Sudden No Start

[NATE1987]

Hey,

First post here so forgive me if i miss something.

I own a 1994 Mazda b3000 se standard.

Had a misfire for the past few weeks (not super consistent). Feel like it began shortly after i changed my Air filter. Couple times it stalled due to the misfire. Have recently done an oil / filter change, and fuel filter.

Decided to see what was going on. Disconnected the hose leading from the MAF to the throttle. Also checked the sparkplugs (noticed it was running rich due to dry black fluff on the end of the spark plugs). Loaded up on a some parts to try and help correct the issue (didnt install yet) because when i went to start the truck again it would crank and not start.

Checked the usual. Has spark, compression, and fuel. 5 of the 6 cylinders in the 120psi range. one is between 90 and 100. battery is fully charged.

Not sure where i should head next on this thing.

Any tips?

 

[Josh B]

Hello Nate, welcome to TRS
I'm sure you'll get plenty in the not too distant future.
Did that motor have a distributor or a coil pack?
Good luck with it man

 

[NATE1987]

Has a distributor.

 

[Josh B]

Has the check engine light come on at all ?
Have you double/triple checked the vacuum lines and such?

 

[RonD]

Welcome to TRS

Your compression gauge is off, expected on 1994 3.0l would be 155-165psi

Was the spark plug on the LOW cylinder different than the others?


You will have a Fuel Pressure Regulator(FPR) on the engine's Return fuel line
It has a vacuum hose attached, check that hose for gasoline, if found replace FPR, this would cause Rich runing

Old O2 sensors can also cause Rich running, when they get older they "tell" computer engine is running Lean, so the False Lean causes Rich running.
O2s should be changed every 100k miles

 

[NATE1987]

Has the check engine light come on at all ?
Have you double/triple checked the vacuum lines and such?

Hey there. No check engine light at all. Will go over the vacuum lines again. Thanks

 

[NATE1987]

Welcome to TRS

Your compression gauge is off, expected on 1994 3.0l would be 155-165psi

Was the spark plug on the LOW cylinder different than the others?


You will have a Fuel Pressure Regulator(FPR) on the engine's Return fuel line
It has a vacuum hose attached, check that hose for gasoline, if found replace FPR, this would cause Rich runing

Old O2 sensors can also cause Rich running, when they get older they "tell" computer engine is running Lean, so the False Lean causes Rich running.
O2s should be changed every 100k miles

I did the compression test on a very cold engine which I feel might contribute to the low reading.

Spark plug in the low cylinder was the same as the rest. From what I’ve read doesn’t seem low enough to cause a non-start.

I guess I’ll start at the air filter and check connection to the throttle since that’s the only change recently.

 

[NATE1987]

Turned out to be a corroded rotor and distributor cap. Running like a top now.

thanks for the input

 

[Josh B]

haha, that's good news, it's also the first place to look when there's a miss with a distributor

Sorry, but it's been awhile since I've had one

 

[alwaysFlOoReD]

Turned out to be a corroded rotor and distributor cap. Running like a top now.

thanks for the input

Thanks for the update.