One thing I forgot to point out:
On initial startup (and even after a cool-down period), the engine will
run a little bit rough due to the warm-up cycle on the O2 sensor(s).
This is normal (takes about 2-3 minutes max)...the lean-out "pop" was
not.
- Bernd
-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Bernd D.
Ratsch
Sent: Sunday, May 25, 2003 11:49 AM
To: dakota-truck@dakota-truck.net
Subject: DML: Cold-Start Hesitation - Finally Fixed
After going through a lot of different options and tests, I finally
found the cold-start (rough running) problem on the truck.
I know a few others have had this same problem and it could also be a
fix for you...but you'll need to check first.
Problem:
On initial (early AM startup), the engine runs rather rough (like it's
got some sort of huge cam in it) and back-fires through the intake. Went
through TPS, MAP, O2, IAT, and a few other options as well (including
fuel sync and distributor alignment). Everything checked out fine and
well within spec.
Solution:
Coolant Temp Sensor was off by 4K ohm (lower than normal) causing a
leanout condition. Remember, the CTS also works like the old chokes on
carbureted engines (engine warm-up). Early AM CTS resistance should be
about 9.4-9.8K ohm for my area (74-78 degrees F). Sensor was at 5.7K
ohm...this equates to 104 degrees at cold-start (not good). PCM thought
engine was warmer than actual temp and was leaning out the fuel a little
early.
No more backfire or lean-out condition.
- Bernd
This archive was generated by hypermail 2b29 : Fri Feb 06 2004 - 11:46:21 EST