check alternator output--ours cars are getting a little age on them.
Curious--is your clutch in or out when warming it up?
If I dont left mine warm in neutral with the clutch out it will have a little stall point. I guess the engine needs a little load on it? IDK--just noticed that on mine.

 

I usually start in neutral. Therefore, the clutch is not engaged.

It could be the alternator or the computer as it controls the output. It has to be an electrical issue as the interior lights almost cut out and come back on again in an instant. There may be a clicking sound coming from the engine at the same time the idle goes from eratic to steady.

 

it may not be the alternator if this happens every time--i dont think the alternator would just have a moment of not charging correctly--it probably would continue to not charge correctly? No recovery?
let the clutch out after the engine starts ( in neutral lol)--see if that does anything?

 

Slipping belt?

 

I think it is computer or vaccum related. Unlikely it is belt slippage as the tensioner works well and there is no slippage at high rpm.

We know that there is a problem with the bypass valve and this is the cause of our idle issue. We tried various springs in the valve however, we could not find the correct combination. Danny will be looking at revising the bypass system to resolve the overall idle issue.

 

/\ what does you maf log look like at idle - how many g/s and over what range ?

 

run the by pass without any spring--hehe. Seriously try it.
what type by pass do yall use?

 

wshen I go to the tuners I should be able to get these measurements. At this stage I do not have a way to take these measurements.

 

The bypass valve is custom made...probably why we have this issue. I would assume without the spring it would always be in boost.

 

replaced worn coils. Need to fix the exhaust leak again as I did not follow the correct procedure with the gasket sealer.

This leak could be why my car is running rich

 

i think i might have a solution to the bypass issue, the problem is the valve is taking its reading pre-blower, literally right next to the bypass, it is getting a certain vacuum reading from right in front of the compressor. as soon as the bypass opens the vacuum is now coming from the engine UIM; which may be a different value. If these two vacuum readings are significantly different, the valve will flutter as it cycles opening and closing.

Perhaps plumbing a different vacuum reading right from the UMI or anywhere post blower will produce a consistent vacuum reading that will prevent the valve from fluttering at idle.

 

We think that a redesign of the bypass valve is required. It may involve moving away from the spring actuation to a flap that could be computer controlled.

By using this method you can tune specific commands at various throttle positions.

 

/\
Sounds like a horrendously complicated solution to a very simple problem ....


Bypass valves - when set up properly .... WORK !

 

ours work fairly well. We have the bypass plumbed pre blower/post blower--it is plumbed right off the intake mouth of the blower and right off the outlet side of the s/c. we do have a much longer intake before the TB/maf though. That may be whats helps us? We also idle at 1100-1200rpmsl

 

where is the vacuum signal taken from OD?

 

the pettit UIM--always use a dedicated line. Nothing else going to it.

 

Also an issue with hymee, its branched

 

or you could reassemble the existing bypass valve. It may require a redesign of the internal parts as the existing spring setup does not work well.

An off the shelf part if available may work as well. To fix this issue requires several trial and errors with various options.

For me fixing this problem is on the bottom of my list as I have adapted my driving style to accomodate the problem.

 

I am going to take my spring out, and drill and tap for a vacuum line from the Hymee UIM. Under boost it should provide pressure to keep the valve closed, and obviously any vacuum will keep it open. I only worry about the transition from vacuum to boost will be smooth without the spring, I am pretty sure the compressor should flow enough to close it and the bypass isn't large enough to bleed off to much boost during the transition.

 

I idle at 950 - 1000

 

MEH!!! lol.

 

ESS was dirty with metal fragments, oil and dirt stuck to the sensor. However, cleaning this did not resolve the problem. The next move was to replace the dirty air filter and it seems to have a made a bit of a difference.

Took it for a drive today on take off I red lined in 1st gear then a quick change to second then red line again successfully without bogging down however when I red line to 3rd there is some hesitation still. While the problem has become better it is not totally resolved.

This problem was far more pronounced before the filter change.

I behaves perfectly on normal driving conditions however, I am trying to replicate track driving conditions so I am trying to get it perfect.

I now have to wait till the end of April to get the car to the tuners as the tuner at GT Auto is going to taiwan for a month to tune cars there

I will try cleaning the MAF sensor with a contact cleaner this time as I feel the carby cleaner I used did not do a good job as it appears it is a AFR issue with the car running rich.

 

if the air filter was that dirty--then the maf probably needs cleaning AND the throttle body?
Could be soooo many things. Glad you are getting there--even if progress is slow.

 

I did not realise how dirty it was until I held them next to each other. The old filter was black compared to the pink new filter.

 

then its doing its job at least!