TR674 Posted November 5, 2018 Report Share Posted November 5, 2018 Hello kind folk, I'm having a problem with 5 & 6 injectors having air in the line when left over night. It takes them a while to get pressure up and a nice spray cone. No external leaks I can see on the metering unit. I've bled them a few time now and still same result when left overnight. There is a lot of previous info on this forum, but I don't know where to start. The fuel injection system falls into the Dark Arts for me......... Regards Craig Quote Link to post Share on other sites
Mike C Posted November 5, 2018 Report Share Posted November 5, 2018 Make sure the check valves in the MU nozzles connecting injector lines 5&6 are working. Quote Link to post Share on other sites
TR674 Posted November 5, 2018 Author Report Share Posted November 5, 2018 Thanks Mike. this is most likely a dumb question, but how do I check them for correct working order? Quote Link to post Share on other sites
GT6M Posted November 5, 2018 Report Share Posted November 5, 2018 if yer on a so called newer filter type, the yans that so called specialists sell, then its this thats the cause of alot oft problemo,s ev a good think aboot it, a clue for ye, think deisels other things can be leak,n O ring int ends, allowing fuel t,sneek oot faulty non return valves int MU injector pipes get,n to hot, boil,n fuel int pipes an causing vapour lock. esp whenst engine is shut doon, as fuel is then sit,n int pipes, no moving as when pump /engines going move pipes away frae the rocker box if they clamped onit. leave bonnet open , let hot air oot the list is quite long if ye want it sorted for good,!! most moderns ev a fuel cooler, t stop fuel get,n too hot t,boil an this wid electroniic injectors, yer cars got basicly a olde diesel pump method of working, { pressure t,open injectors } air int system will kill the engine, ye gotta get rid oft problemo, and yer no alone, as most unfettled TRs suffer same fate M Quote Link to post Share on other sites
Mike C Posted November 5, 2018 Report Share Posted November 5, 2018 You could try removing the banjoes and blowing the non return valves clear with compressed air. Quote Link to post Share on other sites
Mk2 Chopper Posted November 5, 2018 Report Share Posted November 5, 2018 Have you tried swapping those injectors with say 1&2 to see if the problem is with the injectors or the MU? Do they rattle when you take them out and shake them? Could be the o ring has gone hard and is dripping/draining the fuel out over night. Quote Link to post Share on other sites
TR674 Posted November 6, 2018 Author Report Share Posted November 6, 2018 Chopper, yes the 'nipples' at the end of the injectors rattle. All others still have fuel pressure behind them. Quote Link to post Share on other sites
Mike C Posted November 6, 2018 Report Share Posted November 6, 2018 So 5 & 6 rattle , the rest are held closed by fuel pressure? You wouldn't have used any stale Australian high octane recently, it really attacks elastomers like O rings and non return valves . Quote Link to post Share on other sites
TR674 Posted November 6, 2018 Author Report Share Posted November 6, 2018 Mike, I use high octane as the car has higher compression (shaved head) and won't run on 91. I have to assume it was fresh going in........... Quote Link to post Share on other sites
Mk2 Chopper Posted November 6, 2018 Report Share Posted November 6, 2018 Sounds like the o rings are the issue, if you can get some it's fairly easy to sort out. If you run the car the day before and then the next day undo the fuel lines to those injectors you should see there isn't any fuel inside the top of the injector which confirms it's bleeding past the o ring inside. Quote Link to post Share on other sites
TR674 Posted November 6, 2018 Author Report Share Posted November 6, 2018 Thanks Chopper. I'll replace the O rings. Quote Link to post Share on other sites
Mike C Posted November 6, 2018 Report Share Posted November 6, 2018 1 hour ago, TR674 said: Mike, I use high octane as the car has higher compression (shaved head) and won't run on 91. I have to assume it was fresh going in........... Most of us have to use 98+ , but don't let the Australian stuff go stale in the tank. I add Stabil if I'm leaving the car unrun for more than a few weeks. Stale fuel will damage O rings and most other elastomers in the system. Hope you've solved the problem. Quote Link to post Share on other sites
astontr6 Posted November 6, 2018 Report Share Posted November 6, 2018 1 hour ago, Mike C said: Most of us have to use 98+ , but don't let the Australian stuff go stale in the tank. I add Stabil if I'm leaving the car unrun for more than a few weeks. Stale fuel will damage O rings and most other elastomers in the system. Hope you've solved the problem. To combat modern petrol all the elastomers must be made out of 'Viton B' minimum or you will have problems. Only use PI parts that have the correct elastomers in them i.e. injectors & MU's etc. old P.I. parts will fail & give you a lot of aggro. Bruce. Quote Link to post Share on other sites
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