Throttle Body and Intake Manifold

Injectors have several FAULTS that require replacement of the “clips” and/or the injectors.

Just because the injectors have 2-3 ohms of resistance…you cleaned the injector terminals…and they pass the suction vacuum test, don’t mean they are GOOD-TA-GO! Rolling Eyes  Shipping away your injectors…to have them “SONIC CLEANED” is pretty much a waste of $50-$60…cause you can flush your injectors yourself.

Hey…….that looks the same as a STORED FUEL TANK! Shocked

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Once the PINTLE….or the HOLE has rusted away the tolerances… there is
little help that flushing an injector can correct a INTERNAL FUEL LEAK! Rolling Eyes

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Same as a CONTAMINATED STEEL FUEL TANK….& STEEL FILLER NECKS & STEEL FUEL LINES, EXTENDED STORAGE of a Starquest IS PURE HELL ON THIS CAR!

NO-NO-NO……. Shocked those are not Phillips in your Starquest!
Those ARE……..*REED PRINCE*. That explains WHY you become a HACK not knowing the difference. Crying or Very Sad

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Left: #2 Phillips Right: REED PRINCE

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NOW THINK…REED PRINCE (or a least compare tips) and a EXTENSION TYPE BIT! Wink

That FAT-SUCKER ain’t gonna fit into that WELL! Rolling Eyes
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Below: An EXTENDED REED PRINCE w/ socket driver. Wink

Throttle Body Shaft Seals….nope, they don’t come in any “kit”….are more effort to replace…and Ether testing is RECOMMENDED FIRST! These take a lil’ CAUTION! Rolling Eyes
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MF520067 before 9/86
MB554316 after 10/86
MF520067 is no longer available
MB554316 is $1.90 from

Below: Felpro!
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Kit # 1529 ain’t gonna come with the CORRECT BASE GASKET!
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And neither will the Echlin kit! Rolling Eyes
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Neglected cooling system is PURE HELL TO YOUR ENGINE! Shocked

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This gasket comes with sealant for a reason. It has to hold back the BOOST/MANIFOLD VACUUM & COOLANT PRESSURE/VACUUM (when it cools down)!! So this gasket works pretty hard. This is a COMMON FAILURE!! If you extend park this car because “it’s broken” Rolling Eyes well……. You can imagine the damage to the METAL inside from sitting around with “COOLANT” INSIDE IT……….which is WORSE if it’s NOT DISTILLED WATER mixed with ANTIFREEZE……..ANTI-RUST!! Shocked
Injector O-rings ONLY…..MD614110 NO PIC.

The “SAS Fixed” screw is what the DEAD-STOP…or REST POSITION for the butterfly is.

In the 88 factory service, pages 14-32 thru 14-35, is how you ADJUST your TPS. (adjusting & TESTING the TPS are TWO different things) Rolling Eyes

As you can see…there is a bracket that blocks easy access to that screw
(in red) because…if you turn it, the TPS will need re-adjusted!

The instructions in those pages…are how to RETURN IT TO WHERE IT SHOULD BE! Shocked Or…use the PICS! Wink

Most of the used TBs I have come across are in a VIRGIN STATE and that’s GOOD NEWS! Cool

However….84-86 did not have the “Fixed SAS” screw…so you COULD NOT SCREW-UP by turning it! Very Happy

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The screw on the left is the ISC adjusting screw…and *YOU* are NEVER to back-it-out! It merely adjust the ISC STOPPER LEVER to MAKE SURE the ISC GROUNDS the ISC “nose switch” when it is returned to IDLE!
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Removing the ALLEN METRIC PIPE PLUG (6mm) will test your patients.
YOU MUST HEAT THAT TOWER TO EXPAND IT…& “COOK” the Loctite to about 450*F! A metric size hex….with a 1/4NPT thread! Go figure. Rolling Eyes

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Now…are you afraid of, FIRE-N-DA-HOLE? Shocked *IF*…you DID NOT ALLOW AIR/OXYGEN TO ENTER THE TOWER….FUEL WILL NOT IGNITE! Wink PERIOD!
HEAT IT…NOW REMOVE THE FLAME…back-out the plug!

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Or…a HEAT GUN WILL ALSO WORK! And…you can dismantle it further and allow the fuel to dry out!

