From: John De Armond
Subject: Re: 2001 Lazy Daze V10 acting up
Date: Wed, 21 Sep 2005 02:34:27 -0400
On 20 Sep 2005 21:09:48 -0700, email@example.com wrote:
>My Ford V10 has trouble in the mornings. It fires up, then wants to
>die. After warming up, it's OK. The motor has about 56K on it and uses
>no oil. I've switched to higher octane gasoline and the problem seems
>to have gone away.
>Anyone else having this problem? I'm wondering if the refineries are
>skimping. My manual calls for 87 octane min. Maybe I'm getting 86.5
>from the pumps? Could also be that my engine needs a tune up, which is
>why I'm making this post. Anyone else going through this?
Octane won't affect this. The only thing Octane affects is the
engine's ability to resist knock. If a fillup affected the running
then the most likely explanation is that you moved from one area to
another and got a different botique blend of gas.
Is your check engine light on? Need to know the codes if it is.
Usual causes of what you experience in descending order of probability
Vacuum leak. Check the dipstick for seating and the oil filler cap
for tightness. Even a minor leak will cause that behavior. Look for
split hoses, particularly where they attach to the manifold. I fixed
yet another customer's car (hey, we're a full service restaurant :-)
that had that problem last week.
leaky gas cap. The EVAP system test is a discontinuous one so the PCM
might not have tested the system lately. A loose cap will definitely
cause cold starting problems. Also, check the EVAP tubing for cracks.
Idle Air Control solenoid. Ford's is more likely to stick than GM's.
(Ford's is a PWM'd solenoid while GM's is an actually stepper motor.)
If you remove the solenoid from the manifold and turn the ignition
switch on, you should see the plunger stroke over its full stroke at
least once. Inspect the ports in the manifold for carbon buildup.
Stuck or leaking EGR valve. This should set a discontinuous
diagnostic test code and light the check engine light but sometimes it
doesn't. Check the valve as with the IAC solenoid above.
Oxygen sensor. This doesn't directly affect cold start but it does
affect the long term fuel trim stored in the computer.
Bad intake air or engine coolant temperature sensor. Sending the
wrong temperature to the PCM will cause a bad mixture condition during
cold start and warmup.
Stopped up fuel filter. I'm putting this down the list because this
happens rarely. At least to the extent the fuel pump can't force fuel
through the filter. Low fuel pressure would be observed at the
injector rail test port.
Worn fuel pump. Low fuel pressure would be observed at the injector
rail test port. Several codes would be set - lean surge, O2 sensor
out of range, the long and short term trim values would be maxed out
rich, etc. If you get this far down the list, I'd trundle down to the
local AutoZombie and borrow their fuel pressure tester and check it in
the parking lot. A 2 minute job.
Bad mass airflow sensor. Not likely on an engine that young but after
everything else is eliminated, time to take a look at that. You
pretty much have to rely on the OBD output to a scan tool for that
diagnosis. While you're poking around the MAF, look for cracks in the
rubber boots connecting the MAF to the intake.
Bad Throttle position sensor. That would cause other problems too,
such as poor shifting and acceleration and would set a code and light
the check engine light so not very probable.
If the check engine light is NOT on, then I'd suspect an IAC solenoid
sticking when cold or the EGR valve malfunctioning. Pretty much
everything else will also cause warm engine problems, at least enough
to light the check engine light.
Give me some of the information I mentioned above and if possible, get
the OBD scanned and report the codes and I'll try to narrow it in a