Proper timing idle setting - 1986 Toyota MR2

Bill, you could possibly have a vacuum hose leak. With motor running, open your hood and listen carefully for a hissing sound. If you hear one, try to pinpoint where it's coming from.

The first thing to do is not set up the idle speed, but to set the Idle mixture screw to lean best idle setting. First, turn in the mixture screw until the engine dies or runs worse, then back out the screw (recommend turning ¼ to ½ turn at a time). The engine should pick up speed and begin to smooth out.

The battery has nothing to do with the idle speed

air idle control valve, I dont belive you have a ideler set screw..I do belive the problem is what I have Listed..........Best of luck


How can I tell if I need a new air idle control valve?
If your car has a rough idle or the idle cycles up and down, then chances are that you have a bad idle control valve. On modern vehicles, the purpose of the idle air control valve is to regulate your idle, and keep the idle smooth. The idle valve is controlled by the ECU or the computer, and when in gear the idle should be between 800 and 1000 rpm, and not in gear, between 700 and 900 rpm

to get the perfect tune you will need to get the car on a dynamometer (a sort of rolling road)they will sort out the timing/mix
for the whole rev range/road load/speed.
all you can do at home is idle/timing settings for tickover.
find a specialist tuning/race builder local to you (im in the u.k.)

Sounds as though you have a vacuum problem...check your hoses to and from the carb...

P1505 - Idle-Speed Control Valve Closing Solenoid Control Circuit Electrical
P1507 - Idle-Speed Control Valve Opening Solenoid Control Circuit Signal Low

The knock sensor will cause the ignition timing to ******, which will cause a lack of power, however, it's important that the engine camshaft/crankshaft timing was set properly when rebuilding the engine, if this is off, the engine will have no power and you could set the knock sensor code.

Hope thats help.

Check and clean th egr valve or just replace it. Sometimes I have seen that both the EGR and the IAC need to be replaced and sometimes, people only replace one. I personally on my own vehicles when this happens I just replace both at the same time

As a factory Nissan trained Technician with dealership experience - it can be many things, but it sounds alot like a mis-adjusted or faulty TPS, and/or a faulty IAC(Idle air control) valve - I'd try the TPS and set to appx. .50 vdc (.47/.49) Volts DC and if that isn't it, I'd definitely look to the idle air control valve ( allows for air bypass - sometimes called bypass air control valve). May then need base timing and idle set at shop with OBDII ignition disabling option, for seting timing and idle, otherwise computer won't allow proper setting...then if connector to IAC is OK - should be just fine...

Your camshaft and crankshaft pulleys have to be properly aligned upon installation of the timing belt. The cogs on the belt, should fit precisely with the teeth of the pulleys. Your # 1 engine cylinder should be moved to "Top Dead Center" before installing the belt. This means no compression once the top of the piston cylinder reaches the top of the chamber.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/david_62314e5b2470e8b5

Yes you can,

do this with your RPM setting,

you ahve to just set you engine race settings,

try & having funn with your car,

THNX