Ignitor Box Mod 88/89 only..ECU upgrade for pre-88

[norats]

WARNING 1988-89 only!

 

The igniter box on stick-shift cars can be tricked into allowing 10.5 psi boost by moving one wire - basically, the wire that determines if the car has an automatic or manual transmission.

 

Step by step:

 

1) with the engine off, key out of the ignition, unplug the battery.

 

2) Locate the 2 millimeter thick black+yellow wire (black wire with a yellow stripe) at the igniter module near the ignition coil. Cut the wire near the connector - on the igniter side of the connector.

 

3) connect the cut wire from the igniter (NOT the stub remaining in the wiring harness side) to the 1.25 millimeter thick red wire on the igniter connector.

 

4) tape off the stub wire from the black+yellow wire in the connector since this wire continues to the ECU.

 

5) re-connect the battery and go for a test drive.

 

The boost should build to 10.5 psi or so at all RPMs now. If not, there is something is wrong with the igniter module, solenoid, knock sensor, or the turbo waste gate. The boost will still drop to 7 psi when knock is detected.

 

One extra bit to add to that post... the wires may CHANGE COLORS as they go through the connectors... on some 88/89 igniters the black+yellow wire turns into a lime green wire between the igniter box and the connector. This lime green one is the wire to cut. The end coming from the igniter is then spliced into the other wire. The end poking out of the connector is taped.

 

You can do this mod if:

 

1. your igniter box is a metal box (87 and earlier cars had a small plastic igniter box)

 

2. You have the 3 port waste gate as Hendu described. It should have two vacuum hoses running to an electrical vacuum switching valve attached to the top of the air filter box.

 

3. You have a 5 speed, not automatic tranny. Autos come with this mod already done.

 

Courtesy: Mike C   Thanks Mike!

[lionkilla]

I'm about to upgrade my '87 (stick) to an 88-89 ECU. Could I change the spark box @ the same time & use this mod?  Anyone tried this?

 

thx,

 

s  

[mikec]

The 88-later ECU will allow the car to handle the increased boost (the 87 probably will hit fuel cut at 10.5 psi) but otherwise isn't important.  When you add the 88+later ignitor though you'll also need the 88-later style 3-port turbo wastegate actuator and the little electric solenoid on the air filter lid.  That's a lot of work really; the mod is intended for people starting with 88+later cars as a quick and free mod.  For those with 87s, the better option is to swap in the 88-later ECU to get around the boost cut, and then to add a manual boost controller to raise the boost limit using the stock 87 turbo wastegate actuator.  With a boost controller, you can dial the boost beyond the 10.5 psi of the 88-later cars - as long as your fuel system can keep up (good pump, filter, injectors, etc.)

 

mike c.

[jeff]

so is a auto knock box a bolt in upgrade to a 5 speed car. can i install a 88 box in my 87?

[mikec]

The ignitor boxes are the same for 88-later cars, regardless of transmission type.  The wiring harness of the car tells the ignitor box what type of tranny is installed; my mod cheats this wire on the stick-shift cars to make the ignitor think the car has an automatic tranny which removes the below 4000 RPM boost limit on the stick-shift 88-later cars.  You could adapt an 88-later ignitor to your 87 but it won't make any difference on your boost levels... boost is controlled by the wastegate actuator.  Unless you install the 88-later 3-port wastegate actuator, your 87 turbo is stuck at 7.5 psi no matter what ECU or ignitor you have in the car.  The two new ports on the 88-later 3-port wastegate actuator are the "switch" that the 88-later ignitors use to select between low (7.5 psi) and high (10.5) boost on those cars.  But it's still the wastegate actuator's job to actually control the max boost.  That's why I recommend using some sort of manual boost controller (Dawes Device is a good, inexpensive one) on the 83-87 cars instead.  It works with the stock wastegate actuator to let you dial the max boost above the stock limit.  Yes, you COULD put in the 88-later ignitor, control solenoid, and 3-port wastegate to go from 7.5 psi to 10.5 psi boost on your 87... but that's a lot of work for only 3 psi increase.  With a simple manual boost controller, you'll do 10% of the work AND you'll be able to go above 10.5psi as well.  Assuming the rest of your car can take it: fuel system can keep up, 88-later ECU which can compute the fuel needed for boost levels above 7.5psi, etc.

