2.5 na - Cold Cranking

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chriswood6725

Member
Posts
87
Hi All,

I recently purchased a 1986 2.5 NA Diesel, it was a pig to start on a cold morning but was absolutely fine when warmed up, hardly smokes at all, even from cold

I have replaced the battery for a decent sized unit, plus a set of glow plugs and replacement fuel lines that were weeping a bit - it now starts from cold within a few seconds of cranking.

Is this a normal characteristic of these older engines or can I get it to start any better? Previously I have had a 200tdi and a 2.5TD which I feel started better that this... I have a video of it from cold, but cannot work out how to add it?

Thanks

Chris
 
chriswood6725 said:
Hi All,

I recently purchased a 1986 2.5 NA Diesel, it was a pig to start on a cold morning but was absolutely fine when warmed up, hardly smokes at all, even from cold

I have replaced the battery for a decent sized unit, plus a set of glow plugs and replacement fuel lines that were weeping a bit - it now starts from cold within a few seconds of cranking.

Is this a normal characteristic of these older engines or can I get it to start any better? Previously I have had a 200tdi and a 2.5TD which I feel started better that this... I have a video of it from cold, but cannot work out how to add it?

Thanks

Chris
Click to expand...

How cold is it? A lot of old diesels may take a couple of goes on the plugs to start if it way below zero.

If everything is perfectly set up a 2.5na will start right away down to about -5. My 2.5td does! :)

Do you know it is important not to touch the accelerator during cold starts?
 
Yup, foot is off the throttle during start

Temperature was around freezing point last night. I think it's as good as I can get it to be honest?
 
chriswood6725 said:
Yup, foot is off the throttle during start

Temperature was around freezing point last night. I think it's as good as I can get it to be honest?
Click to expand...

So long as it starts within a few spins, so as not to heat up the starter or flatten the battery, it will be fine.

If its starting ok in this weather it should be right on the button when the weather warms up :)
 
I find mine starts better if it's turned over without heaters. Then do it again having used the heaters. Not touching throttle the whole time.
Why that shouldbe, I don't know but it seems to work.
 
SpringDon said:
I find mine starts better if it's turned over without heaters. Then do it again having used the heaters. Not touching throttle the whole time.
Why that shouldbe, I don't know but it seems to work.
Click to expand...

Probably because you have a few little leaks in low pressure side, so it loses a little pressure overnight, and turning it over a few times first pressurises it up again before the actual start. Or your lift pump is on its last legs! :)
 
that does sound a bit misfirery when first started. like 3 out of 4 cylinders have been preheated and the cold one takes a couple of revs till its hot enough to fire properly.

Mine was like that but i replace all the glow plugs and cured that and starts with about 1 crank now.

i note you have replaced your glow plugs though, what brand did you use? not inconceivable that one is dodgy.

also worth checking the wiring loom for the glow plugs, the end one on mine was a bit iffy so recrimped a new joint and fine now.

also get a compression test to rule out HG probs/compressions probs
 
flat said:
i note you have replaced your glow plugs though, what brand did you use? not inconceivable that one is dodgy
Click to expand...

Good suggestion :)

I have found some of the cheaper ones are pretty poor quality. I use Denso in mine, find they work really well, and only a few quid more than the cheapies.
 
Turboman said:
Good suggestion :)

I have found some of the cheaper ones are pretty poor quality. I use Denso in mine, find they work really well, and only a few quid more than the cheapies.
Click to expand...

in have just fitted some intermotor ones - whoever they are - watch this space, i paid £4 each at a local motorfactor

They 4 that came out were, 2 x britpart, 1 x valeo 1 x unbranded lol

easy to check the new ones, take them out and see if they are dry and light grey/brown (working) or sooty/black and wet (not working)

they should read 1.5ohm (iirc) between the nut and the body of the plug when tested.

2 of mine were open circuit lol
 
As above need good glow plugs with good connections, saying that I fitted 4 new Britpart ones last May and it starts on the button every time however cold.
Did fit a good heavy duty battery but that aside it starts on around one to two full cranks as long as its had about 20 seconds on the glow plugs prior to cranking (in really cold weather)
 
flat said:
in have just fitted some intermotor ones - whoever they are - watch this space, i paid £4 each at a local motorfactor

They 4 that came out were, 2 x britpart, 1 x valeo 1 x unbranded lol

easy to check the new ones, take them out and see if they are dry and light grey/brown (working) or sooty/black and wet (not working)

they should read 1.5ohm (iirc) between the nut and the body of the plug when tested.

2 of mine were open circuit lol
Click to expand...

Yes, I have tested glow plugs before! :rolleyes: it is better to wire them all up and make sure they physically glow red, then you will be sure.
 
chriswood6725 said:
Yup, foot is off the throttle during start

Temperature was around freezing point last night. I think it's as good as I can get it to be honest?
Click to expand...

It's also important to make sure that the throttle cable and throttle linkage on the pump are not pulling the throttle open even when you've not got your foot on the throttle. I also know of some people who increased the idle speed using the throttle and not the idle speed adjuster.

I ran one of these engines for many years, and I found on a COLD day with plenty glow it could sometimes take a bit of cranking (don't wimp out) hold that key (if no cranking smoke appears stop obviously as there's something else wrong) and keep going. I once on a VERY COLD day filled the whole street with white smoke before she burst into life - a good battery is paramount.

Good timing is important, this can be done very simply by undoing the pump nuts just enough so that you can move the pump body to advance or retard it but since yours runs well with no smoke I would say leave it alone. Looking at the smoke you had I would suggest its about normal for this engine in the cold. Leave this as a thought for later after playing with glow plugs and things.
 
Last edited:
flat said:
Wasn't referring to you dude was meaning for the op if he wanted to test them without taking them out!
Click to expand...

No worries! ;) :)

After reading this thread I decided to conduct an informal, un-scientific, and un-verified test on diesel cold starting this morning. :D

First up was the Clio. 1500cc na direct injection, 2002, 113,500 miles. Waited until the glow plug light went out, and turned the key. It cranked for 3-4 seconds, and then started. Bit sluggish at first, took about 30 seconds til it seemed to be running on all cylinders.

Next the 90. 2.5 td, indirect injection turbocharged, 125k on the vehicle, but the engine has only done 25k on a Turner engine. Count of 25 on the heater setting, then turned over. It started on the second compression, and a lovely smooth idle after ten seconds.

Lastly the tractor, Perkins indirect injection, about 4 litre, 1983, 6000 hours.Took two goes with the cold start aid, cranking about ten seconds first time, then another go on the flame start thingy, started up fine on the second spin.

To be fair, I think this is an indication of wear levels and care in maintenance, rather than any comment on the relative merits of the different engine types.
 
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