Doing This Will Make Your Engine Run Better


rev up your engines, today I’m going to
show you how to fix a car in this case of this lexus when a bunch of trouble lights
come on in the dash, in this case it’s got the check engine light it’s got track off,
maintenance required, check vehicle speed control, and this giant one here
that just tells you warning something wrong as I happening so we start with a
simple thing, we plugged the scan tool under the dash in this case it just goes
onto here and plugs right in here then they have the key on the on position
with the lights on, but the engine not running, then we let the scan tool do its
thing it takes a minute or so and lo and behold this baby’s got 14 different
codes now the first thing we wanted to do is look at the P codes those are
the codes that have to do with the running of the car, it’s PL 171 174 then
1 7 174 which then we know those are real serious codes then there’s the C
codes, now we’re going to start with the P codes because the P
codes will make this vehicle not pass the
state emissions test, the customer wants it to pass the emission tests, he knows
it’s an old car it’s almost got 200,000 miles on it he wants it so it’ll run
decent and pass the emissions test and I know for a fact on these lexus says they
have strange software all the Toyotas do that if you get a P code the check
engine light comes on but often that turns the traction control system off
automatically by software, so you get the track off light in this case there
probably isn’t a failure in the track system, it’s just the check engine system
is making that trip the code, now this is a v8 engine so it’s got number one side
and number two side but both sides are running lean they either have too much
air or not enough fuel let’s hope it’s a vacuum leak something that’s relatively
simple to find, but I’m not all that hopeful it’s going to be a vacuum leak
and here’s why, I looked at the freeze frame data and it shows that the P0
one-seven-one code occurred at 63 miles an hour and then I checked the pl 174
code it also tripped at 63 miles an hour so the code tripped at a relatively higher
speed vacuum leaks affected engine the most at low speeds when the engines
barely going you got a vacuum leak that’s gonna affect the air fuel ratio a
lot more when you’re going slow than when you’re going fast normally with a
vacuum leak you’ll get the freeze frame data showing the car was going slow but
if there’s a problem in the fuel system itself not sending enough fuel
that’ll generally hurt her at a higher speed but we’re gonna check for broken
parts anyways you never know what could have come off or gotten loose, so we’ll
take the stupid cover off it and as I look around there’s no obviously broken hoses
or connectors, so go to the air filter assembly check that, get the clips off
and welcome take it out not much working room, it does have a leaf in it but it’s
pretty clean that’s not a problem, but this mass airflow sensor
it could be dirty, so let’s take it off they’re often hard to take off so I get
a long pair of pliers squeeze it try to pop it off it can be a real pain in the
butt, then we unscrew the thing to a little screws they often stick so
push down real hard you don’t want to strip them out, there it comes, now these
sensors can often get dirty I can see there’s a reasonable amount of dirt on
the little part here and then there’s an inside part so we’re gonna clean it, and
when you do only use mass airflow sensor cleaner, you just spray it that’s
cleaning the part that you can’t see turn it over, spray it then there’s stuff
inside, you spray that one way and then the other you want to get it nice and
clean, then you want the thing to air dry for about half an hour, you don’t want any
residual stuff to be sucked in, or any cleaner left on here, this stuff
evaporates off, doesn’t leave any residue that’s why you have to use the mass
airflow sensor don’t use carburetor cleaner, then after half an hour
put it back in and put the screws in the holder place
then plug the connector back in never clean up with the connector in, you don’t
want any power going to it when you’re cleaning it, it snapped to cover back on
and put the stupid beauty cover back on then, we’ll take you for a spin,
we know the code came on at 63 miles an hour, so we’re gonna go drive at 63 miles
an hour, well here goes nothing well let’s hope it’s something, and I’ve also
reset all the lights so all those warnings that were on before are all gone, now
you’re do want to go for a good 20 30 minute road test to really run it
through to make sure it’s testing everything, well now the road test is
over and all those nasty lights haven’t come back on, let’s get the scan tool and
see what it says it’s doing its thing, look at that now
there’s no codes at all, even though we didn’t work on the traction control
system the code didn’t come back because as I said in these things if you get a
check engine light come on, that will often turn the ABS off it’ll turn the
traction control off, even though there’s nothing wrong with those systems it’s a
software thing, that if the car isn’t running right it won’t let it operate
those systems, so now thanks to the Handy scan tool and the ability to have freeze
frame data, you always want a scan tool that can record the freeze frame data, so
when there’s a trouble code it’ll show you exactly when it occurred and all the
data that were around then when it did occur to fix it right, because as a
warning to anyone, when you get an old car like that fixed and it’s ready for
inspection, take it in and get it inspected, cuz you never know what some
other electronic thing is gonna go wrong and if it runs fine and it’s got a
little light on, what the heck you can drive at another year until its
inspection time again, so if you never want to miss another one of my new car
repair videos, remember to ring that Bell!

About the Author: Michael Flood

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