I have recently purchased a 1992 XJ6 with some mechanical problems.
I hope to get some advice from other members to help figure out the most logical steps to correct. I was told by the seller that there was white "smoke" upon start-up for a couple of mornings but the car seemed to run OK for those days. Then car was started and taken on the freeway,it ran a short distance billowing more white smoke, then died. It has not started since.
No visible water in oil or oil in water.Exhaust pipes coated with black soot, as if running too rich or poor ignition. I have done a compression test, with #1 cyl at 220 psi;#2,#3,#4,#6 all at 170 psi; #5 at 90 Psi. Looks like a head gasket problem most likely, but I think it should still start, although run poorly.When removing the gas filler cap after trying to start, it sprays gas and air OUT under pressure (not whooshing In). I would like to Identify whatever else is going on prior to removing/replacing head gasket.
Car is in beautiful shape, has 148,000 miles. I have just replaced coil, but not the external condensor/capacitor. Any thoughts on next steps?

 

Weak #5 sounds like a head gasket. If so check your cats (both the ones in the ex manifolds and the ones in the ex pipes).plugged cats can cause the head gasket problem. Also make sure that you are getting fuel pressure and that the fuel rail is clean.

 

Thanks for the tips. I am unsure how to check the catalytic converters. Do they get plugged and restrict the exhaust flow to a point where the engine cannot run?
I disconnected the fuel line at the firewall end and had continuous flow while cranking, but have not purchased a fuel pressure gauge to measure pressure.
All electrical diagnostic tests come back within normal limits (according to Haynes)with two exceptions: Primary and secondary resistance levels on the coil were outside listed parameters (primary tested 1.1 ohms, and secondary was 7,300 ohms), so I replaced the coil. No change, but have good spark at the plugs.The resistance as tested at th water temp sensor(the one with two wires) was approx. 5,000 ohms, have not yet replaced. So... I have fuel, spark, compression,(albeit one cyl is low) but no starting. I would think it should start but run poorly.
Anyone have any other ideas??
Thanks for your time.

 

to check the cats disconect the manifolds from the head and the exhaust pipes and blow air thru each to see if there is a good flow of air thru them (usually a two person job on checking the air flow). also on my xj6 that had plugged cats the extra pressure from the cats not letting the exhaust flow screwed up the injectors,cleand rail and replace the bad injectors(with used ones from a pull a part yard).When after resurfacing the head and doing a valave job i punched out the cats in the manifold and reinstalled them (the car still passed emission test) punching the cats out is a real painj in the ***.also check fuel pressure