Re: slight idle problem and acceleration noise

["jtrealtywebspannet" <jtrealty@xxxx>]

To get the motor to idle smooth all 6 cylinders must be within 5% of 
each other in all respects. All of the fuel injectors must have 
perfect patterns and similar pressures, all spark plugs gapped and in 
good shape, all ignition wiring in top shape, all cylinder pressures 
within 5% and so on. If you have 1 cylinder out a little the idle 
drops and then the idle motor tries to compensate. By time the 
correction kicks in you are on the better cylinders so you overshoot 
because the correction was too late so now the idle motor tries to 
slow the motor down and now you have the hunting you notice. Start by 
checking the cylinder pressures. If they aren't within 5% nothing will 
help. If they are close have the fuel injectors checked and cleaned on 
an injector tester. Properly set up the engine can be "super smooth".
For the noise you hear check the idler bearings for the fan belt, 
they get noisy before they fail. Very common for Deloreans to have the 
idle improperly set up, most mechanics don't understand the system so 
they try to "fix" things by turning adjustments. 
David Teitelbaum
vin 10757



--- In dmcnews@xxxx, Soma576@xxxx wrote:
> Hey all,
> 
> thanks to Gary (checksix), i was able to find the problem with my 
idle not 
> kicking down. my throttle was incorrectly adjusted ever since i 
bought the 
> car in 2000!! well it kicks down like it should, in fact, the car 
seems to 
> have a lot more kick now than it used to! i love it!
> 
> my only complaint is that the idle is a little random at idle speed. 
the 
> needle seems to hover around 750 or so, and it moves around all over 
the 
> place randomly from about 450 to almost 1000, then it goes back to 
750 for a 
> bit, then dances, then back to 750. i know the engine isn't 
supposed to be 
> super smooth, but seems a little excessive. what can i do to 
smoothen things 
> out? i know my engine CAN be better because it used to be until i 
adjusted 
> everything over again. sometimes it is so erratic my oil pressure 
never 
> drops to 40 like it usually does at idle speed.
> 
> also, i've had this problem for a while too - on accelerating in any 
gear in 
> any manner, i hear a noisy vibration sound from the engine between 
about 2500 
> to 2900 RPM. you can go slow and it starts, or you can go fast, 
it's there. 
> it's quite high frequency, sounds metallic. it used to sound like 
air 
> whooshing in an odd way, but lately it's sounded abrasive. it will 
do this 
> upon deceleration too, but it doesn't sound as loud.
> 
> any idea what this could be?
> 
> Andy
> 
> Soma576@xxxx
> 1982 DeLorean DMC-12 VIN#11596
> Fargo, ND 58102
> 
> 
> [Non-text portions of this message have been removed]