ecu fault code 66

[Jayman68]

got a continuing problem with error code 66 keeping on appearing. Legacy series 2 1997 ej20tt obviously.

Error code calls up low boost primary turbo, or excessive overboost, also something about a voltage difference?

Pit of a pain, as it keeps going into limp mode. All that has happened is that i have replaced motor recently. All bolt on accessories from previous setup were retained, and i didnt have the problem earlier.

Both turbos have been replaced and a couple of air leaks in the vaccuum lines. Any body got any ideas?

[Robbks]

ahhh, i remember this the old Code66

1) do you have a boost gauge? If not buy one.
2) are you 100000000% sure that all the vac lines are in the right spot?
3) when you replaced them, did you check for any restrictor pills in the lines?
4) what are you using for boost control?
5) what turbo's are on your car now?

Another good idea for you is to wire two switches onto the ECU reset connectors and mount them in a convenient place
you WILL need to reset your ECU often.

Steps to fix the problem

1) temporarily remove all boost control (disconnect) and simply connect the wastegate actuator (Primary turbo) to the compressor outlet nipple (boost source)
Drive and test to see what happens, report back here
2) one by one go over EVERY Vacuum line and solenoid in the system and within the BBoD
remove them one at a time and clean them with UEC or carbie cleaner
including the hard metal lines and teh caps of the solenoids
replace any broken or cracked hoses or fittings

3) you want to remove all the solenoids and vacuum lines that operate the top port on the ECV
trace them back through the BBoD and it should end up leading back to one of the connections on the bottom of the TMIC
remove it all and block up the (Clean) solenoids (should be 2 now unused) by looping a piece of vac line from the inlet to outlet

Now, There is a hose that goes from the Secondary Turbo Bypass Valve (plastic "U" shaped thingy) near the secondary turbo back to the BBoD
you want to put a tee piece in this hose and connect the tee piece to the top port of the ECV
this should solve most of the problems with it either blowing open too early or staying open too long
you can adjust the amount of pre-spool on the secondary by lengthening or shortening the ECV actuator rod
this process is to undo the locknut and with the car idling
lengthen the rod until you hear the ECV start to rattle, then tighten it about 1-2 turns
you may need to finely adjust it longer if you get no pre-spool, or shorter if you get too much and it won;t close properly when coming back to single turbo operation

try this, then get back to us

also check the operation of the BOV, secondary BPV and Primary wastegate

If you can't identify these items. don;t touch a thing,. you'll only fark it up worse

[Jayman68]

Okay. Some answers. Q1. Yes I do run boost gauge. Q2 yes positive all in correct order. Q3 restrictor pills WTH? Q4 and Q5 both factory.

The rest will have to wait for a little bit for further report back, as car is in panel shop for beautification at the minute. Will report back approx 4 - 5 weeks.

[Robbks]

ok, forget the factory boost control, it's rubbish
a good MBC will do the job nicely

and i meant which pair of factory turbo's?
VF16/17, 18/19, 26/27, 25/27, 32/33..?

[AWDDave]

Okay. Some answers. Q1. Yes I do run boost gauge. Q2 yes positive all in correct order. Q3 restrictor pills WTH? Q4 and Q5 both factory.

The rest will have to wait for a little bit for further report back, as car is in panel shop for beautification at the minute. Will report back approx 4 - 5 weeks.

The restrictor pills are the little plastic jobies that go inside the hose to restrict the hose down to a smaller sizing... means that less vacuum will flow through them due to the restriction. From memory, there were 2-3 of these (correct me if I'm wrong Robbks)

[Jayman68]

Bit of an update here. Put motor in for full machining works and replacement of factory internals with custom parts. Now received all parts and need to assemble. Hoping this solves the problem. Crankshaft Rebuilders performing all machine works, so best quality workshop undertaken works.

Forged rods and pistons. Custom cam grind, will post specs in next few days for those interested. Fully balanced, blueprinted, and cc'd heads and flow matched porting. Will need remapping of factory Ecu and other components once running. Assume high flow injectors and exhaust at least. HPW to do all dyno and remapping works, believe they have expeience and expertise to complete this. Hoping to have running by Easter. Built for 24PSI, should be reliable horsepower without major strain to driveline.

Still working on brake upgrade. GC8 WRX STi rear rotors, calipers and hubs ready to go, just need fronts.

[Dropz]

Sounds like it'll be a weapon, do you have a members ride thread with photos? If not, make one please

Are you keeping the TT setup or going to a big single turbo?