annoying hot/warm starting problem

[Romulus]

Hi,

my '96 3.9l has got this rather annoying problem.
After driving for a while and then turning the engine off, from about 5 minutes after 'engine off' and up to 20 minutes, when I try to start engine again, it kicks in but immediately dies, then with my immediate second try of starting, starts up just fine, but tends to idle a bit erratic (in PARK) for about 5sec then settles down with no further problems.
I did have an earlier erratic idle problem when in drive, changing the stepper motor only made a difference for about a day. After that, I replaced leads, dizzy cover, rotor and new spark plugs, the erratic idle in 'DRIVE' problem was then solved, leaving me now only with the above described starting problem.
Any suggestions would be appreciated, thanks! :)

[westonben]

When you changed the stepper motor, did you check the mating surfaces and clean those up too?

Also, try to clean the MAF both internally and the electrical connectors to it.

After that... maybe lambda sensors?

[Romulus]

stepper motor was replaced by Ritter L/R service centre, so I have to assume they did it correctly....also, I have no idle problems as such, only those brief first few seconds after 2nd start up. Also, no problems starting cold.
OK, will clean out the MAF and check its connections, lambda sensors, what and where are they located?

[westonben]

The stepper motor could be replaced without cleaning the mating surfaces and still have been fitted correctly. Unclip the connector to the stepper and using 5mm (i think) allen key, unscrew the the housing that the stepper screws into and remove it. Check the gasket and clean it internally. 10 minute job so easy to rule out.

I'm not too sure about whether the lambda sensors could cause your problem. They are the O2 sensors on the front downpipes on the exhaust. They measure the CO in the exhaust which is fed back the ECU to help control the idle. Might be worth waiting for someone else's thoughts on this before heading this route, I don't think the O2 sensors are very cheap.

[rovercare]

Might be worth waiting for someone else's thoughts on this before heading this route, I don't think the O2 sensors are very cheap.

Nor are they fitted to Aus built D1s;)

[Romulus]

The stepper motor could be replaced without cleaning the mating surfaces and still have been fitted correctly. Unclip the connector to the stepper and using 5mm (i think) allen key, unscrew the the housing that the stepper screws into and remove it. Check the gasket and clean it internally. 10 minute job so easy to rule out.

thanks for that...now THE question, where do I find the stepper motor??, been trying to actually locate it, manual is not very clear or I just don't know how to read ;)

I'm not too sure about whether the lambda sensors could cause your problem. They are the O2 sensors on the front downpipes on the exhaust. They measure the CO in the exhaust which is fed back the ECU to help control the idle. Might be worth waiting for someone else's thoughts on this before heading this route, I don't think the O2 sensors are very cheap.

OK...thanks!

[westonben]

No D1's in Aus have Cats fitted?

In that case, maybe you could have the MAF tuned. Do you get any smoke??

Another easy check is the throttle plate. Whilst you've got the MAF off clean the plate too.

Let us know how you get on.

[rovercare]

No D1's in Aus have Cats fitted?

In that case, maybe you could have the MAF tuned. Do you get any smoke?

Nope, no cats either

[justinc]

Your disco has a fuel temp sensor on the fuel rail at the front of the engine. (Black plug on a black sensor) It's purpose is to aid hot starting by 'leaning out' the fuel delivery when engine is warm to aid in smooth quick starts. This could be all it is. I would also check and clean the throttle plate and intake, as even with a new stepper motor, this needs to be CLEAN.

JC

[Romulus]

not that I'm aware of....I did however notice that it is running rich.....spark plugs were sooty as well as exhaust pipe....

[Romulus]

Your disco has a fuel temp sensor on the fuel rail at the front of the engine. (Black plug on a black sensor) It's purpose is to aid hot starting by 'leaning out' the fuel delivery when engine is warm to aid in smooth quick starts. This could be all it is. I would also check and clean the throttle plate and intake, as even with a new stepper motor, this needs to be CLEAN.

JC

by throttle plate I assume you mean the accelerator coupling, cruise control coupling etc, I did clean all the linkages, springs etc and applied a touch of oil, air intake is the MAF yes?

[101RRS]

Check the ignition module they get hot and develop a dry joint.

Garry

[westonben]

The throttle plate is inside the plenum chamber, remove the flexible hose between MAF and Plenum and you'll see it. Clean the MAF and this at the same time.

[Romulus]

thanks!....OK, will do a bit of cleaning and checking and will update here in a few days.
Thanks for all the advise so far :)

[Romulus]

OK,
have done a fair bit of cleaning as advised by various members, it does not seem to have made much difference.
As yet I have not replaced any sensors.

