decus

Hi all, I have a VG30E that doesn't want to start. When I try all I get is one loud "clunk" metal type noise. Trying again gets the same noise. Just before this the car was idleing funny (surging up an down), but not enough to stall the car.

Battery is fine. I bench tested the starter, seems fine.

I tried to rotate the engine by hand (with a socket) and it seems to rotate once and then won't go any further, I then went the other way for a full rotation until it hits the same barrier.

I'm guessing that is not normal and i might have some serious damage (possible t-belt?)

Greeny

iTrader: (43)

Your timing belt sounds like it's ok, when you turn the engine by hand you build compression in the heads, thus your engine gets hard to turn due to the pressure build up. if the t belt had broken(smashed valves= no compression) the engine would turn by hand with ease.

Go have your starter tested at an auto parts store.

decus

Thanks, I'll get the starter checked during the week. I have a running donor car so might try its starter as well.

Another thing, over the past 2 months or so the auto tranny has started to slip and change rough, would a failing transmission cause a similar no start?

Edit: Forgot to mention that the reason I thought the engine rotation was weird is because I've rotated the engine on my 300ZX (VG30ET) by hand and know the pressure buildup, but this was a different feeling. More like a "no chance in hell of doing it by hand" type deal

Greeny

iTrader: (43)

The easiest way to tell if your t-belt is broken would be to remove your distributor cap, then have a helper watch the rotor button while you turn the crankshaft, if the rotor button turns= good belt, if it doesn't= 500lb paper weight.

Wiking

I doubt the tranny, smtg is now broken... Hell would more probable melt all valves and you could rotate engine while waiting the magma flow towards CAT...
Once in a zillion belt may break and jam, VGE still ok. Whose gf did that, wrote here?

Rough change --->TPS?
Check: Transmission Control Unit (Multi-page thread 1 2 ) by rmdl51

decus

Didn't have a helper, but I turned the crankshaft and the rotor had moved. So that means the t-belt hasn't broken.

I'll get the starter checked/try another and go from there.

internetautomar

iTrader: (30)

take the plugs out and see how the engine turns.

maximaman1313

I was doing my fuel injectors, grant it mine is a ve. But I had fuel overly pour into 1 cylinder.. like an idiot i tried to start it with it in there thinking it would just go down into oil pan. I tried to start it and no rotation, just a metal clunk...

I did what automart did, pulled all plugs, and tried to start it...motor spun.
Maybe you have a realy bad injector o-ring, and a cylinder is full of fuel so much it shorts the plug when it tries to spark? I think thats what happened with mine.

definately pull plugs and see if it spins. guess go from there. car ran and drove before but had wierd idle isssue?

viperbite

hmm like everyone else said, check starter first.

im new to these motors but it could seem like if your belt skipped a tooth your valves could be seizing your motor.
im looking at a max right now that has similar issues. keep us updated im curious to know what causes this. thanks.

CapedCadaver

iTrader: (8)

but if the tbelt broke and the engine broke a lot of crap in the valvetrain couldn't something jam and prevent engine from turning, making a "loud clunk, metal type noise" and making it hard to turn the engine?

Greeny

iTrader: (43)

Not any I've seen. they all just bent the valves sideways so the valves could no longer seal the intake/exhaust openings= no compression.

CapedCadaver

iTrader: (8)

ah. i've seen "dramatizations" on nascar broadcasts of a broken valve spring causing the valve to get pounded by the piston, snapping off into the cylinder bore, and jamming at TDC the next stroke by. Thereby puncturing a piston and voila, dead engine.

decus

I can't seem to find my deep socket set, so I didn't pull the plugs yet, will do that tomorrow and post the results.

I tried a known good starter and it didn't help, so that rules the starter out.

I did notice a new symptom. After I had rotated the engine by hand (probably left it half way between the "stuck" point) and then tried to start it, it seemed to try to start and then clunk, same noise as in the first post. Further attempts to start just result in the same clunk (as in the first post). So it seems the engine is trying to start but is getting stuck on something??

