[Corsa C 2000-2006] 1.4 Twinport Problems

[olly_richman]

Hi, I'm new to here and new to corsa's, I have just bought a combo dual fuel 1.4 with issues, It has the twinport engine and factory fit lpg.
When I bought the van it had bottom end issues (No compression on cylinder 3) I have had the engine rebuilt (Head had already been done), with new timing chain, pistons and rings etc.
The van runs very quietly with no rattling or smoking or using any oil or water, it is however dog slow.
It is fine once you are over 4000, but has a bad lack of power between 2-3.5K, so much so that unless you are doing 75+ on the motorway it won't hold it up hills.
It shows no fault codes on my generic cheap OBD scanner,
I have changed the MAF, front lambda, exhaust from cat back (was like a swiss cheese), changed the plugs and coilpack (Delphi), blanked the EGR (although apparently these engines don't like having it blocked, so may take the plate out).
The air filter is clean and all the breathers are ok.
Sometimes if doing a constant speed like 30 in 3rd it will be juddering or surging a bit.
very Occasionally it seems to just get better for a minute then just go back to being slow.
I am thinking it could be timed up a tooth out, or the ECU is faulty, I don't think its injectors/fuel as it has exactly the same issues on LPG as petrol.

Any help suggestions?
Cheers,
olly

[Taurus]

The timing can be tricky on these as there are no marks on the engine. Plus I've seen a few fitted with aftermarket chains that time up fine when the chain is new, but they stretch a bit quite quickly and then the timing is out. So you may well be right re. timing being worth checking. You need a timing kit to do it, which is a bit of a pain. If you are anywhere near me you can borrow mine, or else it's a case of getting hold of one

Sealey VSE243 Petrol Engine Timing Kit - Vauxhall/Opel 1.0, 1.2, 1.4 - Chain Drive

The other thing I'd suggest is checking it out on opcom, which is a much better way to check the engine than generic readers.

Having the EGR blanked should be fine. The only issue you sometimes get is the EML coming on at motorway speeds, but it doesn't cause a running issue.

[olly_richman]

Hi mate,
Thanks for reply, engine was rebuilt 1500 miles ago, It brings up a p0340 cam sensor code on the pedal test but doesn't bring the light on, if you unplug the cam sensor it does bring the light on and performs noticeably worse. I have replaced the cam sensor.
I have noticed the twinport doesn't open when you rev the engine under no load. When the engine starts the twin port is open, after a couple seconds it closes, the no amount of revving will open it again. If you disconnect the MAF the twinport stays open.
My next port of call is checking the timing, I have a friend who is a mechanic and has got a timing kit so will borrow that, problem is time, I have to use it for working away every week so don't have much time at home. If that doesn't cure it then I'll have to get the ECU checked out I suppose!

Thanks for help

[Taurus]

They will throw a cam sensor code if the timing is out. I had one a year or so back, just had a timing chain done and the guy had got it slightly wrong. Kept throwing the cam sensor code.

[Rob]

beaten to it by paul. as said timing is out.

[olly_richman]

Just a quick update, I have checked the timing, actually a lot easier then I thought TBH. The inlet cam was about 10 degree's out, god knows how he managed to do that when he rebuilt the motor, It has now stopped throwing the cam sensor code and seems to be a little better performance, definitely less flat/dead spots in the rev range HOWEVER it still seems pretty slow to me, maybe because I'm used to driving bigger motors but I still think it should have a bit more poke, next stop, a proper code read on opcom I suppose, it is also better on fuel now.
On another note the crank pulley notch was 180 deg out! Is this easy to put back wrong on these engines? I had to find TDC manually with a bit of threaded bar.

Thanks for your help lads, any more ideas gladly accepted!

[Rob]

get the lpg tuned.