[T3] Temp sensor and MPS problems on new motor

[Keith Park]

The cam was in a T4 non-stock engine.  You can go mild cam with D jet, but
it requires careful tuning, not sure if the early or late pressure sensors
have enough adjustment opportunities to handle another cam tough but you
DONT want to run a lightened flywheel with the D version of the T3 D jet.

Idle mixture in the T3 is the issue to change, in the T4 version of the D
type FI you can adjust it and really get things working nicely with a
non-stock setup, the late T3 FI (E type) doesnt have this but does have the
5 signal generators which elminate the speed transition problems at 1200 and
1800 RPM.  I may have to dig into the control unit to add an adjustment when
I put the T4 motor back in the square again.  wont know till its up and
adjusted to see where the idle mixture is, fortunatly its not critical, but
the ethanol REALLY changes things and that may be the clincher.

I have a buddy with a modern closed-loop Dodge Challenger SRT8 that wont run
properly without Nontenol in it, the NY gas is outside the range of its self
adjustment.

Keith'


Topnotch Restorations
topnotch at nycap.rr.com
http://www.a383ina68.addr.com/radiorest/main.htm
71 Squareback  "Hothe"
65 Notchback  "El Baja Rojo"
93 RX7  "Redstur"
87 Golf  "Winterat"
 

-----Original Message-----
From: type3-vwtype3.org [mailto:type3-vwtype3.org-bounces at lists.vwtype3.org]
On Behalf Of Jessica Chase
Sent: Sunday, February 21, 2016 9:05 PM
To: type3-vwtype3.org at lists.vwtype3.org
Subject: [T3] Temp sensor and MPS problems on new motor

Hey guys!

Jim..I was writing this post when yours came in so I'll think on what you
said and respond to it later. But I can comment on our fuel pressure gauge.
It's an Actron gauge from Autozone that we modified it to accept a 5/16
hose. 

Here's what cold start is like with the pressure sensor unadjusted. The
video shows lean AFR's, hunting (or loping?) rpms, and stable fuel pressure.


https://www.youtube.com/watch?v=f3phST7MFWE&feature=youtu.be
<https://www.youtube.com/watch?v=f3phST7MFWE&feature=youtu.be>

Here's another that shows what happens with the air temp sensor unplugged.
It changes by a lot more than 10%!!! This is the idle AFR we drove home with
the other day when we got bad gas mileage and didn't have an AFR of above 12
while cruising at 70 mph.  If you have decent computer speakers, you can
also hear what's going on with the idle throughout both videos. 

https://www.youtube.com/watch?v=6RN75xveTaY&feature=youtu.be
<https://www.youtube.com/watch?v=6RN75xveTaY&feature=youtu.be>

20 more miles today on our adjusted MPS and all is well and smooth. Idle is
good, throttle response is good, cruising is good. 

Keith, how did you get your motor to run with a non stock cam? We went with
stock because of all we heard and read about how important the cam is to
producing the correct vacuum signature for the MPS. We have a
counterweighted crank and lightened flywheel though and unless I'm crazy,
you can really feel the difference at idle (so much smoother) and under
acceleration (quicker without all that weight spinning around).
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