Jump to content
Sign in to follow this  
jon dee

Heatsoak causing difficult starting ?

Recommended Posts

I have noticed recently that if I shut the car down when it has been driven for a while (nothing excessive) it can struggle to start cleanly if I start it again after half an hour or so. Needs a couple of tries and sometimes cranks fast for 2 or 3 seconds before catching. Starts perfect from cold and if re-started after a short stop. 

Given that that the under hood temperature (especially on the turbo side) is pretty high after a run this certainly appears to be a heatsoak issue.

Is this a common thing with the n54 ? And if it is, can it be cured or is it just something I have to live with ?

Cheers...

Share this post


Link to post
Share on other sites

Isnt this one of the typical first signs of the HPFP failing?

Might want to have the fuel pressure logged and see that its not dropping.

  • Like 1

Share this post


Link to post
Share on other sites

I dont think its heat soak, I have personally never seen it with my 335i and I have got pretty hot on occasion. HPFP would certainly be something I would check ans well as injectors. Probably wouldn't hurt to replace plugs and even coils if they are old. 

Share this post


Link to post
Share on other sites

Haven't got round to figuring out how to log pressures yet, but I will look into it. I can read codes though, so will check if there are any recorded. Car had all new coils and plugs not long before I bought it, and it runs well in all other respects without putting any fault lights up on the dash,

Just as an aside, I would have thought that the engine would need more enrichment for a cold start than it would for a hot start. So if the pump pressure was failing would it not have problems with cold starts also ?

Cheers...

Share this post


Link to post
Share on other sites

Your signature says you have an MHD tune, you can use MHD to log

Share this post


Link to post
Share on other sites
21 hours ago, KwS said:

Your signature says you have an MHD tune, you can use MHD to log

Yeah... I remember seeing that somewhere., but I think you need some other program for viewing the logs? Anyways I will be looking into that later tonight.

As a matter of interest I was competing in a club hillclimb event today and the car made many hot starts after sitting anywhere from a couple of minutes up to half an hour. It started perfect every time so maybe the few times it had to crank longer than usual were just random events? I'll wait and see if it becomes a regular thing before I start worrying :)

Cheers...

Share this post


Link to post
Share on other sites

Looks like if I want to make logs all I need to do is purchase the MHD "Monitor" module and I'm good to go. Then export the logs as .CSV files and read them with Megalogviewer or any similar program that reads and displays logs. Bit busy at the moment but I will get onto this next week and see what I can find out.

 

Cheers...

Share this post


Link to post
Share on other sites

You can upload the logs through the mhd app to datazap, which is an awesome free site for reviewing your logs. The logging module is well worth it. 

  • Like 1

Share this post


Link to post
Share on other sites
On 2/27/2020 at 3:09 PM, KwS said:

You can upload the logs through the mhd app to datazap, which is an awesome free site for reviewing your logs. The logging module is well worth it. 

Yep Datazap is really useful.

 

Share this post


Link to post
Share on other sites

Got the Monitor function unlocked and working. Checked out Datazap and made an account... even loaded a little log of me fiddling with the gas pedal in the garage. Will have a shot at doing a full throttle log when I get a chance but need to know.. how fast is an e92 335i auto traveling in third gear when it hits redline ?

If it is more than 100kph I'll have to start planning :) 

Cheers...

 

Share this post


Link to post
Share on other sites

Interesting, I see that some people use their WOT logs with Virtual Dyno to get an idea of what power/torque they are making. I used that app quite a few years ago for the same purpose on my Corolla and found it moderately useful. The current version even has the e92 335i characterised, so no need to create your own profile.  Handy for folks that don't have a phone with accelerometer built-in.

Cheers...

  • Like 1

Share this post


Link to post
Share on other sites
56 minutes ago, jon dee said:

Interesting, I see that some people use their WOT logs with Virtual Dyno to get an idea of what power/torque they are making. I used that app quite a few years ago for the same purpose on my Corolla and found it moderately useful. The current version even has the e92 335i characterised, so no need to create your own profile.  Handy for folks that don't have a phone with accelerometer built-in.

Cheers...

So John what does it say you 335i is making?

Share this post


Link to post
Share on other sites

Early days yet :) But I will be running up the hill at Alexandra Road this weekend so will try the auto log function and see if I can get a decent pull logged. Won't be any good for Virtual Dyno but should be able to see if the low pressure pump is up to the job.

Cheers...

Share this post


Link to post
Share on other sites

You can do that check just by giving it Wot in 3rd on the road. Don't need to hit redline.

Share this post


Link to post
Share on other sites

You got my interest, so I thought I would school myself on how the LPFP works. Now I know that it is not just a simple mechanical pump and FPR. It is driven by an electric motor powered by a PWM controller working in closed loop with a pressure sensor. Basically what you do when CAN bus rules your world :) Apparently the control loop does this...

torqvfm_slopegraphic-png.20428

If I understand correctly, the DME commands the pump controller to run at a duty cycle that is expected to deliver the required amount of fuel (calculated by the DME). If either the pump or pump controller is not performing to spec, then the fuel delivery and/or pressure will be lower than commanded. And this is why we should be concerned if the logged pressure drops below 50psi.  A quick search told me that the target LPFP pressure is 72.5psi (?).

