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3.4 won't start...


BandaorICE

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Ok this one is very new to me. As I was coming to a stop the car sputtered and died, it wouldn't start. The car is a 92 Lumina Z34 with the 3.4. The motor will crank and crank but nothing.

*The car has fuel to the rails and the injectors are working fine, just replaced the FPR, the fuel pump is working fine.

*There is spark through the coils, they are brand new coils, new plug wires, pulled the plugs to make sure they were gapped right.

*Changed the CPS (worse thing to change on a 3.4), has a new IAC, new MAP,

*Alternator is remanu but was replaced less than a year ago, battery is holding a charge.

 

**Found a problem tho, There is no compression in cylinder 6. We stopped testing because it started to rain. The timing belt is fine, there is fresh oil and coolant so it's not like it seized.

**This all started when my driver-side window switches sparked. The voltage of the battery would surge when I tried to close the passenger side window. I checked all the fuses and they were fine. I checked the grounds to make sure. My thought could be the computer...but would that cause no compression if there is spark and fuel?

 

What could be the problem?

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Well, we all had a brain storm, the reason there is no compression...the valves are stuck open, which means it is possible the timing belt lower in the motor lost all its teeth and is just cranking away. That is our guess. I won't know anything until tomorrow.

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After a couple days of rain and now sunshine, I pulled the timing belt cover off to discover a few teeth missing at a certain pully. Ok more then a few. Any directions to 3.4 timing?

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That sounds like your problem.

 

I think I seen a post here with the instructions. The manu timing marks are most likely worn off. There is supposedly a special tool thats needed, but the mech who did mine says theres another way.

 

 

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  • 3 weeks later...

how sure are you that all the valves are closed on those cyls? if one is open and the timing belt is not moving the cams they are going to stay open.

 

when you crank does the timing belt move with the engine cranking?

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well, I got the belt on and timed and everything together, went out to drive it and it was missing...BAD. and there was a metal to metal type of noise...well i figured it was the valves...maybe one broke or something. Did the compression checks and the first 4 were fine, the last two were gone. The car ran but in second gear and at 40MPH it missed. Everything was fine, coils fuel and whatever.

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WOW. You and I are running parallel threads here!

 

Four choices

 

1. Throw the car away.

2. Pull the heads and replace the valves yourself.

3. Get replacement heads and swap.

4. Take it to a shop and let them do it.

 

I am opting for #3 because it is the fastest way for me to get 'er back on the road.

 

On the cam that you have, when you time it, set both flats up. Then on the even bank (left or front cam carrier) turn them 180 degrees over. There is a service manual update for that. They inadvertantly made the cams with the flats ground 180 degrees off for 2,4,6 cyls.

 

Once you have set the timing correctly, ensure the marks on the cam gears line up. If not, re-create them. I used white spray paint and a sponge. I sprayed the paint onto cardboard and used the sponge to mark the white line across the cam gears where they meet.

 

After that, then I put the timing belt back on. I had to re-adjust the right (firewall side) cams as they moved one gear tooth.

 

Well, time to get my shite together and tear this engine apart again. Yea, fun!

 

I am just glad that I don't have to take the engine out to remove the heads.

 

On my buddies Toyota Corolla, you have to pull the front motor mount just to replace the water pump! Thank God for American made cars!

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My biggest thing is the metal to metal noise. It "sounds" like it is coming from the front cam carrier under around or above cyl 2. Its no like a knock, it sounds like metal grinding, or like a pully grinding. I tried everything I could. I'm heading out to some dealerships, see what kind of financing I can get. If I can get what I want, its bye bye to the Z34. If not, it's time to tear apart the motor.

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