'88 3SFE engine: no vacuum ANYWHERE!
geronimo
out what is causing an extreme loss of power when the car is driven
just a short ways. Idling, sitting still, it will run just fine.
After driving a short ways the engine loses power to where it will
only go walking speed. The check engine light has never come on.
Spark voltage remains good. I found that the fuel press. regulator
fuel ports were all clogged up with black hard deposits, like narrowed
down to a pencil- lead size. I cleaned out the ports and checked it
for operation with a vacuum tester. But This did not fix the problem.
So I checked the control vacuum to it. ZERO. At idle, or at high
speed...zero. Then I checked the input hoses (two) and output hose on
EGR valve...zero. so I put the vac gauge on the P-E-R ports at the
throttle body....all three are zero. There is no vacuum either at
idle or at high RPM. SO it is no wonder it is so screwed up. I
believe these three ports are the source of vacuum for the entire
control system, aren't they? How can all three be plugged?
Do they all join inside the throttle body and are fed by one source
(I guess it is something like a venturi)? I guess next step is to
remove the throttle body (hope the Haynes explains this!) Maybe it
needs to be sprayed out with Berrymans' B-12 chemtool to unclog them?
It is a new gauge, so I sucked very gently on the end of the test
hose, just to make sure it is working. Its a good gauge! thanks
geronimo
john...@hotmail.com
carbon. What's the maintenance like on this car? Timing belt, plugs,
gaskets, EGR valve cleaning, etc?
Are you getting power brake boost? If so your engine is generating
vacuum, just not getting to the small ports. If you clean the P-E-R
ports (I mean run a wire and see it physically come through) and still
not get any vacuum then you have a serious leak somewhere. I'd think
you'll get low vacuum, but NO vacuum? Check all gaskets, cam/crank
seals, etc for inexpensive starters.
Daniel
> How can all three be plugged?
> Do they all join inside the throttle body and are fed by one source
The vacuum ports on the throttle body are separate. They port vacuum at
different degrees of throttle opening.
If you just changed the timing belt, double check to make certain the
valve timing is correct. If you're one tooth off, you could be losing
vacuum.
john...@hotmail.com
and they control the EGR modulator. You'll get increasing vacuum
readings at first the E and then the R port with throttle plate opening
up to full engine vacuum.
But there should always be full engine vacuum at the P port, as well as
the brake booster port, or the PCV hose.
Jason James
<geronimo> wrote in message
news:7vkpd21gu854i9j54...@4ax.com...
There are varying levels of vacuum, dependent from where in the intake
system the vac is being sourced from. Manifold or below the throttle-valve
vac is the highest. The brake-booster uses maximum vac from the here. Other
parts of the engine use lessor vacuum and may give you the wrong impression
if its not registering on a gauge designed to indicate max-vac.
Engine vacuum is highest during run-down from high revs (throttle-valve
shut) and at idle. During wide open throttle (WOT) eg during accelerating,
vacuum takes a big dive and is the reason the power-brakes has a resevoir
incorporated into its diaphragm chamber. It also means you need a one-way
valve in the booster vac-line to the booster to stop stored vac from
bleeding back into the intake during low vac engine operation.
If the brake-booster has a ruptured diaphragm, the engine will run rough and
power assist will be reduced. In this case you can usually hear a hissing
sound inside the cabin, coming from the power booster.
If your brakes work fine (the brake pedal should fall slightly after engine
start), its not likely there is a severe vac loss problem, but all the same,
you need to check all the small vac hoses for splitting etc
The PCV valve can cause engine performance problems if it is stuck open.
Test it by plugging the PCV line temporarily at the end which accesses the
cam-cover. Apart from that, you maybe looking at ignition or fuel pressure
problems. Is the air-cleaner OK?
