This page deals with some of the common questions that we get asked and features any of the latest updates on SDS products. From time-to-time, we may also publish the latest system and technical updates for our installation manuals.

If you have a question you'd like answered about SDS fuel injection just drop us a note by fax or E-mail to racetech1@telus.net

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Technical Updates
FAQ frequently asked questions

Tech Articles
Tuning on a DynoJet
Sequential Injection Realities
How to Build a Surge Tank
Fuel Pressure Regulators
HP vs. Injector Flow Rate
Tuning Via EGT vs. Wide Band/ Narrow Band Meters
Fabricating an Intercooler
Fabricating a Turbo Header
Tuning with an SDS Mixture Meter
Start and Warmup Programming
Fuel Values and Cams
Injecting a Lotus Excel
Pushing it Too Far
Injectors
Phantom Problem
Engine Map Examples
Airflow, Fuel Flow, HP Formulae
Hints on Hall Sensor/Magnet Mounting EM-3
Tips for FSAE Teams
How to Fabricate an Intake Manifold
Hints on Hall Sensor/Magnet Mounting EM-2
Ignition Tuning Ideas for Turbos
Tuning TPS Only Systems
How to build a fuel rail
Chips vs. Programmable EFI
How Much Power?
Dyno Thoughts and HP Losses
Intelligent Engine Modifications
Basic EFI Theory
Ignition and Combustion
Fuel Octane vs. Horsepower
400 hp Street Honda

Technical Updates

03/14/07 Tach Signal Source for EICs

Some newer cars present problems in finding a tachometer signal source which is required for ECIC and D system hookup. This link may be helpful: http://www.autometer.com/tech_installation.aspx

12/14/06 Fuel Cut Programming on Deceleration

Some people have siad they experience jerking or bucking on decel when using MAP cuts (1's or 0's at high vacuum MAP ranges). We have found the following to be useful in minimizing this:

1. Don't enter 1's or 0's in the high vacuum ranges. Below the idle ranges of say -18 to -22 inches, enter smoothly declining values about 2-3 lower in each range. Example: -20 value 30, -21 value 28, -22 26, -23 24 etc. right to the highest vacuum value available for your MAP sensor.

2. Check your closed throttle TP value in Gauge 3 mode. If for example, it is 8, enter 9 (one greater) in your TP Fuel cut window.

3. Your fuel will now be shut off whenever your throttle is fully closed and rpm is above 2000 rpm. You should feel the fuel come back on gently as rpm falls below 2000 rpm. This should minimize jerking and bucking on decel.

10/06/07 V16 Software is Available for EM-1, EM-2, EM-3

09/25/06 Wideband Voltage Conversion Chart

AEM TO WMS WIDEBAND CONVERSION

01/31/06 Air Temperature Values Update

New air temperature correction values. These apply to EM-4 and EM-3 ecu's. New values will give a more consistent mixture over full air temperture ranges.

New air temp value matches the old value at 70 to 75 deg F temp, so new values won't change your mixture at this temperature. New values will lean mixture more than old values, as temperatures get hotter. New values will add more fuel as temperatures get colder.

How to enable access to air temperature values:

EM–3, EM-4 SETUP MODE AIR TEMP ACCESS

Unplug hall sensor plug from ECU.
Power up the ECU with the programmer plugged in.

Momentarily ( ½ second ) short out pins 6 & 7 on the hall plug port on the ECU using a wire or setup tool (provided by SDS ). See drawing above.
You will see SETUP TEMPSENSOR in the programmer window.
Push the > 4 times until you see SETUP AIRTEMP.
Push the +1 button once to get AIR TEMP ACCESS.
Push +10 to exit setup mode. Now the programmer is back in it's normal mode of operation.
Now scroll by pushing the > button, best to hold it down until the programmer scrolls into the air temperature values.

Note: Aircraft applications we enter default values at the cold and hot end in case of sensor failure. These values should be set to 70.

To hide the air temps from the main programmer screens when you are finished changing the values, repeat the first section until you see SETUP AIRTEMP. Press the +1 button once, then +10 to exit.

07/11/05 Engine Misses

Recently our 240SX turbo test car started to develop a miss around 4500 rpm under boost. This was intermittent at first then became progressively worse over the next few months. Fuel pressure and delivery volume was first checked static and it was fine however when checked at 40 psi, the delivery dropped off below what was required to feed the engine under boost. When a fuel pressure gauge was taped to the windshield and the car driven, the pressure would start to come up as the boost did, then start to fall off. This clearly showed that the pump was not putting out enough. We installed a Walbro 255lph kit but the miss still persisted. Every once in a while, the engine would run horribly even at idle and part throttle. Upon scoping the power inputs to the ECU, we found some large noise spikes which may have been resetting the coil pack processor, causing these misses. We tested various anti-noise solutions in the ECU and got most of this fixed. Sometimes the miss at torque peak came back however. Upon checking the spark plug leads which were about 6-7 years old and near the turbo, we found 2 with broken conductors. Replaced these, noise spikes were gone, misses were gone and it pulls all the way to redline again. Again, 2 basic problems happening at the same time, plugs wires and fuel delivery. Check the basics first.

06/27/05 Interference on 4F Coil Packs and ECUs

On two of our test cars, dirty power supplied to the new style coil packs have caused rough running problems and ECU resets. When the voltage supply was scoped, large noise spikes were evident. When we rewired the coil power and ECU directly to the battery via a relay, the problems disappeared. We recommend doing this if you experience these types of problems. The D manual contains a schematic for a typical hookup.

03/18/05 Option Relays

Many people seem to be having trouble getting the relay options to work on SDS. People expect to see voltage at the output of the computer's option wire. These outputs are ground switches so they do not "send out" voltage. Please follow the diagram carefully. On some relays there are 5 terminals, and the one that is in the middle is 87a which is not used but can be confused with terminal 87 which is used. Wrong hookup can damage the relay driver chip after several minutes of power being applied, since the chip temperature gets very hot. The relay driver chip contains thermal protection and current limiting, which does save the chip from instant failure in the case of wrong connections. If your relay does not work right away turn off power quickly and investigate.

As of January 21/05 and beyond it is okay to supply the option relays (+12V connection) with direct constant battery power. We have changed the ECU circuits so that power cannot leak through the relay drive circuits, which kept the ECU powered up on older ECU's. Of course it is recommended to have a fuse between the battery and the relay, and locate the fuse as close to the battery as possible in case your wire shorts to ground. Size the fuse according to the device being controlled.

03/04/05 D (fuel only) System and EIC Tach Signal Source on Cars With Coil Pack Ignitions

If you are having difficulty locating a compatible tach signal wire on these vehicles, you may be able to use an MSD PN 8913 tach adapter to supply the D system ECU or EIC with a suitable tach signal. The following web link may assist you in locating a tach signal wire: www.rostra.com/techsupport-main.asp

09/13/04 Crane XR700 Spark Box Compatibility

Several people have tried to use these to provide an SDS tach trigger signal without success. They ouput a very noisy signal causing multiple triggering of the SDS ECU and erratic running. We don't recommend the use of the XR700 with our systems.

WARNING! YOU SHOULD NEVER USE THE MSD BYPASS PLUG FOR ANY REASON WITH THIS TYPE OF SDS SYSTEM. USING THE BYPASS PLUG WILL DAMAGE THE SDS DRIVER TRANSISTORS.

No other wires should connect to the SDS ignition signal wires. No tach adapters are required to make the SDS and MSD boxes produce a spark at the coils. If your factory tach does not operate with the DIS-2, you will require the MSD8920 tach adapter.

08/09/04 Data Logger Connections for MAP and RPM Signals EM-4 F Systems

We get many requests from people now who wish to connect a data logger to our systems. Most are concerned with getting rpm and MAP sensor outputs. The green tach output wire from the coil pack is generally configured for a 200V peak signal output at 2 pulses per crank revolution on 4F systems and 3 pulses per rev on 6F systems. By removing the bottom coil pack cover, this output can be re-configured to a 12V output by moving the marked jumper block from the 200V location to the 12V location. Some loggers will require a 5V signal. This can be tapped from pin 12 on the main ECU DB25 connector. You will have to solder a wire here. A MAP sensor signal can be tapped from the center pin on the MAP plug (green or white).

07/05/04 Importance of Fusing Components

Many of the damaged components that we have returned to us could have be saved if the user had installed proper fuses as recommended in the manual. This applies especially to F coil packs where a 7.5 amp fuse should be installed. If you start blowing a fuse, DON'T install a bigger one, find out why it's blowing first. Installing a 10 or 15 amp fuse on the coil pack offers no protection and will result in fried drive transistors or fried coils if something goes wrong. We recently had an ECU returned to us in which a huge fire had started inside and completely ruined it (photo below). Obviously very high current flowed through this component for a long time to cause this type of damage indicating an unfused component somewhere along the line.

06/29/04 Concerns with Aftermarket Fuel Pressure Regulators

We have had several people over the past few years report problems with some aftermarket fuel pressure regulators. In most street applications, aftermarket FPRs are a waste of time and money and simply not needed. It is essential that the fuel pressure be accurately controlled for any EFI system to meter fuel properly. We have seen at least 5 instances now with Mallory FPRs in particular where fuel pressure was floating all over the place leading to no start conditions or inconsistent running. People usually blame the computer. If you encounter problems like this, check the fuel pressure by tapping a gauge to the windshield and drive the vehicle. The best course in many cases is to retain the OE FPR which are extremely reliable.

