G60 cold start issue. Have I missed something?

[Blue MK2 0]

Hi all.

 

I have a cold start issue with a g60. It starts fine when cold but when i press the throttle (on cold) it sometimes misfires and cuts out or when i rev high enough the engine stalls.

The engine wont start after this as it seems to be flooded.

Just before the revs drop and engine cuts - it back fires. - leads me to timing fault.

If i do manage to start it...it misfires.

 

When its warm there is no misfire and starts/stops as normal.

 

The spec is:

 

1870 cc bottom end

Standard loom, g60 ecu , SNS chip and standard chip both tried.

Wossner 83mm pistons

Piper 268/268 cam

68mm pulley

All pulleys are toothed. not standard

Ported and polished/CNC head (may be bigger valves im not sure)

Green standard g60 injectors with 3 bar FPR - doubt these should cause cold start issues even though this should run reds.

 

I've tried:

New distributor

New distributor cap and rotor arm

New genuine blue engine temp sensor

New 1m length of throttle to ecu pipe

New FPR

New injectors

Swapped a working ISV

Swapped for good leads

Swapped g60 sparks out my other engine.

Lambda is removed.

Swapped coil

fuel pump is also new.

coPot sensor also swapped.

 

Checked:

Loom completely checked to ECU plug

throttle switches,

There was a break on the earth coolant temp sensor wire. I added an earth - fixed

Reset the ecu

Adjusted timing as the 8v guide. Most of the pulleys are aftermarket and had to make my own marks.

All earths checked and cleaned up.

 

02 sensor - Not checked. Could be this?

Also thinking the valve over lap and/or the previous owner has fitted the timing belt with it being a tooth off. Compression was about 100-110psi in all cylinders which i believe are low.

 

When the engine is warm it runs fine and pulls like no other g60 ive owned.

 

 

What have I missed?

 

Any tips would be much appreciated.

Edited November 9, 2014 by Blue MK2

[Blue MK2 0]

Ok I think I've figured it.

 

Prev owner said it was tuned/custom ecu chip without the lambda and after studying the digifant - it needs the lambda.

 

I checked the lambda and its a wide band. Prev owner was definitely a bodger. Looks like the wide band kit has been taken out and sensor left in its place out of pure laziness.

 

I'm lucky I had all the new parts off my other g60 engine.

 

New sensor ordered.

Edited November 10, 2014 by Blue MK2

[Blue MK2 0]

Nope...still doesn't run right.

 

Spotted the cam a tooth out. Adjusted - now perfect.

 

Genuine lambda fitted - no difference.

Tried another ECU

Tried another ecu with standard chip

Tried another co pot

 

Symptoms I still get: Stall on cold if rev the engine. Hard to restart again due to plugs being too wet.

 

If i let the engine idle and warm up - it's fine but this should not happen. This one has got me!

[Rustynuts 0]

I would have a really close look at your injectors, you say they are green but i know there are 'other' green injectors out there. Based on what you have said it seems the only area to look at. Check the wiring whilst you are at it

[Blue MK2 0]

Standard g60 greens bud. Wiring has been out and thorough checked.

 

Think I need to get this head off and have a proper look inside. Cylinder 1 and 4 have shiney pistons. 2 and 3 have carbon build up/possibly oil from a previously blown charger but cant tell.

 

A compression test shows 110-125psi on my new gauge (thought my old one was faulty) on all 4 which I know is low but this is has 83mm pistons and a cam. I get no smoke, no oil loss or coolant loss but the prev owner may have thrown some head gasket seal liquid in there. I really want this head off and have a proper look.

 

It misfires on idle but when warm its perfect and very quick.

Edited November 19, 2014 by Blue MK2

[Rustynuts 0]

I am just wondering if you are getting blow by on the head gasket. If the head has not been skimmed properly you might get this when cold but when up to temp the expansion may cause this to close and therefore run fine.

 

I agree get that head off, those cylinders should all be black I would have said.

[Blue MK2 0]

Yeh was thinking the exact same.

 

I've also just noticed im not getting 12v at the red injector wire. Im sure ive had 12v there before.

 

Red wire has continuity to earth but 9v when i turn over the engine (fluctuates). 0 volts with ign on. Think were onto something here.

Edited November 21, 2014 by Blue MK2

[Rustynuts 0]

I understand the ecu fires the injectors by switching the earth @ 12v. So I wonder if the ecu at less than than 12v might well switch the injectors for too long causing over fuelling?

[Blue MK2 0]

Just checked.

 

Injectors plug:

red wire - 0v with ignition on.

brown/yellow - 0v

 

Start the car - and get 13v when running on the red wire.

13v on the brown/yellow (as its in series)

 

Now I'm sure the red wire should be 12v when the fuel pump primes. Just changed the relays and double checked the wiring. Even bypassed the alarm incase the relays inside the box were faulty.

 

Still cuts out when I hold the revs up on cold.

 

 

Head off tomorrow me thinks. Just hope the pistons are ok and the prev owner didn't run it lean.

 

Wish me luck...

[Rustynuts 0]

I will, best of luck.

[Blue MK2 0]

Turns out you were right. I inspected the injector wires (it was the very first thing I did) turns out its actually melted where I couldn't see it and the wires were touching.

 

My dad took the head off for me anyway because I was skeptical about the pistons being forged 83mm. These are standard 91mm.

 

After speaking to the previous owners. Not one of them touched swapped the bottom end.

Remember the G werks mk2 golf demo car? the "1.9". Yeh sure...

Edited November 25, 2014 by Blue MK2

[Rustynuts 0]

Good news on the wiring side of things, not so good regarding the bottom end. I hate people who sell stuff as something that it is not especially when it is not easy to check. Having said that it has decent spec and it goes well so bolt it back together and enjoy