Mk1 mx5 no power when cold

[gmaster]

Hi Folks new to the web site and looking for some help, My Girlfriend has a MK1 mx5 1990, 1.6 Automatic.

from cold in the morning the car will rev up fine, but when you put it in drive and go to pull away there is now power you will have your foot fulley pressed on the acc pedal and the car will go no were its dead no power what so ever.

I have replaced Plugs, cooliant temp sensor, cleaned MAF, Carried out a compression test all ok. Cleaned out throttle body, Gear oil looks good and clean ( oil was not replaced just checked is there a filter in the gearbox)

I am fast running out of ideas so any help or tips are very welcome I have a very unhappy Girlfriend at home

Kind regards

Gary.

[charged_rs]

try replacing your ht leads , then your coilpack if they dont work

mx5's are notorious for eating ht leads

[gmaster]

its not a misfire just no power

[Steve]

cooliant temp sensor

There are 3, did you change the green topped one at the back of the head?

I think your problem might be O2 sensor related, but as said above, change your igntion leads first if you haven't in the last 20k, they don't necessarily cause a misfire when bad. Get the blue NGKs if possible.

[sidewaysreilly]

load test the leads first ........they spark in pairs so can confuse...........unplug every wiring connection and clean..........MAF sensor dirt can be a problem for an auto trans...........clean it with alchohol or brake cleaner.If that dont work ill find a way........

[mx5ash]

The fact that it revs fine but won't move sounds to me like something to do with the gearbox rather than the engine.
Mine has a habit of having small fits like that aswell (also an auto), not complete loss of power but reluctant to get going. Does it go away when warmed up?
I've always put mine down to the need for a oil change (gearbox no engine)
And yes there is a filter in there.
Ash

[franksm]

Do the rear wheels get hot ? If so, you have a seized caliper that's dragging on the disc (as if the handbrake is jammed on)

Pop the spark plugs out and see what colour they are - should be a blackish, grey. Anything else points to ignition (leads/plugs/coilpack) or fuel (fuel filter) problems most likely. Is there any soot on the back bumper around the exhaust ?

Does the car rev okay when out of gear ?

Could be the timing belt has jumped a tooth too - that makes the engine lethargic but can also give pops and backfires.

[mx5ash]

Heres a link to changing auto trans fluid. Must do mine when it gets warmer/dry.
http://forum.miata.net/vb/showthread.php?t=162443

[ger]

shortnose crank?
Does the lower pulley wobble?

[sidewaysreilly]

check that the overdrive switch is working correctly and then check the o/d solenoid. If i get a chance i will scan a few pages and get them to you if you pm me details.

[twail]

I'd say its more than likely a something physically stopping it from moving rather than an engine problem, as you said it revs up fine in neutral.

[leamyj]

Any chance that the ecu is in limp-home mode???