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[MaDfx]

Weird one - At least it is to an inexperienced chap like me. I have done an exhaust manifold swap. Running before - ran for about 2 mins really lumpy after refitting but now it won't start at all - and there are no error codes - no OBVIOUS schoolboy plugs hanging off, fuel in tank and pressure on rail, all fuses in tact too All relays click over as they should.... Fitted a new Dizzy cap and arm...(originals were a bit cruddy but I have seen worse) I have a spark, but no fire. Now I know that the new manifold was oiled up to prevent corrosion in storage and this did burn off externally and internally. My thinking is it has coked the lambda and/or the cat has disintegrated and blocked the exhaust. In the absence of fault codes I am mystified. The only other thing that I am thinking is that the crank sensor has gone? There is only a faint whiff of unleaded at the tailpipe. So fuel is not getting through somewhere, either down the exhaust or out the injectors?

Anyone else any ideas?

1995 4.0 petrol Auto

[Lukemagnum]

Have you put the HT's back in the right order?

Try putting your old components back on.

Your O2's should easily handle a bit of oil mist and will only influence fuel trim, it shouldn't stop you starting it.

[demonicwillow]

If you have a spark then your cps is working, check the inside of the new dizzy cap, xj distributor shafts wear elliptically quite badly, if its worn then when a new rotor and cap is fitted the rotor smashes the contacts inside the cap, refit the old rotor and cap n see what happens.

[MaDfx]

Thanks for the suggestions. I have it nearly fixed....

I have tried all the suggested fixes, plus tested all the sensors and injectors (compared resistance across all 6) on a fluke, Spark definitely there with old and new parts. The Old Dizzy cap is corroded but not worn on any contacts so I am guessing no eccentric wear??? I even loosened the manifold/downpipe joint to see if back pressure was the issue... Nothing... So I have air, I have power in and out of the coil (so there should be a spark) and I have no error codes still. Still cranking and no smell of fuel from the rear. So lets start at where the fuel comes from then.... New Filter... No leaks.... Five more litres in the tank... Check the pipework... Ahhhhhh.... could this be the problem...

I have had the tank off to weld the panel round the tailgate pin. When putting it back on, the fuel pipe from the pump to filter was wedged above the return pipes, which were then clipped in place.... In my defence I did that bit in the dark.

Re-routed the fuel pipe under the return pipes. Tried to start it again and It's firing intermittently but not starting. Strong smell of fuel at the rear now.  Pulled the plugs, they are coated in carbon and they were clean before.... I am guessing that the restart before it died it was running with a weak spark due to the dizzy cap crud which has layered up some soot... so I am charging the battery again and cleaning the plugs with an old toothbrush and fingers crossed, running Jeep... If not, new set of plugs in tomorrow night!

[demonicwillow]

Sounds like the ht leads are in the wrong order to me 

[MaDfx]

It was the fuel pipe being trapped and truly terrible spark plugs. The HT leads were in the right order. You were right Lukemagnum - Lambda is back to normal after a 10 minute run. Time to top off the coolant and give it a big burp and run it to the MOT station... Thanks for your input!