Megane 225 no start issue

[James5]

Evening all, for some reason I bought another meg 225 I really don't know why was more of an impulse buy.
Anyway the car was a none runner when I got apparently the fobs didn't work or start the car and it wouldn't crank. So I fitted a new battery to the car when. I got it and hey the fob unlocked and locked the car and the car cranked (did not start). Also noted that I had keyless entry which was unexpected.
Anyway so I done compression test all 4 perfect, checked fluids and again all good. I then removed the sparkies and replaced with new OEM ones, I also replaced the coil packs with brand new, car still didn't start so I thought let's check fuel to rail and yep loads of fuel. I bought a brand new OEM tdc, and brand new OEM injectors and guess what I still have the same issue.
The car cranks over coughs then dies anyone have any idea's? I am thinking it's spark related as the spark plugs are wet, I have removed coil pack 1 with spark plug and it arcs fine dueing cranking I'll try the other 3 tomorrow.
Do we have a wiring diagram for a 55plate 225?

 

[James5]

Worst case I do have a spare set of forged pec rods from one of my old f7p engine's. I am sure it will be fine though with a decent map.

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[SP33DY]

Yeah you can only compensate so much using bigger injectors, best way is with a pressure source on the fpr. I'm impressed with the new set up on new meganes 5 bar line pressure and 3 bar regulated at the rail.

 

[Ewan]

Yeah you can only compensate so much using bigger injectors, best way is with a pressure source on the fpr. I'm impressed with the new set up on new meganes 5 bar line pressure and 3 bar regulated at the rail.

Is that the setup on the mk3? I mistakenly thought it was a rising rate pressure. Not that I really know what I am talking about mind you..

 

[SP33DY]

Yeah that's on the MK3, it has a rising reg on the fuel rail.

 

[tutuur]

5,5 and 3,5 bar mate and yes it has a rising rate regulator, but still returnless. Although i don't see any harm in that till silly power

 

[SP33DY]

So are we guessing we've got about 1.8 bar of boost before we start getting into fuelling problems?

 

[tutuur]

yeah that should be about max as you'd want a bit of room.

I know the french gontier racing 380bhp megane is running 1.8 at 6000rpm

 

[Neal R19]

This is all very informative.

So to summarise (seeing if I've got this right):

Mk2s have a returnless system with a 3.5 bar regulator in the tank keeping static 3.5 bar pressure in the line and rail all together

Mk3s also have a returnless system, but have a 5.5bar regulator in the tank, keeping a static 5.5bar pressure in the lines, then the rail has its own 3.5bar rising rate reg.

However you can't fit the mk3 rail to a mk2 because the inlet manifold is different, and you cant fit the mk3 inlet manifold to a mk2 head because the ports are different.

Is that right?

 

[tutuur]

Spot on mate

 

[James5]

Just to update its back to non starting lol
Going to look at the engine loom specifically, tdc wires, injector wires and coil pack wires, I seem to have very wet sparkies today so no spark

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[James5]

Well I am back to square one car still not working after lwVing it or a couple of days go back and yet again no spark and no injectors firing I have tested all.wires from injectors, coil packs and tdc sensor all back to ecu and all fine , I checked the condition of the new tdc and that's looks really good, cleaned up the spark plugs.

I pulled the ecu out to have a look and opened it up all looks really good inside no water damage or anything at all.
It's definitely an electrical issue somewhere.



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[DaveL485]

You cant just swap out the ECU for testing purposes on these can you?

 

[DaveL485]

Mk2s have a returnless system with a 3.5 bar regulator in the tank keeping static 3.5 bar pressure in the line and rail all together

Thats crazy. In absolute terms, then, if I run 1.5bar boost the relative fuel pressure drops to 2.0bar.

The more boost I run, the less fuel pressure (relative) I get at the injectors...which is the exact opposite of the rising rate principle most turbo cars employ that maintains the relative fuel pressure between manifold and injectors.

Good info to know, even if its a bit mental.

 

[Neal R19]

Spot on mate

Can you at least put a mk3 head straight on a mk2 bottom end?

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[James5]

You cant just swap out the ECU for testing purposes on these can you?

Unfortunately not need to change loads of parts to do it

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[andybond]

Unfortunately not need to change loads of parts to do it

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Can you make it throw a fault ?

 

[James5]

Can you make it throw a fault ?

How can I do that suppose I could unplug something and see what happens

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[andybond]

How can I do that suppose I could unplug something and see what happens

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Exactly.

I am curious if the ECU is reporting all it could.

 

[Ewan]

Can you at least put a mk3 head straight on a mk2 bottom end?

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Sorry to hijack your post again James5!

Not sure about swapping just the heads, I believe the mk3 runs slightly lower compression. I know that the Pistons have revised ring landings on the mk3 to improve their strength. With the inclusion of VVT on the mk3, I don't know if the valves have a higher lift as well.

 

[Brigsy]

Did you get clip up and running ??