Page 20 of “Introduction and Master Troubleshooting” in the 88 Starion service manual says they are NATIONAL PIPE THREADS.(NPT) “I” say they are American pipe threads. And after you chase the threads a little deeper……..YOU’LL say they are American pipe threads. Laughing

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Coverting 1/4″ x19 to 1/4″ x18.
Use a COMMON 1/4″ x18NPT pipe tap to chase-it a lil’ further.
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STOP! Rolling Eyes What GROUNDS the “mixer” body? Rolling Eyes  The (4)…8mm bolts! Just how CORRODED are yours? Shocked

Replacing the Mitsu pipe plug with a BRASS, 1/4″ NPT allows you to SPOT CHECK your fuel pressure very fast! Wink

DANGER! NEVER…run a 24-7, fuel pressure gauge, under the hood! Shocked They are known-to, break-apart!= you set your ENGINE, ON-FIRE! Crying or Very Sad
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STOP! Pay ATTENTION to the LENGHT of these small screws.
They are different for a reason.

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CORROSION of these 4 bolts will RESTRICT grounding the “mixer” = the ISC can’t perform its job, CORRECTLY!
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Some GOOBER has jacked-with the ISC, idle-speed-set-screw! Rolling Eyes It’s nearly MAXED-OUT! Mad
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AHHHH, shit! Rolling Eyes The butteryfly is UP-SIDE DOWN!!

Those numbers on the butterfly should be ON THE BOTTOM! Crying or Very Sad

When that red Loctite don’t see oxygen….in about 2 minutes you’ll never get those screws removed again. Shocked
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below: The EARLY model Starquest did’t have the “Fixed SAS” screw but this is the ear it would be installed on LATER models.
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Notice the length of the LEVER where the ISC makes contact to the throttle shaft. This would be a early model….84 to 86.
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This “MIXER” is a later model used in 87 to 89 models. That, round-head screw, “Fixed SAS screw,” IS NOT TO MAKE CONTACT with the throttle shaft!
It IS NOT a IDLE SPEED SPEED CONTROL SCREW!!  It’s only purpose is to prevent the BUTTERFLY from LOCKING ITSELF into the bore…making it stick.
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The hex-head screw to the LEFT is the ISC/MPS idle speed control screw.
CAUTION! If you turn that screw…it CHANGES THE TPS SETTING VOLTAGE!
So….you would need to RE-ADJUST the TPS idle speed voltage back too .48 to .52 volts.

This is NOT HARD to do this…but you need to be AWARE that turning that screw can make a problem if you DO NOT re-adjust the TPS.

FSM says: “Curb idle speed 850rpm +or- 100rpm!” Rolling Eyes
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Again…the red screw on the left is the ISC idle speed screw. The engine would need to have the ignition timing set to 10 to 12 BTDC and the engine should be completely warmed up to re-adjust idle speed…..followed by the re-setting the TPS voltage.

The THROTTLE CABLE must have a little SLACK… Rolling Eyes or the CABLE would
be holding it OPEN! Shocked
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This is a later model “MIXER” so this PORT (in red) is plugged.The EARLY “MIXER”, 84 to 86, had an additional nipple.
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ALL MODELS had a additional MANIFOLD VACUUM NIPPLE the feeds the HVAC (heater and air conditioning) and the CRUISE CONTROL too.
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Check yours… Rolling Eyes because the VACUUM HOSE are NOTORIOUS for the boost to BLOW-OFF that vacuum hose. Rolling Eyes

This is a easy cure. Remove the nipple and use a center punch to FLARE-IT a little.
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If you don’t fix it…UNMETERD AIR IS ENTERING YOUR ENGINE! Shocked
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Another cure. However you’d need to re-tap the manifold a little deeper using a 1/8″ NPT-27 pitch to convert to this SHELF unit.
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YOU NEED TO UNDERSTAND GROUND #11 & its continued PATH! The BRASS eyelet has a 10 gauge wire that dead-ends to the intake manifold, GROUND #3, so the ISC/MPS has a good ground source.  A KNOWN HIGH-RATE FAILURE OF GROUNDING THE INTAKE MANIFOLD which SCREWS with the ISC/MPS & EVEN THE ECU! Shocked

The 14 gauge wire is……YOUR ECU (computer) GROUND!! ……..IT TRAVELS VERY FAR to the ECU! Better see to it being SPOTLESS!

