Petrol starting misfire probs only after running on LPG

[jrtonks]

Has anyone else ever experienced anything like this?

I had HKL look at the car last Friday (ongoing saga - not their fault though, they've been quite helpful). They changed the injectors for a smaller size and re-did the mapping. Car seemed to be running much better on LPG, but that evening the MIL (Orange engine fault) light came on. It's never done that before.

When I start the car now - only after it's been running on LPG - it misfires like mad for about 15 seconds and then settles down and runs normally (It is starting on petrol).
If I run it on petrol for a bit, instead of LPG, before I switch the engine off, it starts fine - no misfire at all.

I imagine this has something to do with the orange engine light. Has anyone any ideas? It's almost as if the petrol ECU is learning something bad from the LPG.

James
Volvo V70 2001 T5
Zavoli Zeta/Alesei

[dougie487d]

you will have to read fault codes because off eng managment light on which will point you in a direction

[andyvee]

Agree with Rossko - I have experienced the same with a Zavoli system on a Frontera 3.2 V6 - your mapping on gas is miles out so the fuel trims are going haywire.

When you start on petrol the fuel trims are now way out and it takes a while to correct back once the ECU goes closed loop after the lambda sensors heat up.

Get it set up again BUT run on petrol for a week (ouch!) to get the fuel trims back to where they should be first otherwise it is a waste of time.

Andy

[jrtonks]

I think you're right about this. I've been running it on petrol today - a long journey - and the MIL light has gone out again.

I've just bought the interface and software for the Zavoli LPG system from Ebay. When it arrives I want to have a go at setting it up properly. Do you have any hints?

Oh as an afterthought, when it was last serviced, the LPG fitter changed the injector nozzles as he said they were too big. I think he went from 3MM to 2MM (although not entirely sure). Are the new ones too small for this car (Volvo V70 T5 - 250bhp)?

All help is really really appreciated.

[andyvee]

My tip is do 2 autocals on the trot - it tends to be a bit more accurate. Save your config 'as is' first so worst case you can go back to the original setup. I personally would write down all of the settings and then do a factory reset before starting. Installers have access to an extra page on the software with the full map on it, but you shouldn't really need this as in most cases the software as it stands should suffice.

You need to be able to see what the fuel trims are doing so beg/borrow an OBDII reader that works with your car.

Get it right at idle first so that the fuel trims don't budge when switching between gas and petrol (a few percent each way is fine, but if it jumps 5% or more worth adjusting). You can do the adjustments from the F5 Modify carb page. There are some wideband adjustments (8 in total) you can make on this page which should sort out all but the most demanding mapping problems.

This is a 2 person job, one driving and one on the laptop. You need to concentrate on the Very Low Load and Low Load Idle and Out of Idle settings.

Which version of the software did you get? The later versions are a lot more accurate on the autocal, the latest version AFAIK is 5.0.7.256 - you need to do a firmware upgrade and reset to factory defaults before starting with this version though, not for the faint hearted and make sure you know what all of the settings should be - injector type, type of rev signal, ignition type, sensors, reducer, etc. You should have a Super reducer on your power output - if you haven't then the wrong reducer has been fitted (there is an S in the serial number of a Zeta Super Reducer). My power output is about 210bhp on a 6cyl and I have the super reducer and the largest nozzles for Matrix injectors, do you have Matrix (square black box) or Pan?

If you aren't confident in what you are doing then leave to the experts - you can easily make things worse!!

And Ross is right (as usual!!) - you need to know why the MIL is coming on in the first place.

Andy

[jrtonks]

This is all good stuff thanks. I just bought a variety of injector nozzles - 2.6 & 3mm. The 2.4mm ones that are in there at the moment are too small - this is what started throwing my petrol ECU out in the first place.

The software & harness arrrived this morning. Like you said, I don't have access to the 'professional' map page. The software is version 4.7 - which is a shame. You don't happen to have links to the later software & firmware do you

The MIL light codes (as read by the Volvo dealer) were related to fuel trims - so it looks like that suspicion is confirmed.

I was going to have a crack at changing the injector nozzles to the next size up and recalibrating tonight. I don't have access to an OBD2 reader - is there any way I can fine tune without?

Appreciated,

[jrtonks]

As an afterthough - yes, the regulator is a Super.

[jrtonks]

I contacted Zavoli in Italy by email & they responded PDQ together with the latest software and a pre-set map which they say is the one for my car. This map mixes petrol with the LPG from 3500rpm to keep the turbo happy and loads of other things I'd never have thought of doing myself. They said the map is for 3mm nozzles.

