I will do a bit of searching, but I wanted to see if anyone had some ideas. Here are the details of the car:

2.2L Motor, 10.1 Comp
Stock ECU
FIC 1100cc + Surge tank/Cosworth rail set up
3.5" MAF
93OCT
Kelford C Cams + Cosworth dual spring kit
TBE
4" ETS core

To help focus the discussion, the intake was tuned BEFORE the build, so the MAF and injectors are scaled properly, timing has been verified. There are no boost leaks. Assume the 'basic' mechanical issues have been analyzed and addressed.

The tune is in a start up calibration. Idle set to 1050, MAF scaled, MAP based load tables have had a 5% delta added to them.

Here is the problem: When you start the car it works perfectly. Let it just sit there and idle and you get trims in the +/-5% range, all temps in perfect order. If you rev it, when it comes back down to idle, it starts to stumble, and appears to have a severe misfire type state. The oil pressure drops, as expected, because of the erratic idle. The head starts to sounds like it is slapping the chain against the valve cover...again, expected due to the erratic idle and 'misfire'. IF you drive the car, it runs perfectly. If you bring the idle up with the acc pedal, the noises go away and it sounds as you would expect.

So the question is, why does the car suddenly not want to idle properly. The cams are not so aggressive to cause this. It is bad enough that I do not want to drive it b/c the idle issue. It can stall, and with a new motor, oil pressure is key.

Any thoughts guys?

John

 

Log your mivec int and ex and see if they are doing what your map is calling for. How much oil pressure do you have at idle?

 

I can do that. I think it is fuel related some how. The motor only starts to mis when the afrs go to 16/17ish. Which is reasonable with big cams.

What are you thinking with the MIVEC?

 

I've seen these symptoms before. Mivec not doing what you tell it to do will lead you down "path a". Mivec doing what it's told will lead you down "path b".


The 4b11t is a great motor, but the electronics that mitsubishi placed around the platform can sometimes make it a tuning nightmare. Running through a systom of 'checks and balances' will allow you to interpret your issues either mechanical, tuning related, or electrical.

Feel free to give me a buzz at the shop tomorrow if you need to chat.

 

I will give you a ring tomorrow. I am the worst when it is my own car. All sensibility goes out the window...lol Any customer car, I will breeze thru, diagnose and fix no issues at all...my own, I am terrible.

 

like I said in the pm - try +10% instead of +5% for the 3xMAP tables.

also what is your current injector scaling on the FIC1100's?

 

I tried 1040 and 1140(or about there...dont recall the exact numbers) I have an idea that I will try tomorrow. I will keep everyone posted.

Thanks for the insight.

J

 

1040 sounds about right for pump..

if it was 1140, then you might be compensating a bad scaling with the MAF...

I would still like to see a log of it occuring...

 

The key symptom was the MIVEC. It can not hold a target. If you let it sit and idle, no problem. The target and actual are very close. If you blip the throttle, the EXCam goes to -30. Sounds like an oil pressure issue. That is exactly what it is. There is very low pressure at idle..<10PSI. Once you rev it, pressure builds to 40psi. SO I have a call into the motor builder(this one was assembled by a third party...lesson learned maybe.) I want to give them the benefit of the doubt on this. I just can't see the Evo pump(oil) going at 5000miles. Stranger things have happened I guess.

J

 

the cam will only move with pressure

so not enough pressure should mean it wont move...

but post up a log

 

I found out the issue. It was mechanical. I am working out the details with the builder before I post any pics. Thanks guys.

 

Definitely keep us updated so no one else makes the mistake...

 

In for updates, good luck!

 

Will do.

 

yes please do tell... i have seen this behaviour on another car..

wasn't sure if it was my imagination or not