The Dreaded Misfire

Well just to update.....

Still running poor... draining money and motivation.

Things changed and checked.......made no difference.

- had 3 different injector looms Britpart and now on a genuine landrover.
- new injector seals.
- new AMC head, noticed oil level up slightly. now fine.
- new fuel regulator genuine.
- new fuel pump genuine.
- checked fuel pressure 60psi at head.
- new straight through exhaust as I thought centre box may be blocked.
- all injectors tested ok
- put a new injector in 5 as was going up to -10 cylinder balance and
appeared wet around 5 exhaust port. Its now + 2, but cylinders 1 and 2
now going into minus figures.
- exhaust manifold skimmed flat as still showing wet around exhaust port 5.
- new intercooler and silicone hoses as found air leak.
- new wastegate for turbo.

I found that the engine is lumpy around 1000 revs and starts with a distinct diesel knock sound. which cylinder I don't know as nanocom not showing anything way out on balance and its hard to pin the sound with a stethascope.

On driving seems very underpowered to 2000 revs then from 2000 to 2500 revs starts to misfire when the autobox wants to change gear. I reset the gearbox and it drove ok 1st,2nd and 3rd all at 2200 revs. That was short lived and symptoms returned as soon as more load put on engine. The engine will smooth out after 2500revs, but is still underpowered.

I have considered that I have a bent rod, but the vehicle can run ok when it wants, although only for short periods.

I'm wondering if the problem is with the autobox, as the tcu reduces engine torque on gearchange and possibly causing misfire.

Checking live data with nanocom, it shows everything working as it should. manifold pressure is slow to reach 220kpa but thats about it. checked turbo and there is shaft play, but I was told this is normal.

So thats where I'm at. Its still wet around exhaust port 5, but this is the lowest part of the manifold. It still misfires 2000 to 2500. I have a diesel knock sound at low revs. I've booked it in with a specialist I was told about, so I'll have to wait and see the diagnosis.

I will let you all know the outcome, as I hate threads that don't have a solution to help others.

what about the wastegate modulator? i mean this one www.discovery2.co.uk / Waste Gate Modulator - Over boosting or that's what u mean by "new wastgate"? ...if not check the connected pipes too

I've swapped the modulator and the wastegate actuator. Got a replacement actuator from forge Motorsport. Its a bit bling, but that was the only place selling replacements.

One thing I've noticed, is that when its driving badly, there seems to be delay in the throttle response. Press the throttle lightly and get nothing for the first 20mm, then the engine seem to jump and rev up. When its driving ok, the throttle is more progressive and no delay.

Might be clutching at straws, but it might ring a bell with someone.

Just a wild guess but it may be the throttle pot has a worn spot. You've changed everything else.

sabredylan said:

I've swapped the modulator and the wastegate actuator. Got a replacement actuator from forge Motorsport. Its a bit bling, but that was the only place selling replacements.

One thing I've noticed, is that when its driving badly, there seems to be delay in the throttle response. Press the throttle lightly and get nothing for the first 20mm, then the engine seem to jump and rev up. When its driving ok, the throttle is more progressive and no delay.

Might be clutching at straws, but it might ring a bell with someone.

Click to expand...

Seen this before... is this an EU2 or EU3 engine (get us the last 8 digits of your VIN if unable to say) and can you tell the part number on the ECU?

It also appears that you've seen this http://www.landyzone.co.uk/lz/f50/td5-misfiring-cutting-out-problem-finally-solved-125039.html

Have you tried a good known working ECU?

Rgds
Matt

Shifty1962 said:

Just a wild guess but it may be the throttle pot has a worn spot. You've changed everything else.

Click to expand...

Would this show up on the voltage readings on nanocom? If so what am I looking for?

MTurri said:

Seen this before... is this an EU2 or EU3 engine (get us the last 8 digits of your VIN if unable to say) and can you tell the part number on the ECU?

It also appears that you've seen this http://www.landyzone.co.uk/lz/f50/td5-misfiring-cutting-out-problem-finally-solved-125039.html

Have you tried a good known working ECU?

Rgds
Matt

Click to expand...

The engine is EU2, vin is 1a721073 and ECU part number is msb101340

Ive re input the injector codes using nanocom. One thing that confuses me though is say I type in code NLNMA and write to ecu, when I re check, the code says NLNME.

sabredylan said:

Would this show up on the voltage readings on nanocom? If so what am I looking for?

Click to expand...

