Saab lpg issues..

[colin33]

Just got myself a Saab 9-5 2.3 turbo, was told there were slight lpg issues but they seem more than 'slight'.. On acceleration there is a big misfire, unless you accelerate very 'gradually'. It stinks of gas, and it seems practically every joint to /from each injector is leaking. I'm gonna start by re-hosing all these. At the moment the 'Baracuda' injectors are loose, and fitted as close to the inlet spuds as possible, fed from a 4 branch splitter. It's untidy, and I'm wondering if it would be better to install a set of fixed reg fast injetcors I have left over from another install. However, that will mean much longer and unequal hose lengths from injector to manifold spuds. What do you guys think?

System is: Stag -300-4 ECU, Zavoli Zeta reducer, Baracuda injectors.

[LPGC]

Does the Saab have the Saab engine or later Vauxhall engine? The Vauxhall is the more difficult to calibrate properly.

The Baracuda injectors are high flow but slow in respone, not injectors I would advise on the Saab (and particularly not on the Vauxhall engine'd model).

Good results have been had with OMVL injectors on Saab turbos but I would advise you fit Hana 2002 A+ 1.3 Ohm single injectors which should prove an easy swap for the single Baracuda's, you'll still have to recalibrate regardless of which injectors you fit though. I removed some Baracuda's from a relatively unchallenging (to convert properly) vehicle the other day, again they were unsuitable for the vehicle due to the slow response. I did a thread on this fix on a different forum, I may get around to copying and pasting that thread onto this forum.

Very likely the Zeta reducer (even a Zeta S) isn't up to the job, especially if the boost has been uprated. If pipe joints leak at idle they will definitely leak under boost conditions when there may be another 2bar of pressure in gas lines compared to idle. Would probably fit a bigger reducer while I was making any changes to the gas system, the Stag 300 ECU isn't capable of petrol addition either...

I've done quite a bit of work on LPG'd Saabs for an Aussie guy who lives and works in the UK specialising in big power Saabs and modifying Saabs, he makes the 2.3 into a 2.5 litre, fits a bigger turbo and different manifolds etc and runs them at over 500bhp lol. Full power in top gear would wreck the gearbox because 5th isn't as strong as the other gears. Been out in his cars with him, will easily spin the wheels in 4th.

[colin33]

Hi Simon, it's a 2006 with the B235R (260bhp) engine I believe, in standard form. I bought the car to tide me over while I fixed the engine on my Vectra, but wasn't anticipating another load of work to get it running properly! The reducer is a Zeta-S. Do you think my omvl reg fast injectors would be better than the existing Baracuda? I want to minimise spending and I have some here, but unsure how they'd work with the longer injector to manifold pipe length? (30-45cm)
I know very little about the history of this car, it was converted around 2011 by Anglia Autogas, who no longer exist as an lpg installer, so have no idea whether the original set-up worked well or not. The guy I bought it from had only had it a year, and told me it had never run properly on lpg. Not surprised with the amount of leakage!
If you weren't so far away from me Simon I'd be bringing it up to you to sort out, but for now I'm happy to take your advice I don't expect to be spinning the wheels in 4th though

[colin33]

Just looking at ordering some new hose, but what size hose is usual on these injectors and manifold spuds, 5mm or 6mm? And is lpg hose any different to fuel (petrol hose) can I use either?

[Gilbertd]

Very, petrol hose will turn to mush if you put LPG through it.

[Brian_H]

The OMVL injectors are 6mm > https://tinleytech.co.uk/shop/lpg-parts ... sl-904502/

The Baracuda ones I'm not sure, LPGshop suggests they are also 6mm https://www.lpgshop.co.uk/lpg-autogas-b ... injectors/

I'd use the gas/lpg type injector hose, I think you will find 6mm petrol hose won't stand up to gas long term, plus its likely to be much thicker than lpg hose so may be difficult to get onto the spuds with clips. (Edit - I took a while typing this out so didn't see Gillbertd's reply until after hitting submit!)

I'd also check the vapouriser iteslf whilst your looking at the car - I'd be suspecting some of your smell of gas may be starting from there, either due to a failed vapouriser diaphram (likely to show up as leakage via the vacuum connection but can fail in other ways) or due to a lack of hot coolant/getting too cold and struggling to control pressure effectively. Also likely to show up as a struggle to start once its been run and shut off for a while, as well as possibly explain your popping on gas. If you have access to obd diagnostics for the car it might be an idea to check if a particular cylinder is the source of the misfire, as that might allow you to rule it out being ignition related rather than gas related as well (though you need to stop the leakage either way obviously).

