Hello everyone, this is my first post here looking for help. My 2007 LR3 HSE (petrol 4.4 V8) has problem of requiring longer-than-expected cranking before starting, worse in colder weather. The symptom is not very consistent, sometimes it starts after 1-2s of cranking, sometimes it cranks for 6-10s before firing or may even require a second crank event (after the first times out). I have found that spark is not present during this time (at least on one cylinder I removed the plug from to watch for spark); however, the moment I see spark the engine is starting up.

I also have found that during this time of cranking (before starting) the engine RPM is reported as 0 (via GAP tool). The moment I see the RPM change from 0 cranking speed, the engine is basically already running. If i remove the fuel relay (to prevent engine starting) I see the same signals... some amount of time after starting cranking, the engine RPM increases from 0, but the amount if time cound be 1-2s, or much longer.

The engine runs 100% smooth after starting. There are no error codes (nothing related to the engine anyway, just a couple due to LED interior lights and a damaged ultrasonic park sensor).

I do not believe this is due to fueling issues (pump, relay, wiring, etc) because I have already gone though all of that. Fuel pressure is present, i can hear the pump prime for 3s after key on, etc. The battery is good and when a charger is on the vehicle it doesnt seem to make any difference. Spark plugs were also recently changed but they had made no diffference.

I believe engine RPM is measured by the crank sensor. I changed the crank position sensor and checked its pins over but its no better. It seems the cam sensors are not responsible for starting, more for cam adjustment when running (?). Next I plan to check over the wiring between the ECM and the crank sensor, and ECM connector etc. I may also scope the CKP but the odds of two bad sensors seems slim.

The problem seems worse in cold weather, and cold weather (Canadian winter) means you have less opportunity to get it started before you need a boost! The LR3 has 330 000km, its been mine for 12 years and its had relatively few problems, my family's favorite vehicle and i would like to keep it running!

Here is a link to a video of it cranking, but with no spark for several seconds (at least on this one plug), but as soon as spark is present (presumably on all cylinder) the engine fires up fine.
https://photos.app.goo.gl/Q87KPKbVpLJTV14h6

An image is attached of a relatively short crank before start (before non-0 RPM is registered), and after key off, a second starting attempt but this time with several seconds before start (several seconds before non-zero RPM). I am going to assume the delay in spark as shown in the video is directly related to the delay in the measured RPM during cranking.

I understand that if this is due to the immobilizer I should not have any engine cranking? I know on some vehicles (like my Toyota) engine will crank but not start if the immbolizer is preventing the vehicle from starting.

Am I wrong that RPM should be registering as soon as the engine is cranking?

Tonight I plan to go over the CKP wiring and ECU connection. This is my first post so hopefully I am following proper etiquitte


the first start on the left of the graph, after cranking is started (marked by the crank request) with engine starting moments later. Second crank request with much more cranking time before starting. It seems as soon as RPM is recongized it basically goes immediately to running.


Fuel relay removed to prevent engine start, engine cranking and several seconds later the ECU showing non-0 RPM... i suppose this proves that rpm should be registering even during a non-start.

 

I will add that the scope waveform from the CKP, right up to the ECM pins, looks fine. ECM pins looked clean and were cleaned again, and I dont see any sign of water that was ever in the e-box. The signal is present as soon as cranking starts however no RPM is reported as this is happening (see picture). Some time later, (could be 1s, could be 5s) right as RPM is reported on the IIDtool as non-zero, the engine is already basically running, fires up perfect and runs perfect. The long cranking is typically worse at first start in colder temperatures. Following starts are almost always better. I am wondering if under harder current draw (cold engine cranking) I am experiencing a voltage drop somewhere preventing the ECM from reading the Crank sensor (although starting with a charger on the battery doesnt have much effect on the severity of the problem).

I have a hard time believing the CKP signal (as read by the ECM and reported to RPM) is non-existent for a few seconds, but then is suddently present and working perfectly.

Possibily communication to the Gap IIDtool momentarily pauses during the cranking, producing the 0 rpm?

On the off-chance my theory about Does anyone know what other sensors might prevent engine spark? I will scope the cam sensors tonight, but I feel if they were defective i would know it (unplugging a cam sensor leads to a "F" - tranmission fault and i think reduced power mode. With an unplugged cam sensor (i just did one side) the vehicle starts up exactly the same and seems to run fine. A missing CKP however prevents starting altogether (although one time a forgot to plug it back in I actually had the vehcile start, barely, maybe running 1000rpm).

