With in the last week my heater core decided to leak under the dash... so i bypassed it using a single 'U' hose. Looking back on the day and before i started i turned the car on and revved it straight away and the idle dropped... It almost felt like the car was going to conc out So as the day went on i had done the heater core and the car ran perfectly! Taking my car out tonight for a cruse around the town... I felt the car to chug along instead of running smoothly. I had noticed the chugging happening mostly when the car was in drive (as it is an auto) stopped at the lights. The chugging even happened traveling at 60km/h. The chugging still occurred but lessened in neutral. The only time the car stopped chugging is when i put the foot down and gave it a flogging. It then went away for a minute or two but then came back again... I thought it may have been the ptu? or something to do with the heatercore bypass? or even bad run of fuel as i was on empty before doing the bypass. Anyone got any ideas?
Most likely ... you've accidentally bumped the wiring loom and dislodged injector and/or coilpack wiring plug(s) on the two rear cylinders. Try pressing the wiring plugs firmly down and see if the roughness goes away. Another possiblity is the det sensor wiring has been disturbed and you are in safety boost. An ECU diagnostic will confirm this. ifso, check tech section for the wiring plug location.
ive checked and pressed together all the wiring plugs that i may have disturbed yesterday all around the back of the motor and the ones on the rear cylinders. Nothing seemed to work the car still runs rough and sounds as if its a deeper popping tone from the exhaust instead of purring like it had been before hand, its missing a beat. As soon as i rev the car it seems to drop in the revvs for a slight half a second and then go back to normal. But as it goes up to normal you can tell the whole cars rumbling... It aint like no normal shack it really rocks the car! Even my passenger noticed it last night. My car is a japspec 1990 non-turbo automatic 2 seater
grab a screwdriver and hold the handle to your ear and the tip on the injector connector, make sure there is the ticking sound of the injector working, it should be the same for all of them. If they are all ticking along nicely check all of your vacuum lines in the area you were working on. I know what you are going through, i've been through it recently myself
also if you cannot hear any obvious vacuum leaks grab some hose, hold it to your ear, have a mate rev the car and hold it just above idle and start listening to the air hoses around the engine.
ive gone checked the injectors with a screw driver and they were ticking fine, then i herd a air leak.... so now ive just got to find which hose it could be? Is it that easy to disturb the air vacuum system? Its also hard to know what noises your listening out for when its all new to you. one question i have is how could this upset the car? is it due to fuel air mixtures being not at the correct ratio? thanks fellas for the help and ill post up again if i have anymore trouble
as i recently found out after a plenum pull, these cars get very annoyed when their vacuum system is disturbed. if you get something like a busted PCV hose they sometimes wont even start! my air hose that joins directly to the balance pipe developed a crack, that played some havoc with the usual smooth running of my zed. Get some hose and listen around the engine... youll find it
Sounds like the dog leg hose between the air regulator and the balance tube. It is the one with the 3 red arrows pointing toward it in the below pic.
thats the one that has a lovely crack on my Z... too bad getting parts for these things in perth is like pulling teeth...
