Okay, i bought a perfect 91 GTU........perfect except it doesnt run very well at all. I was told it is a bad rotor, but cant bring myself to yard out the motor until I am sure of this(the shop that diagnosed it is not reputable or rotary knowledgable). So........ what are the symptoms of a bad rotor?? Heres what its doing. It starts pretty easily then revs to about 2000rpm, and slowly dies. It blows white smoke too. I can keep it running if i tickle the gas pedal, but it has very little power. It probably IS a bad rotor, but if its something else i would be happy. So what do you experts think???

Drew

 

The fact that it starts at all is real good news.. Does it sound real rough and lumpy when it runs? That could be a blown apex seal. If you really want to know the condition of the engine's internals, you should do a compression check.

It sorta sounds like you have an intake leak. That, or clogged cats or fuel filter could do that. Give the ATF trick a shot (do a search on the forum for how to do it).

-Tesla

 

Yank out the spark plugs and turn it over... it should make a nice rhythmic whump whump whump sound like an air compressor, sorta. Another way is to have a friend turn over the motor(with just leading plugs pulled) and put your thumb over the hole. Each rotation should try and push your finger off the hole 3 times. If you really wanted to know, and wanted numbers, you could take it to mazda for a compression test... i think its like $70 though. I'm no expert though, see what others say


~Jesse

 

Ok im really stupid on 2nd generation LOL , but on my 85 12A i did this (dont laugh LOL) Was take a regular compression guage for a piston motor, and using a digital camera i filmed a mpeg video of the needle. Played it back in slo mo to see the 3 bounces of the needle. Holding the reset button in of course with black tape....

The listening test works well too, but not very accurate unless its really really bad.

Never thought about it but it sounds like an air compressor.

 

Blowing white smoke is a BAD thing... sounds like possibly bad coolant o-rings. Take the coolant fill cap off and start the motor. If it pumps coolant out it's toast. If it blows big bubbles in there it's toast.

Brad

 

MMO that **** son

Regards,
Wagondriver69