jimhill2000
New Member
- Posts
- 2
Hi, This is my first post so please forgive if I've put it in the wrong place or done something wrong!!
I bought my Disco (1995, V8 3.9) last year knowing that it had some faults. Since then my life and income seems to be coming more and more filled with fixing it, which I wouldn't mind if I actually got to drive it!
When I bought it I had to fit new head gaskets and a valley gasket to fix the problems it had, then all seemed fine until it was MOT time.
It failed it's first MOT for pretty much everything, most of which was sorted but the big problem remains - emissions and/or Lambda readings.
When it first failed, the theory was that the Cats may have been gone and that it could need a full service. NEw (albeit cheap) cats were fitted, along with air filter, spark plugs and all the usual bits. It still failed on emissions.
As I didn't have the facility to measure emissions myself, I contacted the local mobile mechanic to come round and take a look. After an hour of looking he felt that the problem may be something major. One thing led to another and in the end I pulled the engine out and rebuilt it from the ground up.
It's had crankshaft reground and new bearings (as the oil pressure seemed to take a while to build up), new pistons rings, heads skimmed, new camshaft and hydraulic lifters, oil pump overhauled, new HT leads, Irridium spark plugs - basically all the mechanical stuff in the engine has been removed, inspected, cleaned or replaced. Even had a new manifold on one side (drivers side) as the existing one had a crack in it.
Once rebuilt, it took an age to start, finally it started, it seemed to come into life when the ignition timing was moved way out of spec and brought back into line whilst turning it over but this may be a red herring.
Eventually it was all ready for next MOT - emissions better but still failed so new lambda sensors fitted. Try again, still fails. Tested the lambda sensors with the local mechanics gear and it seemed that one was faulty - yet another one fitted.
MOT again, still failed. I've tried resetting the MAF sensor (setting the voltage across two of the pins to 1.8volts with the ignition on but the engine not running) and this improved things but it failed MOT again.
Now I'm getting bored with trying to get the CO readings down blindly so I bought a Gunsons emissions test thing. The readings don't seem to tie in with the "official" test station figures but they do let me know when the readings are getting lower. A bit more messing about with MAF and I finally get the emissions down.
Off for another MOT. Whilist doing the emissions test, the drivers side exhaust, down to the cat, got so hot that the MOT had to be abandoned - it was glowing. Getting hot enough to melt the starter motor wire running close(ish) to the exhaust. The MOT tester asked if I'd fitted a cheap set of CAT's, which I had, so I made the decision to put the old ones back on as changing them made no difference.
I'm sure I've missed some things out as it's now failed 6 MOT's and I'm no further forward. It seems like it's over fuelling on the drivers side, but I can't yet prove this. Today I've used an infared thermometer and measure the exhaust temps on warm up. As it seems to be over fuelling, I've switched the injectors from one side to the other in case one (or more) of them is on it's way out. Still no difference. On starting the engine from cold, the drivers side CAT is a good 50 - 60 degrees(C) hotter than the passenger side after only a few minutes.
Getting desperate now - I need to get my Disco running as I'm moving house. Does anyone please, PLEASE, have any ideas!!! I'm all out of them and after spending the best part of £2500 on the engine so far I'm quite keen to drive it somewhere other than to and from the MOT test station!!
I bought my Disco (1995, V8 3.9) last year knowing that it had some faults. Since then my life and income seems to be coming more and more filled with fixing it, which I wouldn't mind if I actually got to drive it!
When I bought it I had to fit new head gaskets and a valley gasket to fix the problems it had, then all seemed fine until it was MOT time.
It failed it's first MOT for pretty much everything, most of which was sorted but the big problem remains - emissions and/or Lambda readings.
When it first failed, the theory was that the Cats may have been gone and that it could need a full service. NEw (albeit cheap) cats were fitted, along with air filter, spark plugs and all the usual bits. It still failed on emissions.
As I didn't have the facility to measure emissions myself, I contacted the local mobile mechanic to come round and take a look. After an hour of looking he felt that the problem may be something major. One thing led to another and in the end I pulled the engine out and rebuilt it from the ground up.
It's had crankshaft reground and new bearings (as the oil pressure seemed to take a while to build up), new pistons rings, heads skimmed, new camshaft and hydraulic lifters, oil pump overhauled, new HT leads, Irridium spark plugs - basically all the mechanical stuff in the engine has been removed, inspected, cleaned or replaced. Even had a new manifold on one side (drivers side) as the existing one had a crack in it.
Once rebuilt, it took an age to start, finally it started, it seemed to come into life when the ignition timing was moved way out of spec and brought back into line whilst turning it over but this may be a red herring.
Eventually it was all ready for next MOT - emissions better but still failed so new lambda sensors fitted. Try again, still fails. Tested the lambda sensors with the local mechanics gear and it seemed that one was faulty - yet another one fitted.
MOT again, still failed. I've tried resetting the MAF sensor (setting the voltage across two of the pins to 1.8volts with the ignition on but the engine not running) and this improved things but it failed MOT again.
Now I'm getting bored with trying to get the CO readings down blindly so I bought a Gunsons emissions test thing. The readings don't seem to tie in with the "official" test station figures but they do let me know when the readings are getting lower. A bit more messing about with MAF and I finally get the emissions down.
Off for another MOT. Whilist doing the emissions test, the drivers side exhaust, down to the cat, got so hot that the MOT had to be abandoned - it was glowing. Getting hot enough to melt the starter motor wire running close(ish) to the exhaust. The MOT tester asked if I'd fitted a cheap set of CAT's, which I had, so I made the decision to put the old ones back on as changing them made no difference.
I'm sure I've missed some things out as it's now failed 6 MOT's and I'm no further forward. It seems like it's over fuelling on the drivers side, but I can't yet prove this. Today I've used an infared thermometer and measure the exhaust temps on warm up. As it seems to be over fuelling, I've switched the injectors from one side to the other in case one (or more) of them is on it's way out. Still no difference. On starting the engine from cold, the drivers side CAT is a good 50 - 60 degrees(C) hotter than the passenger side after only a few minutes.
Getting desperate now - I need to get my Disco running as I'm moving house. Does anyone please, PLEASE, have any ideas!!! I'm all out of them and after spending the best part of £2500 on the engine so far I'm quite keen to drive it somewhere other than to and from the MOT test station!!
