Apologies for off brand, any suggestions re odd slow start problem?

OAT · 2025-08-07 13:57:59

As I mentioned in another post, I am struggling with a very odd cold start problem on my Honda van. Four mechanics, 2 dealers and two old school, have had a go with no progress.

The dealer I actually used charged £140 for 1 hour's diagnosis and any fix that could be done within that hour. No diagnosis, but he did fiddle and try but no improvement. Since then, their reception doesn't answer my calls or emails.
The other one was even worse. After explaining symptoms...

On a cold start when ANY electrical demand (open window, turn wheel, press brakes, indicate, etc, etc.) is made, it causes an instant stall, seemingly caused by electrical supply shut down. All is ok when full operating temp is reached.

The manager, no less, suggested it was an auto gearbox problem. I think because engaging drive also causes stall. Unlikely as it seemed to me, I asked about them investigating and diagnosing. He said they couldn't, as they farm out all auto gearbox work. I realise that this may be economically justified for them, but I would have thought it a matter of professional and brand pride, to at least be able to diagnose a fault in one of their own products. I explained this to him, exchanged a few more words and left.

The issue is complicated by it being an import not sold in Europe, and so dealers don't have the software. Also, once warmed up, the issue doesn't occur so you only get one try at a fix per day.

I am wondering it there is any possibility it might relate to dodgy alternator output? Could it be incapable of delivering required output at low temps and low revs? The output measures ok before any electrical demands are made.

I realise this is way of topic here but know there are some good mechanics about, any ideas?

Last edited by OAT (2025-08-07 14:01:10)

kenbw2 · 2025-08-07 23:49:09

This is beyond any of my experience, but I know "modern" engines have a clutch on the alternator that (dis)engages the alternator when the battery is fully charged.

Could it be that this clutch is somewhat seized causing extra drag on a cold engine that's just above stall, causing it to stall?

No idea if that's a valid line of investigation, but it's a thought

OAT · 2025-08-08 02:18:00

It's a complete mystery. I don't even know how much electronic control there is. It is 2000 so didn't expect too much, but something weird is going on. Being an import, I can't even find basic info on the engine.

I wanted to do an under heavy load alternator test from cold. But of course it reads 14v or so, then goes dead when the engine stalls, telling me nothing at all.

I think I will try an alternator swap but they are not cheap, and they are tricky to get at.

RegW · 2025-08-08 13:09:36

I see Honda and 2000 and I think auto box but what model and spec would help
petrol? deisel? 2WD? 4WD? stuff like that

OAT · 2025-08-08 22:27:59

RegW wrote:

I see Honda and 2000 and I think auto box but what model and spec would help
petrol? deisel? 2WD? 4WD? stuff like that

Stepwaggon - petrol injection - AUTO - 4wd

2.0 K20 engine i-VTEC (Honda Civic Si, Acura RSX, Honda Accord, Honda CR-V)

Last edited by OAT (2025-08-08 22:33:09)

OAT · 2025-08-08 23:00:50

kenbw2 wrote:

Could it be that this clutch is somewhat seized causing extra drag on a cold engine that's just above stall, causing it to stall?

My initial thought was drag. First indication of course was instant stall when put into drive. Suggesting too much drag for the cold engine. But it had no sign of wanting to creep.
I also found it stalls with any electrical demand, turning the wheel was quite a surprise, as was indicating!

If it was an older vehicle, I would go straight for a failing alternator under load, but with ecu's, sensors, anti emissions, etc, who knows.
The guy I went to see down south had the proper Honda software and that didn't find anything. He did a full reset (whatever that means), stopping, starting, running up to temp. Didn't seem to make any difference. This leads me to think it's mechanical, but I am only clutching at straws.

RegW · 2025-08-08 23:49:59

It sounds as if someone has read looked for fault codes, but fault codes only occur under specific conditions
and while they can be very useful, dont alway tell the full story.
I've had fault codes lead me up the garden path at times.
As you can easily force the fault by turning the wheel etc to stall it, that actually helps
believe it or not
It's the intermittent faults that can drive you mad

I'd get my multi channel scope on it to monitor various systems and see if I could spot any sudden drops or spikes when the fault occurs.
But
that's taking the complex route, starting simpler....
I dont know the mileage but do know its 25 years old and all those bells and whistles and electrical gubbins make it a pretty complex machine and electrical connections can degrade due to mechanical wear, oxidisation, rust, heat etc.
Honda PGM-fi is a good system but depends on good clean signals so I suggest checking cleaning as many connectors as you can and just as importantly, good grounding too.
Poor connections and grouding can cause signals to fluctuate and give an ECU conniptions.