Jason
geronimo
Air filter is new. I took off the throttle body and used Berryman
B12 and shop air on the P-E-R ports. Now that the engine is back
together, I realized there is a capped port on the back side of the
manifold, just made for tests. So I checked it there at idle and it is
20 in. vac. So I then checked the P vac. by connecting the gauge up
to the P line where it attaches to the temp. controlled vacuum
switch. As it should be, there is 20 in vac there also. And that
switch is switching the vacuum on when the engine gets up to temp.
That vac switch is for the evaporative canister I think. The E port
very slowliy goes from zero to about 5 in. as engine is revved. I
believe that particular port is very restrictive, unlike the P
port...hopefully it is supposed to be! The R port goes from about 0 to
10 in. quickly as the engine is revved.
With the fuel press controller vac line connected, I have only
about 37 psi on the fuel line between the engine and the fuel filter
at idle. As a test to see if the fuel press controller was doing
anything at all, I pulled the vac line off, and RPM increased a bit.
The fuel pressure gauge went from 37 toi 45 psi. So with the vac
control line pulled off and capped, I think this just sets the
pressure controller so that it bypassing the least amount of fuel,
raising the press to max.
The brakes work great, no hissing sound, so I think they must be
getting normal vacuum.
The main thing I need to know is if that vac press. in the intake
manifold is normal.....or low, indicating I have a vac. leak
somewhere.
Should I look at the EGR system? THey look like they could be the
original parts with nearly 200K moiles on them. Could this cause a
sudden loss of power, slowing down to a crawl after driving some
miles?
Will definitely check the PCV valve out!
At least my oil pump, water pump and timing belt change went well, and
it is no longer leaking a drop of oil anywhere or leaking any coolant
either.
THe other issue I have is with the fan control switch. I found the
original bad, had a pinhole leak in the bulb, and so it had stopped
switching...it was just stuck grounded, and this keeps the fan off.
Well I went and bought a new one from Autozone. Install it and I have
the same problem...the fan never turns on at normal temps. I had to
again pull the connector off to get the fan to run. So I checked the
new switch by immersing it in boiling water. Yes, at 212 deg. the
switch does open, so it is functional. but isn't the fan switch
supposed to turn fan on at around 185-190 deg? The car will sit there
idling in hot summer weather, and it never turns the fan on!
Thanks, Geronimo
thanks, Geronimo
geronimo
Now it has a much worse problem. It is over- heating. When I was
working on the throttle body, I bumped the temp sensor (the gauge
sender), and knocked the contact part off. So I had to remove the part
where the radiator hose, and sensor and vacuum switches are mounted. I
installed a new sensor, and remounted the assembly on the engine with
the two nuts. That is all I did. I thought that perhaps the
calibration of the new sensor was not the same as old one, but I
checked the engine temps with a laser temp gauge when it was edging up
towards the red zone, and it was at 225 deg. ! Shut it off real quick!
The sensor was not quite the same, the sensor body is a little longer
than original, but don't see how this would cause some major
restriction of water flow. The radiator is topped off and cooling
system is not leaking a bit...not even at 225 deg.
Before working on throttle body and changing the temp sensor, it was
running at mid-scale on temp gauge as it should. There is only one
fan coming on, the one on the right side, but it is apparently
adequate (when all is normal) enough by itself, it seems. Or should
both come on ?
From the Haynes manual, I think the RH side one is supposed to be
turning on with the A/C....but it is the RH one that is being
controlled by the fan control switch on the thermostat housing. The AC
isn't working yet, not charged, so I would guess that is why one fan,
in my case the LH one...is never coming on.
IF only I was rich and could just take it to an auto repair shop. ;-)
Geronimo
john...@hotmail.com
geronimo wrote:
>The E port
> very slowliy goes from zero to about 5 in. as engine is revved. I
> believe that particular port is very restrictive, unlike the P
> port...hopefully it is supposed to be! The R port goes from about 0 to
> 10 in. quickly as the engine is revved.
I think the vacuums there are a little low, even with the tiny ports.
You should be getting near full manifold vacuum, which you stated is
about 20in. So you are getting vaccum from the engine, and pretty
health at that, 17-22 normally.
