Would seem mixture went rich (or nearer to correct from previous drastically rich) when it switched to LPG.
Since it is more likely it went rich from correct or a bit lean, first thing first, is mixture correct on petrol?
Assuming it is, go into the map screen, select all the numbers in the table, press enter and apply minus20% to all those figures. Now, when you run autocal again, autocal will begin with a leaner mixture to start with so rpms won't rise as much when it switches to LPG.
Incidentally, if mixture is reading correct on both banks on petrol (lambda flick), sometimes you get a rise in rpm when switched to LPG due to a problem with petrol injector(s), i.e. some flowing more than others so per cylinder mixture isn't correct (only average is correct). If LPG injectors are all good, the increase in rpm can then be due to efficiency gains of the engine when mixture is correct on all cylinders. Particularly sometimes if engine has done a lot of miles on LPG and petrol injectors haven't been used much, or been clogged due to owner running on petrol with next to no fuel in the tank so injectors get fed with mucky tank dregs that made it past the fuel filter..
Simon
Also note that you might not see actual results of any changes to RPM detection settings you make until after ignition has been turned off. Sometimes it even takes shutting software down and re-starting software.
Where necessary (so not with more recent ECUs) I connect to one of the coils. One coil means one coil per cylinder, two coils means wasted spark, RPM means one pulse per engine spark (tacho usually), so RPM2 may work with wiring you have. If you get no reading or inconsistent reading with a particular setting here, try the 'weak; option.
Simon
Wonder what went wrong with your old ECU, since it was working before you started any work? Since a sure fire quick way to destroy an ECU is to apply 12V to chassis or earth connection while the other earth is actually connected to earth, might be worth one more check of wiring.
Best to click 'reset the ECU', enter all basic settings, run auto-calibrate.
At this point calibration it should be roughly OK on a P38, but you should note actual pressure when running on LPG, repeat the above but this time enter that actual pressure as the reference pressure when entering basic settings.
Only now start to adjust the map manually.
This is because (1) you won't know the pressure supplied by the reducer while running on LPG until you've actually checked it while running on gas and (2) the shape (as opposed to just the values over the whole) of the map will have been adjusted from standard to suit the last vehicle the ECU was on, while auto-calibrate simply lifts or lowers all the numbers in the map by X%. For most people it will be easier to start from a clean slate regards map shape and default map shape isn't usually far out on a P38.
Simon
That's 'em, but I wouldn't bother on a vehicle that doesn't pick fault with petrol injector resistance either!
I keep some 124's on the shelf, and because I fit a wide range of ECUs not just AEB I sometimes have to cut the plugs off 124's to hardwire... An upshot of this is that I end up with some loose plugs, which can be wired to bypass a 2568 (and certain BRC ECU's) entirely for diagnostics where suspicion is that LPG ECU or ECU loom/plug doesn't reconnect petrol injectors but are difficult to access.
No reason why it shouldn't work... if it's a good 'un and external wiring or component isn't the real issue!
Brown green brown, 150 Ohm? Although I believe each will be in series with a petrol injector while running on gas, resistor plus injector roughly 165 ohms. So say 14v battery voltage, series current of 85mA but voltage over the resistor would only be 12.7v.. At 12.7v and 85mA the resistor would dissipate 1.08watts. if resistor is rated at 1w resistor it's probably gonna get warm..
Obviously 165 Ohms is way different to petrol injector resistance (usually 13 to 16 Ohms)... Some petrol ECUs (not on P38s) notice this and interpret it as a disconnected petrol injector. so is necessary to address emulation resistance on some vehicles by fitting extra resistors in parallel with the LPG ECU emulation (about 40 Ohms usually does the trick). AEB124's are a neat way to do this, especially when using AEB2568 ECU's because they are a plug in solution (to injector break looms). Using AEB124's even where not necessary should take some heat off the ECU internal resistors.
Simon
Damage or just discolouration, though... Old boards that still work fine seem to get a bit discoloured in areas.
Reckon the big resistors are for petrol injector emulation?
Some of the other suffix boards are a different.design. Not related to your problems but since we're looking at a board might as well mention that if any of those little components at bottom left of top pic go wrong, you lose either peak or hold current to LPG injector(s). I dunno if some of those little 2 pin jobbies are diodes/resistors or what, but I do know that at least some ECUs use special diodes for timing peak.
Already mentioned I have an old broken OMVL ECU here (works OK on LPG but doesn't reconnect one of the petrol injectors when running on petrol).. I'm feeling semi inspired to have a look inside, see if there's anything obvious wrong. I will have a few other broken old ECUs laying around somewhere too..
Simon
I don't think there'll be a problem loading B calibration file into C ECU. Calibration should be almost right, but if 5V issue has been causing incorrect pressure and temp readings calibration may need minor adjustments after the upload.
