 You seriously add nothing to this community besides your oh so hilarious sarcasm and witty remarks. Quote Link to comment Share on other sites More sharing options...
Night Fury Posted October 7, 2008 Report Share Posted October 7, 2008 Quote Link to comment Share on other sites More sharing options...
Crazy K Posted October 7, 2008 Report Share Posted October 7, 2008 I don't think the engine is spinning when the ignition is off, otherwise there'd be the feeling "engine braking" going on. You'd hear it too especially if you have a loud exhaust. well.... the car was restarting without me using the starter.... so WTF? Quote Link to comment Share on other sites More sharing options...
oldscsc Posted October 7, 2008 Report Share Posted October 7, 2008 I don't think the engine is spinning when the ignition is off, otherwise there'd be the feeling "engine braking" going on. You'd hear it too especially if you have a loud exhaust. well.... the car was restarting without me using the starter.... so WTF? Well that's how you pop the clutch on a manual...the engine is moving. Ever watched the driveshaft? Whenever you are moving, engine running or not, it is also moving. Quote Link to comment Share on other sites More sharing options...
w-bodys_are_the_best Posted October 8, 2008 Report Share Posted October 8, 2008 My cousin's first vehicle was a 1978 Ford F150 2x4 with a 302 and IIRC 2 bbl carb, he was being designated driver for his older brother, and his older brother being drunk, reached over and turned the key off going down a hill at 60 mph, well he still had his foot on the gas, turned the key back on and it blew the muffler in half from all the gas built up. He was very pissed and made his older brother buy him an entirely new exhaust system as the pipe was pretty rusty anyways. Quote Link to comment Share on other sites More sharing options...
Brian P Posted October 8, 2008 Report Share Posted October 8, 2008 I don't think the engine is spinning when the ignition is off, otherwise there'd be the feeling "engine braking" going on. You'd hear it too especially if you have a loud exhaust. well.... the car was restarting without me using the starter.... so WTF? I think one of us needs to try this with the hood off I don't have any more 4T60 cars though .... All you bud!!!! Quote Link to comment Share on other sites More sharing options...
Night Fury Posted October 8, 2008 Report Share Posted October 8, 2008 I do! But I can't get it out of the garage! Quote Link to comment Share on other sites More sharing options...
ns87 Posted October 8, 2008 Report Share Posted October 8, 2008 hey.... any way to determine RPMs when going down the road with the ignition flipped off? (besides driving with the hood off to see if the belt is turning) I can answer that!! My car has stalled numerous times on the highway over the years. Usually when I'd crank start it in neutral, the RPMS would start off around a little under 2000rpm ~65mph I think Does this sound right? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.