The OTHER END of GROUND #11 is GROUND #3 and travels thru a MALE/FEMALE SPADE CONNECTOR and is frequently CORRODED!  And SERVICE the EYELET & it’s BOLT TOO!  Run a 8mm tap into the manifold, too!

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CORROSION of these 4 bolts will RESTRICT grounding the “mixer” = the ISC can’t perform its job, CORRECTLY!
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Its final destination…the ISC GROUND is received via the “NOSE SWITCH”!
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You need to build a 4-pin round connector to test and adjust the ISC/MPS.
This one was built from a ABS connector but many imports use a 4 pin round connector to build with.

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THOROUGHLY…INSPECT YOUR CONNECTORS!  Although they SEEM to be well-sealed..IT AIN’T! Rolling Eyes CORROSION HAPPENS! Crying or Very Sad
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These are the tools you would need: The adapter harness, A 6 volt battery, an AVOM & DVOM (not pictured)

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YOU MUST: slacken the throttle cable (none attached here) to make sure the tension of the cable is not holding the butteryfly open.

You are going to cycle the motor…extend & retract the motor with the 6 volt battery to make sure it works SMOOTHLY and RETRACT it all the way IN!Image
Reverseing the polarity changes from extend to retract. DO NOT use 12 volts to do this! Rolling Eyes If yours is jamming-up (not smooth operation) Professor Quest will sell you a ISC/MPS for $65.

Note: 84/85 was only a ISC. It didn’t have the MPS (motor postion sensor)
until 86 or 87 models.
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ALWAYS calibrate your AVOM to ZERO RESISTANCE (knob on the side, usually) cause you NEED to do a CONTINUITY TEST FIRST!

PAY CLOSE ATTENTION HERE! The intake manifold has it’s own 10 gauge ground wire (ground #3) that COMES FROM GROUND #11 ring eyelet just BELOW YOUR BATTERY!

It is a KNOWN HIGH FAILURE of that ground circut (including your negative battery cable) and the ISC/MPS is FREAKING OUT due to a poor ground!

The VERY FIRST topic of the SOS covers the GROUND SYSTEM!
http://sosmanuals.minagera.org/battery-neggrounds-ign-coil/
You need to understand your Starquest!
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Ground the black AVOM wire to the TB. Use the RED AVOM wire to the RED wire. As demonstrated here, there is NO CONTINUITY here. WHY

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WHY is: Cause somebody turned-that-screw-in REMOVING THE ISC “NOSE SWITCH” FROM TOUCHING THE THROTTLE LINKAGE! Rolling Eyes

Early cars didn’t even have that screw. It was INTRODUCED to prevent the throttle butterfly LOCKING INTO THE HOUSING.

This screw is refereed to the “Fixed SAS”. It is a FAILSAFE screw and NEEDS to be returned to it’s original position.

Failure to follow this EQUATION…you car could run like crap, erratic idle searching, etc etc.

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Now that I backed-down the screw (removed rubber boot for better viewing) the AVOM indicates continuity is restored.

The FSM says “one turn” but is that a 360* turn? NO! Should have a gap about .010-.015″.
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As indicated with rubber boot removed for better viewing. Wink
The FSM suggest do this to REPLACE the TPS. However, if your TB wasn’t JACKED WITH (screws tampered with) this would be unnecessary.

Example: If your throttle cable was EVER removed (rebuilding a TB) you MIGHT have removed the SLACK from the cable without realizing this. Meaning: the CABLE is holding open the BUTTERFLY…NOT THE “Fixed SAS” screw. PAY ATTENTION TO DETAILS! Embarassed

But…If you give it TOO MUCH SLACK, you can’t reach WOT! (wide-open throttle) buttertyfly position!

A FAULTY MPS..(motor position sensor) which is a mini-TPS can create the ISC to “search” for idle speed!

READ…and understand this! Rolling Eyes
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The diagram (on the left) does NOT show being connected via the adapter harness to BOTH the ISC & MPS. HOWEVER….READ INSTRUCTIONS 1-4!