> Should I look at the EGR system? THey look like they could be the
> original parts with nearly 200K moiles on them. Could this cause a
> sudden loss of power, slowing down to a crawl after driving some
> miles?
EGR is a simple system that really doesn't go bad except they get
plugged up with carbon and stick either open or shut. Do a simpel test:
First measure the vacuum at the EGR port hose. You should get 0 (no
vacuum) at idle. If you get vacuum at idle at the valve, you have a
problem. Also pull vacuum of the EGR valve and see if the engine runs
rough or stalls. If so, it's ok. If no change then the valve is not
working.
> At least my oil pump, water pump and timing belt change went well, and
> it is no longer leaking a drop of oil anywhere or leaking any coolant
> either.
Let's see: your upper rad hose gets hot and then the lower get warm to
hot? If so your thermostat is opening and your water pump is working.
Because if hot water isn't coming out into the radiator, your fan
switch isn't going to turn the fan on (while at the same time your
engine overheats because hot water stays there).
So your fan is working as you bypassed the switch. At least that's
good. The two coolant fan switches operate at different termperatures.
Usually 20 def-F apart. If one is at 185 then the other is at 205. The
higher one switches on the condenser fan if it's not on already because
of the AC.
john...@hotmail.com
- Water pump (is the right pump installed? is the timing belt properly
tensioned? etc
- Thermostat. (is it operning and the valve opening height within
spec?)
The new coolant sensor: is it spec'ed for 1988 3SFE? If so, physical
apperance may change over the years. What's important is the
temperature response:
See Figure 1, Autozone's free repair guide:
http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/13/e2/83/0900823d8013e283.jsp
BTW, the guide implied the 3SFE has only 1 level of fan switching, at
199 deg-F only. Then the AC fan is controlled by turning the AC on
only. I am not sure about this.
geronimo
John, would the cooling fan switch for the second fan be on top of
that header (or whatever is called) mounted on the left side of
engine, the same header that the top radiator hose goes to, and has
two temp-controlled vac switches and the gauge sensor ? There is on
the top side of it another switch or sensor that has a two-conductor
connector...its not like the fan switch on the thermostat housing that
has a single conductor. I am asking because I need to locate and
check the other fan switch, see if it is bad also.
The thermostat is a new one and is known to open fully, and as I said,
after initial test runs after replacing timing belt, water pump, oil
pump, was maintaining the engine temp gauge at mid-scale. It is only
after checking throttle body and changing out gauge sensoro that it
has the over heat problem.
Could the timing have jumped? Would this cause overheat possibly? Yet
engine power has not changed a bit, nor idle speed.
Autozone apparenty gave me the fan temp switch that actuates at the
higher temp! They can't tell you what the specs are for any electrical
part, that is the problem with Wells/ Autozone parts. No specs are
included in the box with the part! But I think the same is true of
internet vendors....no specs. So I guess I am out $35 for an
incorrect part that they don't accept returns on as it is now used.
I didn't really have to bypass anything to get the RH fan running...I
just leave it unplugged from the new fan switch. Funny thing is
that I pulled both fan control relays...yet the fan still contines to
run! Have to pull the CDS fuse to get it to stop. I am having lots
of trouble with this, partly because I am an ameteur, and also because
the wiring diagram in the Haynes manaual is just a generic one
covering several model years, and on my car is not the same as shown.
The diagram doesn't show two fan temp switches, it shows the AC fan as
only controlled by a relay.
Thanks, Jim
Also, please clarify which vacuum port should not have vacuum at idle.
There are ports /hoses on the modulator and on the EGR valve itself.
I do know that there is no vacuum signal to the vac. control port on
the top of the EGR valve, and nothing changes when I
connect/disconnect it.
Thanks, Jim
geronimo
Checked radiator hoses from a cold start. Yes, after a couple of
minutes at idle, the upper hose got hot, before the lower hose began
to heat up. So it seems water pump and thermostat are still OK.
