As it was me that had asked Simon about the workings of an Etagas system, I figured I may as well carry on here. My interest was because my mate in France has recently acquired a P38 Range Rover fitted with an Etagas system but it ran very roughly with a strong smell of gas. I was down there this weekend so we set about getting it sorted.
I knew it was an Etagas from photos he'd sent me when he first got the car.
Two of the early metal bodied manifold units and a reducer with loads of blue tape on the wiring (not exactly CoP11 compliant then). In addition the coolant plumbing was in parallel with the heater matrix with about 8 potential leaks and the pipework run high up making it the highest point in the cooling system. This probably explained why it only switched over to gas sometimes as it only sometimes got sufficient flow to get it hot enough. Time for a bit of maintenance I think.
I told him that he probably needed to give the steppers a good clean with carb cleaner so he got stuck in to that. The gas hoses were rock hard and cracked with age so he ordered some hose from Tinley Tech and replaced the main feeds from the reducer to the manifolds. It still ran very badly and smelled strongly of gas. I told him not to try it again until I got there to have a look at it.
Started off by replacing the coolant hoses with nice new hose I took down with me and fitted that with new reducers to connect the 16mm hose for the reducer to the 19mm hose on the Range Rover heater hoses. He'd also ordered some new 4mm hose to go between the manifolds and inlet spuds as the ones on there were also hard and cracked but hadn't done anything with that. So while I get stuck into the coolant hoses, he started taking the old small hoses off. They were rigid and the only way they would come off was by squeezing them on one side with a pair of pliers so they cracked and came off in bits. All was going well until one of the brass nozzles in the manifold snapped off flush with the manifold.....
We found that a T15 Torx bit was a bit too fat to go into the remainder of the nozzle but by grinding the end of it to a point it could be tapped into the brass and the 5mm threaded piece unscrewed. Then we tapped an M5 thread onto the end of a bit of copper brake pipe and screwed that into the hole instead so we had something to connect the hose to. Carried on and, a little more carefully, removed and replaced the remaining hoses. Time to try it and see what happens.
Ran the engine until the coolant hoses to the reducer were nice and warm and blipped the throttle, the LED on the switch came on to show it running on gas, it ran roughly and I got a facefull of Propane out of the heater vents. That's not right. So time to look for a leak. Soapy water squirted around showed nothing. Tried energising the tank solenoid and no leak. Tried energising the reducer solenoid and got a very big leak from the reducer although still couldn't see where it was coming from so the reducer came off to be put on the bench. We figured that if we couldn't find where it was leaking from we could always use an air compressor instead of gas. Undid the screws holding the top on and found a pristine looking diaphragm and a big spring. Nothing appears to be wrong with that. Unscrewed this diaphragm and found another one underneath it. Alongside that was a 6mm drilled hole in the reducer body so we figured that if this diaphragm was allowing gas through then it would be coming out of that hole. Took the diaphragm off and it was split. Now we had a problem so thought that even if it only lasted a few minutes we should be able to confirm the problem if we could get it to seal. So both sides of it were coated in silicon sealer and we went for lunch.
I finished my coffee and went to join him in the workshop, took one look at the diaphragm and asked what the hell he'd done to it. He'd decided to improve the seal by cutting a piece of rubberised canvas from a boat cover and sticking that to the old diaphragm. Not sure this is going to work but there's two chances, Bob Hope and no hope probably. Put the reducer back together and bolted it back onto the car. Energised the solenoids and both opened but no smell of gas. Started the engine, got it warm, blipped the throttle, it changed over and ran like a dog. But at least it ran. It sounded to be on no more than 6 cylinders so I plugged my code reader in and looked at the lambda outputs. Bank 1 was switching nicely but bank 2 was showing permanently lean. Turned it off and pulled one of the steppers out of the bank 2 manifold (the one Simon has called stepper B). It looked fine but we had no way of knowing if it was or if it was doing anything so decided to swap it with the one from bank 1 manifold. That way if the problem moved we'd know if it was a dodgy stepper at least. Swapped them over and started the engine again, blipped the throttle and all 8 cylinders burst into life on gas. We'd cracked it! Whether the spring or something had jammed when he'd taken it out to clean it or it simply hadn't been making a good electrical contact we've no idea, but it was working so we weren't going to play about with it any more.
The gas pressure is way out so causing the fuel trims to shift quite a lot when run on gas so now it runs poorly on petrol when it first changes over as the trims have to reset themselves again abut as the diaphragm is double the thickness it was that should be sorted once the new one arrives from Autogas 2000 along with a new nozzle to replace the broken one.
The only remaining problem with it now is that the gauge reads permanently full but that may have something to do with the two wires (green and white if I remember correctly) from the ECU not being connected to anything, just left dangling near the bulkhead. He has since had a brilliant idea and cut a hole in the boot floor and put a bit of perspex in it so he can see the gauge on the tank just by opening the boot. However this does mean that he's had to leave the gas tight lid off the 4 hole tank so I've pointed out that this isn't such a good idea. If anyone recognises the gauge type and can tell me how it needs to be connected, it would be much appreciated......