[SS-Traveller]

Originally Posted by Jeroen

For instance the 'dreaded check engine light'?

Rarely would a CEL shut down the engine. More likely, it would make the car go into limp-home mode with the revs limited to a certain level, say 40-50% of redline rpm.

Originally Posted by Jeroen

I actually carry a handheld OBDII meter in the back of my Jaguar XJR

I've always wondered how robust these instruments are, and whether they can survive constant battering when packed into the boot of a car traversing Indian roads.

Originally Posted by Jeroen

On many cars, disconnecting the battery will reset the ECU partially and is known to often clear these sort of issues.

True. But if one has a trouble code that caused the CEL to come on, erasing that trouble code by "rebooting" the ECU won't do much unless one fixes what's wrong. OTOH, removing power from the ECU on many vehicles makes it lose its memory (I am not sure if in some newer vehicles, ECUs have "non-volatile" memory and would not lose their memory when power is removed?), so "rebooting" will force the ECU to re-learn the car's behaviour. It will start with default settings/maps and adjust fuel/air mixture, timing, transmission shift points, etc. based on how the sensors behave in subsequent driving - at the very least, it might reduce the fuel efficiency, and many an Indian owner may not like it!

If one wants to "reboot" the ECU, remove the battery cables and wait about 15 to 30 minutes. And then reconnect power. The wait after disconnecting power is required because these have capacitors (IIRC that is what those are called? correct me if I am wrong.) which continue to supply power to the ECU after battery cables are removed. It takes a bit of time for the capacitors to drain.

[kaushik_s]

Excellent article. This surely going to help loads of people.

One thing I've learnt the hard way is to have the fuel lines clogged due to particles in the Diesel. Normally when we go to off-beat places like Ladakh, Arunachal etc we have to rely on open fuel sold in jerry-cans. Many times these diesel will have lots of particles and which will eventually block the fuel line completely and would create air lock. In such case just normal priming of the pump won't work and we have to go a bit dirty to get the line cleaned. Option is to open the fuel line at the pump and suck in using mouth as hard as possible (yeah a very dirty method and be careful not to drink the fuel ). Probably blowing in to the pipe also might work but there is a filter at the end of the pipe, inside the fuel tank. So not sure if blowing into the pipe would work as effective as sucking in the fuel. The fuel inlet cap also need to be kept open during that time. This is what had to be done when we had a similar problem in Arunchal and the nearest service center was around 300kms away.
Experts, please correct me if this is not a right procedure or there is any better solution. But this is what saved us that day when we were stuck and my car just refused to start as there was no fuel coming from the tank due to the clogged line (a big thank to the Indian Army for the help during this failure).
Regards,

[Jeroen]

Originally Posted by SS-Traveller

Rarely would a CEL shut down the engine. More likely, it would make the car go into limp-home mode with the revs limited to a certain level, say 40-50% of redline rpm.

I've always wondered how robust these instruments are, and whether they can survive constant battering when packed into the boot of a car traversing Indian roads.

True. But if one has a trouble code that caused the CEL to come on, erasing that trouble code by "rebooting" the ECU won't do much unless one fixes what's wrong. OTOH, removing power from the ECU on many vehicles makes it lose its memory (I am not sure if in some newer vehicles, ECUs have "non-volatile" memory and would not lose their memory when power is removed?), so "rebooting" will force the ECU to re-learn the car's behaviour. It will start with default settings/maps and adjust fuel/air mixture, timing, transmission shift points, etc. based on how the sensors behave in subsequent driving - at the very least, it might reduce the fuel efficiency, and many an Indian owner may not like it!

If one wants to "reboot" the ECU, remove the battery cables and wait about 15 to 30 minutes. And then reconnect power. The wait after disconnecting power is required because these have capacitors (IIRC that is what those are called? correct me if I am wrong.) which continue to supply power to the ECU after battery cables are removed. It takes a bit of time for the capacitors to drain.

Partly true on the CEL. One of the conditions that can lead to the CEL is problems in the ignition system, notably HT cables, Coils etc. If they are wonky you might not be able to start. It'll crank just fine, but won't start.

More importantly is that on cars of say 10 years you will have some degradation of the various connectors, busses, wiringloom etc. There is some resilience built in. For instance I will always get various bus-related error codes when I hook my OBD to my car. Normally nothing to worry about. But what does happen that over time certain condition might reach some sort of threshold. And all of sudden you get all sorts of funny problems and messages. Resetting with an ODB or by disconnecting the battery is often a very easy cure for these "spurious" problems. You don't solve the problem as you point out, But you cure the symptoms and the engine will live with these little electronic problems very happily for quite a while. These sort of fault are really near impossible to diagnose. Mostly they don't matter, but sometimes, somehow the ECU all of sudden gets its knickers in a twist a spews out some codes and a CEL. Time to reset.

Very few car mechanics would be able to figure and diagnose spurious problems. They'll do the reset right away. It takes more than a fancy Manufacturer Engine Data Analyzer. You will need at least a scope, various signal generators and a lot of knowledge on how to read the various electronic and electrical diagrams. You'll need to isolate each bus and test it appropiate signals, re-connect, check the function of the next etc. etc. Very tedious, very expensive, unless you can do it yourself and you don't need to pay for the time.

Don't know if an OBD meter would survive the trunk of Indian car on our typical Indian road. On the upside, they have no moving parts, other than an on/off switch, usually one PCB, a battery and a display. Lets put it like this, if a multimeter would survive in the back on an Indian car, so would an OBD meter. If in doubt go for a ruggedized version!

Yes, resetting the ECU means that it needs to re-learn. But in practice you would hardly notice. And again, what with Indian traffic and Indian roads I doubt that you would notice a real impact on your fuel efficiency at all. We're talking what 50 - 80 kilometers max for most systems. And probably after 20 kilometers it has already tuned to 75% of the end values. It depends a little bit on the ECU and how many cycles it needs to run before it's fully tuned in. But they are default programmed to be on the cautious side of safe, emission wise that is. So fuel efficiency is intially impacted a bit, but again I doubt most of us would notice unless you go looking for it. (I certainly wouldn't notice it on my 380HP V8 )

I doubt you need to disconnect for 30 minutes. these are minute capacitors, so probably a minute would do you could. At least has done it for me.

Also, if you're working on slightly older cars, that use sort of Bosch Motronic system or similar early/mid 90's, there is no actually learning. It's all hard coded in a chip. You can change or remap the chip, but once its installed, that's it. It's there forever, power or no power.

It's always good to check on a manufacturer specific forum what are the top 5 reasons for not starting. For instance, other than the very usual, no fuel, no spark, etc, on my Jeep Cherokee the crank shaft position sensor was notorious for malfunctioning. Sometimes it would through a code, sometime it wouldn't. But every Jeep Cherokee owner knows how to replace one and carries a spare, just in case. Only happens to you once, you go online and figure it out very quickly.

No start with no crank on a Alfa Romeo Spider Series IV is 9 out of 10 times a wonky relays which means the ECU doesn't get powered. I must have fixed it at least twenty times during our Spider drives all over Europe on as many Series IVs' This is where the analytical approach takes a back seat to experience. If you worked on similar cars for a long time, you sort of built up your own mental database of things to check first and check quickly before going into diagnostic mode.

My brand new, restored, 1973 Royal Enfield has developped a little problem. I have no experience with these at all. Very simple engines and carburetors. But I'm really back to basic, studying diagram, drawings trawling the various RE forums around the world to try and get some sort of diagnose before I take my tools to it. Lots of fun though!

Jeroen

[srsriharsha]

I have had issues with Starter motor on my old Zen where in it would make the Click sound.

Hope this help would help a lot of people

[SS-Traveller]

Originally Posted by Jeroen

More importantly is that on cars of say 10 years you will have some degradation of the various connectors, busses, wiringloom etc. .... get various bus-related error codes...Mostly they don't matter, but sometimes, somehow the ECU all of sudden gets its knickers in a twist a spews out some codes and a CEL.

When that happens, wouldn't it be more likely for the car to go into limp-home mode than refuse to start/the engine cuts out?

Originally Posted by Jeroen

...if a multimeter would survive in the back on an Indian car, so would an OBD meter. If in doubt go for a ruggedized version!

Heat, dust and vibrations usually kill digital multimeters here when parked in the trunk for a year (I've killed one). Moving coil multimeters die a quicker death .

Originally Posted by Jeroen

But in practice you would hardly notice. And again, what with Indian traffic and Indian roads I doubt that you would notice a real impact on your fuel efficiency at all. We're talking what 50 - 80 kilometers max for most systems.

True. But a lot of people do notice minute changes in FE on their MID consoles, and do get worried about it!

Originally Posted by Jeroen

I doubt you need to disconnect for 30 minutes. these are minute capacitors, so probably a minute would do...

Most forums seem to advise 15 minutes.

Originally Posted by Jeroen

Also, if you're working on slightly older cars, that use sort of Bosch Motronic system or similar early/mid 90's, there is no actually learning. It's all hard coded in a chip. You can change or remap the chip, but once its installed, that's it. It's there forever, power or no power.

The default mapping - don't some errors also send the new-generation ECUs into default map mode?

Originally Posted by Jeroen

It's always good to check on a manufacturer specific forum what are the top 5 reasons for not starting. For instance, other than the very usual, no fuel, no spark, etc, on my Jeep Cherokee the crank shaft position sensor was notorious for malfunctioning.
No start with no crank on a Alfa Romeo Spider Series IV is 9 out of 10 times a wonky relays which means the ECU doesn't get powered.
This is where the analytical approach takes a back seat to experience.

Couldn't agree with you more on that statement!

Originally Posted by Jeroen

My brand new, restored, 1973 Royal Enfield has developped a little problem. I have no experience with these at all. Very simple engines and carburetors. But I'm really back to basic, studying diagram, drawings trawling the various RE forums around the world to try and get some sort of diagnose before I take my tools to it.

Some of the best Enfield experts are in Delhi itself, close to you! Start a thread in the 'Motorbikes' section on Team-BHP, and I'm sure you'll get pretty detailed answers.

[ramzsys]

My Ikon D(the old 1.8 motor with mechanical pump) has developed an intermittent starting problem. On the cranking times when it doesn't start, it behaves as if no diesel is fed into it. It starts in the next or 2nd next crank, though.

The car has autocop installed, but then the starter motor runs and power is supplied to the pump switch(fuel stop solenoid) even at the no-start situations.

So is it the classic air-in-the-diesel lines case?

[dhanushs]

Originally Posted by Jeroen

I actually carry a handheld OBDII meter in the back of my Jaguar XJR, because these car are notorious for throwing out spurious alarms and warnings all the time.

Originally Posted by SS-Traveller

I've always wondered how robust these instruments are, and whether they can survive constant battering when packed into the boot of a car traversing Indian roads.

I've got one of those Chinese OBD readers, which connects to your Mobile, and does everything that a proper diagnostic tool does. Costs dirt cheap (Some 800 bucks) and is pretty reliable. I've been using one for more than 2 years and all the while its lying in my glove box.

That said: In Indian cars, I have yet to hear about a case, where the CEL would shut the engine down, and if it did, it didnt just get OK by clearing the codes. However, where the OBD reader comes handy is, for example, when there is water entering the sensors, and creates error codes, which is not cleared even after the water dries off. And you can clear these codes from your mobile, without actually removing the battery, and loosing the trip info, passcode for the stereo etc..

Originally Posted by ramzsys

My Ikon D(the old 1.8 motor with mechanical pump) has developed an intermittent starting problem. On the cranking times when it doesn't start, it behaves as if no diesel is fed into it. It starts in the next or 2nd next crank, though.

I'd suspect the glow plugs.

[SS-Traveller]

Originally Posted by ramzsys

So is it the classic air-in-the-diesel lines case?

Originally Posted by dhanushs

I'd suspect the glow plugs.

Air in diesel lines will neither allow starting on 2nd crank, nor let the engine run smooth after that even if you manage to fire it up. Glow plugs is a common reason to need a long crank/2nd crank in diesels which do have glow plugs. Also, maybe it's time for a pump and injector recalibration on the bench, if not done recently.

Originally Posted by dhanushs

I've got one of those Chinese OBD readers, which connects to your Mobile, and does everything that a proper diagnostic tool does. Costs dirt cheap (Some 800 bucks) and is pretty reliable. I've been using one for more than 2 years and all the while its lying in my glove box.

Would you please mention the brand & source where you bought it? A PM will do too!

[Arch-Angel]

Voted the thread a well-deserved 5 stars. Thanks for the article SS-Traveller.
This reminds me of our old premier padmini which had issues starting and dad used to fiddle around a little in it and it used to purr back to life. p.s I liked the flowcharts and illustrations.

[Jeroen]

Originally Posted by ramzsys

My Ikon D(the old 1.8 motor with mechanical pump) has developed an intermittent starting problem. On the cranking times when it doesn't start, it behaves as if no diesel is fed into it. It starts in the next or 2nd next crank, though.

The car has autocop installed, but then the starter motor runs and power is supplied to the pump switch(fuel stop solenoid) even at the no-start situations.

So is it the classic air-in-the-diesel lines case?

Could be, do a few easy checks. Loosen one of the fuel lines at the HP pump or injector, whichever is more easy to get at. Have someone start the engine. If diesel does spurt out, it something different, like perhaps the glow plugs as suggested. If there is no diesel spurtin out, you need to start checking the pump, solenoid and possibly any blockages that might be present (e.g. filter). Don't know your car specifically but on many Diesel (and petrol) systems there is check valve built in the low pressure circuit of the fuel supply. The purpose of the check valve is to keep a slight overpressure in the low pressure fuel line when the engine is stopped and to prevent fuel draining back into the tank. Sometimes they are externally mounted, close to the tank, but they could also be part of the feed pump assembly. (which often is inside the tank)

If the checkvalves fails you tend to get the exact symptons you describe. Initially when starting the car, no fuel gets to the HP pump. Continuous starting or a few intermittent start will refill and pressurize the fuel lines. From there on the engine will start and run normally.

If your car has such a checkvalve there is an easy check: Leave the car overnight and then loosen any connection in the fuel line betweent he HP pump and the check valve. If properly pressurized a small amount of fuel will come out. No fuel, most likely a faulty check valve.

Depending on where the check valve is located it could be a very easy job or a pretty big job. I had this exact problem on my 1998 Jeep Cherokee. There the check valve is part of the pump assembly. You need to replace the comlete pump. The pump sits in the fuel tank and you have to drop the tank to get the fuel assembly out of the tank. It's not particularly difficult, just a bit akward to get at and the usual rusted bolts meant I spent the better of Saturday fixing this little annoying problem.

Although there are some who would advise not to bother to repair the checkvalve, just start longer/more often, I'm not in favour. Reason being that the HP pump will be subjected to running during cranking with little of no fuel in it. It's the fuel that also provides lubrication of the plunjers. So you could be looking at early wear and tear of your HP pump and that is definitely an expensive items on just about any car/engine

Jeroen

Originally Posted by dhanushs

I've got one of those Chinese OBD readers, which connects to your Mobile, and does everything that a proper diagnostic tool does. Costs dirt cheap (Some 800 bucks) and is pretty reliable. I've been using one for more than 2 years and all the while its lying in my glove box.
.

Interesting, although your definition of dirt cheap ($800) is somewhat different from mine. My little handheld cost around $75 and it is actuallly a pretty sophisticated one that also does a lot of online measurements.

See http://www.amazon.com/U581-OBDII-EOB.../dp/B000MLF7CS

I also have the auto-engenuity OBD software package with the Jaguar specific module. (see http://www.autoenginuity.com/ )

That only cost me $500 and gives me identical diagnostic capabilities as main stream Jaguar dealers have in their workshop

Note from Support - Please use the 'Multi-Quote" option to reply to multiple posts, instead of submitting back to back posts.

[SS-Traveller]

Originally Posted by Jeroen

...dirt cheap ($800)...

Dhanush meant 800INR = $15. That is definitely cheap!

[Jeroen]

Originally Posted by SS-Traveller

Dhanush meant 800INR = $15. That is definitely cheap!

Definitely cheap!

Hadn't realised "bucks" could mean INR as well.
Still getting used to lakh and crore and how we write those big numbers here in India. Everytime I look at any financial bit of data I'm struggling.

Jeroen

[dhanushs]

Originally Posted by Jeroen

Interesting, although your definition of dirt cheap ($800) is somewhat different from mine. My little handheld cost around $75 and it is actuallly a pretty sophisticated one that also does a lot of online measurements.

See http://www.amazon.com/U581-OBDII-EOB.../dp/B000MLF7CS

I also have the auto-engenuity OBD software package with the Jaguar specific module. (see http://www.autoenginuity.com/ )

That only cost me $500 and gives me identical diagnostic capabilities as main stream Jaguar dealers have in their workshop

Originally Posted by SS-Traveller

Would you please mention the brand & source where you bought it? A PM will do too!

Jeroen, it is 800 INR.. Well, the real price is $0.99 and rest is for shipping!

SST, I got it online. From ebay (.com) . Just search for ELM 327 bluetooth OBD reader.

[VeyronSuperSprt]

Long before a car gets into a "My car won't start" mode there would be various signals that she gives you indicating that she's going to get into that mode.

If one follows the best maintenance practices judiciously and the car is driven only by one person you will probably never ever experience this except if it is the battery going down on you. And even then, there would be various signals before it does happen.

A very good practice is to listen to the car when she talks to you. She's doing that every single second when you are driving and her language, if you understand it and are a true blue enthusiast, can be even more entertaining than the best music system except when she has a problem. Trouble is, very few people understand her language and even fewer ever bother to listen. And that's why, like all women do when you don't listen to them, she finally gets into a 'My Car Won't Start' mode.

[ramzsys]

Originally Posted by dhanushs

I'd suspect the glow plugs.

Glow plugs work fine. Each plug is consuming significant Amps.

Originally Posted by SS-Traveller

Air in diesel lines will neither allow starting on 2nd crank, nor let the engine run smooth after that even if you manage to fire it up.
maybe it's time for a pump and injector recalibration on the bench, if not done recently.

1) Once started, idling is smooth. No fuel starvation symptoms or engine stopping in between.
2) Pump overhauled and injectors reconditioned few months back. Engine started fine after that and this starting trouble occurred only from a week back.

Originally Posted by Jeroen

If there is no diesel spurtin out, you need to start checking the pump, solenoid and possibly any blockages that might be present (e.g. filter).

Yes, diesel is not spurting out from the injector side when the engine is not starting. Pump was overhauled very recently with all seals, so i have shortlisted it to solenoid switch. Moreover, i have fitted an electric pump before the diesel filter assembly(there is no low pressure pump in the tank).

So the doubt is, will a solenoid malfunction? A solenoid may either work or wont work, but intermittent working, that too when starting only? Is that possible? I do not have the exact tool to remove it(as the solenoid switch in the pump is tilted towards the engine, FWD car) so i have decided to take it to a garage later, as this is not exactly a serious issue.