I repeated the turning back by hand and then starting again and the same thing happened.

Any ideas as to what else to look at?

Wiking

If there still is smtg salvageable, try figure out ... but dont bang. Listen what Inetautomator says =plugs out.

Peek under T-belt cover, valve covers, lift up & try turning wheels, disconnect tranny (just axle out) and try turning engine.

Edit: ...try to get an estimate how many degrees the engine rotates. This may exclude half of the suspects.

internetautomar

iTrader: (30)

that's a different issue. when a valve spring breaks, the valve just drops down so the piston can smack into it in all sort of weird ways and bend and rotate and potentially break it if the valve isn't strong enough.

Greeny

iTrader: (43)

+1 This usually happens on a nascar engine due to excessive rpm=a few valves get floated=snap of the valve spring retainer= valve drops down=

When a valve spring breaks on a nascar engine, the engine is still able to run for a while after this, At nearly 10,000 rpm = a loose valve flopping around getting slapped by a piston every .100th's of a second(approx.). Vs. when a timing belt breaks, the engine shuts down immediately after the break, thus the damage is quick and final.

CapedCadaver

iTrader: (8)

true b/c just 1 valve isn't enough to shut the engine off right away, whereas the tbelt controls the whole valvetrain. makes sense now.

akurtzer57

iTrader: (4)

I recently had the same problem but I Could turn it over by hand with the plugs out. When I tried to start with the starter it hit the same spot and stoped. I thought a bad spot on the flywheel but it turned out the starter was crap. Problem solved. Get that starter checked out.

maximagician

i know firsthand (92 gxe)+(90 stanza.....minima)that the torque converter can stripp
out internaly but i kinda doubt that could sieze an engine although they spin together
(lift front wheels up put car in every gear and spin tires by hand and listen to the trans?)
you could also wiggle the shifter or make sure its in park?
also pull off the 3 belts and turn crank by hand incase alt,ps,or compressor is siezed?

decus

Sorry for the slow reply, was away for easter.

Pulled the plugs and #3 and #5 were wet, with what I think was fuel. With them out motor rotated by hand freely and I also tried to start it and the motor spun. Couldn't see into the chambers very well (couldn't tell how much fuel was in there) so put new plugs in all around and it started up.

I noticed and fixed a cracked vac line to the FPR (well, I think it is the FPR), could this be my cuase? Or would I be looking at injector problems? I notice that the oil looks/smells like it has fuel in in...I will change it, but want to find the cause first.

Thanks for everyones help

internetautomar

iTrader: (30)

a malfunctioning FPR could cause a flooding problem.

decus

Ok, turns out it was coolant and not fuel in the #5 plug

And the milky white look of the oil gives me a bad feeling that the head gasket is gone. Thats would be the only cause right?

That being the case I'm thinking it will be easier to swap this other donor engine I have in. Next question, is it easier to drop the engine+tranny or lift them out (is it even possible to get them out together?)

Wiking

Thats could be the only cause.

Swap also all seals, belt [if any], exhaust studs... etc

internetautomar

iTrader: (30)

yes'm you got a blown head gasket.
redo the donor motor while it is out of the car, and keep driving on the bad one until the donor is done.

BenStoked

iTrader: (7)

mostly, the consensus seems to be "its easier to drop both(together) thru the bottom", however, you gotta consider the whether the lift you use for the engine will reach enough to put the engine on the ground while still clearing the car, and how to remove the engine/tranny from under the car when its dropped.

decus

While I'm pulling the other engine and doing the t-belt etc, would it be worth running some of that liquid "fix a blown head gasket" type stuff through the car?

Has anyone had any luck with them? Can't see it doing any more harm (except maybe to the radiator), but don't want to waste my money

hoyshnin

iTrader: (1)

i've actually heard oatmeal works (and holds up a long time), i've also heard that liquid stuff works too

internetautomar

iTrader: (30)

the stop leaks may plug up the heater core, heater valve, and radiator.
not a risk I'd run