Landy 90 Hybrid Posted February 7, 2008 Share Posted February 7, 2008 Afternoon all, I wasnt sure which sectio to put this in as she is a RR/90 hybrid, so here goes. She has a 3.5 engine in, ran fine when I got her, although my Dad always thought she had a slight lumpy idle, like she had a pot off, but ran great when driving. After a while, up until a couple of days ago when driving, especially when accelerating quite hard she would miss. It is like the all 8 pots would miss, not just one, if you know what I mean. Only for a split second then ok again. Now this is becomming more frequent. I have changed all leads and no difference. I looked inside the cap to see if there was any tracking but nothing. I dont know if its connected or not, but when revving her up, in P or N, and quickly back off the engine will cut out as the idle speed appears to drop too low, but this doesnt happen when driving? The dizzy is a type that I havent seen before (but there again I am used to a simple setup on a series!!) Inside there is a clear plastic cover type thing that is screwed down, Lucas on it I think, and on the outside of the dizzy, on the right hand side, if looking from front of vehicle is a small box of tricks. Does anyone have any ideas as to where to start and look for probs as I am hoping to have my first trial in her on Sunday and would love that to happen Your help/advice is greatly appreciated. Kind regards Jonathan Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 7, 2008 Share Posted February 7, 2008 Is it on Carbs or EFi? Quote Link to comment Share on other sites More sharing options...
Landy 90 Hybrid Posted February 7, 2008 Author Share Posted February 7, 2008 Is it on Carbs or EFi? Sorry, its on EFI Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 7, 2008 Share Posted February 7, 2008 The tech archive is your friend: Flapper EFI diagnostics Hotwire EFI Diagnostics Also a search in the Range Rover forum (where your engine came from) may prove useful since there seems to be an EFI problems post every five minutes in there Quote Link to comment Share on other sites More sharing options...
Landy 90 Hybrid Posted February 8, 2008 Author Share Posted February 8, 2008 Cheers for those pdf documents for fault findings. I have had a read through the flapper type, which mine is. I may be completely wrong here but I dont think the problem of the spluttering momenterrily when applying power is due to that. Has anyone else had this kind of problem? Kind regards Jonathan Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 8, 2008 Share Posted February 8, 2008 OK you've read it, have you actually done any of the checks? Quote Link to comment Share on other sites More sharing options...
Landy 90 Hybrid Posted February 8, 2008 Author Share Posted February 8, 2008 TBH no I havent done any of the checks, that was my plan for tonight when im back from work. Quote Link to comment Share on other sites More sharing options...
SteveRK Posted February 8, 2008 Share Posted February 8, 2008 If all 8 cylinders are cutting out and the 'sensation' is abrupt i would suspect ignition before looking at fuel. Low tension circuit - check ignition coli connections and ensure the area is clean as HT could track if covered with all etc. Depending on the age/model the ignition amp is either on the side of the distributor or by the coil - they are reputed to be troublesome. Worth while bending and twisting all related electrical wiring to see if the is an internal fracture - the worst kind of fault to trace! Quote Link to comment Share on other sites More sharing options...
Landy 90 Hybrid Posted February 10, 2008 Author Share Posted February 10, 2008 Hi guys, I have nad no chance of having a look this weekend as ive been loaded with cold, but thanks for the advice given. As soon as I can I will get it sorted. I missed the RTV today too so not very chuffed. Are there many members on here from the North East, Durham area? Kind regards Jonathan Quote Link to comment Share on other sites More sharing options...
Landy 90 Hybrid Posted March 13, 2008 Author Share Posted March 13, 2008 Evening all, just to keep you informed, and to see if anyone can shed some light. I have performed some of the tests in the fault diagnosis manual, and the results are as follows: Lucas 2AM AFM Test 6 - Voltage across resistor wire in AFM potentiometer - should be 1.55v - actual 1.55v Test 7 - Voltage through AFM potentiometer & the wiring to ECU Step 1 - should be 4.3v +- 0.2v - actual 4.34v Step 2 - should be 3.7v +- 0.1v - actual 3.72v step 3 - should decrease to 1.6v -+ 0.1v - actual 1.66v Test 8 - Ohms - Check internal resistance of AFM and wiring to ECU .............actual readings at.....ECU ...AFM Plug.... AFM socket Pins 6 & 8 - should be 360K - 396K....395K..........395K Pins 6 & 9 - should be 560K - 616K....614K..........614K Pins 8 & 9 - should be 200K - 220K....219K..........219K Test 9 - Voltage at throttle pot Step 1 - should be 4.3v - actual - 4.3v Step 2 - should be 0.325 - actual 0.30v (within tolerance) Step 3 - should be 4.5v MAX - actual 3.78v Test 10 - Resistance of air temp sensor in AFM I didnt have a temp probe so couldnt measure the temp, but measured the resistance and was within the scales provided Given that the voltages are mostly within tolerance, but the internal resistance of the AFM was quite a way out, how would this effect running, does it look like this could be causing me problems? Thanks in advance for your help Jonathan Quote Link to comment Share on other sites More sharing options...
nas90 Posted March 14, 2008 Share Posted March 14, 2008 What spark plugs are fitted? A good start with a V8 is to check plugs. I have only used NGK plugs in 20 years of V8 ownership, anything else is pants. Ignition is next and a good set of OEM leads, distributor cap and rotor arm. Get a good spark on an NGK plug and bingo! Quote Link to comment Share on other sites More sharing options...
landmannnn Posted March 14, 2008 Share Posted March 14, 2008 Diagnosis from afar is not ideal, but the most common problem with efi is air leaks. All those pipes need to be airtight, often worth jubilee clipping them to make sure. If this doesn't cure the problem you really need to go through all basic tuning systematically...timing, mixture, plugs etc. RV8s are very forgiving, they will run reasonably well on completely the wrong settings. Quote Link to comment Share on other sites More sharing options...
Landy 90 Hybrid Posted March 15, 2008 Author Share Posted March 15, 2008 Well I tried another AFM today and still had the problems, I was convinced that was the problem. Driving me mental now!!, I am going to miss tomorrows RTV She has had a new set of plugs, NGK's this week along with new leads, bosch ones. I will have to check timing and stuff next I guess, dizzy etc. Oh well, I am sure you guys will be kept posted. I think it will be something datf, and hopefully not too expensive! Jonathan Quote Link to comment Share on other sites More sharing options...
wuas680 Posted May 24, 2008 Share Posted May 24, 2008 Well I tried another AFM today and still had the problems, I was convinced that was the problem. Driving me mental now!!, I am going to miss tomorrows RTV She has had a new set of plugs, NGK's this week along with new leads, bosch ones. I will have to check timing and stuff next I guess, dizzy etc.Oh well, I am sure you guys will be kept posted. I think it will be something datf, and hopefully not too expensive! Jonathan Jonathan, I'm having similar problems with my 3.5 EFi Disco. I am also in the Durham area (Consett to be precise) so was just wondering if as a fair amount of time has passed if you managed to get rid of your gremlins. My problems are it will drive ok, but under powered for a V8, but at idle runs rough, and just had the awful event of it not starting for 5 minutes then coughing and spluttering unless the pedal was off idle. I love my Disco but wish i'd stuck with diesels - swaps anyone? Quote Link to comment Share on other sites More sharing options...
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