While I had my 1.6 engine out for a clutch change I was persuaded by a friend to fit a 1.8 as it should give me a little more torque for trialling.
I bought a 1.8 and have fitted into the car. There was a couple of wiring issues with the swap and I have had to sort out a return for the fuel rail.
The engine now runs but the problem is I cannot get it to idle.
I am using the 1.6 ECU at the moment. Am I supposed to use the 1.8 ECU? I have a programmable ECU that was going to be a later project. If I am supposed to use the 1.8 ECU I might fit it instead.
Thanks.
Hold on this is getting messy.
If you change the ECU you need the matching immobiliser package then you need to get new keys with the pattern of the old 1.6 keys and the electronic number of the 1.8 keys.
The 1.8 Mk2.5 engine needs the 1.8 ECU to run the VVC I think.
Maybe it would have been easier to put the 1.6 back in.
Mmmmmmmmmmmmm!
Drumtochty points out that this is a MK2.5 car, so the 1.6 engine very similar to MK2(non VVT) but different ECUs dependant on year.
If you have fitted the MK2.5 1.8 VVT engine, I would imagine there have been several challenges.
No knowledge of this type of engine change and hopefully you can confirm what engine has been fitted and someone who has done this before will chip in.
I would have wanted the engine loom + all ECU, immob parts, etc from the engine donor car.
Good luck!
If the OP had to run a fuel return line in then I suspect that the replacement engine was from a pre-facelift car or even an NA…
As previous posters have said, I’d have wanted the ECU and harness to go with the engine to rule out the unknown. You’re into diagnosis I think. When you say it won’t idle, does it try and stall? If you hold the throttle just off closed does it run? If you screw the idle screw all the way out does it idle then? There’s a lot of questions but trying to run an early 1.8 off a facelift 1.6 ECU does add a lot of unknown…
Drumtochty, I think the same now, should have kept 1.6.
It’s a 1.8 non VVT engine with all 1.6 wiring and sensors so should run reasonably well.
Roadster Robbie, Engine runs off idle and sounds OK. I have tried the idle screw and it doesn’t make much difference.
I have got the wrong end of the stick by reading some American matia crud which led me to believe this was a reasonably simple swap, which is why I didn’t request ECU and keys.
I have an EMU ECU which I will have to fit now, once I can find the corresponding electrical connections so I can make a conversion loom to keep the original loom intact.
The 1.6 ECU may be expecting higher fuel pressure at idle on it’s (assumed) returnless system than a return fuel system offers. Could it be that it’s not injecting enough fuel as manifold vacuum will lower the fuel pressure in your setup at idle?
Where is the old 1.6. Can you get it back!
Got to say I much prefer the MK2/2.5 1.6 engine to the 1.8. Lovely smooth engine and seems to be less problematic than the 1.8.
only 110bhp but imagine a turbo would work well?
I’ve just spoken to someone who has successfully transplanted a MK2.5 1.8 VVT engine into a MK1 1.6.
He also fitted the diff and all wiring set up to run the car road legal.
I say successfully because it was fine for two weeks before he upset something and contacted me with what appears to be an ECU/immob problem that has stopped the car running.
The installation time was minimal for the engine. What took the majority of time was joining the VVT engine loom to the rest of the cars loom for lighting, etc.
This would not have been anything like as difficult on another MK2.5 car.
All sorted. It was a catalogue of errors on my behalf but I got there in the end.
I did have an exhaust leak on one of the joints, which I ignored at first. On inspection this joint was upstream of the second lambda sensor. I fitted a new gasket and the engine ran better but still didn’t idle.
After unplugging and plugging various sensors, clearing faults from the ECU I sprayed a bit of brake cleaner around the manifold. The engine note changed indicating my previous idea of an air leak.
I removed the manifold to find that I had fitted the wrong gasket. In the dim light of the workshop I hadn’t noticed the fact that the port of the gasket was lower than the port on the head. This would have allowed lots of air to bypass the air flow meter.
Fitted the correct gasket and she runs like a dream. Was the gasket from a VVT engine?