Please Help Engine won't start

[4runnin]

I had the exhaust fitted and drove the car home (first drive), engine seemed to be running fine except it didn't like to come back to idle (would stall if the engine revs weren't slowly brought back down) and the motor was running very rich. the following day while driving the engine stalled and would not start, it now seems that the engine is flooding with fuel in all cylinders.

have checked all the following as per work shop manaul

Checked all sensors Crank, cam1 + cam2, air flow

removed and cleaned ISC

check ignition coils, igniters (replaced igniters as well), have spark at all cylinders.

engine computer in diaganostic mode either normal or test says noyhing wrong (i.e check light continually flashes)

i think the timing belt may have moved when the engine stopped as when i checked the alignment of timing marks the right hand side cam timing mark was out so have redone timing belt and everything lines up perfectly. Could this have done damage to pistons, valves, etc

engine is a 1990 crown running (err not running) in a 1984 toyota 4runner running 1994 v6 gearbox and transfer case

any help greatly appreciated

thanks
John

 

[Kiwi.in.aus]

Your engine is non interferance so no worries about that , however have you checked your O2 sensors that are mounted in the exhausts ?
Just maybe they are not in the right place or a good position and they are reading way out causing the richness ??

 

[4runnin]

the richness is now flooding the engine and not allowing it to start from what i can tell...the exhaust guy said the exhaust was running hot because of the excess unburnt fuel in the exhaust but from what i have read the oxy sensors don't come into play until the engine warms up is this true?

thanks
John

 

[gloverman]

Checking fuel pressure and the EFI temp sensor might worthwhile. Is is possible that the return to the tank is restricted - ie crushed when being stacked on a hoist. Excessive fuel can cause the spark plugs to fail. I would suggest fitting some hotter cheap ones while you are sorting the problem. Good luck. Kelvin

 

[Cobber]

Check the o2 sensors have been pluged back in. Check that the cold start injector is switching off.

 

[4runnin]

ok, i have had the injectors cleaned and removed the exhaust (i a thought that if the cat had melted down and was blocking exhaust flow then it would not start) i now starts but will only run on 4 cylinders (LH bank only) the RH bank is not firing, there is spark from the coil and there is spark to all plugs no's 2 4 6 8, as no's 4 and 6 fire of the other distibutor then it is not distributors, rotor buttons, coils or igniters as far as i know. i thought maybe compression but would be very strange for compression to be down on a complete bank, the cam timing is absolutely 100% correct, so that leaves the cam not turning or the valve clearances or possibly stuck valves, has anyone got any other ideas on what they think the problem could be before i start pulling apart and checking clearances etc

Thanks

John

 

[gloverman]

Sounds like time for a compression test. There are a few of these around which have locked up in the camshaft department. If it's a interference model then it gets real nasty. I hope yours hasn't done this. Good luck

 

[Lextreme II]

I had the same problem. Recently changed my head gasket and when install everything back. My timing gear was little off like 2-3 tooth. The car kept cranking but hard start or stay idle. I called my friend JamesN and he brought his Celsior and we compare timing points. My cam gears were off 2 teeth.

To check the timing point. The crank is no brianer. Align the crank pulley mark to zero. I am sure you are slightly off in the cam gears. The black metal plates behind the cam gears has a raise mark on it. You should line up the cam mark to the back plate mark. If you open up the spark plug cover, you will see it at around 3-4 o' clock on the right cam and 10-11 o' clock on the left cam.

Adjustment can be done quite easy without dissamble the whole thing. Loosen the tensioner under the car by the crank pulley and slightly pull the timing belt and rotate the cam gear while the belt doesnt move. You can do both sides. Once the points are aligned, you can reinstall the tensioner back. Best of luck....

 

[jordys ski boat]

your pistions and valves will be ok the bottom end can rotate without the
cam belt on
i have broken a timming belt at 3000 rpm went home and got a spare and off
i went
i had the same problem with only a few cylinders firing it was trying to start
but just wouldnt start
i tryed everything to do with the ignition still nothing
i hade near new iridum plugs so i thought they will be ok
i week later still the same
i got the old rusty plugs out that come with the engine from the wrecker
and cleaned them and checked the gap and away the engine went
just like a new 1
what i am saying is it will be something small
just take a deep breth i know what your going through

 

[BLOWN EA]

hey there i had the same problem that you have just that the right bank was ok and the left one was not runing. i chased all the wiring down and it was that one of the wires had come loose on the coil and then i was away again good luck with it

 

[Zuffen]

A coil wire shouldn't take out one side of the engine.

Each coil feeds a distributor.

Each distributor feed two cylinders on each side of the engine. There fore acoli should take out 4 cylinders but remain balanced across the engine.

I'd go with Gloverman and check the whole cold start circuit plus change the plugs for a fresh set.

 

[Lextreme II]

Its funny some mentioned ignition coil. I was testing my car earlier with 4 right spark plugs out along with the leads uninstalled and no maf. Believe it or not the car still started. Idle sucks, but it was running. Interesting to know.... So even if one of the two coils is bad, then the car still run. I have many experience with 1uzfe running with only one ignition coil.

 

[4runnin]

Problem found, as below

Sounds like time for a compression test. There are a few of these around which have locked up in the camshaft department. If it's a interference model then it gets real nasty. I hope yours hasn't done this. Good luck

Pulled the cam pulley today and found the knock pin broken then started pulling the camshafts thinking i'll take it get the knock pin removed and replaced then i discovered the front intake camshaft bearing all scored i.e no oil at bearing so stopped and rang the place i bought the engine from and now have to pull the engine and take it back to them for them to have a look and replace engine... thank god it's still under warranty for another one and a half weeks. by the way non interference model

Thanks Gloverman for the tip where to look.

Thanks all for your help hopefully can have the car back on the road by the end of the week and then can finally look at getting engineers certificate

Thanks again all

John

 

[4runnin]

I also started look at valve train as it is about the only way a V8 can lose compression on 1 complete bank... the other ways that it could are very remote chance of happening all on 1 bank.

just a thought for others that may face the same problem.

John