Repairing the Taurus: Lower Intake

This is the third, but pos­si­bly not final install­ment of our 2002 Tau­rus repair adven­ture.  Here our goal is to get at the gas­kets between the low­er intake man­i­fold and the cylin­der heads.  Poor run­ning at idle often indi­cates vac­u­um leaks and these gas­kets are the last cul­prits we can point to.  They’re also the most dif­fi­cult of the intake gas­kets to reach.  Our inter­net research tells us that the low­er intake man­i­fold gas­kets are a com­mon prob­lem on the Durat­e­ch engine made by Ford.

One note: if you’re going to remove the injec­tors, it’s best to shut off the gas sup­ply and the eas­i­est way to do that is to unplug the rollover switch which is near the trunk light on the pas­sen­ger side wall of the trunk.  It’s also worth not­ing that releav­ing the pres­sure of the fuel sys­tem is eas­i­est done by run­ning the engine — so you’ll want to have done this before com­plet­ing even the first step.  How­ev­er, if your fuel rail or injec­tors are already leak­ing, shut­ting off the fuel sup­ply is suf­fi­cient as the pres­sure will run out.  The fuel sys­tem is under about 40 PSI pres­sure and gaso­line is nasty stuff.  Nota Bene!

Taurus Engine In One Piece

Tau­rus Engine In One Piece

Air for the engine comes in through the fil­ter (a square box right of the engine … just out­side of this pic­ture).  The MAF sen­sor is in the round tube lead­ing to the throt­tle body (where the light is point­ed, rough­ly, in the pic­ture).  Then the air is dis­trib­uted for­ward by the six ducts that are rough­ly in the mid­dle of the pic­ture.  We took this whole assem­bly off in the upper intake plenum and spark plug post.  This post assumes you’ve removed the upper intake plenum as described in that post.

Taurus Duratech Lower Intake

Tau­rus Durat­e­ch Low­er Intake

For some rea­son, Ford decid­ed to split the upper and low­er intake.  It may be a nod to the dif­fi­cul­ty of plac­ing the intake back on the engine or it may be sim­ply required by the man­ner in which the injec­tors and fuel rail are fas­tened to the low­er intake.  In the pic­ture you can see the two halves of the low­er intake in place.  The injec­tors and the fuel rail have been removed from this pic­ture.  The gas­kets we’re after are on the bot­tom of these two plas­tic bits.

Taurus Lower Intake Covered

Tau­rus Low­er Intake Cov­ered for Safety

Remov­ing the fuel rail is 8 bolts — 4 short and 4 long.  The long bolts go through the low­er intake into the cylin­der head and the short bolts go into a cap­tured nut on the inner side of the low­er intake.  The next step is a lit­tle scary the first time: you pull up on the right end (the left end of the fuel rail attach­es to the gas sup­ply) of the fuel rail hard enough to either pull it from the injec­tors or pull the injec­tors out with it, or a lit­tle bit of both.  In the pic­ture, we’ve cov­ered the low­er intake man­i­fold with two rags to pre­vent lit­tle pieces from falling into the engine.  This is par­tic­u­lar­ly impor­tant for parts like the O‑rings on both ends of the injec­tors.  The amount of force required to remove the fuel rail is sur­pris­ing­ly large until you strug­gle to put it back in — it’s one of those design choic­es that make you want to force car design engi­neers to work on their own prod­ucts.  Once you have removed the 8 bolts, there is noth­ing else hold­ing that rail but friction.

At this point, only two bolts (each) are hold­ing the low­er intake in place.  Removal and replace­ment is easy.  As before, we used a lit­tle grease to stick the gas­kets into their chan­nel as the gas­kets have a propen­si­ty to fall out when we’re try­ing to put the intake back in place.  It is always very impor­tant to make sure you don’t drop any­thing (like the gas­kets) down the intake.

