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Codes

Pulled codes on my 86 5.0 SEFI and got a #94 and #33.  Is the EGR code more likely the valve itself or could it be the vacuum solenoid?  If I have the car warmed up and I take the vacuum line off the EGR valve I can feel a very slight vacuum on the end of the line.  It feels like it's trying to pull in air but it's sputtering a bit.  As for the thermactor code, haven't checked to see if there is air flow in the line yet, but i'm just wondering if that code most likely means the air pump is bad.  Any input would be helpful.  Thanks!  :bowdown:

Re: Codes

Reply #1 –
this is gonna be tricky to find and i suggest you start off with spraying carb cleaner on various vac related fittings.  your probably dealing with a slight leak or cracked line that ties in the TAN or GREEN ports.  It might be possible that a cracked BLACK line is also the cause. The TAN and Black work together to coordinate eec signals so the air pump will operate. The green works in the egr system.  ALL three together as a team work out various delay/purge valve so as to completly confuss you beyond your wildest dreams. Other things to consider would be to manually disconnect the beginning and the end of each color vac line.
red
tan
pink
black
green

then,,
plug off one end and put suction on the other.


i have several solenoids behind my coolant fill tank and i found that the main (red) line that plugged to the base of all these solenoids (long tan plastic tube) had a crack in it.

now a days,, none of the solenoids are used because i have no emission devices operating.
I hope this link helps you out......http://www.therangerstation.com/Magazine/Summer2003/VacuumLeaks.htm


Im collecting some data in my Engine/Emissions-Diagonsis Shop Manual for resistance values of various emission solinoids in our cars so i can post them later on.

I have'nt gotten too far yet but hope this might help

EGR/emissions solenoids (codes)
Dual Thermactor Air control Solenoid Valve- both should read 51-108 ohms
EGR Solenoid Vacuum Valve Assembly - both should read 32 to 64 ohms
EGR Valve Position Sensor EVP-?
Electronic Vacuum Regulator EVR-?

a couple things i noticed are the like the Dual Thermactor Air Control Solenoid Valve.... They both work together and one solenoid happens to be the """""VENT VALVE"""""""""
I wonder if that vent *screen* gets dirty and if so is id cleanable.  The venting system is a very very important part of the egr system and if its closed,, it trickles backwards and effects devices within the "vac delay valve systems" as well as air pump operation.

These are many reasons i decided to get rid of this stuff and tweek my timing, remove my injector screens,removed my egr, placed on a larger TBI and adjust my FPR. 
Ive drastically reduced the odds of possible vac leaks as well as other piece parts that might leave me sitting.

the vac opperation is so so very complicated.  Its something id rather not put in my memory because there is so much going on.

Re: Codes

Reply #2 –
The 33 code indicates there is not enough flow during the test. The 94 code is for an inoperative Thermactor system on the right side.

EGR is never active at idle. If you are seeing vacuum at idle, your vacuum solenoids could be bad. I'd test the EGR valve first since it's easier than the solenoids. Hook up a vacuum pump to the EGR valve and pull vacuum to see if it holds. If it does not, replace the valve. Probe the EGR position sensor (orange/black) and pull a vacuum up to 10 in. The resistance should change smoothly and stop moving ~4 in. If this checks out, it is time to check the solenoids.

I pull the solenoids off the car to make it easier to test. Follow the vacuum line from the EGR valve to find out which solenoids are EGR related (Not sure of the location for 5.0s). There should be 5. TAB, TAD, EGRC, EGRV, EHC. This page gives you a good overview of Ford sonic EGR. The EGRV is normally open. The EGRC is normally closed. Apply vacuum (or blow through them) without applying a voltage to see if they do/don't pass air. Next, apply 12V to the appropriate terminal and apply vacuum/blow to see if the solenoids are operating correctly. I ran wires from a 12V riding lawnmower battery to test my solenoids.

As jcassity suggested, it could be a broken vacuum hose, but if you felt vacuum, this wouldn't be the case.

The 94 is most likely a bad oxygen sensor. A 44/94 together normally indicates a bad AIR pump. Unless the AIR line going into the left head is obstructed, there is no way for one side to fail and the other to pass. EEC-IV tests the Thermactor system by directing air into the exhaust manifolds and seeing if the O2 sensors go lean.

Everything I've said and an order of magnitude more is in Probt's books (1) (2). They will pay for themselves the first time you use them and give you a higher understanding of how the EEC works, in a top-level systems view.

Re: Codes

Reply #3 –
Quote from: JeremyB
EGR is never active at idle.

except during warm up???  correct?

His egr having vac at idle was also a concern of mine but i must have distracted myself by rambling on.


btw,, i like the way you troubleshoot.
Not to give you any ideas or anything but i have found that a computer powersupply makes for a great garage use multi power output device.

mine is a 500watt power supply that had a blow fuse.  I soldered in a fuse holder and installed a car fuse like what we have on our fuse boxes. the fuse holder is on the outside of the power supply case.

its also my chordless tool charger,, 12vdc .8a output

Re: Codes

Reply #4 –
Quote from: jcassity
except during warm up???  correct?

EGR is only applied during cruise and light acceleration when in closed loop. My car ('87 3.8L) will begin EGR operation ~2-3 minutes after starting.

Different processors have different strategies of going into closed loop. Some wait a set time, others wait for a certain ECT, other wait for a certain number of cross-counts (O2 going above/below .45V). To the best of my knowledge, the A9x processors do not rely on ECT to go into closed loop. (It is an often repeated myth)

Re: Codes

Reply #5 –
something that is never mentioned

when our cars were rather new, there was the EGR recal, where they intalled a "delay" valve, basically slowed the opening og the EGR valve up, so it wouldnt send a "shock" of gasses into the intake track

that could cause a code 33
It's Gumby's fault.

Re: Codes

Reply #6 –
Quote from: Tbird232ci
something that is never mentioned

when our cars were rather new, there was the EGR recal, where they intalled a "delay" valve, basically slowed the opening og the EGR valve up, so it wouldnt send a "shock" of gasses into the intake track

that could cause a code 33


The EGR recall was just on the 2.3 Turbos and maybe on the 3.8(dunno never owned one), but definatly not on the 5.0.

Re: Codes

Reply #7 –
ill double check on the cars, because i could swear they all got it
It's Gumby's fault.

Re: Codes

Reply #8 –
yeah,, they put a delay valve on my car,,pass side,, way back when it was kind of new.