Closed Loop Knock Control for Haltech ECUs
 

It sounds a little sales pitchy but it has all the info in it:

Yes! Finally closed loop knock control for Haltech ECU’s! Not to mention simultaneously pulling BOTH leading and trailing for rotary applications!

This means you can have the ecu automatically pull timing (1 to 8 degrees) when the engine begins to ping or detonate.

I designed and developed this circuit myself out of frustration with the lack of closed loop control in my E6K that I have on my ’87 Turbo II. Having rebuilt a few too many engines, I am very familiar with the ill effects of detonation.

I also once owned a $500+ J&S knock control computer but was disappointed with the lack of ability to retard the trailing timing and the limited control over the amount of timing pulled during a knock event.

This circuit is the solution to these problems.

This circuit will work with any Haltech ECU that has the timing trim feature (See List below). The knock box has a GM connector that plugs directly into the 3-prong trim connector of the Haltech harness. The other two wires leaving the box go to +12VDC and the output of the GM knock module.

The circuit is adjustable to pull between 1 and 8 degrees timing when experiencing knock. This circuit works very similarly to the J&S unit, where it immediately pulls timing upon a knock event and then slowly gives it back over a period of a few seconds. It will also re-pull the full amount if during the rebuild time more knock is experienced. However, this circuit will pull both the leading and trailing timing together so unlike the J&S unit you will not have to increase your split to avoid the very dangerous situation of firing the trailing first.

This unit will work with any 1-wire knock sensor. This unit also utilizes a GM ignition module. This is needed to convert the noisy, varying voltage, of the knock sensor output to a clean step pulse. This module can be found in nearly any GM car/SUV/truck manufactured in the late 80’s and early to mid 90’s with electronic ignition (see picture). It is located on the firewall and requires only a pair of side cutters and a nut driver to remove it. This takes about 5min. I have picked them up for between $5-10ea in junkyards. These modules can also be bought new for less then $50 but will not include the connector which makes it much easier to wire.

All knock box units are tested for functionality and pre-set to pull 4 degrees when experiencing knock. This value can be changed (between 1 and 8 degrees of retard) by simply adjusting a screw if desired.

A small amount of soldering is required for installation. There is no hard wiring to the ECU, the entire system can be disabled by unplugging the trim connector or simply disabling the feature in the software. It took about 30min to install the knock box and GM ignition module in my car. I will also include complete instructions and a wiring diagram for the entire system (knock sensor, GM module and knock box).

This knock box is compatible with Haltech ECU models:

E6X
E6K
E6S
E6GM
E6GMX
E8
E11

Here are two part numbers for the GM knock module that I know will work. There could be many more that will also work. I’m not even sure if the one I have is one of these. I got mine off an early 90’s Blazer and Astro van that I know work.

PN 16126761, $57
PN 16128261, $53

Found at: www.gmpartsdirect.com

This box is built with very quality electrical components, and is 100% soldered for the best possible quality. I test and set all units before shipping them, and they are guaranteed to work as described. If you are unhappy with it just return it within 30days for a full refund.

See pictures by searching "Haltech Knock Control" at a popular auction site.

-Justin

does the amount of timing pulled vary by the amount of knock detected?

I also want to see how this works in comparison to the j&s or any other commercially available lnock unit.

The factory mazda knock units don't work above 5500 (IIRC), will this one?

I was planning to do something similar based on a commercialy available knock controll kit. It would be easy to do, but for the price there is nothing even close to available.

BTW with the e8 e11 you may not be farmilliar with them since you have an e6k. The ign trim gives three levels of controll. coarse, medium and fine they are +or- 20, 10 and 5 deg respectfully. So I am guessing that would skew the amount of retard those units would see by allot when used with your device.

Hey Justin,

Good to see you've finalized your knock unit. I wanted to ask you, wouldnt it be easier to sell the entire thing with all components to make it simpler for the end users?

Will you post the diagrams on here or will we have to buy it first? :D

No. It pulls the full amount when the engine knocks.

Yes, the box does not have any rpm related limit built into it.

In the case with either the e8 or e11 the full pull setting could be any of the three of these (5, 10 and 20deg max retard) and also fully adjustable anywhere in between these too.

Justin

Yes, it would. Rather than raiding a bunch of junkyards for the ignition modules myself I may possible develop this part of the circuit too. Depends on interest.

I'd like to recoup some of my R&D cost. Believe it or not, I have a ton of hours in this and quite a few extra electrical components.

Justin

Is this unit accurate when used with a rotary engine, when compared to a J&S or other commercially available knock detector. (I wouldn't want to be the one to test this)

Is there any provision for a knock light, to let you know when the unit was active? (I guess this would be easy to do)

It seems like a knock light of some sort would be mandatory for a unit like this. I wouldn't want to be driving around with something like this saving my engine as sort of a bandaid. Without knowing about it, so that I could come in and fix the problem, or alter the timing.

im interested...

Accuracy of this box does not change depending on the type of engine. Finding a knock sensor that is "tuned" the the engine block you have is probably desirable. As stated this unit will work with any 1 wire knock sensor.

I have this installed on my '87T2 and I witnessed is working many times. The Ignition Trim value, viewed in the Engine Data Page, will tell you real time exactly what it is doing. This value can aslo be datalogged.

A knock light could possibly be integrated into a future design. As mentioned above a quick glance at the Engine Data Page, or a datalog, will tell you if it is in use.

Justin

Try searching "haltech knock control" at a popular auction site.

Justin

Yeah, you could probably do something like what the MSD knock alert does, which is have a 10 led bar that fills up depending on the knock level. If you put that on your little controller box and make the interface connection wires to the trim input on the haltech longer, it could be dash mounted and serve as a feedback to view its opperation. That be a cool addition for your version 2.0 :D, i think the Haltech people should see your little invention.

I think the Power FC market is a lot bigger than the haltech market, are you going to be able to make someting compatible for that ecu? Nice work by the way

So what are you basing that opinion on?
I guess you're refering to the 3rd gen user then because that's all the power FC's are generally good for. The rest of the rotary users are not important.

I have no experience with the Power FC. Does it have any manual ignition trim function like the Haltech?

Justin

No it does not, too bad too.

Wow man your a dick head :) . Calm down

Are you kidding? Power FC being a bigger market than Haltech??? Thats strange thing to say.

especially when this would work with any haltech on any vehicle.

Any Haltech with ignitino control of course, but since the E6 has been around for, um, well, about roughly 20 years. :D

wow, impressive. wonder if it could be made to work for the new wolf.....ill have to ask my tuner

it can be made to work on ANY wolf!

as long ad the unit has a linear analogue output from anywhere between 0-4,5 volts you can use it on any version!

thumbs up justin!!! too bad i just got my j an s for 4 times your asking price :(

Good work

George

I just found your ad on the public site by accident, I was looking for a knock sensor for the FD and saw yoursauction so I was about to ask if any has seen this before and if it really worked. But then I saw this tread.

Wolf ECU
 

This circuit has an output of 2.5V until it experiences a knock event, at this point the voltage immediately drops to a lower voltage (adjustable between 0.1 and 2.4 volts, which correspnd to the -1 to -8 degrees of retard). If someone would like to fill me in on what the Wolf would need as an input to pull timing I may be able to offer a version to work with the Wolf EMS.

i.e. With a haltech 2.5V = 0 degrees advance or retard, close to 0V = full retard (-8degrees) and +5V = full advance (+8degrees).

Justin

Is the voltage firmly clamped at 2.5V ref max? There is no danger of input voltage to your sensor module possibly raising and causing your unit's output to actually add timing?

Good point Ludwig, Justin i think the unit shouldnt even raise the voltage passed 2.5v to advance timing beyond zero degrees, that way theres no risk. And should have protection against voltage spikes so it will definately not go beyond 2.5v.

Is to hard to do?

a dick head who can build and run low 9's in a stock bodied fc
crispeed=the man