Basic enigne tuning

Post Sun Dec 25, 2005 11:35 pm

Well the engine ain't been spot on since I built it. I know it's to do with the tuning as i've had a play and cocked it all up. At the moment its running rough from idle to 3000 rpm on part thottle. If I give it full thottle it goes really well.

I've messed about with the thottle body screw and need to know what the measurements should be for the butterfly. I also want to check other items such as the O2 sensor and anything else you can think of.

Thanks

Chu.

Post Mon Dec 26, 2005 2:28 am

Have you still got the standard chip in since the conversion? Are you still auto - they are hard to tune lower down the rev range. Have you checked the ICV? It would be good to check the timing and the CO2. It does sound as if you're not getting enough air in though.

Post Mon Dec 26, 2005 10:25 am

MONSPORT42 wrote: It does sound as if you're not getting enough air in though.

Or too much, unmetered, at idle/part throttle.
Check for air leaks on the inlet side of things (split hoses, failed gaskets, etc.) before you get to involved.

Post Mon Dec 26, 2005 11:10 am

MONSPORT it's a manual now (sorry dude) and I have got a zone chip in there. But it wasn't spot on before, but it's a good place to start. As for the ICV, I have cleaned it out and it's a little better. Also did you mean check the cam timing?

Brianmoooore all the hoses seem ok except the one that goes into the cam cover as it's a little bit worn at the connecting end, but doesn't seem that bad. I have thoroughly check the intake boot as I know these crack. As for the gaskets, all are new apart for the throttle body gasket which will be changed soon.

But like I said the butterfly adjustment screw is definaely in the wrong place and I could do with adjusting this correctly, and need to know how to adjust the CO2.

BTW it's a M20 2.7

Post Mon Dec 26, 2005 5:03 pm

Sorry Chu, can't help with the butterfly measurement. Best way to check CO2 is to go to a friendly MoT station and ask nicely if they can give you the emission reading. You can adjust the CO2 with the alan key screw on the AFM but you really need to be connected up to an emissions sensor to do it properly. Failing that it's a garage job or good old fashion Sun tuning machine which shouldn't be too expensive. That should sort out the rough running if as you say its just 'basic' mechanical tuning. If everything mecahnical is OK then you may need to custom map the chip to adjust the fueling/air/ignition at lower load.
One thing just sprung to mind. I had a problem once with rough running which turned out to be a poor connection in the multiplug connector sited on the engine block below the throttle body which governs the injectors. The rubber boot had become perished and the damp was getting in. A long shot...but you never know.
How are you finding the manual, does it feel more powerful/better?
Good luck

Post Mon Dec 26, 2005 5:44 pm

You need a remap if youve changed anything dramatic like added a cam or changed the capacity.

Post Mon Dec 26, 2005 7:36 pm

I think you need an RR tune to see what it's doing, if it's got a fault like an air leak/miss fire then they will be able to pick this up or if theres no faults but the ECU can't keep the engine in tune due to your mods then you will know you need to be looking for a remap/Mega squirt/MAF and Unichip/ETC.

Post Mon Dec 26, 2005 9:57 pm

MONSPORT42 wrote:One thing just sprung to mind. I had a problem once with rough running which turned out to be a poor connection in the multiplug connector sited on the engine block below the throttle body which governs the injectors. The rubber boot had become perished and the damp was getting in. A long shot...but you never know.

I'll give that a check thanks.

MONSPORT42 wrote:How are you finding the manual, does it feel more powerful/better?
Good luck

I don't think it's one of my better desisions. Especially with it being a cabriolet, it just seems a bit of a pain to drive sometimes as you can't just relax and do things whilst driving (eating and drinking). I think it got a 3.73diff, but pulling off in 1st in this weather it just spins the wheels so i've not been able to G-Tech it properly yet.

I'm on the standard cam in the 2.7 so hopefully I shouldn't need standalone. But I am going to consider it. Just can't afford it yet as the stereo needs upgrading really.

Well i'm off friendly MoT station tomorrow then.

Post Mon Dec 26, 2005 10:43 pm

I expect you'll get used to it and you'll get a smile back on your face in the dry! Torque converters do have their uses tho. Now you've lost the auto you can look at a wilder cam etc if you have a mind (and budget) to.
Hope you get it sorted. Here's my lump with MAF fitted

Post Tue Dec 27, 2005 1:08 pm

whats actually involved in fitting the hot wire MAF is it a DIY job

Post Tue Dec 27, 2005 1:31 pm

bigkev wrote:whats actually involved in fitting the hot wire MAF is it a DIY job

Not really DIY as you need to use a piggyback ECU like a unichip to convert the signals. Then it will need RR tuning.