My Brother has bought a 2001 Freebie, need advice

[Soren Frimodt]

Yes, that is correct after over 6 years on this brilliant Forum I have finally found my way into this section!

Well long story short my Brother has bought a 2001 Freelander 1.8 Petrol. It has some faults (don't all Landies?)

In particular it has a very rough idle, and doesn't start very well. Further when picking up the revs from idle it sputters and generally doesn't seem happy with life. It runs quite smooth ones you get the revs up, but doesn't pull as it should.

Now, googling the issue finds many a suggestion, and most of them we've sort of ruled out. We've checked the compression and the highest reading was 125 psi and the lowest 110 psi the lowest being cyl. 4. This is of course not perfect but shouldn't be the cause of this I'm sure.

The Lynx tester keeps telling us there's a fault with the Manifold Pressure Sensor. If we erase the code it comes back as soon as the engine has been running. But looking on the Lynx it does go up and down in pressure depending on throttle position and engine speed. At idle it stays around mid 60'es (kPa) Can this be the reason for the rough running?

Is it a fault in the ECU itself as it seems to be located in there?

Or do any of you have any other suggestions?

Cyl. 4 doesn't seem to get as hot at idle on the exhaust as the other three and if you spray a slight bit of starter fluid in the inlet it purrs like a kitten.

Any ideas?

[discomikey]

when I get home ill pull you the test data for the sensor.

it should have either a certain voltage output or resistance through it in certain conditions, this is how you tell if it is bad or not. if it is bad the reading can still fluctuate, however only in the wrong "range" hence the code probably says something along the lines of "MAP sensor out of range bank 1" or similar.

Bank 1 you can ignore as it is not a V engine, therefore it is the only bank.

HTH

[discomikey]

have you got a noid light set? they will tell you if the injector is being told to pulse, if not then its electrical, if yes then pull the plug and check for a change in note, like you probably already do to diagnose a miss in your carby engines.

I would consider an injector leak off test after that (assuming that petrol injectors can be leak off tested???)

what is the P code its actually throwing up?

[Soren Frimodt]

Thanks mate We've tried all the 'good old tricks' that I would do on a carb'ed engine, water on exhaust manifolds tells us there is a difference, takes about three times longer to evaporate on cyl 4. Pulling off the plug lead doesn't really seem to do any differently whether its cyl 4 or any other, it just stumbles slightly more. At revs you can hear it clearer but still sort of the same no mater which cyl you disconnect. Yes I have been thinking about injector seeing as the starter fluid misting of the inlet makes it run smooth. But I feel about about disassembling anything in that area before its deemed absolutely necessary seeing as it is all plastic in the intake area.

Can't remember the code exactly but something with mostly zero'es It says 'Intake manifold pressure fault'

[dave88sw]

Just a thought, does it pick up if you spray starter fluid around the inlet manifold to head join, just wondering if you have an inlet leak.

[Soren Frimodt]

doesn't seem to that no, only if sprayed directly into the inlet. I know the plastic is prone to develop cracks but it doesn't seem to be the issue. My main problem is that I am yet to have confirmed whether the fault in the MAP sensor could be the cause alone, because changing it must mean another ecu, which then has to be coded to the vehicle..

[FridgeFreezer]

Could be leaky MAP sensor pipe, bit cheaper than a new ECU. The inlet manifolds do crack but can also wobble and loosen the gaskets / leak coolant into the inlet.

[discomikey]

do you have a vacuum leak? if you have a mityvac type thing you could tee it in and check that against the specs, if it wasn't firing a spark then that would come up as a fault code too. does your reader support live data? watching the lambda readings can give you a good idea of a fuelling issue, (on the rich side means its injecting but not burning on at least one cyl, on the lean side means that its not injecting on at least 1 cyl)

somewhere in the world there should be a set of specs for that too, lambda ideal mix as a rule should be 14.7:1 air to fuel. although how that translates into a signal at the sensor Im not exactly sure as its different for each vehicle.

[FridgeFreezer]

somewhere in the world there should be a set of specs for that too, lambda ideal mix as a rule should be 14.7:1 air to fuel. although how that translates into a signal at the sensor Im not exactly sure as its different for each vehicle.

On standard Zirconia sensors 14.7:1 is 0.5v, that's the same for all of them on everything. It's only weird cars like RRC's that use Titania sensors, or wideband ones (5+ wires) that would be different. Mind you, the signal will never hit 0.5v as it's a knife-edge switching response from the sensor, all you can say is <.5v is leaner, >.5v is richer, but if it's nailed at <.1v or >.9v something's not right.

[Soren Frimodt]

Thanks for the input guys. We've tried disconnecting the MAP vacuum line and sucking on it. We got it all the way down to 34 kPa. and if we disconnected it without doing anything else it read 98 kPa which is probably just a default maximum. The tester we are using does support live data yes and I have been looking at all of it however it isn't all of it I get completely, as in I don't know what its supposed to be. Also there is something weird about the decimals. For instance the o2 sensor reads between 1 and 7 volts depending on how warm the engine is. But I take it that is 0.1 to 0.7 volts otherwise it'd make no sense. So probably the o2 sensor is working as it should. In my very limited experience of injected car engines usually a bad o2 sensor doesn't make it run this rough, its mostly a problem when checking the CO at the MOT station. I think the next step is to try and blast a bit of injector/valve cleaner through the inlet with the engine running to see it will loosen any soot on an injector and possibly make it run a bit better. If it doesn't do any difference I fear an ECU swap is next. Just wondering if I can recode that with the Lynx? If I could it would be easy enough to just get one from a scrappy.

