Lacking UMPH

Archives of Posts to the NZ MX5 List back in 2000
Bill Rehm

Lacking UMPH

Post by Bill Rehm » Wed Dec 06, 2000 2:48 pm

Hi folks

Maybe it's just me, but my 91 MX-5 seems to lack power and acceleration as
compared to when I purchased it 2 1/2 years ago (not to mention poorer gas
mileage). The odometer "shows" 92,800K's, had air filter and plugs changed
at 84,200K (at least that's what the invoice says), ignition leads changed
a few weeks ago, and the oil with filter last changed at 89,000K. A new
clutch was required at 75,200K. PS: I tend to have a "lead foot" with most
of the last 8,000Ks Urban/City driving.

Can anyone suggest any tests that a garage can perform (not too expensive
please) or road tests that I can perform (acceleration/time trials
maybe???) so I can relax knowing its my mind, and not the car, that's

Regardless as to whether the problem is the former above, are there any
fuel/oil, etc additives or other tips anyone has found that tends to
improve performance short of installing a turbo?

Thanks in advance


Gary Morrison
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 100
Joined: Sun Jun 04, 2006 3:24 pm
Location: Wellington

Lacking UMPH

Post by Gary Morrison » Wed Dec 06, 2000 2:55 pm


Have a talk to Howard, he has my G-tech. Running a few checks with that in
your car and comparing with a similar car will tell you if yours is abnormal


Black is the new black.
Black is the new black.
Posts: 600
Joined: Thu Apr 13, 2006 11:20 pm
Location: An Eastern Beach

Lacking UMPH

Post by zorruno » Wed Dec 06, 2000 4:49 pm

haven't managed to use it yet - didn't get to the last event as I was
planning. We are possibly going to run some stock 1.6 vs 1.8 tests this

Peter Sweetman

Lacking UMPH

Post by Peter Sweetman » Wed Dec 06, 2000 6:48 pm

Just a thought - have you adjusted the timing at some stage. If so it is
possible for it to slip if the bolt is not tightened correctly. Or if
advancing too far your performance will also drop off. If checking the
timing with a timing light remember to connect the GND & TEN terminals on
the diagnostic box first. (located by the airbox)If you do not ground these
terminals the automatic advance /retard will keep adjusting the timing to
where it should be and give you a false reading.
Just an idea.
Make sure the spark plugs are the correct heat range.


ian cole

Lacking UMPH

Post by ian cole » Wed Dec 06, 2000 8:21 pm

If you want your timing checked I could have a quick look at no cost, my
workshop is in Waitoki. Ian Cole

At 14:48 06-12-00 +1300, you wrote:


Lacking UMPH

Post by Ray » Wed Dec 06, 2000 9:43 pm

its more than likely you are used to your car now, a couple of things come to
mind, has the cam belt ever been changed that you know of, i have seen one with
so much slack the tensioner can't take it up and it ended up 2 teeth out on
the exhaust cam, same thing, big loss of performance, also the fuel filter,
the one that sits under the plastic cover in the rear subframe (drivers side)
may need changing, but that doesn't account for high fuel usage,(lead foot eh!)
i would check the valve timing, along with all the usual checks mentioned, some
you've already done
Good luck

Ray :-)

Turner, Phill W

Lacking UMPH

Post by Turner, Phill W » Thu Dec 07, 2000 10:44 am

Agree on the cam belt .. I have a 94 Mx & hit 100K recently and routinely had
the belt replaced as part of the 100k service ... imagined or otherwise the car
felt much brisker than it had been. Others have indicated improved "feel" after
changing the cam belt at around the 90k to 100k mark.


Phill Turner
MX 5 Club Victoria Aus


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