jjay Posted October 17, 2009 Share Posted October 17, 2009 Hi all, new to the forum so please be patient with me... really sorry for the long post but am trying to give you the history of whats been going on... recently purchased a 2000 on w reg 1.8 freelander with blown head gasket. Wanted one for ages and this one came up so thought i would bite the bullet and go for it. Had my local trusted garage fit the modified multilayer head gasket/shim,stem seals,modified green inlet manifold gasket and modified studs, head skim, new modified oil ladder, new modified expansion tank and cap, new modified thermostat assembly with pipes for radiator (old thermostat removed and blank fitted), new waterpump, new cab belt/tensioner, new alternator belt, new coil, new rotor arm, new leads, new dizzy cap, new battery... dont think ive left anything out?! so thats the history of whats been recently done. But..... now it seems i have a over fueling problem? starts perfect from cold and warms up fine, and also starts perfectly from hot. heater blows hot air, no mis fires etc. when you dab the throttle it takes upto 15 secs to drop back to tickover(which is a bit wierd), very strong smell of fumes from exhaust when hot but not when cold... and small amounts of white smoke from exhaust when warm. I have left the engine running for 2 hours and does not go above half way on temp gauge and radiator fan kicks in and out as it should with a nice hot rad and coolant does not drop at all so good coolant flow. The idle control valve is fine as the engine revs gradually fall as the engine warms up, and adjusts the tickover when you put load on the engine like lights and heated screen. this would also indicate the ecu is reading the temp sensor ok as it knows the engine is warming up and reducing tickover as it warm up. I have now replaced the coolant temp sensor (brown one for ecu) and read the resistance on it when its hot which is 400ohms = approx 85 deg c which is correct. I have also replaced the lambda (o2) sensor in the exhaust manifold, i have checked the voltage output on the lambda as it warm up and when warm, you can see the volts rise from .2 to .9 over a few mins as the engine warms up. from research .9v is very rich. i have checked the voltage at the ecu and also reads .9v so no break in the wires from sensor to probe, and have done the same for the temp sensor at the ecu (400 ohms) so i have no breaks in any wires. So it seems the ecu is being told the engine is warm, the exhaust gas is rich but isnt doing anything about it! i.e. leaning the mixture (reducing the injector pulse open times).... Two things i dont quite understand 1) i cant find a inlet air temp sensor anywhere? and 2)does the throttle position sensor also control the amount of fuel injected or is that just for the hill descent etc? (as when you unplug it the hill descent and t/c lights come on!) i am now confused as to whats going on.... and having spent quite a lot of money am starting to get a bit dis-heartened now any help please! thankyou... Quote Link to comment Share on other sites More sharing options...
pinny Posted October 17, 2009 Share Posted October 17, 2009 i know its a long shot but i had a head gasket go on a maestro van replaced gasket etc but it smoked like a steam train and the fumes made your eyes water i found this to be antifreeze burning which had filled the exhaust silencer etc after a lot of thrashing about this cleared just a thought ,chris. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 17, 2009 Share Posted October 17, 2009 Have a read of the V8 EFI diagnostics manual in the tech archive - it's not the same as the Freebie but a lot of the principles of EFI are in there. The ECU injects fuel based on all the sensors, but not all are relevant all the time. Air temp sensor is probably in the airflow meter. Have you checked the MAP sensor tube is connected properly to the ECU and engine and not split/leaking? A vacuum leak will make the ECU think the engine is under more load than it really is. It could be the antifreeze in the exhaust, how long have you run it for & have you given it a good run up & down the motorway to blow the cobwebs out? Quote Link to comment Share on other sites More sharing options...
jjay Posted October 18, 2009 Author Share Posted October 18, 2009 that is a good point about not reading all the sensors, as i know the lambda sensor is ignored over approx 3000rpm. This is the wierd thing though, there is no air flow meter! it uses a tps (throttle position sensor which is a variable resistor on the end of the accelerator butterfly shaft) to know how far the butterfly is open on the inlet, the ecu then knows how far open the butterfly is and can calculate how much air is going into the engine (along with engine revs). bizzar system!. i know the type of system your on about though as ive owned a rangerover 3.9 efi and had problems with the air flow meter on that one. the lambda sensor on the exhaust manifold is def showing .9 to 1v which is a very rich mixture, so its a fuel delivery problem as opposed to something in the exhaust. i have taken the inlet air duct completley off and searched everywhere for the air temp sensor and cant find one? replaced the vacuum tube going from the inlet to map sensor in the ecu tonight and still the same (couldnt see any split on the old one but worth a go...). from some research i now know the tps has a 5v feed from the ecu, but does anyone know what the output voltage from the tps should be at different throttle positions? or what the resistance of the tps is? as am starting to think this could be the problem...(although could be map sensor failure or something in the ecu?)? thanks for all your input so far! Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 18, 2009 Share Posted October 18, 2009 Aaah me not paying attention then thought they had a MAF as well as a MAP. In that case it's probably a normal speed-density MAP system and not working out the fuelling from the throttle position sensor. The TPS is used only to detect acceleration inputs (like an accel pump on a carb) and to disable the lambda sensor under high load (pedal pushed right down), although it may be used to adjust other aspects slightly depending on how advanced the system is. Quote Link to comment Share on other sites More sharing options...
jjay Posted October 18, 2009 Author Share Posted October 18, 2009 that was a nice link with lots of info! thankyou! the ecu uses the vacuum pressure and air temp to work out the air density... which leaves me a little bit worried as now i really need to find this air temp sensor! anyone out there know where it is please Quote Link to comment Share on other sites More sharing options...
jjay Posted October 18, 2009 Author Share Posted October 18, 2009 oh and tested the tps sensor... 5volts on the top wire, 0v (ground) on the bottom wire, and varying voltage in relation to the throttle position on the middle wire. Middle wire starts off at .65v at idle and finnishes at 4.9v at full throttle, a nice smooth increase in voltage from fully close to fully open with no voltage drops so seems to be working fine. have also carried out the re-calibration of the tps with the ecu, which is ignition on to position 2, depress throttle fully to floor and release 5 times, ignition to position 0, wait a min and start. didnt make a blind bit of difference. so think the tps has been eliminated from possible suspects....so its really starting to look like the air temp sensor which i cant find or the ecu is faulty so really need to find the air temp sensor! Quote Link to comment Share on other sites More sharing options...
jjay Posted October 18, 2009 Author Share Posted October 18, 2009 found the location of the inlet air temp sensor!!! found it on number 4 cyl injector inlet branch and its green. so gonna replace that tomorrow and see what happens then.....but what a stupid place to put it right next to the cyl head, its not going to get a true reading when the engine (and thus inlet manifold) gets hot, its gonna heat up the sensor too!!! mmmm ah well will let you all know what happens Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 18, 2009 Share Posted October 18, 2009 but what a stupid place to put it right next to the cyl head, its not going to get a true reading when the engine (and thus inlet manifold) gets hot, its gonna heat up the sensor too!!! mmmm ah well will let you all know what happens It's not that stupid - after all the thing is tuned to have the sensor there so the tune will be correct for the conditions it sees. Quote Link to comment Share on other sites More sharing options...
jjay Posted October 19, 2009 Author Share Posted October 19, 2009 have just replaced the inlet air temp sensor and still over fueling, its looking like the ecu's the only thing i havent replaced yet so thats te next thing im going to change...off to the scrap yards! Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 19, 2009 Share Posted October 19, 2009 Fuel pressure regulator (in the tank I think, as one piece with the pump & filter)? Quote Link to comment Share on other sites More sharing options...
jjay Posted October 20, 2009 Author Share Posted October 20, 2009 right have just replaced the engine ecu with an identical unit, now it will start for about a second and then die and thats it!. The key fob still works fine for central locking etc, dash lights up as it should, done the throttle position sensor calibration. Just wont start? plug the old ecu in and fires up straight away....does it now need re-programming or something? ? ? ? Quote Link to comment Share on other sites More sharing options...
jjay Posted October 20, 2009 Author Share Posted October 20, 2009 just spoke to a auto electrician and yes you do have to have it re-coded to the vehicle, the main control unit (ccu) talks to the engine ecu, and if the two codes dont match up then it wont start!. so its now booked in for tomorrow for reprogramming.... then i can get back to testing to see if the overfueling problems finally cured! or will have to look into fuel pressure regulators and fuel purge canister valves Quote Link to comment Share on other sites More sharing options...
jjay Posted October 21, 2009 Author Share Posted October 21, 2009 just got the freelander back after replacing the ecu and having it re-programmed...guess what..... STILL THE SAME!!!!! have now disconnected the vacuum pipe for the purge valve and blanked off the inlet pipe where it fits, that didnt cure it either.... am now gettin a bit p*ssed off with this vehicle Quote Link to comment Share on other sites More sharing options...
jjay Posted October 21, 2009 Author Share Posted October 21, 2009 going to try the last thing i havent replaced which is the fuel pressure regulator on the injector rail as suggested by fridgefreezer.... fingers crossed....(and yet another £52) that makes £832 so far trying to fix this problem along with the other £735 ive already spent, time to cry in my cornflakes! the ird had better not pack up next! lol Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 21, 2009 Share Posted October 21, 2009 I thought the fuel system was returnless with the pressure regulator in the tank? Certainly mine only has a feed line, no return. Quote Link to comment Share on other sites More sharing options...
