Fw: [Diy_efi] Lumpy engine in closed loop cruise

[Geoff Harrison]

I think what is happening here is a misunderstanding of 
"cruise". My old brain may be behind the times,
but to me 85 MPH is a bit over cruise. (unless it's an F1 or 
CART - tongue in cheek).
Geoff H


----- Original Message ----- 
From: "Mike" <niche at iinet.net.au>
To: <diy_efi at diy-efi.org>
Sent: Friday, October 21, 2005 1:57 PM
Subject: Re: [Diy_efi] Lumpy engine in closed loop cruise


> At 12:19 AM 10/21/05, you wrote:
>>Why to you say it is heavy load ?  they is almost no boost. 
>>0.3 bar max  which is nothing really.
>>Throttle is about 5-10% so the turbo is just ticking over.
> huh ? Did I miss-read when you said:-
>
> "In 5th gear,  trying to hold steady 85 mph,  3500 rpm, MAP 
> about 100-130 kPa"
>
> Am I correct in seeing that as absolute manifold pressure at 
> that cruise ?
>
> To me that says you are at close to atmos pressure in your 
> manifold to
> keep it at 85mph, thats a fairly high pressure for cruise - 
> isnt it ?
>
>>How do I richen it up,  that is one of my problems.  If you 
>>can the VE tabels will the BLM not pull it back.
>
> Dont know anything about your ECU, maybe aftermarket 
> performance
> people can help. However, I have occasionally had similar 
> problems,
> came down to electrical connections on air flow meter, the ECU 
> interpreted
> this as faulty and switched in and out of limp mode.
>
> If the car is more than 5 yrs old really worth checking 
> connectors, often
> just cycling them (plugging in and out a few times) can help 
> diagnose.
>
> Other thing that occurs, make sure all your low voltage leads
> are well away from your high tension (EHT) . A common problem 
> on the Nissan
> engine used here in the commodore is the cyl 1 ignition lead 
> being really
> close to the crank angle sensor leads and the tags breaking so 
> there
> isnt the normal separation, this allows high tension voltage 
> noise to
> get imposed on low voltage signals this can cause ECU to 
> misread
> crank signals, in your case make sure the MAP is not being 
> misread
> because any high voltage leads cannot corona discharge 
> influencing
> the main sensors. On one forum in Australia we had one guy who 
> went
> through 4 crank angle sensors - suffice it to say - he didnt 
> know having
> good EHT leads right next to low voltage leads would or could 
> be an issue
> ie. Even  brand new good leads allow some corona effect...!
>
> Fortunately its not as if its plasma ignition, that would be 
> far worse
>
> <chuckle>
>
> Rgds
>
> Mike
>
>
>
>>Dermot
>>
>>
>>
>>>Bit of a heavy load for cruise,
>>>
>>>And yes does sound a bit lean, can you richen it up by
>>>20% and observe the effect ?
>>>
>>>Rgds
>>>
>>>Mike
>>
>>
>>Regards from
>>
>>
>>Mike
>>Perth, Western Australia
>>VL Commodore Fuse Rail that wont warp or melt !
>>Twin tyres for most sedans, trikes and motorcycle sidecars
>>http://niche.iinet.net.au
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