But I digress... since it takes fuel to make hp and more fuel to make more hp, one would guess that maximum fuel flow will occur at the point of maximum power.

BVfR3.jpg

Using this example of an (allegedly) bone stock 2010 e92 335i peak power occurs at around 5600rpm so as pointed out above, there is no need to redline the engine to check the performance of the LPFP. Full marks to that man :)

Cheers...

 

Share this post


Link to post
Share on other sites

Dayam... I do a bit of improvising myself, even use zip ties for holding things in place. But using them to hold an in-tank pump together is next level bodge !!! Pleased to see that you put it all back to stock so the next owner of the car didn't have to deal with fuel problems.

Reading between the lines it seems that the stock fuel system does have the ability to handle modest performance upgrades. MHD suggest that it should be OK running up to E30 tunes before a LPFP upgrade is required. Hopefully, as I'm not planning to run any kind of ethanol mix in the foreseeable future,  that extra capacity will keep the stock pump in my car working for another 20 or 30,000km before it needs replacing.

Cheers...

Share this post


Link to post
Share on other sites

My stock pumps ran stage 2+ without issue, so heaps of headroom on 98 octane.

Share this post


Link to post
Share on other sites
On 3/11/2020 at 1:50 PM, jon dee said:

... I will be running up the hill at Alexandra Road this weekend so will try the auto log function and see if I can get a decent pull logged. Won't be any good for Virtual Dyno but should be able to see if the low pressure pump is up to the job.

Should have stuck with the auto log... might have got something useful if I had done that. Instead went with manual logging thinking that I could log a whole run (maybe 2 minutes worth) as I used to do with my laptop. Turns out manual logging only captures 10 seconds worth of data so I got four 10 second logs of the car idling. The learning process would be much shorter if the instructions actually included a wee bit more useful information.

image.jpeg.e3281aef86da9b4940cfdfc7cc6bfa0c.jpeg

Never mind... it was a fun day out and I managed to improve my time each run, so happy with that :)

Cheers...

 

 

Edited by jon dee
  • Like 1

Share this post


Link to post
Share on other sites

Having a bit of a tidy up and found a vid from Port Road...

Not fast but a good day out talking sh*t with the guys :)

Got one from Alexandra Road as well...

Another beaut day in the sun and fresh air :)

Cheers...

Edited by jon dee
Found another vid
  • Like 1

Share this post


Link to post
Share on other sites

I'm with the Hutt Valley Motorsport Club which runs Port Road (twice each year), the Wallaceville Hillclimb, a winter Motorkhana series and assists the Wellington Car Club in the running of their Shelley Bay Sprint and Alexandra Road events. The Hutt Valley club rooms are in Petone and club night is the first Thursday of each month.    https://www.huttvalleymotorsport.co.nz/about

NB: Club nights not happening at the moment of course. It will be on the facebook page when they start again.

They are active on facebook and a great bunch of guys. Everyone with an interest in motorsport is welcome to come to a club night and there is usually an interesting car in the club rooms to highlight some facet of the sport.

Once you are a member of a club and have an appropriate MANZ licence you can enter events run by other clubs providing your car meets the requirements of the supplementary regulations regarding safety features and driver's apparel. I run a standard road car which does not require a cage, HAN's device, double layer suit etc., and only have the basic M-Grade licence. If you are serious or want to run on gravel or race on circuits you will likely need a higher grade of licence. But then if you were serious you would know all of that :)

Cheers...

Edited by jon dee
After thought...
  • Like 1

Share this post


Link to post
Share on other sites

Ah yes I thought it might be Hutt Valley. I had a licence 30 years ago, would be like you wanting to run a street car at a few events every year.

Share this post


Link to post
Share on other sites

Barely driven the car this year but have collected a few upgrade bits to install, so that will give me something to do during winter. Will move up to Stage 1+ and see how that feels. Also been thinking a bit further down the line and considering (a) if downpipes are really worth the effort, and (b) if running an e30 blend on Stage 1+ might be a better option ?

Which brings me to the big question which it seems impossible to get a straight answer from the interwebz... does putting an e30 blend in the tank create instant death to all manner of mechanical parts, or is the car designed to handle a mild ethanol blend with no ill effects ? I do understand that ethanol is hygroscopic so I would need to use a fuel stabilizer, but other than that... any problems ?

Cheers...

 

Edited by jon dee
typo...

Share this post


Link to post
Share on other sites

Been doing a bit more digging and the e30 question seems to come down to how often you fill your car up. Appears that ethanol fuels don't like sitting around in the tank for long periods, especially in cooler/damper climates such as here in Wellington. Other than that I can't find any hard evidence that running a tank of e30 through a stock n54 335i (with an appropriate tune) does any measurable harm.

So, while I like the idea of trying an e30 mix just for giggles, my car does not get a lot of use and it can take months to use up a full tank. And apart from the occasional short sprint event there is not much opportunity to safely unleash the full performance of the car even as it stands. Leaving aside the obvious suggestion of using the car a lot more often, I am forced to the conclusion that e30 must stay on my automotive bucket list for a bit longer.

On the other hand, I see no real disadvantage to installing downpipes :Troll-min:

Cheers...

  • Like 1

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.

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.

Loading...
Sign in to follow this  

×
×
  • Create New...