1.8 NA Engine idle

[MGStephen]

Iv just done the head gasket on the 1.8 75. Starts drives perfectly etc.

The issue im having now is its a bit reluctant to start, but after a few turns she will fire up fine. The idle on the car can be varied, sometimes it rises alone upto 3k ish or can be about to stall.. Now i havent touched any of the inlet manifold it was literally unbolted whole from the head.

any ideas?

[rich17865]

Coil packs, leads, plugs, IACV, throttle step position, air filter, and a variety of other things.

Worth a trip to your local T4 operator I think.

[MGStephen]

Coil packs, leads, plugs, IACV, throttle step position, air filter, and a variety of other things.

Worth a trip to your local T4 operator I think.


Coil packs and leads have been changed for known working ones ( 1.6 45 ) Plugs filter have been changed for new items from Matt at DMGRS. I will check the IACV and change that along with resetting the TSP.

Local operator is a fair distance away from me sady.

Il have a look this weekend and see what happens

[rich17865]

Is there another diagnostic device that can set the throttle steps? I wonder if launch can do it.

[marinabrian]

I'd have to say do a compression test first ;)

When you replaced the HG, what state were the exhaust valves in ?

Brian :D

[mick160]

After doing the HG on a 25 the wife had years ago I had a similar problem, car would start ok but then idle at about 3k.

After checking all the obvious and much (much, much) head scratching I found that the connectors in the wiring loom for the throttle position sensor and camshaft sensor were the same and i had connected them up the wrong way round. Swapped over the connections and, hey presto, priblem solved.

Dont know if its possible to make this mistake on our cars but could be worth checking. :o

[Saga Lout]

As Rich rightly says, it could be many things, an obvious one is some kind of air leak or the TP sensor. If it was mine I'd go back to the timing first and check the settings and start from there, also check the engine earth leads as a loose one/dirty one can cause this sort of thing.

[MGStephen]

I'd have to say do a compression test first ;)

When you replaced the HG, what state were the exhaust valves in ?

Brian :D

Everything looked find and dandy, all clean with minimal carbon deposits

After doing the HG on a 25 the wife had years ago I had a similar problem, car would start ok but then idle at about 3k.

After checking all the obvious and much (much, much) head scratching I found that the connectors in the wiring loom for the throttle position sensor and camshaft sensor were the same and i had connected them up the wrong way round. Swapped over the connections and, hey presto, priblem solved.

Dont know if its possible to make this mistake on our cars but could be worth checking. :o

do you know i think you might be correct!

i will check tomorrow :)

As Rich rightly says, it could be many things, an obvious one is some kind of air leak or the TP sensor. If it was mine I'd go back to the timing first and check the settings and start from there, also check the engine earth leads as a loose one/dirty one can cause this sort of thing.

Timing is bang on. Fully checked and its fine. Only one earth was disturbed and thats been checked.

[mick160]

Did you manage to get this sorted? :shrug: