Hi guys new here any of your knowledge appreciated. i have a 94 toyota seca liftback had new head fitted after crack in the previous one COSTLY. about 9 months later a heater hose blew but car did not overheat.Hose replaced all good. Problem I'm having is very hard to start first thing have checked plugs etc,also whatever it is affects the idling it's way high up to 2000rpm sometimes drops as engine warms up not always. also losing coolant very slowly no sign of where from no sign in oil and no visible leaks.also when first fires very rough for the first 5-10 seconds then ok. ANY IDEAS ?

Heater hose blew.....

9 months sounds like they didn't re-torque your head mate.

No vacuum leaks anywhere? any hissing? idling at 2000 RPM should reveal some hissing sound from any air leak.

Fix the leak which is possibly the head gasket as mentioned. Possibly water leaking into the cylinders is affecting starting charge.

 

If you have not bled the cooling system properly, the ECU water temp sensor can result in high idle.

Thanks for replies I also have sneaky suspicion it's head gasket,also had oil leak on the vavle cover gasket you could visibly see oil coming out when cranking motor have tensioned three nuts and seems ok.still should prob replace.Whatever the prob when driving and slowing down revs go up & down weird shit.

As mentioned, if you solve your water loss then properly bleed the cooling system, you may find it disappears

how does the coolant temp sensor make the revs go up with this motor, the only thing I've ever experienced with faulty or dry sensors is too much fuel.

Does it try to rev the engine with the idle air control valve to make it hurry up and get hot??? (edit, I'm very wrong here see next post)

That would be backwards, to get the engine hot fast you add more fuel. Well thats what every ECU ive ever had does. :/ (edit, I'm very wrong here see next post)

I think there might be 2 issues here,

'intake manifold gasket' (do these engines by any chance have a liquid cooled manifold) or

'head gasket plus some sort of vacuum leak causing the RPM surges'

Edited February 28, 201610 yr by rebuilder86

sorry, I'm incorrect in saying it gives more fuel to heat it up, it gives more fuel because it has to to run properly.

So it would do that plus open the IAC a bit to hurry things along.

My bad.

losing coolant slowly?..... I'd check compression, the health of the engine, first........and pressurize the coolant system too for pressure hold while cold....... high rpms, hard starting? air leaking into engine, leaning the mixture for starting, and causing hard starting. spray some starter fluid around intake gaskets and vacuum hoses after warmed up and during...... owner 87 corolla retired car mechanic