PS the ECU wouldn't know if the MAP pipe was leaking would it? How can it know if the reading is true or false?

[FridgeFreezer]

PS the ECU wouldn't know if the MAP pipe was leaking would it? How can it know if the reading is true or false?

Unlikely, a leaky pipe would just result in a lower vacuum reading, it'd just look like more throttle.

[Ally V8]

Long time since I did any diagnostic work on a K series... But 60Kpa at idle is way too high,should be more like 35-40. The ecu will struggle to find a sensible injector duration to make the engine run correctly.Get the right Map reading and it should come back right.

BTW the oxygen sensor on K series engines gives a very messy output,even when the engine is running well,as long as the output voltage from the sensor crosses the 420mV threshold up or down, they seem to be satisfied.

[Soren Frimodt]

Thanks Ally V8, just the kind of info I was hoping for. It really isn't much good getting a lot of data from an engine if you don't know if they are good or bad

The weird thing here is that when we tried sucking vacuum in the tube with the engine idling it didn't change note at all, and we got it all the way Down to 34 kPa IIRC. But perhaps not for long enough? my Brother used his lungs and he only held the vacuum for a couple of seconds, you think we should try it again with a surringe or similar?

[Ally V8]

You may struggle trying to suck that hard ! Let the manifold depression do it,and look for reasons why the live data reading is high.

[Soren Frimodt]

yeah I see your point, but the reason for the false reading can only really be internal in the ECU right? Unless of course there is something wrong with the rubber hose of course which is the first thing we'll check

[Bowie69]

Or any leak on the inlet tract....

[discomikey]

as well as it "holding a vacuum" a mityvac can be used "tee'd in" to read "live" vacuum figures, i.e. running the engine with it plumbed in and don't pull the trigger,

with stuff like this it is highly unlikely to be the ECU, it may be worth looking up a bloke called "scanner danner" on youtube, he is some form of us college diagnostics teacher and seems to know his stuff. he does videos on diagnosing different faults by looking at electrical sin waves and the sorts.

most of the time he uses an oscilloscope, but these tests can be repeated using either a mulitmeter or a diagnostic tool with live data, albeit less accurate in terms of samples per minute. but the method and key points will apply for sure.

we were taught at college this sort of stuff using some of his video's

[Soren Frimodt]

Righto! For those of you patient enough to follow this slowly progressing conundrum, I have a bit of news.

Yesterday we ran some injector cleaner trough the engine and it helped immensely on the Idle stability. However it didn't help on throttle response, pulling power, staring or for that matter the error with the MAP sensor (obviously) So, we set out to make absolutely sure there were no leaks in the intake area, and with a special lengthened hose on the Starter fluid we tried every single crack and gasket surface, no difference in idle whatsoever. So sure this is not the problem. After some head-scratching and pondering we decided to buy an analog vacuum gauge to check whether the readings from the ECU were false or true. Now the problem here is that the analog gauge has a default on 0 kPa and the default on the ECU is 98 kPa. So obviously they start from different ends of the spectrum. The ECU says 66~70 kPa and the gauge says 28~30 kPa which makes sense when you think about the fact that they come from different ends of the spectrum. So we decided it was time to compare with a known working car, and so we compared with a mates 400.000kms oil using, but smooth running Freebie. This had a reading of 45~50 kPa on the analog gauge. (we didn't have the time to connect the tester)

So all in all this tells me that his worn old engine draws more vacuum than our engine, so clearly something is wrong internally in the engine, correct? I see no other obvious reasons but sometime you miss the most obvious, so please do tell if you guys think there is something I've missed

[Bowie69]

Check the compression on the 400K motor and compare then? This would give a good indication if that is the cause or not.

[Soren Frimodt]

Thanks Bowie, but sadly that is not really possible. Suppose that in the it would be cheaper for us to buy a functioning car cheap that has failed MOT and then move the necessary stuff over. Especially seeing as this also needs the viscous, prop and rear diff. Would just love it if we could find the cause to this weirdness.

[discomikey]

i cant see how bad compression could cause low vacuum to be honest, although it would explain the poor cold starting and pulling power. have you checked ignition timing? and valve timing too?

[Soren Frimodt]

Hmm I suppose and engine that has say a bad valve would suck less in the intake?, and seeing as it doesn't really use any oil I suspect the somewhat low compression could very well be in the valves.. But I can see this thing is really expensive in engine parts, so if we open it up we better watch out not to spend silly money. But perhaps a simple valve job would work wonders

[Bowie69]

Basically yes, vacuum is in some ways measuring the efficiency of the engine, and to a point, the efficiency increases for a given compression ratio.

So a less sucky engine is likely to drink lots of fuel, whereas a smaller high comp engine will use less, generally.

[Soren Frimodt]

So to finish this up, after 1,5 month we finally found the culprit! I could've refurbished, installed and tuned like a 120 points and carburettors in this time! I know I know, stop bitching about old mechanics, just couldn't help myself!

So anywho keeping a very tight hold on that infamous parts shotgun all the time telling my Brother not to just buy sensors and boxes, finally we found out what was causing the low vacuum and what to my ear sounded like ignition firing way too late. The lower cambelt gear on the crank, one of the worst attempts on making a keyway is what Rover in there wisdom has done here and it had worn and twisted the lower gear, making the reading from the crank way off from the cams, ignition and therefore also the injection. Not having a Cam sensor, the engine didn't know what was wrong with itself. So once again a computer can't tell you everything that is wrong with these things. And apparently this is a very common fault. So there you go!