Engine Runs On 5 Cylinders After Overhaul

[Iceman22]

Hi.

I got a problem with the engine only running on 5 cylinders after overhaul. Have changed pistons, valve seals, all gaskets etc..

I did NOT have this problem before.

This is what happened first time when I tried to start it:

- Fuel pump did make strange noises when turning on the ignition, the engine would not start at all, turned out to be the fuel rails connected opposite direction

- After connecting them correctly the fuel pump sounded normal again, and the engine started right away, but it was leaking gas from the fuel pump.

Turned out to be a fuel hose that suddenly cracked and needed to be replaced (fixed).

Now, the engine starts and runs ok, and the gas is not leaking anymore. But the cylinder 5 is not running.

There is spark, but no fuel coming from the injector (plug is not wet and no smell of fuel)

The other cylinders are fine.

I have NOT disconnected the injectors during the overhaul.

Things I have tried so far:

Another spark plug and coil (no difference)

Restarted the ECU

What can be the problem you guys think?

I appreciate all the help I can get.

Edited June 10, 2010 by Iceman22

[James_03]

Gummed up injector. Tap on the body with a screw driver, fairly common when they sit for a while not being used.

Alternatively pull the CAS out, and with a multi/test light verify that no5 is getting correct current.

[Iceman22]

Thank you for the reply, will test it asap. How do you recomend to clean the injector?

Any more suggestions is appreciated.

Btw, the car was only unused for about 2 weeks..

Edited June 10, 2010 by Iceman22

[James_03]

Thank you for the reply, will test it asap. How do you recomend to clean the injector?

Any more suggestions is appreciated.

Btw, the car was only unused for about 2 weeks..

You can't really clean the injector yourself. You can remove the small top filter and then blow out with compressed air, but that's probably the extent of it.

They need to be cleaned via ultra sonic, and you would most likely remove them all to have this done not just a single injector. If they have only been out of action for 2 weeks, then you will probably get away with just tapping on the body and getting it going again.

If you are concerned about flow pattern etc, that's when you would remove them for cleaning. If it runs fine when you get no5 going, I personally wouldn't bother.

[Iceman22]

I see. Should I tap the injector before I start the engine or after it has started ?

[James_03]

I see. Should I tap the injector before I start the engine or after it has started ?

Just tap it whilst running and it should come good.

[Pal]

also make sure all the injector plugs are pushed in all the way.

[Iceman22]

I tried tapping it several times but it didn't change anything

I have removed the air manifold now and trying to remove the injector and see..

Any more suggestions ?

[snozzle]

are you getting voltage to that injector? u can buy injector plug testers that light up wen the plug gets a pulse if u dont know how to check it with a multi meter

if pulse is there, change the injector

if there is no pulse, check ecu loom for damage or possibly try another ecu

[Iceman22]

I swaped the injector that was on cyl5 (the one that didn't work) on cyl1, and the other that worked on cyl5.

Turned on the engine, and the same problem was still there, injector on cyl5 don't let any fuel. So the injectors is not anything wrong with, It must be some wiring that are damaged or not plugged correctly

[aphid]

so put a multimeter across the plug and measure duty cycle/Hz

[Iceman22]

Turned out it was 0 compression on that cylinder, now it will be exciting to found out what caused it after removing the head.

When looking through the spark plug hole, I can see that the piston is like new, silver color, while the 5 others are black of oil.

The pistons are new, and I didn't hear any abnormal sounds when firing the engine up, so hopefully the piston is not damaged.

[Guilt-Toy]

something silly happened in the head. possibly a stuck lifter of valve or bent valve or something.

It is not something serious. good luck with it and let us know how it goes

[Iceman22]

I hope so, will let you know when I find it out, I'm soon finish removing the head.

[Iceman22]

I promisied to let you know how it goes.

Well, I removed the head and the 5th piston, and didn't see any problems.

The piston was like new, didn't have any oil on top or anything like the other pistons that worked.

Piston is properly installed, valves are opening/closing and are not looking to be bent or anything. The cylinder wall was also fine (it had good compression before the rebuld).

So I contacted a mechanic, and he said I probably installed the cambelt / camshaft wrong, that caused the 0 compression when firing up.

Do you guys think it's possible to get 0 comp. when installing the cambelt/camshaft wrong? I was making sure all the 3 markings were correct, and rechecked 10 times, and it was OK.

I have really never done a rebuild before so I could do something silly...

Edited June 24, 2010 by Iceman22

[Bl4cK32]

rings were put in the right way?

[Iceman22]

Yepp, the rings were fine...

[Duncan]

can't see how you can get 0 compression without a valve problem.

and if there was something wrong with the "cambelt/camshaft" it would affect every cylinder the same way.

unlikely to be rings, even if installed incorrectly eg overlapped you would get a little compression.

assuming its a 33 gtst maybe a stuck hydraulic lifter? I don't know much about the hydraulic lifter setup.

[snozzle]

sounds like a valve isnt seating properly, can be due to many reasons

get the head checked out properly, valve seats, valves, the lot, esp on that cyl

[Iceman22]

I tried turning the engine around with the head on today (cam belt was off). Then I seated a spark plug on each cylinder (one at a time) and tried to see if there were any difference when turning the engine around.

I could feel that there were compression on 5 of the cylinders (more strenght needed when turning), but on cylinder #5 I couldn't notice any difference with the spark plug seated or not seated.

So since the engine block can't be the problem, then it has to be something with the valves like you guys say. Since I can't see any fault by myself then it's best I take it to a professional workshop. Will let you know what the problem is/was when I solve the problem

Edited June 26, 2010 by Iceman22