 

It's a common misconception that the ECU controls the max boost... no.  The wastegate actuator does this. 83-87 cars have one upper limit set by the actuator.  Via trickery, the 88-later cars get two boost limits by incorporating two actuators into one body - and the ignitor+solenoid duo select which one is active.  The ECU has absolutely NO INPUT to this.  So why change the ECU from an 87 style to the 88-later style?  Well, the original StarQuest ECU was designed with fuel curves appropriate to the factory set max boost levels.  When you crank up the boost via a manual boost control (Dawes Device or whatever) or by swapping in the 88-later 3-port actuator, you will probably go beyond the range the ECU can handle - i.e. you will be stuffing more air into the engine than the ECU ever expected and the tables/equations in the fuel map get confused... ergo the fuel supply goes off and you get the famous "fuel cut."  The 88-later ECUs have much smarter software tables/equations that do NOT get confused until much much higher boost levels - anywhere from 17psi to beyond 23psi depending on which iteration you get.  Consider this (somewhat lame) analogy:  you are a home handyman and have just bought a home handyman style tape measure from your local Home Depot, Lowes, whatever.  Call it the "87" style tape measure.  Odds are it can read 8 to 12 feet max - pretend that means 8 to 12 psi instead.  For most home projects, that works just fine and dandy - the tape measure is longer than any board you're likely to measure.  But now you decide to work on some big and fancy project - such as a new hand railing around that 15 foot by 15 foot patio.  Now you need to measure really long boards at the home center to find one that is at least 15 feet long... your "87" style tape measure just doesn't go that far.  You need the Professional's "88" style tape measure that can handle boards 23 feet long.  But just because you now have the "88" style tape measure doesn't mean your patio suddenly expands from 7.5feet to 10.5feet or whatever... ya gotta do some work to get there first.

 

Having said all that, there is ONE reason to swap in the 88-later style ignitors into an 87 (or any car with the plastic box ignitor for that matter): the metal box ignitors seem to be FAR MORE RELIABLE.  The plastic box ignitors fail 99% of the time by having an internal connection from the case mounted connector to the circuit board bust...  usually the ignitor works fine when the car is cold, then after the ignitor gets warmed up by the engine it craps out...  and as time goes on it craps out faster and faster (cooler and cooler temps) until it one day quits working altogether.  The 88-later ignitors don't seem to do this.  So, if your 87 box is showing signs of dying, it may be worth it to replace it with the more reliable 88-later metal box ignitor.  To do this, you just need to match up your existing 8 wires on the factory wiring harness to the 87s ignitor to the like-colored wires on the 10 pin harness of the 88 ignitor.  Leave the 2 "extra" wires disconnected - these are the wires for the solenoid which is useless (unless you also add the 88-later 3-port wastegate but there's no good reason to do that compared to the Dawes Device, right?).

 

mike c.

[jeff]

good reply Mike.my idea was to do just what you mentioned and get all 89 stuff for my 87(three port wastegate,switch on air can lid etc.) right now i just have a 89 ecu and 87 knock box.and my wastegate actuator shortened. my car pegs 14psi and never falls on its face. i have one 88 eco that i plug in and it will make the boost guage dance all over like crazy.....

[89Bluequest]

ok I tried this and was wondering is the ignitor box the large gold box next to the coil? I did what you said and the car ran like s*** and started to try to have an electrical fire. I located the right color wires and connected them and I was pretty scared after thinking I may have caused an electrical nightmare. Thank god it's fine. I think I will just wait until I get my MBC. Later

 

Mark

[chubacca_tsi]

Can i just use an ignitor box off an automatic car.

[mikec]

As I stated in a previous post... the ignitors (and ECU) are identical between 5-speed an automatic tranny cars for 88/89 model years.  The wiring harness is different depending on tranny type and it's the harness that "selects" the mode of the ignitor and ECU.  Swapping your ignitor with one from an automatic won't do a thing.  My ignitor box mod modifies the harness at the ignitor box to trick the ignitor into thinking the car has an automatic.  The ECU still sees stick shift though.

 

mike c.

[chubacca_tsi]

I got an auto starquest but im converting to 5-speed do I still got to do the ignitor box mod. thanks fo help

[jeff]

read Mikes post in answer to my question. you will see...

[85Quest]

Would I be able to take an 88 ignitor box and put it on my 85 Quest? Are the wires the same that go into it? Difficulty? Worth it?

 

"Sarge"

[FontanaTSI]

Ok, I did the ignitor mod but am I suppose to do something to the wastegate as well? I have an '88 with a TurboXS MBC but It doesnt seem to allow me to change the boost level. I also shortened the actuator rod and I'm pretty sure that the mbc is installed correctly ???. Please help!

 

Jerry

[Redliner777]

Doesn't the 88-89 setup cut the boost down to 7.5 if it detects knock? and wouldn't this be a good reason to swap in the 88-89 actuator and all?

[Chris.RO]

 I need more details how to trick ECU for higher boost,like colour for wire,exect location on wich conector and also on the car.

 I DON"T HAVE COMPLETE WIREING FOR STARION 2.6TURBO INTERCOOLER european one.