05/05/04 Remarking Magnet Ends

Some people have rubbed off the blue marking on their magnets while handling and mounting them. To find the marked end again, follow this procedure:
1. Power up the ECU with the Hall sensor plugged in
2. Wave a magnet over the black square on the Hall sensor (E) or the blue marked black square element (F) with the programmer in the magnet window screen.
3. If the display does not read SEEN, flip the magnet over and try again. The magnet end facing the trigger element of the Hall sensor which makes the display change to SEEN is the blue marked end.
4.Mark this end.
5. With the marked end facing up, the magnets will all stick together in a line with the marked end up. Mark all these ends accordingly.

03/15/04 Resistor Spark Plugs

For engines experiencing RPM ERR codes which cannot be solved by other means such as moving Hall sensor cables or changing spark plug wire types, it may be beneficial to switch to resistor type spark plugs.

01/13/04 Hall Sensor Reliability

We have a fair number of people complaining about problems with Hall sensors. Most of these problems are caused by poor brackets holding the sensors. If you can't lift your engine up by the bracket, it's likely not strong or stiff enough. We recommend using two bolts to hold the bracket to the engine (not one), the bracket should be made from 3/8 to 1/2 inch thick aluminum plate stock (not 1/8 inch flat stock) and needs to be as short and stiff as possible (not 4 inches long out in space from the attachment points). If you follow these instructions, you will likely have no problems EVER with the Hall sensor. Between our shop cars alone with SDS installed for the last 11 years, we have accumulated 36 years collectively of 100% trouble free performance from our Hall sensors. Most have never been touched in the 2-8 years they have been installed, none have ever been changed due to failure or damage.

Proper bracket left. The one on the right won't work!

Read the Tech article on this subject for more info: Hints on Hall Sensor/Magnet Mounting EM-3

10/23/03 Extra Injector Controller Cutout at High RPM

We have seen a couple of cases where the EIC loses the rpm signal from the stock ignition system above 5000 rpm on some VW engines. This causes the LEDs to go out and the controller to shut down fuel delivery. Units showing this symptom can be returned to us for a modification to the tach filtering circuit to eliminate this problem.

09/23/03 Mystery Timing/ Detonation Problems on Engines With Rubber Damped Crank Pulleys

We have seen several cases of unexplained detonation and ignition timing changes. These were caused be slipped harmonic balancers where the rubber portion has lost its bond on the inner or outer pulley sections, causing the outer section to rotate relative to the inner section fixed to the crankshaft. It's worth verifying that TDC on the pulley is actually TDC on the engine, otherwise your ignition timing may be way off.

08/13/03 Concerns When Using Multiple Throttle Plate Induction Systems

We have recently had several calls from people running induction systems with one throttle plate per cylinder and independent runner manifolds using our systems on street driven vehicles. These people often complain of marginal driveability under low throttle openings and/or low rpm conditions. We have never recommended the use of our systems with IR manifolds for the street, especially when using a MAP sensor for load sensing. The situation is worsened when combining this hardware with hotter cams, resulting in an unacceptable vacuum signal for the MAP sensor. This is race type hardware, generally not suitable for street use unless the user accepts decreased driveability and/or switches to TP load sensing

The vacuum averaging canister required on IR applications will result in a lower than actual vacuum reading than would be seen on a plenum type manifold setup due to the fact that all the ports which don't have a valve open to establish flow are leaking air into the cannister. There is no way around this and this is the reason why few OEMs use speed density EFI systems with this hardware, they usually use an airflow/mass sensing system instead. Also, 95% of all production cars use plenum type manifolds. Our general rule of thumb for using a MAP sensor in any street application is a minimum of 15 inches of idle vacuum. Less than this any you may have to switch to TP load sensing with its own disadvantages. Race stuff on the street is usually fraught with compromises often not worth the gains in power after you live with the car for a while. Big, open mufflers bore into your brain on the highway, hot cams make the bottom end, driveability, fuel economy and emissions suck, huge turbos have big lag and high compression/high boost leads to detonation and broken engines running on pump fuel. Use your noggin here and don't expect miracles.

06/17/03 Blowing F Coil Fuses/ Ignition Timing Values EM-1- EM-4

If you are having trouble with blowing the 7.5 amp fuse on your F coil pack, it may be caused by having excessive ignition timing below 2500 rpm. We don't recommend exceeding 35 degrees of total timing (rpm + MAP advance) at 1750 to 2250 rpm. Certain software concerns create high current draw on the coil pack which can exceed 7.5 amps and damage the drive transistors if not fused. V12+ software addresses this software concern.