I'm aching to try out the upgrade, but need to borrow a friend's laptop with a 9-pin serial port. Unfortunately he's printing out wedding invites tonight (and tomorrow) arrggghhh.

If this works I'll post to say. I really recommend other users contacting Zavoli to see if they have a map for their cars. So far I'm impressed with their customer service.

J

[lpgelite]

It could be worth your while buying a USB - 9 pin serial adapter plug. Cost is a few quid off evilbay or slightly more from a computer shop.

My OMVL Dream XX1n uses the same electronics and RS232 lead for the generic AEB hardware.

For whatever reason the RS232 lead via an adapter works better than the native USB interface. Don't ask me why...

[andyvee]

I contacted Zavoli in Italy by email & they responded PDQ together with the latest software and a pre-set map which they say is the one for my car. This map mixes petrol with the LPG from 3500rpm to keep the turbo happy and loads of other things I'd never have thought of doing myself. They said the map is for 3mm nozzles.

I'm aching to try out the upgrade, but need to borrow a friend's laptop with a 9-pin serial port. Unfortunately he's printing out wedding invites tonight (and tomorrow) arrggghhh.

If this works I'll post to say. I really recommend other users contacting Zavoli to see if they have a map for their cars. So far I'm impressed with their customer service.

J

Well done! I have contacted Zavoli in the past and they have always referred me to the 2 UK distributors. One of these I have found particularly unhelpful, along the lines of you aren't trade so we don't have to talk to you.

Maybe your previous contact with HKL stood you in good stead - I am waiting for HKL to get back to me with availability of the new adaptive Zavoli ECU.

Andy

[jrtonks]

New adaptive ECU? I like the sound of that. Tell me more?

I've often wondered why the LPG ECUs don't come with a lead to connect them into the OBD2 port for a few days - so they can make the adjustments whilst you drive.

Regards,

[andyvee]

Exactly what the adaptive one does.

You do the autocal with adaptive turned off, and then turn on the adaptive setting. It then monitors the long and short range fuel trims via 3 wires connected to the OBDII connector and effectively has a LPG fuel trim on the gas ECU so that it adjusts to compensate for any errors on the mapping.

I guess the mapping has to be fairly close to start off with, so I doubt it will negate a bit of fine tuning before turning on the adaptive setting.

Once HKL confirm a price and availability I might well go for an upgrade.

Andy

[jrtonks]

Sounds like a plan

I spent half of last Saturday trying to adjust the ECU to make the car run better. Eventually I decided the injectors are tapped into the manifold too far from the inlet and switched the software to Anticipate Injection Sequence mode. I have no idea what this does, but I have to say it makes the car run a lot better.

I changed the switchover to 'on-deceleration' to make that smoother. The power is OK - not nearly as good as petrol, but OK. A lot better than it was with the smaller 2.4mm injector nozzles in (changed up to 3mm). Most importantly I don't seem to be upsetting the ECU fuel trims so much. It's starting fine from cold now.

I also changed the injector type to 'Zavoli 2'. I don't know if I have 'Zavoli 2' injectors though, as I can't find any way to identify them. They do say 2A on them (they are the PAN ones). The installation instructions don't make any reference.

It still idles noisily - but steadily at least. On petrol this car is almost silent. This might be a by-product of the injector hoses being too far from the inlet, or maybe it's just the injectors are noisy (they are, but I wouldn't have thought this would carry into the interior so much).
I'm going to try lifting the injector modules up off the engine and see if the noise lessens. I doubt this will be the problem though. I've thought about using those nozzles with the Teflon straws - any experience?

Appreciated,

[andyvee]

Zavoli 2 is a new setting the software - according to Zavoli it shouldn't be used!

If you have PAN injectors then set it back to Zavoli.

Can you read the petrol fuel trims whilst driving?

Badly transalted quoted from Zavoli documentation:

ANTICIPATE INJECTION SEQUENCE
It is a guided procedure which allows you to automatically perform an injection sequence and
anticipate the injection of fuel. The new timing of the injection sequence is determined in part by
the “Number of Benches” control (section F2 Lambda). This operation may improve the vehicle’s
performance, especially if the gas injectors are not too close to the intake manifold. Please use this function only when necessary, as it prompts the vehicle to ABRUPTLY switch from PETROL to
GAS.

[jrtonks]

I changed the software settings back to 'Zavoli' and it buggered the car up again. Even after another autocalibrate still wouldn't run - so I changed back to 'Zavoli 2'.

Whatever the setting does it seems to improve matters on my car.

I've a little list now. Gonna move the injectors further up the manifold and get an adaptive ECU. This should sort all the probs out (I really hope)!