After that I'd monitor voltages from standing battery to start and beyond to when the battery voltage gets to and holds close to 14v. you may get some clues from that
Less than 13.5V is hardly charging, more than around 15V on that age of vehicle would concern me

thas enough of me rantin for now lol

kenbw2 · 2025-08-09 15:13:08

One option you could try to deduce if the problem is actual electrical demand, or computer trickery is to put an electrical load on the battery directly. Put some jump leads on the battery, and have a load nearby. Maybe a dead battery or something else

1. Connect jump leads (to nothing for now)
2. Do cold start
3. Connect the jump leads to the electrical load

If it stalls, then you know it's not the computer trickery (unless the trickery is reading the battery vltage and acting accordingly)

I don't know if this is a solution, but it might be information I suppose

OAT · 2025-08-10 21:52:31

Strange you should say that.

Another issue I have is that it keeps running down the leisure battery. It is being charged by split charge, but 100ah is dead flat next day. Someone had wired the 12v fridge direct to the leisure battery!

So it was under extra load from the dead battery, and the fridge draw on first startup each day. I wouldn't have thought it was sufficient load to cause stalling but will see in the morning.

OAT · 2025-08-12 18:14:40

Well!
Seems like the fridge draw may be a part of the problem. I was working on other stuff today and had to nip out for some silicone. I forgot all about having disconnected the 12v to the fridge but felt the difference on starting. It ran smoother and actually pulled away with care. Previously, it required warming to full operating temp before trying.

I am beginning to think the temp may be a red herring though. It may just coincide with how long it takes the alternator to get enough charge into the dead battery to ensure reliable running.

The plate on the fridge says 60watt. I wouldn't have though that would have troubled a 70 - 90 watt alternator?
Anyway, I would expect an over discharged battery not to draw anything at all. Like when you connect a charger it usually fails to even detect a battery or refuses to charge it. Perhaps alternators aren't so fussy?

Any thoughts, corrections welcome.

Last edited by OAT (2025-08-12 18:15:31)

kenbw2 · 2025-08-13 02:28:53

I know "modern" alternators can be "clever" - the aforementioned clutch situation. Maybe it reads the voltage and alters its behaviour accordingly? I dunno, clutching at straws

But if you've potentially found the answer, that's amazing news. If it is the fridge then that's an easy fix

OAT wrote:

The plate on the fridge says 60watt. I wouldn't have though that would have troubled a 70 - 90 watt alternator?

Quick correction - it'll be a 60 - 90 amp alternator - 70 amps x 14 volts = 980W. Agree with your point that it should be fine

OAT · 2025-08-13 19:34:56

Well I can't explain how but it was definitely a large part of the problem.

Still need a new throttle return spring to set a consistent tickover and I think it should be ok.

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#1 2025-08-07 13:57:59

Apologies for off brand, any suggestions re odd slow start problem?

#2 2025-08-07 23:49:09

Re: Apologies for off brand, any suggestions re odd slow start problem?

#3 2025-08-08 02:18:00

Re: Apologies for off brand, any suggestions re odd slow start problem?

#4 2025-08-08 13:09:36

Re: Apologies for off brand, any suggestions re odd slow start problem?

#5 2025-08-08 22:27:59

Re: Apologies for off brand, any suggestions re odd slow start problem?

#6 2025-08-08 23:00:50

Re: Apologies for off brand, any suggestions re odd slow start problem?

#7 2025-08-08 23:49:59

Re: Apologies for off brand, any suggestions re odd slow start problem?

#8 2025-08-09 15:13:08

Re: Apologies for off brand, any suggestions re odd slow start problem?

#9 2025-08-10 21:52:31

Re: Apologies for off brand, any suggestions re odd slow start problem?

#10 2025-08-12 18:14:40

Re: Apologies for off brand, any suggestions re odd slow start problem?

#11 2025-08-13 02:28:53

Re: Apologies for off brand, any suggestions re odd slow start problem?

#12 2025-08-13 19:34:56

Re: Apologies for off brand, any suggestions re odd slow start problem?

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