Mazda MX3 I'm stumped

POOCH

MEMBER
1993 MAZDA MX3
4 CYL
FWD
MANUAL
200,000 MILES

1993 mazda mx3 4 cyl, lots of incomplete combustion on a cold start. Makes a big white cloud. Not coolant or oil, smells like the exhaust from a cold engine, just lots of it. Just changed head gasket, no improvement. Injectors cleaned & tested, o2 sensor replaced, plugs, wires, cap, & rotor replaced. What could it be? Also, stumbling or surging under acceleration.

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,650 POSTS

Have you checked the fuel pressure regulator? Also, are you certain it isn't coolant. I realize you replaced the head gasket, but the head could be warped. Finally, have you checked the temp sensor? It tells the computer how rich or lean the fuel mixture should be based on coolant temp and ambient temp.

Let me know.

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Sunday, November 14th, 2010 AT 7:25 AM

RASMATAZ

MECHANIC
75,992 POSTS

Pull the oil dipstick and smell it for gas-if it is- check the injectors and FPR if its leaking if not Try replacing the PCV valve and inspect the crankcase ventilation system

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Sunday, November 14th, 2010 AT 7:29 AM

POOCH

MEMBER
2 POSTS

Engine's not losing any coolant at all. Temp. Sensor checked out ok, but maybe it's intermittent. Sounds like I'll look at the fuel pressure. Keep the ideas coming!

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Sunday, November 14th, 2010 AT 5:06 PM