Hey all, got my 87 T2 with this issue, now it’s time to dig into it.

When i start her up, the idle raises to about 1.5-2k, and drops pretty quickly to about 750, then even lower til it dies, when it warms up the idle surges around 300-750 rpm’s for about 15 seconds maximum then dies. Operates totally normally besides that, has great power, i’ve just been holding my foot lightly on the gas at red lights lol, i have changed the fuel pump and fuel filter, checked for vacuum leaks but could not find any.

Has anybody had this issue before? what fixed it? what are some steps i should take to diagnose this?

 

I would start with simple stuff, like replace the coolant temp sensor, check tps is set correctly and has no dead spots. After that If you want to get really involved, pull upper and remove throttle body and check throttle plate clearances are set as per fsm and all cold start stuff is correct, bac valve is functioning and the dashpot is set correctly. Then maf both resistance and the flap is sealing. Injectors. List goes on but sound a bit like water temp sensor to me

 

great info thank you, are water temp sensors for this car available at part stores?

 

Should be. It’s the green connector on back of water pump housing. It’s a cheap starting point.

 

Atkins rotary has them. Mazdatrix as well. Lots of people claim no vacuum leaks and then they forget to spray starter fluid near lower intake manifold...

 

replaced the coolant temp sensor, definitely idles better than it was, it’ll hold on its own for about a minute now! funny enough also fixed a flooding when hot starting issue i was having lolll

 

half way there aye? Yeah it can play havoc on start up. Could still have a vac leak or tps needs setting.

 

yup i’m waiting to be able to borrow the smoke tester from work. is there a guide anywhere on setting tps?

 

Covered heaps on here. Basically get car warm, really warm. If stock turbo car you need to get the top mount ic off quickly. Bridge the initial set coupler. Key to on position. Check the tps with multi meter probing the green wire and finding a good earth. Set to 1vdc via a flat blade screw next to tps. Key off, unplug tps, probe black wire and green wire. Also check resistance has no dead spots through a slow sweep of the throttle and isn’t too far short of 4.5-5k ohms or passed 6k ohms at wot. Some people set it to 1k ohms at closed throttle rather than 1vdc at closed throttle which is probably close enough but not what the computer is looking for. But all of this is done only after you set idle as any changes to base idle position of the throttle affects the tps. I think there’s a whole write up on fc3spro website too. This process must be done quick as the car cools the values you see on the multimeter (throttle closed) will climb as the thermowax retracts.

any dead spots as you test resistance or out of range (under 4k or over 6k at wot) TPS needs to be replaced. I recommend ordering new from Japan or if you can find cheap enough locally. Grabbing second hand can have you dealing with the same faults, if not now, soon.