Simon
OK I know this is a P38 forum.
Had a customer the other day with a 3.5 Disco, came in unable to run on LPG and didn;'t run great on petrol either. Sorted a few probs with the open loop mixer LPG system (needed new switch which wasn't seeing RPM so never turned gas on) and then fixed the bodged pipe between reducer and mixer and set it up a lot better.
But, he'd messed up ignition timing before he came. So, questions are - Anyone know static advance? Anything to know about timing marks on the front pulley? Likely to be any probs in the dizzy? He has his own timing light and wants to do it himself but I'd hazard a guess he'll be asking me the above questions at some point.
Simon
I don't think there's been mention yet of which vendor's C ECU it is, don't forget if it's a different make to your original one it will need that vendor's software (Zavoli / OMVL / Bigas / Etc sticker on ECU).
Yeh, would be good to read your results with the 7805.
When I read the stuff on calibration it always seems put over in a bit of an over-simplified fashion... will be because I know the iffs and buts and other stuff they've missed out or not explained properly ;-)
Nah, think more front garden with my mates, and going for midnight walks leaving the computer in the tent...But did used to carry a car battery when we went 'wild camping' (no tent) and slept by a fire in a field / bit of no mans land down next to a little river just a couple mile walk from home... Powered a CB, in case we could persuade anybody (females) to join us. Aerial was at least light and worked well, made a diipole using just wire and a loading coil bought from a ham specialist shop in Leeds, decent SWR too.
OB, I was planning on keeping the ECU in line with intention to always have a working old type ECU here but if your struggle continues I might sell to you just to help out; I am likely to get hold of another at some point over the next 6 months or so anyway. But if I were you, unless you can get one really cheap, I'd get a new version. Dunno where you got the switch, but if you go back to the same firm and say you just bought a switch, can they do you an electronics bundle but not include the switch it might work out well? All those crispy wires you'd be replacing, and you'd get a spare pressure sensor too... Or just buy a new ECU.
5v current draw won't be much, it only has to drive the few mA for the sensors.. unless it also powers the electronics in the ECU... But as memory serves there is nothing attached to a heat sink in the case, so would seem whatever combination of bits provide 5v they're not expected to need to sink much heat.. for a 7805 this implies not flowing much current. As a kid I used a 7805 and 7806 to power a BBC computer from a car battery when camping, this setup (overloading 7805 by some margin) needed a massive heat sink which I removed from some electric equipment I found down the quarry (come tip) when out shooting. I was always bringing stuff home to attempt to fix or dismantle for the components hehe.
Simon
The first one is an AEB2568 but with a slight deviation due to being made for Tartarini. It is pinout compatible but uses a different cabin fuel changeover switch and the spec of the temperature sensors it uses are a bit unusual. It you got the Tartarini switch it could be made to work, just cut the usual AEB119 type switch connector off and connect the connector for the Tartarini type switch up, colour of wires all match up. The only other slight difference is in the way Tartarini systems are calibrated, they effectively have a built in shape of map for the (limited) types of injectors that can be set, so the default figures in the user defined map are therefore all zeroes and you enter plus or minus figures to deviate from the built in map (actual map is underlying/unseen map plus figures you enter),.. unlike other systems where (if you have access to the full map at all, sometimes this needs V6 software or hardware key to access) you enter numbers between 0-255 and adjust the map directly. In cases where you can't use V6 software and don't have hardware key on other systems you cannot fine tune the full map, you can only adjust 8 numbers each of which effects a block comprising 1/8th of the actual map, so before V6 software better installers (who wanted fine control) had to buy hardware keys, a different key for each brand/sticker on the front of the AEB2568 ECU. You wouldn't really need the fine control for very good results on a P38.
I have 3 different types of switch connectors wired up to the LPG ECU on my own car to allow testing of ECU's and switches.. This is particularly useful for testing how modern ECUs / firmware fair on a 6 cylinder engine (more on this below) .
No need for me to check the other two ECU's since Gilbert has already done so.
Don't forget it's AEB2568 not AEB2856...
It is very unlikely you'd have any problems using a newer ECU, and even if there were problems they would point to shortfalls in other aspects of your LPG install that you might want to put right anyway, in which case it would run better after making the changes than it could have run with the old ECU anyway.
I like to keep at least one good working example of an old type AEB ECU in stock but at the moment I only have an old OMVL one that is broken because it doesn't connect channel 3 on bank B petrol injector wires together when switched to petrol... works great on gas, but doesn't allow running properly on petrol! They prove useful for confirming install issues are due to modern AEB2568s, which seem to have issues particularly when fitted to some 6 cylinder engines possible example here, leading to another disagreement with Tinley.... I am just about to buy a complete old Zavoli (AEB2568 based) front end, trusting the seller on this that all parts are in good working order.