I will also monitor voltage on the ignition system, and I'll bypass the ignition supressor/capacitor for fun. I appear to have the "new" version (LR004160, it says "4h43-18801-cb" on the side) It also seems these are basically impossible to get, anywhere (local LR dealership, online etc). Maybe coil supply voltage is pulled down during cold cranks and that is preventing ignition...

Apart from self-induced issues (unplugging sensors etc) everything appears normal, no engine codes are produced after an extended crank.

Any input or ideas would be helpful.




This was one of the extended cranks, where moments after this picture the engine fires up and runs 100% smooth. During this time the CKP signal appears good but there is 0 RPM vias the gaptool.

 

For those it may help, I solved this by replacing the starter. The starter was cranking fine however during cranking a lot of electrical noise was being to the CKP waveform, the ECM was not able to detect the timing mark, could not determine RPM and would not fire/run injectors. I believe this problem is made worse in cold weather when cranking current is higher (more effort required to turn over a cold engine). I found this after replacing the CKP sensor (original sensor was fine), scoping cam sensors (they were fine), cleaning ECM connector contacts (they were fine), cleaning ECM grounds (the ones in the front right wheel well, they were a bit grimey but they were not the issue). With the fuel relay out to prevent starting I used a old drill to turn a wheel with timing marks simulating the engine's reluctor wheel (a point every 10deg with one "tooth" missing) to confirm ECM can read RPM fine during cranking when the ckp sensor is isolated from the starter. The new starter cranks the engine around 190rpm vs the old at around 140rpm, it a lot sounds different (sounds like a different vehicle now). This was the original starter on a 330 000km vehicle, likely worn/chipped brushes or commutator although nothing seems obviously wrong with it (I think they call this "polling").



I suspect the higher frequency noise during the timing mark affect the zero-crossing logic and prevent the ECM from measuring rpm



. The vehicle starts very consistently now within ~1s of cranking. The images below show a scope trace cranking (fuel relay removed to prevent the engine from starting) of the old starter (top left) vs the new starter (top right). the simulated cranking from the drill is bottom left. engine running is middle. the signal is clearly noisey only when cranking with the old starter.

 

Just wanted to say welcome to the forum, and that this is a truly excellent post!
I had a similar issue with my last LR3, but it did not vary with temperature.
It was so occasional that I never tried to get very far with a real diag on it, but if I had, this is exactly the route I would take.
Very interesting that it was electrical noise from the old sstarter. Mine had the original starter too I believe, with about 160k miles.
​​​Nice work.

 

Weird issue.... I wonder if the engine capacitor is faulty or if it would even matter in this particular case? Meaning I am not sure if the engine capacitor would eliminate the issue. But since the new starter does not cause the issue, moot point. Something must have been off with it.

 

At one point I did bypass the ignition capacitor/noise suppressor (remove, and join red to red-white to pass 12v through unfiltered), the one filtering power for the ignition coils, but this didnt have any effect. With it removed there would be a non-start because no power is supplied to the ignition coils. Side-note... it is strange that this part is basically impossible to find. The local dealer says is unavailable, and there isnt much online except for used parts. I do have the upated version. I should also say that this long-cranking issue has been getting gradually worse over the last ~5 years, and I did have this happen in warmer weather also but extended cranking times are much less of concern vs. -30 deg C days when you really need it to start.

I did also find that the engine will start in the absence of a CKP signal- after approx 5 seconds of cranking the engine will start and run, i assume resorting to crank sensor data for timing. It will run but in reduced power mode and show all sorts of errors, including "transmission" errors.. and its running horribly but enough to get home. In this state it would actually start more promptly than with a distorted CKP signal, which sometimes took one or full starting attempts before it decided to start.

I think in the last two weeks of troubleshooting I probably added another ~100- 200 cranking cycles to my starter so whatever problem was there, it got progressively worse through all extra cranking attempts (most of which with the fuel relay out).

It has been a few days now and its started perfect every time. This goes to show the value of the GAP tool, plus an oscilloscope in this case.

 

Thanks again for all the detail and followup. I'll have to forward this thread to the buyer of my LR3 that had a very similar, but still pretty intermittent, condition. I also bypassed the ignition capacitor and it made no difference. It is strange that that is one of those mysterious Land Rover parts that seem to be unobtainium.

 

This has been an excellent series of posts. Jrs. Well done!

 

I just wanted to thank you for your well structured post. I have had the same problem over a week and not much response from anyone. It is because of your post that I'm headed in the direction of the starter.

 

OK hope you find your problem. Its been ~8 months with my new starter and it still starts perfectly every time. The gap tool is a must for troubleshooting if you don't already have one!