And I looked at that coolant header again, and there is another
electrical temp switch, a single conductor one, besides the two-
conductor one I reembered seeing. Probably that's another fan
switch. Will take it out and check it also. The Haynes manual shows
the AC /auxiliary fan power going through a high-pressure switch.
Geronimo
geronimo
Well, it dawned on me that yes, indeed, incorrect timing can make
a car overheat, so I checked the timing marks. The cam timing has
jumped WAY off! I did not get the new timing belt properly
tensioned...or the ten miles or so I put on it has stretched it. I
know you can't rely on the spring tension alone. I put more than the
spring tension before tightening the tensioning idler bolt down...but
obviously it still wasn't enough. What is the trick to ensure it
doesn't jump again?
geronimo
Jason James
<geronimo> wrote in message
news:42lsd2lh6r3katu7l...@4ax.com...
>
>
> Now it has a much worse problem. It is over- heating.
Sometimes when trying to suss out a problem in an engine, we can go off on a
tangent, losing sight of the original problem.
If your engine *IS* overheating, then that has to be investigated first, as
it is a major problem which may cause other symptoms to distract you.
Make sure your laser temp-gauge is actually correct in saying the coolant is
reaching 225F. As coolant has a higher boiling point than water a cooling
system in good order will also raise the boiling point by use of system
pressurisation, its imperitive to know the exact coolant temperature.
When I was
> working on the throttle body, I bumped the temp sensor (the gauge
> sender), and knocked the contact part off. So I had to remove the part
> where the radiator hose, and sensor and vacuum switches are mounted. I
> installed a new sensor, and remounted the assembly on the engine with
> the two nuts. That is all I did. I thought that perhaps the
> calibration of the new sensor was not the same as old one,
That's possible, but not to a great degree generally.
but I
> checked the engine temps with a laser temp gauge when it was edging up
> towards the red zone, and it was at 225 deg. ! Shut it off real quick!
> The sensor was not quite the same, the sensor body is a little longer
> than original, but don't see how this would cause some major
> restriction of water flow.
It wouldn't do that.
The radiator is topped off and cooling
> system is not leaking a bit...not even at 225 deg.
OK, so the system pressurisation is working.
> Before working on throttle body and changing the temp sensor, it was
> running at mid-scale on temp gauge as it should.
Exactly where the gauge sits, varies from car to car. This is why you need
an acurate separate test gauge to measure engine temp. I've found that just
measuring the head temparature (the metal itself) is just as good.
Especially aluminium heads like the Camry.
There is only one
> fan coming on, the one on the right side, but it is apparently
> adequate (when all is normal) enough by itself, it seems. Or should
> both come on ?
AFAIK, the fan controlled by the sensor in the radiator bottom tank is the
one which responds to excess heat. The AC fan has its own control when the
AC is on.
> From the Haynes manual, I think the RH side one is supposed to be
> turning on with the A/C....but it is the RH one that is being
> controlled by the fan control switch on the thermostat housing. The AC
> isn't working yet, not charged, so I would guess that is why one fan,
> in my case the LH one...is never coming on.
Yep.
> IF only I was rich and could just take it to an auto repair shop. ;-)
The common things to check have been done in that the water-pump is new and
the coolant is not leaking out. This leaves the thermostat which maybe stuck
shut and the head-gasket or head itself. If either of these is allowing
coolant to be sucked into the combustion chambers, the engine will start to
run rough and lack power due wetting of the spark-plugs. Also, over time,
the coolant level will drop in the expansion resevoir. This will show when
the engine has cooled again.
Usually when this occurs, but not every time, compression gases are forced
into the water-jacket and appear as a constant stream of bubbles exiting the
coolant when viewed at the radiator cap hole in the upper tank. The elbow on
the upper tank where the cap sits needs to be topped-up with water so the
bubbles can be seen.
These days, mechanics have sensors which can pick-up any fuel or other
exhaust gases at the radiator fill hole.