Simon
ECU in 'such as this' (Orangebean above) should work, provided the initial install was done to spec. Due to the none truly sequential nature of early ECUs (not reading any petrol injectors except front on each bank), on an older ECU you might get away with incorrect wiring on rear 6 cylinders where you wouldn't with later truly sequential ECUs. Then, when it works, there is scope (in certain limited situations) for the old ECU to deliver better results than the new one - SInce old ECUs only read Pinj from front cylinders, enrichment during acceleration for other cylinders could be adjusted/mixture enriched or leaned. On newer ECUs the adjustment only allows mixture leaning during acceleration, so, if you have very long pipe runs the older ECU could compensate for delayed gas delivery to ports by pulsing gas injectors for a bit longer, new ECU cannot.
Taught Tinleytech about this a few times, this was probably the most recent
Agreed with all points on 7805 trick, tbh I don't remember now where I connected 5v from 7805 but since it worked when I tried it I suppose must have been to serial connection. I only have one reservation on this... was it a fluke in my case, due to something unrecognised going on... e.g., an actual (communicative) connection on serial might wake some part of the main chip in the ECU, which might be the real reason for ECU working when serial connection is connected.
SImon
Replied to the LPG 5v issue on your other thread..
Been down this road many times before! Old ECUs sometimes fail in this way. Usually before the system fails to operate completely the 5v line goes wrong, which leads to incorrect readings such as temperatures, pressures and tank levels, all of which barring tank level throwing calibration off.
While you're connected with the laptop things can seem better because the 5v is held correct by the serial connection - Installs effected by the latter symptom can seem OK while setting up with the laptop but as soon as laptop is disconnected calibration goes wrong. If the serial connection can make all the difference, so too can a 7805 wired to the 5v wire at the serial port (or attaching 5v from elsewhere on the vehicle, since many vehicles use 5v sensors).
Gilbert might disagree... He took the 5v advice on LPGforum (working on someone else's car) a while ago and found it didn't work in that case.
I suppose if the 5v falls to miilivolts, could be that the main power feed voltage is pulled down when the system tries to power solenoids / injectors, i.e. solenoid coil or wiring short. Or 5v could be pulled down by failed pressure sensor. The temp and level signals can't really pull the 5v down even if shorted because of the ECU internal resistor on each sensor between the 5v rail (each sensor forms half of a voltage dividing circuit, meter of which is what respective AD converter gets).
The bit of track coming out of the switch seems ominous too.
Simon
You're welcome. I also meant to include... I would never fit 6mm on a P38, even for a mixer system, but wouldn't replace 6mm with 8mm if I was, say, replacing a mixer system with a sequential system on one. I've driven loads of P38s using 6mm with sequential systems and none of had a problem.
Simon
I just noticed this thread...
I generally go with 8mm for just about everything I convert these days, but that's just because I stock loads of 8mm Faro pipe and many various types of Faro fittings for this diameter, including fittings that (for 8mm Faro) emulate 6mm copper pipe ends.
Like Gilbert said, 6mm is considered OK to around 250hp. Very unlikely there'll be problems due to 6mm on a P38, even running a sequential system (instead of a mixer system).
Even on most stuff that needs 8mm pipe, 6mm fittings are usually ok unless you're dealing with something a fair bit over 300bhp. Even on a 310hp vehicle, which might use a reducer with 8mm inlet, it would be unusual to ask a supplier for a tank valve with 8mm outlet. For reasons that I don't fully understand but have a bit of an idea on, flow of liquid LPG through pipes isn't totally related to minimum diameter within that feed, an 8mm pipe with 6mm fittings will flow more than 6mm pipe with 6mm fittings.
Because tank pressure fluctuates with temperature and pressure versus diameter dictates flow capability, if you don't have problems in the depths of winter you're unlikely to have problems all year round. The first point here also explains 'even running a sequential system' - A mixer system supplies gas at near atmospheric pressure while a sequential system might supply gas at 1.5 bar. Tank pressure minus supply pressure is the pressure that pushes gas down the pipe, so it's possible to get away with smaller diameters on mixer systems for any given bhp.
Simon.
Gilbertd wrote:
Lpgc wrote:
Post contains a couple of minor errors, unlike my posts ;-)
What's that then?
Only messing mate ;-)
Gilbertd wrote:
So if the air filter gets a bit clogged, the mixture will be permanently rich (not enough air) so the short term trims will be going constantly negative to reduce the amount of fuel and get the fuel/air ratio correct again. This will cause...
Would be true of a petrol carb, LPG mixer system or AlphaN based fuel system but isn't true where fuel injection system meters air flow and/or manifold pressure..