1990 Miata wont start

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12-03-2007, 10:21 AM
kylstryl2005

1990 Miata wont start

I have a 1990 miata and it wont start. It was running and now it won't. I have great compression and great spark, it will crank all day. (till it kills the battery at least)

I thought it was the fuel pump because when I turn the key to the on posistion it does not engage the fuel pump. When I turn the key to the crank posistion it does engege the fuel pump but still won't start. ( I bought a new fuel pump and it responded the same so I took it back) I've been told that is normal for the fuel pump to only start pumping while cranking. Is that correct? I went and bought a new CPU and it made no differance and also a new thing that sets on top of the air cleaner housing, it made no differance. Several people have told me it sounds like the cam senser is bad, and the crank sensor is bad. I know the cam sensor is on the back of the head by the fire wall, is there also a crank sensor some where or is the same sensor being called two different things? I don't want to waste any more money gussing. Can I test the cam sensor some how ti make sure its good or bad? Please advise.
[email protected] Thanks
12-03-2007, 10:28 AM
POS Racing

Is this you - http://forums.dfwmiata.com/showthread.php?t=10775

Call Stevan at Miata Solutions he is the best around!

Link - http://www.miatasolutions.com/
12-03-2007, 10:30 AM
kylstryl2005

No I am someone different.....thanks for the info.............
12-03-2007, 10:34 AM
channelmaniac

OK...

Start simple.

Does it try to start at all or does the motor just spin?

If you have spark then your CAS and your coil packs are OK.

I do have to ask how you know you have spark... because if you pull the plug wires to test for a jump spark you will damage the coil packs... The way to test for the spark is to make sure the metal part of the plug body is grounded properly and look for the spark in the gap of the plug. This will help you test and help you keep from frying a coil pack.

If you don't have proper spark then check the timing belt (open the oil cap and have someone turn over the engine... look for the cams to turn), CAS, and coil pack.

The next is the air flow. If your AFM is bad then it should start for a bit then die.

Beyond that is fuel. Pull a spark plug and smell it... does it smell like gas? Disconnect the fuel line from the pressure regulator input and stick it in a quart jar... crank the engine... are you getting fuel?

If you aren't then it could be a bad relay, bad/dirty ignition switch, clogged fuel filter (under the car near the rear passenger tire), clogged fuel pickup on the pump, bad pump, or a clogged fuel line.

There's a set of pins you can jumper on the diagnostic connector on the NAs to turn on the fuel pump. I forget which ones you jumper offhand.

Where are you located? Maybe a board member is nearby and can give you a hand in diagnosing it.

RJ
12-03-2007, 12:32 PM
black roadster

Have you tried having someone crank the motor while you look in the oil cap reservoir to see if your cam is turning?
12-03-2007, 12:47 PM
channelmaniac

Quote:

Originally Posted by black roadster

Have you tried having someone crank the motor while you look in the oil cap reservoir to see if your cam is turning?

Hello... hello... hello...

Echo... echo... echo...
12-03-2007, 12:56 PM
black roadster

Quote:

Originally Posted by channelmaniac

Hello... hello... hello...

Echo... echo... echo...

Ok. I'll read your response. :rolleyes:

::Banana::
12-03-2007, 01:05 PM
cam76034

You might want to check your timing belt. Remove the oil cap and check to see if your cam turns while someone is starting it.
12-03-2007, 01:27 PM
POS Racing

The master mechanics are leaning towards timing belt!

Quote:

Originally Posted by black roadster

Have you tried having someone crank the motor while you look in the oil cap reservoir to see if your cam is turning?

Quote:

Originally Posted by channelmaniac

Hello... hello... hello...

Echo... echo... echo...

Quote:

Originally Posted by cam76034

You might want to check your timing belt. Remove the oil cap and check to see if your cam turns while someone is starting it.

But kylstryl2005 reports the following :

Quote:

Originally Posted by kylstryl2005

I have a 1990 miata and it wont start. It was running and now it won't. I have great compression and great spark, it will crank all day. (till it kills the battery at least)

So I have a question, If ya got Spark and compression wouldn't it be a safe bet the timing belt is still in place?? :confused:
12-03-2007, 09:36 PM
TurboDuane

If the timing belt is broken, then there would be no spark as the cas won't see any movement.
12-07-2007, 10:06 AM
kylstryl2005

Miata mechanic availble?

Timing belt is good, I have good compression and bright spark, I replaced the Air flow sensor and the CPU and it still won't try to start....just cranks and cranks. I live in N. W. Fort Worth off I-30 and Las Vegas Trail. Anyone with miata skills want to trouble shoot it for me for a few $$$$?????
Kyle 817-247-9581:confused:
12-07-2007, 10:09 AM
kylstryl2005

Timing belt is good. I have good compression and bright spark.
12-07-2007, 10:52 AM
channelmaniac

Sounds like no fuel.
12-07-2007, 10:56 AM
POS Racing

Quote:

Originally Posted by channelmaniac

Sounds like no fuel.

+1

After attempting to start the car do you smell gas??
12-07-2007, 10:58 AM
Treibenschnell

Quote:

Originally Posted by POS Racing

After attempting to start the car do you smell gas??

I didn't know Titus had gone over to help... ::Fart::

::Boo::
12-07-2007, 10:59 AM
POS Racing

Quote:

Originally Posted by Treibenschnell

I didn't know Titus had gone over to help... ::Fart::

::Boo::

Don't forget you would also have a cracked windshield if Titus was involved! ::Rimshot:
12-07-2007, 11:01 AM
Treibenschnell

Quote:

Originally Posted by POS Racing

Don't forget you would also have a cracked windshield if Titus was involved! ::Rimshot:

That's Thumby-Sue for ya!

I will say this, though... the man does come through for a brother!
12-07-2007, 11:56 AM
Titus

::Rant::
12-07-2007, 12:24 PM
cam76034

Quote:

Originally Posted by kylstryl2005

I thought it was the fuel pump because when I turn the key to the on posistion it does not engage the fuel pump. When I turn the key to the crank posistion it does engege the fuel pump but still won't start. ( I bought a new fuel pump and it responded the same so I took it back)

How did you determine that the fuel pump does not engage? Did you jumper the f/p and gnd terminals in the diagnostic connector? I'm thinking relay here.
12-07-2007, 04:38 PM
channelmaniac

Quote:

Originally Posted by cam76034

How did you determine that the fuel pump does not engage? Did you jumper the f/p and gnd terminals in the diagnostic connector? I'm thinking relay here.

Or ignition switch...