And….. Rolling Eyes the WARNING just below it! The ADAPTER HARNESS is attached to BOTH the ISC & MPS….BUT NOT INTO THE MAIN ECU HARNESS!!! That could DAMAGE THE ECU!! Shocked

This is about SEPARATING the test harness from the ECU wiring connector without sending 6 volts of voltage to the ECU! Rolling EyesImage

Testing OHM values, as indicated in the FSM pages, 4-6 ohms.
Note: Both connectors are installed. If not…you may see 2 ohms

FAILURE to “SWEEP-TEST” with a AVOM… Rolling Eyes
you have NO CLUE of what you are doing and how your engine
is gonna REACT! This fucks with your AFR! Shocked

If over 80k miles on the TPS… Rolling Eyes they are typically TRASHED!
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More DETAILED wire information.

Checking AND adjusting the TPS is covered under a different SOS topic.
Here is the link to that topic.

 

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It does NOT have to leak VACUUM or FUEL to be a problem!
HUMIDITY, WATER reaches the FPR and RUST…attaches itself to the DIAPHRAGM! Shocked

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ETHANOL….DEHYDRATES THE DIAPHRAGM making the FPR operate NON-CONSISTENT! Now….add-in a lil’ RUST! Rolling Eyes

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Is that ALL of it? NO! Rolling Eyes If you DID NOT stick with the Mitsu OEM HIGH PRESSURE FILTER (in your engine bay) IF…you installed a AFTERMARKET filter then odds are IT WAS NOT PLATED LIKE MITSU DID! Crying or Very Sad

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Here’s another one….MADE IN CHINA! Rolling Eyes Saving WHAT? $5

When emission parts have been removed….

PAY ATTENION HERE! Rolling Eyes This SINGLE nipple is full time manifold vacuum/boost.

It is the SORCE for the HVAC unit (heater, defrost, a/c) and the crusie control too.
In the right-rear corner of the engine bay you’ll note lil’ white CHECK VALVES (one way valves) so BOOST…can’t reach those accessories.

1. PORTED vacuum (only sees vacuum after the butterfly opens, used just for the Dizzy ONLY) (also #1 controls the EGR as well. After the engine warms up and the ECU turns off the solenoid, the EGR opening rate is directly controlled by the amount of vacuum that port gets.)

3. MANIFOLD vacuum (full time vacuum but is restricted to about 12 Hg)

2. MANIFOLD vacuum (full time…no restriction, BOV ok))

4. MANIFOLD vacuum (full time, no restrictions, HVAC controls and cruise control, BOV ok (known to be blown-off from boost)

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The VACUUM RESERVOIR PURPOSE (not pictured here) is to SUSTAINS a longer duration of the NEEDED vacuum to operate the cruise control until the ELECTRIC VACUUM PUMP (not picture here) turns itself on while PULLING A LONG HILL WHILE UNDER BOOST!

The VACUUM that is already in the HVAC unit is NOT GONNA BLEED-OFF because the one-way-valves ain’t gonna allow that!

Meaning…if you have removed the cruise control…you need a vacuum RESERVOIR like a kick-n-da-nuts! Same with the electric vacuum pump and it’s relay and it’s SWITCH! (located in the RR corner of the engine bay)

Anybody that states otherwise….is a IDIOT, or just haven’t done it themselves. Rolling Eyes

I live at nearly 6,000ft ASL! I am DOWN 6″ of vacuum ALREADY!
(read just below the blue highlighted area)
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Btw…that vacuum hose is NOTORIOUS to have been BLOWN-OFF that nipple because BOOST pushes it off! Hence…..flare it as it is shown in the pic. FIXED!

Port #5: Used in A/T applications, full time manifold vacuum.
Port #6: water coolant leaving the head to heater core & TB.
Port #7: Large manifold vacuum going to the brake booster. (known to dry rot that special hose! Rolling Eyes )
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Special, brass fittings for use of a BOV & wastegate.
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It continues to a port for a stand-alone, vacuum/boost gauge then another port, w/ a one-way valve for the HVAC use.
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Some people claim to take “good-care” of their car… Rolling Eyes
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It wasn’t even positioned correctly!
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WOW! This will be a tough one! Rolling Eyes
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The PREMIUM STANT was $7.90! Shocked (non premium a little cheaper)
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