One thing I should also mention is that it is booked in for LPG conversion/addition, so perhaps I should wait until the LPG has been fitted and see if that makes any diff although the kit I am getting does have fuel start then auto switch over to LPG so it may not make any diff.......
I have opted for the manifold tanks (SCUBA style) in the rear cargo area as I have no problems at all about loosing a bit of storage space height, besides it gives me a nice new project fabricating a false floor and I might even add a drawer or two :)
Since my D1 is fitted with an after market 110L petrol tank I do not wish to loose that.

I am heading o/s until end of September so the LPG will not be fitted until my return and will update here once its up and running on LPG.

[Romulus]

an update on my what was continueing idling and hot start problem.
Today I replaced my injectors as well as fuel pump/sender unit, problem solved. :)
I could not believe how dirty the injectors were, not to mention the injector seats on the fuel rail. I did run injector cleaner etc but still the dirt was amazing.
Also, the PVC coating inside the injector seats on the fuel rail were perished.
Luckily I had a spare 2nd hand fuel rail, so I replaced the fuel rail, new set of recon injectors, new fuel pump/sender unit and hey presto, all my idling and hot start problems are solved.
Also, my stepper motor was loose which would not have helped things, so now I locktite the bugger!!

For your information, I found a really good injector recon place out of the USA, they flow match each set of injectors and supply a report with the set, as well as a 'cheap' supplier of L/R fuel pump/sender units, Bearmack brand, out of the UK, PM me if you want to get more details.

Mty Disco is finally going in for LPG next next, I am retaining my existing long range fuel tank, am having the 'SCUBA' tanks fitted in rear cargo area.

[JohnF]

Can these get fuel vapour lock. I do not know, only ever had this problem on a vw bettle, just wondered.

[Romulus]

I have not heard of a pressurized fuel injection system suffering from vapour lock, if there was 'air' in the system, I would think it would 'purge' itself, but am not sure.
There is a 'relieve/purge' valve on the fuel rail, looks like a bycicle tyre valve, pushing the valve pin down allows fuel to spurt out, not quite sure why that is provided, maybe for 'cleaning' or checking if there is fuel in the rail?

[LOVEMYRANGIE]

an update on my what was continueing idling and hot start problem.
Today I replaced my injectors as well as fuel pump/sender unit, problem solved. :)
I could not believe how dirty the injectors were, not to mention the injector seats on the fuel rail. I did run injector cleaner etc but still the dirt was amazing.
Also, the PVC coating inside the injector seats on the fuel rail were perished.
Luckily I had a spare 2nd hand fuel rail, so I replaced the fuel rail, new set of recon injectors, new fuel pump/sender unit and hey presto, all my idling and hot start problems are solved.
Also, my stepper motor was loose which would not have helped things, so now I locktite the bugger!!

For your information, I found a really good injector recon place out of the USA, they flow match each set of injectors and supply a report with the set, as well as a 'cheap' supplier of L/R fuel pump/sender units, Bearmack brand, out of the UK, PM me if you want to get more details.

Mty Disco is finally going in for LPG next next, I am retaining my existing long range fuel tank, am having the 'SCUBA' tanks fitted in rear cargo area.

I had this happen on the Classic not too long ago. Was more related to crud from the fuel rail rust sticking under the regulator seat causing a lower rail pressure plus fine crap in the injector cups and that jelly that forms from moisture.
Waited till it got to about 1/3 tank, put in 3L of metho and cleaned it beautifully. Always a good idea to change the fuel filter if you get that much fine stuff in there. Have found that the filter element tends to separate from the housing a touch from moisture getting trapped in it and every little thing just goes straight thru.



There is a 'relieve/purge' valve on the fuel rail, looks like a bycicle tyre valve, pushing the valve pin down allows fuel to spurt out, not quite sure why that is provided, maybe for 'cleaning' or checking if there is fuel in the rail?


For checking fuel pressure.

[Romulus]

good idea about the metho.....just keep the orange juice away though!! ;)

[rovercare]

There is a 'relieve/purge' valve on the fuel rail, looks like a bycicle tyre valve, pushing the valve pin down allows fuel to spurt out, not quite sure why that is provided, maybe for 'cleaning' or checking if there is fuel in the rail?

Its called a Schreider valve, used





For checking fuel pressure.

:D

[Romulus]

Its called a Schreider valve, used



:D

sounds like a name out of Get Smart :D S C H RRRRRR E I D E RRRRRRR !!!!!

[PhilipA]

Its called a Schreider valve, used

Err not quite.


Schrader: Manufacturer of tyre valves, pressure to perfection (http://www.schrader.fr/en/r_affRub.htm?rub=8&r=1280)

Regards Philip A

[rovercare]

Err not quite.


Schrader: Manufacturer of tyre valves, pressure to perfection (http://www.schrader.fr/en/r_affRub.htm?rub=8&r=1280)

Regards Philip A

Not quite? the spelling?, I hope that's what you meant;)


Schrader valve - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Schrader_valve)

Sorry about the spelling I *may* or *May* of been drunk at the time of posting:p