Supply = 5 volts at all times

At idle:
Track 1 = 0.8 volts
Track 2 = 4.2 volts

At wide open throttle (WOT):
Track 1 = 3.9 volts
Track 2 = 1.1 volts

All these values are obviously affected by a certain tolerance.

At all times Track 1 + Track 2 = 5 volts (checksum = constant at 5 volts) but the ECU is constantly checking this and will shut the TPS down if the checksum deviates.

Track 3 has no meaning on a EU2 engine / MSB type ECU.

Has the ECU being chipped? Any signs of the top cover been removed?

Rgds
Matt

Not been chipped that I'm aware of. I've had the lid off to see if there was any oil inside, but there was none. I'll check the throttle and see what figures I get.

checked throttle with nanocom. Track 1 and 2 do add up to 5 volts, well 4.98 or something. Nanocom shows a reading in track 3 also, even though it should be a 2 track throttle. Track 3 reading doesn't follow track 1 or 2.

sabredylan said:

One thing I've noticed, is that when its driving badly, there seems to be delay in the throttle response. Press the throttle lightly and get nothing for the first 20mm, then the engine seem to jump and rev up. When its driving ok, the throttle is more progressive and no delay.

Click to expand...

This is typical of a sensor going duff, the ECU hesitates for a second then reverts to the default value in memory and kicks off. Have you followed live fueling parameters through Nanocom to try spot if there are any significant changes between the good and bad engine running modes?

ECU hesitation & rough running spots at high rpm could also be caused by a dodgy remap, but that's ruled out.

Suggest you closely inspect the engine loom, especially in the area around the ECT and going through the AC compressor. It's all very hot in that place and the loom has been known to get toasted and shorted against metal. Most sensors deliver a voltage that is proportional to whatever they are sensing as well as the feed, if the feed (+5 V) is modified the sensors response signal will be impacted.

Rgds
Matt

MTurri said:

This is typical of a sensor going duff, the ECU hesitates for a second then reverts to the default value in memory and kicks off. Have you followed live fueling parameters through Nanocom to try spot if there are any significant changes between the good and bad engine running modes?

ECU hesitation & rough running spots at high rpm could also be caused by a dodgy remap, but that's ruled out.

Suggest you closely inspect the engine loom, especially in the area around the ECT and going through the AC compressor. It's all very hot in that place and the loom has been known to get toasted and shorted against metal. Most sensors deliver a voltage that is proportional to whatever they are sensing as well as the feed, if the feed (+5 V) is modified the sensors response signal will be impacted.

Rgds
Matt

Click to expand...

Checked the wiring around the head and ac compressor, looks fine and renewed the plastic sleeving. Didn't pin the wires for voltage though, just a visual check.

I'm wondering whether the previous keeper has put a 3 track pedal on instead of a 2 track. I read this about nanocom diagnostics:-

"The type of accelerator has to be set according to the pedal mounted on the car. To know if the accelerator
is 2 or 3 trak, you have to read the inputs and check if the 3° track changes his value when you move the
pedal. Normally the euro 2 cars have the 2 track pedal and the euro 3 ones have the 3 track pedal."

Track 3 value changes on mine with pedal position. Like I said previously, the value doesn't seem to follow track 1 or 2.

Track 3 reading nonsense in a EU2 is normal.

Don't think you can install a 3-track TPS in a EU2 engine. The MSB ECU can't handle it.

Trying a working ECU is what would suggest next. Have pretty much covered everything else.

Rgds
Matt

Lengthy post...Sorry.

Well had it to the indy and they kept it for the day......Verdict is they can't find anything wrong with it. Very annoying as there obviously is!!! It has still got a tapping noise, loudest at around a 1000 revs. Engine shakes when it does this and cylinder balance goes all out of sync, being high + on 4 & 5, ok on 3 and high - on 1 & 2. It is also still missing at 2250.

Its really starting to yank my chain now!!!!!! It seems like most places are not skilled anymore and rely on fault codes. No Fault codes, oh it must be right then.

Enough ranting.............

The tapping....I'm drawn to injector 3. When I last adjusted the clearances, I wound the adjuster screw down, but just before it bottomed out I heard/felt a snap. I can only compare this to the snap of a spring under load which moves in its seat. the adjuster then turned a further quarter turn before bottoming out. I wound the adjuster back and forward a couple of times to check this and each time it made the snap noise.The other injectors made no noise at all. Cylinder balance readings on this cylinder seem fine on nanocom, so I don't know whether its a red herring. I don't mind changing the injector, but obviously I want to be sure that is the problem.