jjay Posted October 21, 2009 Author Share Posted October 21, 2009 from x reg (i think?) onwards it was re-designed with the pressure reg built into the fuel pump, but earlier ones have the regulator on the injection rail and is controlled by a vacuum pipe going to the inlet manifold.... a little flat'ish disc mounted on the left of the rail next to injector no1..... Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 22, 2009 Share Posted October 22, 2009 Mine's a 1998 S-plate and has no return line. I'm slightly surprised you've managed to spend that much money and be no nearer fixing the fault Quote Link to comment Share on other sites More sharing options...
jjay Posted October 22, 2009 Author Share Posted October 22, 2009 Mine's a 1998 S-plate and has no return line. I'm slightly surprised you've managed to spend that much money and be no nearer fixing the fault the reason i took it that that was the fuel pressure regulator is that when i visited my local landrover spares supplier and looked on his parts exploded diagram, thats what it was listed as "fuel pressure regulator", but after yourself and a few other people saying its a non return system i investigated further.... theres 2 fuel pipes going to the bulkhead from the tank, so followed these and one goes into the injection rail and the other goes to the purge canister, no return from the injector rail, so yep your right its a non return system so the only place the fuel can be regulated is in the tank! i.e. fuel pump.... so you just saved me a £52 mistake! phew! thanks! so would i possibly be looking at fuel pump? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 22, 2009 Share Posted October 22, 2009 so would i possibly be looking at fuel pump? Possibly - although you REALLY don't want to know how much those cost! If you can find someone with a gauge to measure the pressure in the fuel rail that would probably be worth doing before buying - in fact I'd say you probably need to stop buying things until you've done a bit more testing as this has already been an expensive exercise. There is a fault with some early fuel pumps where the in-tank filter seal goes and they lose fuel pressure, the opposite of what you're saying but I thought I'd mention it anyway. Have you checked continuity from the various sensor wires back to the ECU? I don't know if there is a guide to fault finding the ECU with those engines (edit: yes there is, it's here), there is a lot of info on dvapower.com you may find something there. The engines are used in Lotus & Caterham as well as Rover & Land Rover so you may find info on the net from enthusiasts forums - sometimes different faults occur more often in other types of vehicle. A quick google finds this: http://www.75andztclub.com/showthread.php?t=33183 Also this: The common causes we come across with overfuelling on the dreaded K series usually confined to signalling error on O2 sensor/poor earthing. Coolant temperature sensor error or excessive fuel pressure. Check also the solenoid controlling vapour from carbon canister is not allowing fuel to be drawn uncontrolled. Finally check the integrity of the vacuum hose between inlet plenum and MAP sensor. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 22, 2009 Share Posted October 22, 2009 Just realised on further inspection the PDF linked to is for an aftermarket ECU for the K-Series so ignore that, sorry. Quote Link to comment Share on other sites More sharing options...
jjay Posted October 22, 2009 Author Share Posted October 22, 2009 wow is the fuel pump gold plated or something!!! thats quite a lot of money! Well after reading your post and already having done the things as listed in the 'quote' part of your post, and having carried out continuity tests from all sensors back to the ecu, i have booked it in for a testbook scan next monday. as you say is starting to get a bit expensive now! and could prob spend another £500+ and still not fix it. In the mean time you have given me some good links for reading and should keep me busy till monday thankyou for your help so far and will let you know what happens next!!! Quote Link to comment Share on other sites More sharing options...
jjay Posted October 22, 2009 Author Share Posted October 22, 2009 Just realised on further inspection the PDF linked to is for an aftermarket ECU for the K-Series so ignore that, sorry. oh well.... will have to twiddle my thumbs till monday instead.... Quote Link to comment Share on other sites More sharing options...
jjay Posted November 13, 2009 Author Share Posted November 13, 2009 i finally managed to fix it.. ... the new lambda sensor i fitted was faulty! so fitted a good quality one from NGK and it cured it! why cant people make something new that actually works any more..... would have saved me a LOT of money. anyway can start to use my freelander again now! thanks to everyone for suggestions and help. Quote Link to comment Share on other sites More sharing options...
hsf Posted November 2, 2012 Share Posted November 2, 2012 Had what sounds like a similar problem on a 1.8...........head gasket done,skimmed etc etc but runs lumpy on tickover ,hunting cut a long story short although it would rev and drive super tickover was sooting plugs and rubbish, double checked timing and although I had lined up two lines in centre of cam sprockets I hadnt lined them up with the outer marks,so in effect inlet was one tooth advanced and exhaust one retarded(a bit like I felt!) put it right and now runs sweet. Just make sure you got yours perfect before you throw more money at it ! I have done loads of cambelts over the years yet I lashed this one up !! from now on going to make sure I wear my specs checking timing marks.hope you get it sorted .Paul Quote Link to comment Share on other sites More sharing options...
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