Thread: Is injected gas worth the extra cash

Originally Posted by RonMcGr

Put it this way, do a search on the old LPG system and read the stories about back fire and damage to the intake system.

The injection system is almost identical to power from fuel injection and it WILL use a lot less than an old venturi.

As Pat303 says, why revert to an old system when there is a better one on the market.

Ron Mc, Ron B (P38a), GrahamH, it seems that LPG backfiring is a common occurrence, do any of you have an explanation for it, is it something to do with having a plenum chamber with enclosed air horns, or some other cause, I have had many LPG equipped cars and trucks (all carbied) over the years and have never had a backfire through the induction system, not once, they ranged from LPG only Impco Carby system to various Jap and Italian systems, dual fuel. Yet all you seem to hear nowadays is this backfiring problem, is there a solution, Regards Frank.

In my case, I'm pretty sure it was caused by the slipped liners and water getting past the liner.

After I changed the engine, the problem pretty much stopped. Nothing else was changed.

The injected LPG system is absolutely the way to go with a Rover V8.

There is no argument about that, assuming that we are comparing a well installed VSI system with a well installed fumigation system.

Of course it's possible to have a well installed fumigation system perform better than a badly installed VSI system.

The VSI systems are closed loop, meaning that they take advantage of the constant tuning that the factory's EFI system is doing to maintain the best possible fuel consumption and power.

Originally Posted by tempestv8

The VSI systems are closed loop, meaning that they take advantage of the constant tuning that the factory's EFI system is doing to maintain the best possible fuel consumption and power.

Lawrance, wouldn't that only apply if the EFI system was closed loop. My P38A Rangie is open loop - no O2 sensors in the system ex-factory.

Hi Ron,

Yes, you're absolutely right. I believe that the P38A up to a certain year 1999 (?) and indeed the Discovery I V8 (both with the GEMS ECU) are open loop systems.

The later generation P38A with the "banana" inlet manifold, code name Thor, came with O2 sensors, if I'm not wrong. I'd imagine that the Thor V8 would benefit most from the VSI system, being able to take advantage of the closed loop monitoring system.

Which model year P38A do you have, Ron? Ah, scratch that question, I just saw your sig.

Lawrance

I guess that the VSI system would still be good even with open loop simply because it's not likely to detonate the air cleaner box and MAF sensor into smitheens, which can happen with a carby LPG setup from time to time.

Any savings on LPG will be instantly reset to 0 each time this happens.

One of my friends sold his Disco II after the 3rd explosion. He bought a D3 diesel - I'm totally envious!

Originally Posted by tempestv8

I guess that the VSI system would still be good even with open loop simply because it's not likely to detonate the air cleaner box and MAF sensor into smitheens, which can happen with a carby LPG setup from time to time.

Any savings on LPG will be instantly reset to 0 each time this happens.

One of my friends sold his Disco II after the 3rd explosion. He bought a D3 diesel - I'm totally envious!

Still nobody has come up with an explanation of why the Backfires, I've never had one on any vehicle I owned that was fitted with LPG (dedicated or dual fuel), why the big Bang, Regards Frank.

I had a Ford Falcon on the carby style LPG and it also backfired. Not sure why either.