Inspecting the spark-plugs which are located in deep recesses in the
cam-cover, will show as very clean if they have been subject to coolant
leakage. If the headgasket or the head itself is responsible for your
overheating, you'll be embarking on a repair job which for a novice maybe
difficult. It's important to get the diagnosis right however, and a few
bucks for a good mechanic will be worth it.
Jason
john...@hotmail.com
it:
The CDS 30A fuse is for the condenser fan. The RDI 30A controls the
radiator fan. The radiator fan is supposed to be on the driver side and
the condenser fan on the passenger side.
There is a engine coolant temperatuer (ECT) *switch* on the inlet pipe
(driver side) with the thermostat. This controls the radiator fan and
should have a switching range of 181-199F. It should turnon at 199F (no
continuity) and off at 181F (continuity). The radiator fan can also be
controlled by fan relay #2 and #3 by the ECM in conjunction with the
condenser fan.
The sedans have only one ECT switch; the all-trac AWDs have TWO ECT
switches. The second one is on the water outlet pipe (driver side). The
order looking from the radiator to the firewall is: thermo-vacuum
switching valve right above radiator hose, #2 ECT switch for AWD
models, engine temperature sensor (a variable resistor as described in
the Autozone repair guide I sent, Figure 3 on how to test).
By pulling the ECT switch, your radiator fan should operate. If not,
you may want to check the motor operation by jumpering it to power. Be
careful here with live battery current.
---------------------------------------
Yes, too advanced a timing can cause overheating. This can be verified
by looking at the cam mark with crank mark at 0 deg. No timing light
will do here.
Check the AutoZone guide on how to tension the belt. You should do it
exactly to the word. You should probably change this belt out now it's
gotten stressed by who know what force. I'd use a Gates timing belt
from your local NAPA store. Have you changed out the pulleys as well?
Compare the guide here with Haynes:
http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/13/e6/07/0900823d8013e607.jsp
Tighten all bolts to specified torque. Use a $12 torque wrench from
Harbor Freight on sale will help. Sears Craftsman ones are excellent
too which I enjoy using.
As specified: with the timing belt on the pulleys and all aligned,
loosen the tensioner pulley bolt by 1/2 turn to allow it to operate.
And turn the crank several complete turns (I do it more than the
2-turns specified, it's the only difference). It'll tend to jump tooth
during this stage beacuse of valve spring tension so go slow and smooth
here. Torque the pulley bolt to 31 lb/ft after making sure all the
marks are still aligned. Then crank another several complete turns.
If the belt stretches after a proper installation, then you may have
something seizing and causing the belt to stretch. BTW, over-tensioning
can also do this.
john...@hotmail.com
> (driver side) with the thermostat.
Correction: inlet pipe is on the passenger side.
geronimo
creative wiring on this car before I bought it. When I pull the ECT
switch conn. on the thermostat, the *RH* side fans runs (having lost
the ground from switch). The LH side fan has never run. Not having
experience with Camrys, I assumed it was the aux fan for the
compressor/condenser cooling, and since the AC has lost its charge and
compressor is never running, that that was why that fan was never
running. But it makes more sense for the AC fan to be on the RH side
since it blows on the compressor directly. Does it make a big
difference on cooling performance? I have been doing test runs of the
engine with the RH fan running constantly (temp switch connector
pulled off) any time ign power is on...and it was for a while
maintaining temp at mid-scale--- that is until something happened with
the timing. Is easy enough to swap fan power wires, or fans if the LH
one is no good. Can buy a condenser fan later when I get the AC fixed.
Thanks again, Geronimo
john...@hotmail.com
switch, the driver side fan (radiator fan) is supposed to turn. The
condenser fan (passenger side), according to schematics and repair
guide, is supposed to turn at low speed below 194F regardless of AC
switch being On or Off (!).
So after the important things are sorted out, check the radiator fan
(driver side). You should jumper the power to the fan, because if the
schematics is right then the pressure switch may have a play in the
operation of the radiator fan.
geronimo
Roger on that! Thanks!