 DOES ANYBODY HAVE THIS???????????WOULD BE NICE X-MAS PRESENT FOR ME!

[mikec]

 I need more details how to trick ECU for higher boost,like colour for wire,exect location on wich conector and also on the car.

 I DON"T HAVE COMPLETE WIREING FOR STARION 2.6TURBO INTERCOOLER european one.

 DOES ANYBODY HAVE THIS???????????WOULD BE NICE X-MAS PRESENT FOR ME!

It's NOT THE ECU that controls max boost pressure!  The ignitor (electronic ignition module, aka "knock box" - the large gold box mounted to the fender near the ignition coil) controls the 7.5psi/10.5psi solenoid.  The actual boost level is controlled by the wastegate actuator on the turbo itself; under control of this solenoid.  The ECU may "go stupid" if you increase the boost pressure up too much; once the boost pressure exceeds the expected values inside the ECU tables it totally screws up the fuel calculations.  But the ECU itself DOES NOT CONTROL THE BOOST LIMIT on StarQuests.  The 88-later ECUs have larger data tables - the tables extend to higher boost values - which is why those cars tolerate bigger boost numbers than the earlier cars.

 

mike c.

[Chris.RO]

My car is '89 turbo interc Starion,but knock box is black plastic and one port waste gate actuator(inlet presure is controling it only, no solenoid).If I change the knock box with the metal one from a Conquest what modif shold I do (wireing)and will this be an improvement?Thanks.

[mikec]

The 88-later metal box ignitors tend to be more reliable - they don't have that weak internal connection that plagues the black plastic ignitors.  There is no performance gain though.  If you want a better ignition, you'd be better off going to the MSD ignition or something similar.

 

If you really want to swap to the metal box ignitor, you'll see it has 10 pins compared to 8 pins on the plastic ignitors.  Try to get both the metal box ignitor AND some of the wiring harness from the donor car - say 6 inches worth.  Then you just match up wire colors from your 8 wire harness to 8 of the 10 wires in the new harness.  The other two wires control the solenoid.  There's no reason to add the solenoid stuff.  A manual boost controller is a simpler, cheaper way to get more boost than switching to the 88-later style solenoid & 3-port turbo wastegate actuator system.   The two leftover wires should be end wires on the 10 pin connector; the other 8 wires line up one for one actually.

 

mike c.

[JAinsworth]

Copied from another topic, from Shelby:

 

ok i just did this to my g-sons 86

do your self a favor and get the harness out of an 87-89 car,, 88/89 ecu, and igniter box, 1g mass

swap i out the harness, install the air mass,and igniter box,, swap the injs for the 87-89 pri sec, set up,,, you'l need to run an aditional power feed for the keep alive memory funtion and connect a few wires to the B38 connector,, the stock boost gauge will no longer work,,you need a 5 volt power feed for it and the ecu don't have any extra power feeds , but an after market one will work fine,,

if you have any questions about any thing spacificly let me know i'l try to help you figure it out

 

we did it in one afternoon and drove it that evening :wink:

 

ok no fender remove or any thing like that , and yes any thing this worn out old man can do i'm sure any of you can do just as fast or faster

the only real work to swaping the harness is droping the heater fans assy , it's one modual holding it,, and two bolts one nut and a clamping band where the air goes into the rest of the system,, it'l come down easily but going back up can be a pain,, try grinding off 1/2"

of the alignment post on the fire wall stud protrusion,, this wil aid greatly when puting the houseing back up in place ,,once you look at it you'l see what i mean ,just don't over tighten the nut when you put it back on ,,you have one 12mm bolt on the rigth side going into the pillor post, one top right into upper dash and one 12mm nut right above the band clamp going to the fire wall ,power wire connector and thats it ,

you can see most all of it with the glove box remove'd ,,ONE thing and probly the most important thing to replaceing the harness,,tie a cord to the old harness and alow it to be pull'd into the engine compartment so it can be use'd to pull the new harness back into the cars interior,,use a cord or small rope not a string

 

waste gate solonid , remove'd,, igniter ,, swap'd for 88/89 metal unit or yr the harness matchs ,, sence the w/g solonid is gone the 2 wire on the igniter plug are no longer use'd

awnce the eng is out, so should the rad be geting rod'd unles sit was just done, eather way the rad gets unbolt'd and lean'd towards the engine

to remove the harness routeing behind it ,,no conections to the battery or any power wires are at the battery, altho some of the harness may be ran under or behind some of the vehicle harness at that corner ,with the batt and battery box out you'l have no trouble undoing the harness and runing the new one

 

now the 86 does not have an MPS signal on the isc ,, to use that you'l need the isc from one of 87 -89 cars