Checking the Connection to an AEB-manufactured LPG ECU

We get quite a few questions along the lines of “Why can’t I get my PC to connect to the LPG system?” Broadly speaking, the answer falls into one of the following categories:-

1. Wrong or damaged interface cable
2. Wrong or missing software driver for the cable
3. Fault with PC
4. Wrong software for the LPG system
5. Wrong version of the PC software
6. Wiring problems in the installation.

If you get an error message that says “Impossible to connect. Check connection. (ERR CODE: C01)”, then the problem probably lies with any of the following potential causes.

1                    Wrong or damaged interface cable

Checking if you have the correct cable is not as simple as it could be. Is the cable intended for connection from an AEB-manufactured sequential injection system to a PC? If you don’t know, ask your cable supplier.

Checking for damage is more straightforward. Look along the length of the cable for signs of pinching and abrasion. Check the connections of the wires to the pins. Check for damage to or displacement of the pins. Check for electrical continuity along the length of the wires (not through any intermediate circuitry).

If possible check the lead on another LPG installation that is known to work.

2          Wrong or missing software driver for the cable

This section applies to USB cables only, since serial (RS232) cables do not require a driver.

When the interface cable is plugged into a PC, there is normally a ding-dong sound played to indicate that a device has been attached. There may also be a message to say that a driver has been loaded. If you want to check which driver has been loaded, click Start, Run and enter the command compmgmt.msc /s

Click Device Manager, then Ports (COM & LPT) and look for a USB Serial Port. Double-click it to display the Properties. Click the Driver tab to find the Driver Provider and Version. (Most of the cables that we supply use the FTDI driver).

Drivers for the cables that we supply can be found on our web site www.tinleytech.co.uk/downloadusb

3          Fault with PC

You need to have a PC that is running Windows XP or later. The quickest way to check this is, if possible, to check the PC on another LPG installation that is known to work. Check that the USB port works with another device. Run Computer Management (compmgmt.msc /s) and then Device Manager and look for any warnings or conflicts that may stop the cable from working. Try a different PC.

4          Wrong software for the LPG system

Look at the label on the top of the LPG ECU. It should say AEB, Bigas, Emer, King, OMVL, Romano, Tartarini, Zavoli or possibly some other brand. This should match the name on the software that is being used on your PC. If you run the software, then click Help then About you should see the name of the software and the version.

5          Wrong version of the PC software

From time to time, manufacturers add new features that require a step-change to the ECU firmware and this can cause upward/downward compatibility issues. For this reason, it may be necessary to upgrade to the latest version of the software, or to go back to an older version. In such instances you will usually get a message C04 or possibly C03, that may be accompanied by a compatibility message. Make sure that you have the appropriate version.

6          Wiring problems in the installation

An AEB-manufactured LPG ECU has quite a few connections to your engine. However, only a few are required for it to be able to connect to a PC.

1. Permanent live should be connected from the battery(+), through a fuse via the red/black wire. Check the fuse.
2. Permanent earth should be to the battery(-) via the black wire. Check that you have not mistakenly connected another wire of a different colour that has a close-fitting black sheath over it.
3. Switched live should be connected to the positive side of one of the injectors via the red/white wire that is part of the petrol injector intercept loom. If you have a 5-8 cylinder engine, be sure to connect both red/white wires (one for each bank), since only one of them connects to the ECU.
4. The change-over switch must be connected. Check that the wires have not been pulled out of the back of the plug, and that the wire has not been chafed.
5. The PC interface cable must be plugged into the fly-lead from the LPG ECU. The older ECUs had small, white, rectangular plugs with 2 rows of 4 pins (usually one of the rows had no pins present). The current ECUs have black, oval plugs with 4 pins. These plugs are the same shape and size as the plugs for the pressure sensor. Make sure that you have plugged them in correctly – the long lead goes to the pressure sensor – the short lead should have a cap over the plug that connects to the PC lead.
6. Some of the older LPG ECUs require a pulsed signal on the brown (rev-sense) wire in order to connect.

If you work through all of the above checks, you should find the cause of the problem and be able to fix it. If you still are unable to connect your PC to your LPG ECU, call us and we will do what we can to help.

Which type of LPG conversion kit should I buy?

This is one of the most frequent questions that we are asked and it seemed like a logical place to start our blog. The 2 main decisions about the kit are the type of front-end system and the size and shape of the tank(s). Here we will concern ourselves with the choice of front-end kit (i.e. the engine-bay components).

Multi-point Sequential Gas Injection Systems (SGIS) are the most appropriate type of LPG conversion for vehicles built after 1999. This is the point at which emission controls were tightened and we started to see lambda probes (oxygen sensors) fitted after the catalytic converters as well as before. It was also the point at which OBD2 (On-Board Diagnostics 2) became the norm.

Vehicles built before 1999 that have plastic inlet manifolds should also use SGI Systems.

So, that covers the vehicles that must use SGI Systems, but there are others that have the option to use them. Any water-cooled engine that has electronic petrol injection with individual injectors for each cylinder, and an ECU to control them, and a lambda probe in the exhaust could be converted using an SGI System.

There is an overriding consideration for any petrol-injected engine conversion. It concerns the location of the petrol injectors. An engine with petrol injectors in the inlet manifold (indirect injection) should not be a problem. However, if the injectors deliver petrol into the combustion chamber (direct injection), then special care must be taken to ensure that the petrol injectors do not suffer from over-heating when running on LPG. Each direct injection engine requires specific customisation of the fuel delivery system, and this is carried out by the manufacturer of the LPG system.

So, if you have a direct injection engine for conversion, you will need to check that a system is available for your vehicle and engine code.

SGI Systems work with the petrol ECU to run the engine as the ECU manufacturer intended.

Single-point induction systems work independently of the petrol ECU or carburettor.

There are 2 types of single-point induction system - open-loop and closed-loop. The open-loop type system is fairly basic, in that it has no automated way of measuring and adjusting fuelling as you drive. The closed-loop type system uses a lambda probe to determine if the fuelling is rich or lean and then automatically adjusts it.

For any conversion of an engine with soft valve seats, be sure to use a valve-saver system, such as FlashLube.