Mechanics

POWER STRUGGLE WITH 95 MX3

1995 Mazda MX5

Having trouble with my 1995 mazda mx3. I just got done rebuilding the engine and have been battling a power loss with this car for some time. I replace the clutch, getting 190psi per cylinder, ignition is right at 10 degrees. Replaced alternator, air filter, fuel injectors, MAF sensor, TPS sensor, temp sensor, 02 sensor, distributor, cap, rotor, spark plugs, plug wires. Fuel pressure tested fine but have not yet tested the fuel pump it self. Catalytic converter tested fine. Not sure what else to check it lags on the highway very bad and just not up to power. Thanks
Jon
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Bumpysbro
January 3, 2007.



Try the EGR, fuel filter, In-tank filter/sock-and redo the fuel pressure with and without vacuum-this will nail the pressure regulator and fuel pump, also check all your grounds to the computer.

Some TPS needs an initial adjustment to be set.

Recheck your ignition components-sometimes the coil when heated so bad it goes southbound.

Rasmataz
Jan 4, 2007.
Ya I replaced the fuel filter but did not change a thing, I did change back my fuel pump and saw a noticeable improvement. I have been getting a purge solenoid code from the computer. And I was checking my vacuum hoses the other day and noticed the vacuum chamber was completely filled with gas. Kind of weird. Grounds to the computer are tight and nice and clean. Will check the egr, how can you tell if its defective? Thank you for your help

Tiny
Bumpysbro
Jan 5, 2007.
The egr valve seemed to check out fine, but I did nail down that the fuel pressure when the vacuum hoses on the fuel regulator were disconnected showed no sign of psi change. It says on my manual it should rise 10 to 20psi when either both or one of the hoses are disconnected but the reader showed only a 2psi increase.

Tiny
Bumpysbro
Jan 5, 2007.
Pinch the return line and check what happens to the pressure

Rasmataz
Jan 6, 2007.
When I pinched it the fuel pressure shot up very quickly. I replaced the fuel regulator but no luck on my part. The egr seems to test fine. Car still struggles on highway. Maybe my fuel pump

Tiny
Bumpysbro
Jan 17, 2007.
Fuel pressure tested fine but have not yet tested the fuel pump it self

Put the gauge back On-and monitor the pressure-is it to specs?BTW do you have vacuum to the regulator hose?

-Do a backpressure on the exhaust system to rule out restriction.

Rasmataz
Jan 18, 2007.
I had a backpressure test done and it was basically perfect. Im gonna test the pressure today, the pressure regulator seemed to smooth out the idle and start off but no better power. Ya I got vacuum coming from both vacuum hoses to the regulator. Thanks for your help. Been trying to nail this problem for a long time.
Jon

Tiny
Bumpysbro
Jan 18, 2007.
Disable the EGR and go road test

Rasmataz
Jan 18, 2007.
I unpluged the egr valve and seemed to drive just a little bit better. And im getting codes for it, I tried cleaning it but maybe the diaphram is cracked or something. I also did another fuel pressure test. Fuel regulator came up perfect but my fuel pump came up bad it wouldnt hold any pressure for more then 10 seconds and mazda says the fuel pressure should stay above 21psi for more than 5 minutes mine stayed above 20psi for 5 seconds haha. I dont think there are any other remedies to fix the egr valve except to replace it correct? Thanks I get my new fuel pump tomorrow ill see how much that improves my power.
Jon

Tiny
Bumpysbro
Jan 18, 2007.
I put in a new fuel pump and the car drives better, but ya the egr I would suspect is the problem. With it connected and disconnected you can barely tell the difference and drives a little smoother without it pluged in. Shouldn't it make the car run crappy?

Tiny
Bumpysbro
Jan 19, 2007.
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