[colin33]

Thanks, I'm wondering if the existing hose is not of the lpg type, helping it to leak. I shall order the proper stuff! I've often had to repair leaks in my own two installations, where the hose has started to split at connections, and I've tried every sort of hose clip available but still have to regularly re-cut the pipe. Currently using click-clips but they tend to cut into the pipe eventually. I shall start by sorting out the hose leaks, then look at the reducer. What's your view on the injector hose lengths I mentioned earlier Brian?

[Brian_H]

Sounds to me like they are too long, generally shorter the better. But i don't know your engine and how easy shorter is to achieve - Simon would be better on that front. The lengths sound far too long to me for any injectors really if they are really that long.

Clip wise I've used these https://tinleytech.co.uk/shop/lpg-parts ... or-hose-2/ They are easier to remove than the other types, but seem to work for me. I've had the ones that you have to clamp shut on an install and found them to be a pain, but that was how it came. Ended up using petrol hose clips for those instead. You will probabbly find new hose to be better in that respect as its more flexible.

I'd give the whole front end a going over with soapy water whilst its on gas before you start, as that should tell you whats leaking too.

[LPGC]

Use LPG pipe for LPG not petrol pipe...

The Baracudas do use 6mm pipe. You could fit OMVL's, plenty Saab turbo's were converted using injectors on rails back in the day (including OMVLs) without particularly long pipe lengths and good results can be had with the OMVLs but still I'd go with inline injectors like the Hana's suggested. The OMVLs will be quicker than the Baracudas but won't flow as much gas when open. On turbo's you don't need as big nozzles (as much flow) compared to the power rating as you do on normally aspirated engines but turbo's have short petrol injector pulse duration at idle (for reasons I could explain) and if injectors are slow to respond this can lead to high multipliers and inconsistent fuelling especially around idle. Still, if this has run properly on gas before with the injectors you have fitted now it would point to something else being the problem like probably something related to the gas leaks...

You've said pipe lengths using OMVL injectors would have to be 30>45cm long, this would suggest that the distance between inlet manifold runners for cylinders 1 and 4 are between 60 and 90cm apart... If they are closer together than that then pipe lengths could be shorter? The outlets on the OMVL rail are spaced about 7cm apart, this could reduce pipe lengths to cyls1 and 4 by a further 3cm each.

The later turbo'd Vauxhall engine is more difficult to get good results on partly because of the way it adds 'extra injection' during acceleration, LPG ECU's can filter extra injection but some types of extra injection are more difficult to filter than others. If power is increased on the Vauxhall engine it can also keep injectors fully open momentarily especially as the boost comes in, this also creates problems but these can be dialled out with some ECUs and/or by careful selection of nozzle size and pressure.

[colin33]

Use LPG pipe for LPG not petrol pipe...

The Baracudas do use 6mm pipe. You could fit OMVL's, plenty Saab turbo's were converted using injectors on rails back in the day (including OMVLs) without particularly long pipe lengths and good results can be had with the OMVLs but still I'd go with inline injectors like the Hana's suggested. The OMVLs will be quicker than the Baracudas but won't flow as much gas when open. On turbo's you don't need as big nozzles (as much flow) compared to the power rating as you do on normally aspirated engines but turbo's have short petrol injector pulse duration at idle (for reasons I could explain) and if injectors are slow to respond this can lead to high multipliers and inconsistent fuelling especially around idle. Still, if this has run properly on gas before with the injectors you have fitted now it would point to something else being the problem like probably something related to the gas leaks...

You've said pipe lengths using OMVL injectors would have to be 30>45cm long, this would suggest that the distance between inlet manifold runners for cylinders 1 and 4 are between 60 and 90cm apart... If they are closer together than that then pipe lengths could be shorter? The outlets on the OMVL rail are spaced about 7cm apart, this could reduce pipe lengths to cyls1 and 4 by a further 3cm each.

The later turbo'd Vauxhall engine is more difficult to get good results on partly because of the way it adds 'extra injection' during acceleration, LPG ECU's can filter extra injection but some types of extra injection are more difficult to filter than others. If power is increased on the Vauxhall engine it can also keep injectors fully open momentarily especially as the boost comes in, this also creates problems but these can be dialled out with some ECUs and/or by careful selection of nozzle size and pressure.