It’s worth spend­ing a lit­tle time talk­ing about the fuel rail.  I had replaced it 3 times before we stum­bled upon the method we’ll talk about to replace the fuel rail and each time the rail leaked around the injec­tors.  At one point, I thought that we had dam­aged the fuel rail and called around to find the cost of a new one.  Truth was, nobody stocked or could even order it.  The Ford deal­er said it was con­sid­ered a “vin­tage” part and would need to be ordered from that divi­sion.  Since nobody in the after­mar­ket makes the part, I have to assume that fail­ure is very uncom­mon.  If you encounter a leak, pull it off and try again — it’s not the fuel rail.  It may, how­ev­er, be a bad injec­tor — but there’s only a few places they can leak from.  In one instal­la­tion, we did destroy some O‑rings.  It’s a good idea to have a new set of O‑rings ready for this job.

Taurus Duratech Injectors

Tau­rus Durat­e­ch Injectors

Obvi­ous­ly, if you have a bad injec­tor (you’re doing this repair due to a code that indi­cates a bad injec­tor in a cer­tain cylin­der), you would replace it now.  If you sus­pect a bad injec­tor, rotat­ing them to dif­fer­ent posi­tions it pos­si­ble.  Our set of injec­tors do have dif­fer­ent codes on them, but since we have 3 of one code, 2 of anoth­er and one of a third code, I doubt there is any spe­cif­ic place­ment for them.

The prob­lem we’re going to have replac­ing the fuel rail is that half the injec­tors slope for­ward and half of them slope aft.  They cross each oth­er before reach­ing the “hats” that they seat into on the fuel rail.  From some research and a video online, I had been pre­pare to “work” the rail on from the fuel line end (left) to the right end.  I nev­er actu­al­ly got this tech­ni­cal­ly to work.  The pro­ce­dure is to install the injec­tors (note that they’re keyed to ensure prop­er ori­en­ta­tion) and then work on the rail one injec­tor at a time.

After three fail­ures of this method, we talked about insert­ing the injec­tors into the rail and then push­ing them into the intake.  On engines with 4 cylin­ders, sev­er­al sites and videos advised this was eas­i­er.  It’s not pos­si­ble with this engine as the injec­tors cross.  In the end, we set­tled on a com­pro­mise that worked well.  We insert­ed the injec­tors into the intake only par­tial­ly — such that the key was lev­el with the top of the intake sock­et.  We then were able to use the increased play in the loose injec­tors to work the rail onto them.  With all injec­tors insert­ed into the rail, we then pushed, wig­gled and worked the whole result until the injec­tors were prop­er­ly seat­ed into the intake holes.  Again here, watch the injec­tor key tabs — they need to line up with the low­er intake holes properly.

Anoth­er thing to watch for is the O‑rings.  We found they would some­times bulge below the “hats” of the fuel rail.  We used a slot screw­driv­er to coax the O‑rings up under the “hats” as we were work­ing the whole thing down.  On one failed instal­la­tion, not doing this result­ed in some of the O‑rings being cut down on one side by the metail of the “hat.”

Since we had sev­er­al failed attempts we iden­ti­fied an ear­li­er way to know if we had done things right by the injec­tors.  Rather than find­ing a leak after every­thing was rein­stalled on the engine, we again deployed the rags (to catch leak­ing gaso­line) and recon­nect­ed the rollover switch in the trunk.  Then we switched the igni­tion to on (do not try to start the engine here).  This will pres­sur­ize the fuel rail and show any major leaks imme­di­ate­ly.  If you dis­cov­er a leak, dis­con­nect the rollover switch again, wait for the pres­sure to dis­si­pate out your leak, remove the fuel rail and start again.

Last­ly, you’re going to replace all the parts of the upper intake plenum in the man­ner described in the oth­er arti­cle.  If the engine runs rough at idle, you still have a leak some­where — a hose you for­got or a gas­ket that fell out.  I’m pret­ty sure I could do this repair eas­i­ly the next time, but I had to take sev­er­al runs at each of these prob­lems before I got it com­plete­ly correct.

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