Jump to content
greengrass21

P38 Hot Restart Problem

Recommended Posts

Hi there out there

Hopefully someone can help with my P38 Hot restart problem.I have a 2000 P38 Auto fitted with the BMW 2.5 Diesel engine,on cold start the Glowplugs work and the Engine starts fine,however,if I switch the engine off and try to restart I have to "pump" the accelerator several times before it will start,glowplug lights do not re-illuminate when engine hot.

In addition to the above I also have an intermittent ABS/TC light fault,these lights come on after between 20 and 30 miles,braking is not affected.

Many thanks for any assistance

Share this post


Link to post
Share on other sites

The ABS/TC error is likely due to a sensor. Get the codes read and you'll know a lot more.

The poor hot starting is typical for the BMW-lump once they get older. They were set up too lean for emissions, so when parts start to wear and the timing isn't perfect anymore (due to the chain stretching), there's not enough left to ensure they always start. The problem isn't the glow plugs, it's the fueling. There is an easy fix: you add a timer relay wth an additional resistor to the engine coolant sensor, so the ECU sees a lower temperature and will richen the fueling to start. The timer is important to make sure after 30 sec or so the ECU sees the correct temperature and doesn't continue running rich. A lot of the cheap hot start fixes are just a resistor or only make the glow plugs come on.

Filip

Share this post


Link to post
Share on other sites

Many thanks Filip,would you know where I can source the parts needed and roughly the cost.Will get the codes checked when it goes in for it's yearly test next month.

Share this post


Link to post
Share on other sites

I had the same issue and I can report that the fix does work, ... I bought one from ebay that doesn't seem to be there anymore but there are a couple of others offering a similar thing, I wait till the heater plug light goes out and count an additional 7 seconds after, it starts immediately.

Share this post


Link to post
Share on other sites

Hi Blanco many thanks,on restart the heater plug light does not come back on,only the engine management light as normal,this goes out after about 10 seconds,do you know if your idea(count 7 seconds after heater plug light goes out),will still work by counting after Engine management light goes out.

Share this post


Link to post
Share on other sites

You can get a 12V timer relay at most electrickery shops. This one would do: https://www.12voltplanet.co.uk/adjustable-delay-timer-relay-delay-on-or-off-12v-10a.html

Then you only need a resistor (around 500ohm if I remember) and some wiring.

I wold be wary to buy a black box from Ebay or such, unless you get a schematic and can verify what's inside (i.e. not just a resistor).

Filip

Share this post


Link to post
Share on other sites

Hi filip thank you very much for that,have checked the link and that is exactly what I'm looking for,thank you again for the information.

Share this post


Link to post
Share on other sites

Many thanks to all for your assistance with this problem,have spoken to my local garage,they can fit it for me,however they have never fitted 1 before,has anyone got the schematics for the electrical connections to the Engine Coolant Sensor,the connections on the Timer Relay are 30 I 31 I 87a-- 15 I 87 --

30 I at the top,to the left 31 I, centre 87a -- 15 I to the Right, below 87a is 87 --

 

hopefully this will be of use,if not I will try and upload a picture of timer relay

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy