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-   -   2002 2.7 crd hard to start first thing in morning (http://www.jeepforum.com/forum/f310/2002-2-7-crd-hard-start-first-thing-morning-1477169/)

dpurslow 02-11-2013 02:36 AM

2002 2.7 crd hard to start first thing in morning
 
Hey there,

Recently picked up a 2002 2.7 crd Jeep Grand Cherokee.

had it for 10 days now and each morning, it takes about 7 - 10 seconds of turning over before it catches - and yes I do wait for the coil light to go out.

Then this morning, after a little overnight damp snow, it turned over and over but would not start.

after 5 attempts of turning it over for a out 10 - 15 seconds the car now sounds like the battery is starting to go a little flat, so put the charger on it and went to work in the wife's car.

Prior to today, after it started the first time in a day, it would always start within 2 - 3 seconds for the rest of the day no matter how long you left it to sit and go cold.

any thoughts ?

thanks

Robertc2012 02-11-2013 02:58 AM

Cranking a cold diesel engine at low temperatures will flatten the battery very quickly due to compression.
Try "glowing" the plugs 3 - 4 times in succession before starting first thing in the morning.

alfaitalia 02-11-2013 04:15 AM

Quote:

Originally Posted by Robertc2012 (Post 14946262)
Cranking a cold diesel engine at low temperatures will flatten the battery very quickly due to compression.
Try "glowing" the plugs 3 - 4 times in succession before starting first thing in the morning.

Wont make any difference as on our cars the cars go into a heating mode after the initial high powered glow...so basically even when the glowplug light has gone off and you start the engine the plugs stay powered for quite a while (in the handbook exactly how long) depending on how cold the engine and the ambiant temp is. This is to give a smoother idle even from cold. They always take a little longer to start when its cold due to diesel being thicker when cold. But if it takes more than a 2-3 second crank then you need to look else where. The glowplugs could be out of course but this will also affect cold engine starting when the weather is warm which you dont mention. Most likely is the rubber o rings on the low pressure fuel lines. They crack and the air gets in and the fuel runs back to the tank overnight. People expect to see fuel leaks when this happens but this is rare as these low pressure lines are actually under vacuum not pressure as the fuel is sucked all the way from the back of the car by the small low pressure pump on front of engine (mounted above high pressure pump). No in tank pump on these. Replace them (not expensive but use the green Merc version from the ML270 or E270 not the rubber black Jeep ones!) first as this is the most common fault and if no improvement you need to start looking at the pumps themselves. DON NOT CRANK IT OVER FOR A LONG TIME IF IT DOES NOT FIRE UP! The pumps are only lubed by the diesel passing through them. I found this the hard way after I replaced the o rings I thought that cranking for a while would bleed it back through so did not use bleed valve on top of engine. This cause excess wear in my low pressure pump and the bits of it went a broke my high pump...350 for two pumps (see my fitting guide!). A bosch service agent said that 60 secs of dry cranking is all it takes to damage the LP pump! Either bleed it properly or use a bit of easy start which usually bleeds it fast. Good luck.:thumbsup:

Robertc2012 02-11-2013 07:59 AM

The pre heat cycle is controlled by relay via the ECM based on values from the engine temperature sensors. Lower temperature or cold start sets the duration of initial glow plug pre heat of the combustion chamber - approx 25 Amps per plug.

The post heat cycle is activated after start up at a much reduced amperage, to maintain a smoother idle (9 - 12 Amps).

By multiple glows more heat is induced to the cold cylinders improving the combustibility of the atomized fuel.

dpurslow 02-12-2013 08:47 AM

The glow plugs were changed exactly a year ago, its booked into the garage on friday morning and they are going to replace the pipes listed above, they see this issue quite a lot and are pretty certain thats the issue

I will keep updated

alfaitalia 02-12-2013 10:40 AM

Quote:

Originally Posted by dpurslow (Post 14953463)
The glow plugs were changed exactly a year ago, its booked into the garage on friday morning and they are going to replace the pipes listed above, they see this issue quite a lot and are pretty certain thats the issue

I will keep updated

They are ripping you off if they are replacing the fuel pipes. They are about 20 each and there are four of them..... plus labour. The only bit that perishes is the o rings at each end of each pipe... about 80p each from Merc. Admittedly you have to be careful removing the pipes or the retaining clips snap very easily... them you WILL need new pipes! ....which might be why they want to replace them! The problem is that if you get new Jeep pipes they will come with the crap Jeep seals which will soon perish again. If you just do the the o rings you can fit the much better green Merc ones. They are a better material and a better shape.

Zeolit 02-16-2013 06:30 PM

Glow Plugs
 
Quote:

Originally Posted by dpurslow (Post 14946252)
Hey there,

Recently picked up a 2002 2.7 crd Jeep Grand Cherokee.

had it for 10 days now and each morning, it takes about 7 - 10 seconds of turning over before it catches - and yes I do wait for the coil light to go out.

Then this morning, after a little overnight damp snow, it turned over and over but would not start.

after 5 attempts of turning it over for a out 10 - 15 seconds the car now sounds like the battery is starting to go a little flat, so put the charger on it and went to work in the wife's car.

Prior to today, after it started the first time in a day, it would always start within 2 - 3 seconds for the rest of the day no matter how long you left it to sit and go cold.

any thoughts ?

thanks

Merc engines are NOTORIOUS for difficult cold starts even with only one glow plug deffective.
Make sure you measure the right resistance pulling the relay out . I don't know the value, but you can find it out.
I almost killed my startet 2 winters ago because a grease monky failed to proper check the glow plugs ( 3 out of 5 were blew).
Good luck.

PDIAMOND 11-08-2013 04:01 AM

Hello AlfaItalia and Zeolit,

I have read your posts with interest as I am cursed with this hard start problem and it has not been solved by a variety of mechanics and black box gurus.

It is ambient temp related because In the morning after 10/12 hours layup 15C vehicle starts instantly. 10C takes 20 sec. cranking. 5C can take 40/50 secs. cranking.

Sore on battery , starter and my nerves.

Relevant facts 1. the glowlamp only stays on for 3 secs no matter the temp. - I have changed the coolant sensor and the MAT sensor but no change in glow time which should be 20secs for 10C
2. I have changed the 2 suck lines (Jeep) from the filter to the LP and HP pumps. On inspection of clear fuel lines, before morning start, there is fuel in them and no bubbles.
3. I will consider glow plugs, filter change and pump pressures.
Anything else, please?

Thanks in anticipation you guys obviously have experience.
PD

alfaitalia 11-08-2013 05:17 AM

Actually at 10c and with a stone cold engine the glowplug light should be on for 6 seconds after which point you should crank the engine.....but the glowplug will stay on for 21 seconds after cranking and a further 160 seconds after firing. All figs from factory service manual.
For the light to stay on for 20 seconds the temp would have to be minus 30c!

My bet is still on one of the o rings leaking allowing fuel to run back to the tank when cold. Since diesel gets thicker as it gets colder, the colder it is the longer of will take for the pump to pull it back up to the injectors. I had the same problem which was cured with fitment of new rings.

Look at the clear pipes before you crank her over. If there is visable air pockets then its one of the seals towards the engine. If not then there could still be air in the line from the filter to the tank but the o ring thats failed must be one of the ones on the filter....the most common ones to fail as people have a habbit of NOT changing them when they replace the filter and they get damaged.

PDIAMOND 11-08-2013 06:31 AM

Hi Robert,

I am very interested in your comments. I have replied to the other contributors on this post and would appreciate comments on glowplug timing. In pursuit of my hard start problem, I looked at the short glowplug lamp time of 3 secs, no matter what the temp and changed the coolant and MAT sensor as they feed the temp. info to the ECM. - No improvement in the glow time. Can that be reset in the ECM? by a diagnostics geek? Otherwise is the time affected by faulty glowplugs or relays?
Most mechanics dive for the fuel lines as hard start culprit. I have changed the 2 lines from the filter to the LP and HP pumps and there is fuel with no bubbles visible in them in the morning before starting.
Performance right now is temp 5C takes 40 - 50 secs cranking. Dangerous !! - at 10C crank time is 20 secs and at 15C crank time is instant start.
Any ideas what I try next - fuel pump pressure? fuel filter ? etc

Thanks much
PDIAMOND

alfaitalia 11-08-2013 09:01 AM

Although I see your train of thought as far as glowplugs go....I do not think that this is YOUR problem OP. The reason is that I removed my glowplug relays when I first had my problems to try and eliminate them before i found another reason for the slow start. This was in winter at around 0c (32F) and it added about two of three seconds to the crank time...no more. So i dont think that a glowplug problem would add up to the sort of crank times you are talking about.


By the way, what fault codes do you get on the dash when you do the key dance?

PDIAMOND 11-09-2013 04:54 AM

key dance
 
Hi Dean, sorry to admit I dont know the key sequence for fault codes and cant find in manual. Help!!

Robertc2012 11-09-2013 05:19 AM

Maybe an elemetary question, when did you last change the fuel filter and and check the water trap?

Robertc2012 11-09-2013 05:28 AM

Quote:

Originally Posted by PDIAMOND (Post 17538881)
Hi Robert,

I am very interested in your comments. I have replied to the other contributors on this post and would appreciate comments on glowplug timing. In pursuit of my hard start problem, I looked at the short glowplug lamp time of 3 secs, no matter what the temp and changed the coolant and MAT sensor as they feed the temp. info to the ECM. - No improvement in the glow time. Can that be reset in the ECM? by a diagnostics geek? Otherwise is the time affected by faulty glowplugs or relays?
Most mechanics dive for the fuel lines as hard start culprit. I have changed the 2 lines from the filter to the LP and HP pumps and there is fuel with no bubbles visible in them in the morning before starting.
Performance right now is temp 5C takes 40 - 50 secs cranking. Dangerous !! - at 10C crank time is 20 secs and at 15C crank time is instant start.
Any ideas what I try next - fuel pump pressure? fuel filter ? etc

Thanks much
PDIAMOND

Not very familiar with the 2.7 Unit. The 3.1TD has a fuel heater in the filter bowl which helps to thin down the fuel in cold condition startups.
The poor cold start up can only be lack of fuel at the injectors or insufficient combustion chamber heat.

PDIAMOND 11-10-2013 07:57 AM

fuel filter, key dance
 
Hi AlfaItalia and Robert,

Found one keydance - off/on 3 times and wait for message . My 2002 WJ wont even talk never mind dance. Is there a different dance for different models? The self test for the overhead console is OK. The agent service mechanic knew nothing about the keydance, but had been told of it by a customer .

Fuel filter changed - no water in it. - no heater or water sensor either.

Be in touch.
PDIAMOND


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