As for the misfire at 2250, I'm stumped. Some say its a harmonic of the engine. I'd have that, but not with the revs just hanging there, its a misfire. I'm going to send the ECU for testing. I spoke to Mike at Dynachip who says he can check them.

Just on a couple side notes, to eliminate them.

I checked the fuel pressure and found that it was around 4bar. The needle on the gauge was bouncing rapidly. The gauge is only cheap and not damped. What I did notice is the sound of the fuel at the regulator. It's like a rushing/hissing sound. The pump isn't whining, so is this normal?.....The pump and regulator are new, but the filter head is original with new air bleed.

At what revs should I see maximum boost on the turbo? I bypassed the modulator and attached a boost gauge at the turbo. When driving I was seeing 1bar at the turbo, unless you floored it when it went from 1bar to 1.5bar. These readings where at the turbo so it will be less at the manifold, pressure loss across the intercooler and pipes etc. A defender should see 1.1bar at the map sensor and a disco should be 1.3bar. Watching boost on nanocom, the modulator is activating at 1bar at the turbo, when really it should only activate when the map sensor sees 1.1 bar, my car being a disco. Its as if the ECU is asking for more boost and not getting it, hence activating the modulator early. The wastegate has 1.32bar written on it. This is obviously set at factory. With this in mind, modulator bypassed, the turbo should boost straight up to 1.32bar and open the wastegate to limit boost. This is obviously not happening, it will boost to 1bar unless you floor it. I've pressure tested the pipes and there are no leaks. Unless there is a leak on the inlet manifold, I'm wondering if the turbo is getting tired and not boosting in sync with the fuel map. I've replaced the wastegate with a new one and there is still no change.

Many thanks for all the suggestions.

tapping noise sounds as though it could be injector clearance's
, mine made a metalic tapping just above tickover, but sounded normal at tick over, i wwound mine in 1/2 a turn and tapping disappeared. if possible remove injector 3 if you suspect something wrong and at least inspect and re seat, or if poss try another injector to see if it clears the fault

I'm sure this car is possessed. Still running rough, but intermittent. Reset Injector clearances, still tapping. Sounds more like diesel knock, but annoyingly sometimes it does it(running rough/misfire) and other times runs well with no knock.

What i've found when running rough:

- engine has delayed throttle, taps and misfires upto 2500revs then smoothes.
- delayed auto gearchange and rough/snatchy changes.
- Ace seems to stop working, rolls in corners/ steering needs constant correction.

Found a fault code in the auto ecu - P1884 can message MD IND invalid (flag F_TL_MES).
Apparently this translates to invalid torque signal from engine ecu, however engine ecu not giving any fault codes. Anyone have any suggestions?

I quite recently have similar issue with my Disco 2 '99. It just "died" on road - after that I wasn't able to start it.

After changing dead fuel pump, wiring loom and fuel pressure car has problems to start, sometimes (and it's quite frequently) it just "dies" after that you need to spend some 5-10 minutes with starter grinding to start it again.

After connecting Nanocom - I have discovered that 2nd and 5th cylinders have high readings in '-', 1st and 4th cylinders have high readings in '+'. 3rd cylinder stays more or less around '0'.

I took my Disco to quite good diesel engine specialist that has done a lot of repairs for Land Rover diesels and he measured the injectors and found out that mainly they are all OK - except that they needles are a bit "dirty" - meaning that you need to clean the engine or especially injectors using some special fluid that is added to fuel. Or - if you have such thing in UK - then some fuel stations (like Statoil in Latvia) already sells diesel fuel with those special chemistry added so - running a couple of fuel tanks with this fuel and with high revs should cure the problem.

I'm planning to perform this Thursday - then I'll be able to comment more.

Today I run the engine with half-pressed accelerator for an hour with this fuel system cleaning fuel - and sound of the engine improved a little bit while idling. Tomorrow I plan to run the engine for hour or two and over tomorrow I plan to drive some 600km running just on the fuel system cleaning fuel. Let's see - how it will turn out

you will kill the engine m8.... i hope i'm wrong though

Why don't you check the wiring loom where it passes over the fuel cooler and is mounted through some conduit piping against the engine block. The wires there are prone to chaving problems and can create short circuits. Best to be reached if you undo the fixings of the cooler and pull it slightly forward.

There is also a description of this fault finding and fix on the net but I can not find it right now, if I do I will post the link.

Norbert