05/07/03 Replacing Magnets

We have a fair number of people incorrectly install the magnets on E and F systems the first time. Some people attempt to pull the magnets out by heating the epoxy with a torch or heat gun. Heat over 250F will damage the magnets and reduce their flux strength. These should not be re-installed. Use new ones. It is important to remove all of the magnet fragments before installing new ones also. The EM-4 manuals give plenty of detail on how to install and verify proper magnet placement. Follow these directions exactly and you will save yourself a lot of trouble. Don't rush this job! Contact us if you are unsure before gluing them in.

04/09/03 Care and Feeding of F Coil Packs

We see a fair number of F coil packs damaged by 4 main causes:
1. No 7.5 amp fuse on red power wire
2. Water damage to circuit board
3. Vibration damage to circuit board
4. Improper magnet or Hall sensor mounting

It's easy to avoid damage by following the manual. Use only a 7.5 amp fuse on the red power wire. Don't wail on the coil pack with a pressure washer or submerge your vehicle. Don't mount the coil pack to the engine. Make sure magnets are mounted correctly, sensor is aligned and sensor mount is REALLY stiff and strong.

04/09/03 It Won't Start!!

We have recently seen several cases where the engine would not start. In all cases, the user reported that they had gone through all the troubleshooting sections without result. This section has been refined now for almost a decade and is very complete. IF you actually verify compliance with ALL points in the troubleshooting section, there is a 99.5% chance that the engine WILL start. Latest problems were no fuel delivery (item 13) and improper camshaft timing (item 16). Don't assume, actually check it and tick it off.

02/21/03 Ignition Timing Display Differences on EM-4

Ignition timing BTDC on the EM-4 has a - sign preceeding the value. Values ATDC have a + sign precceeding them. ATDC total timing values should normally be avoided as these are counterproductive to engine life and power. + values for boost retard are fine but would normally be limited to a maximum of +20 degrees. A K will appear behind the ignition timing value in Gauge 2 mode when the knock sensor is active. With excessive knock sensitivity or heavy knocking, total timing may go back past TDC and there will be a severe loss of engine power.

01/01/03 New Magnet Markings on E and F systems

As of Dec. 7/02 all magnets for E and F systems will be marked with blue instead of white. The EM-4 magnet materials were too slippery for the white marking material to adhere. This change is reflected in the latest manuals. This blue color is somewhat easy to rub off so be careful handling the magnets. If you stick the magnets together all blue ends will face the same direction so you can re-mark if you have one with the blue still visable.

12/13/02 Tach Problems on E Systems/F Systems With MSD DIS

If your tach won't work with these combinations, you may have to install an MSD tach adapter PN 8920. Do not use the 8910.

10/24/02 6F Plug Wire Connections

The first 6F manuals omitted spark plug wire connections to coil pack on 6 cylinder engines. Below is this information. New manuals are updated with this info now:

Different six cylinder engines have different firing orders. Three basic rules apply to all engines. These are:

1. Whatever cylinders fires first and fourth in the firing order should connect to coil A.
2. Whatever cylinders fires second and fifth in the firing order should connect to coil B.
3. Whatever cylinders fires third and sixth in the firing order should connect to coil C.

Example #1: 82 Toyota Supra. Firing order is 1-5-3-6-2-4. Cylinders 1 and 6 are the first and fourth cyls in the firing order so they should connect to coil A.
Cylinders 5 and 2 are the second and fifth cyls in the firing order so they should connect to coil B.
Cylinders 3 and 4 are the third and sixth cyls in the firing order so they should connect to coil C.

Example #2: G.M. and Nissan V6’s. Firing order 1-2-3-4-5-6 Cylinders 1 and 4 are the first and fourth cyls in the firing order so they should connect to coil A.
Cylinders 2 and 5 are the second and fifth cyls in the firing order so they should connect to coil B.
Cylinders 3 and 6 are the third and sixth cyls in the firing order so they should connect to coil C.

Example #3: G.M. 3800 V6. Firing order 1-6-5-4-3-2 Cylinders 1 and 4 are the first and fourth cyls in the firing order so they should connect to coil A.
Cylinders 6 and 3 are the second and fifth cyls in the firing order so they should connect to coil B.
Cylinders 5 and 2 are the third and sixth cyls in the firing order so they should connect to coil C.

These are examples. Your engine may be different. Don’t guess at the firing order because damage could result.

10/22/02 Plug Gap on High Boost Applications

On en