The only reason the pipes would be that long is if I put the injector rail where it will fit neatly and comfortably, but I could sit it on top of the rocker cover to keep the pipes short, it just looks a bit naff there and will be very close to the bonnet, not sure there's much clearance. In fact I suspect the omvl rail will be too bulky to sit there, but If I do manage to fit it in what nozzle size would you suggest? 2.5? The picture shows the current set-up, with the Baracudas stuffed in, tight radius on the pipes and all leaky

[LPGC]

You might prevent leaks at the 'gas distributor' end by using an aluminium gas distributor/manifold rather than the plastic one and using some better jubilee clips. The only negative of the aluminium manifold is that the pipe outlets are closer together so you might have to alternate the positions of the worm-drives on Jclips. The type of pipe clips used on this sort of setup can make all the difference but can always tighten Jclips more on aluminium distributors than on plastic ones.

If the existing gas feed pipes were not in the way an OMVL SL rail might fit in the space below the plastic breather pipe?

If you use the OMVL SL's remove the brass nozzles completely. The only potential problem is that if the reducer is Zeta it might not like pressure adjusting away from 1.2 bar, or 1.5 bar if Zeta S, which might be a bit too much pressure. I would still advise the Hana 2002 A+ over either of the other types of injectors but again your biggest problem may be unrelated to injectors. Suggest you sort leaks first, then look at calibration, then start looking at components if no joy? Since you can post pics now can you post screenshots of your LPG settings/map/RPM correction?

[colin33]

Thanks for the advice Simon. The gas distributor doesn't appear to leak, it's the injector pipe ends that leak each side of the injectors, and possibly the pipe ends on the manifold, which are inaccessible and the pipes cut short making it impossible to tighten the clips on a couple of them. It was also leaking around the map sensor, not sure if it was pipe joints or whether leaking back via the reducer, as Brian suggested earlier. I'll sort all the pipework first. I plan to remove the clutter so that I can get new pipe and clips at the manifold end and go from there with a bit of extra pipe to play with. I haven't yet plugged this system into the laptop, I've downloaded some ac/stag software, but will I need to buy a lead/interface? The plug looks the same as my AEB/King set up, are they the same or do I need to buy specific to the ac/stag?

[Brian_H]

If the list from here > https://www.lpg-kits.com/Pages/interfaces.htm or here https://tinleytech.co.uk/shop/lpg-parts ... systems-2/ is right, and I'd suspect it is, then the plug is the same but the centre pins are swapped over.

If you don't want to butcher your lead and don't have the one with interchangable ends, then Tinley have both types listed. The one you need is the Stag/Kme lead https://tinleytech.co.uk/shop/lpg-parts ... -usb-lead/

[colin33]

Thanks Brian, I'm pretty sure my lead is already butchered with a choc block connector from a previous issue, so I'll give it a try over the weekend

[Brian_H]

Just in case you haven't got the right software, theres a load available from here https://projekt-tech.com/diagnostic-programs-pm-23.html as there are several different Stag versions.

[colin33]

I don't s'pose this is helping matters, broken nozzle under the map sensor! Are these nozzles replaceable or do I need to buy a new unit?

[LPGC]

Lol... No that wont' be helping matters at all.

You could replace the whole unit for what they cost, or try to fix another pipetail where that one is broken, or probably easier than fitting a new pipetail block that end up and fit a vacuum T so both the sensor and reducer get vacuum (that is if you want to connect the reducer to vacuum - initially your install didn't have the reducer connected to vacuum).

[colin33]

Lol... No that wont' be helping matters at all.

You could replace the whole unit for what they cost, or try to fix another pipetail where that one is broken, or probably easier than fitting a new pipetail block that end up and fit a vacuum T so both the sensor and reducer get vacuum (that is if you want to connect the reducer to vacuum - initially your install didn't have the reducer connected to vacuum).

Yes this broken T, one end went to reducer, the other to manifold. Just ordered a new one, although your idea of blanking the broken end and T'ing off the other side would've saved me a few quid and a few days I'm now having fun trying to fit the new hose to the manifold spuds, Tinley's 'thunderflex' pipe is a bit slack on the 6mm nozzles, and the extra outside diameter of this hose makes fitting pipe clips 'interesting' ...

[LPGC]

Thunderflex is good quality hose but as you've found out can be a pain in other ways.

How tight were the old pipes and are you sure the installer didn't fit 5mm manifold spuds (nozzles)?

[colin33]

Yes, it's definitely tricky getting into tight spaces, and is a slack fit on the 6mm omvl injectors I'm trying, not sure if the spuds are 5mm but the new 6mm pipe seems tight enough once secured with mini jubilee clips. Had to file away some of the plastic petrol injector casing on one of them where the spud was a fraction too close not allowing the new pipe to slide on. In hindsight it probably would've been better to buy 5mm pipe all round. I've moved a few things around and squeezed the injector rail in, but there are some tight radius's on the new pipe, what do you think?