New engine not starting - need confirmation - NOW STARTED!

Post Mon May 05, 2014 8:54 pm

Hello zoners,

So today I done all the final bits to get my newly built m20 fired up today.

I done all the preparation is starting a new engine and it cranked over, however .....

When it came to start it to check oil pressure I noticed that the oil light did not come on at all. I believe this is because of the faulty oil switch as I earthed the wire and the light came on. Is this correct?

I also noticed there was no fuel, as I disconnected the fuel lines to the fuel pressure reg and the fuel rail and had no fuel come through. I believe this is related to the fuel pump and would need further investigation.

Confirmation would be great on the 2 issues above.

Thanks in advance.

Post Mon May 05, 2014 8:58 pm

You need to check whether you have spark to confirm the fuel related issue, as CPS failure (or plugged into the wrong socket on the loom) will cut off both fuel and spark.

Post Mon May 05, 2014 9:42 pm

SilverShadow wrote:
When it came to start it to check oil pressure I noticed that the oil light did not come on at all. I believe this is because of the faulty oil switch as I earthed the wire and the light came on. Is this correct?

Yes.

Check for spark, as Grrr says.

Post Tue May 06, 2014 7:49 pm

Good news!!

I swapped the cps wiring over on the loom and it fired up!

I also changed the oil pressure switch to a new one.

However I have 2 concerns though;

1) When I cranked the engine the oil light went off, however after like 10/15mins it started to flicker back on. I slightly rev'd the engine and it goes away however returns back on?

2) The oil level seems to be fine by checking the dipstick, however the oil light on the check panel is constantly on? Another sensor perhaps?

Just to note the car in still on the axle stands on the same height, would this cause an issue?

Any ideas on the 2 oil light issues??

good news is that there no knocking or any other nasties!!!

Post Tue May 06, 2014 8:24 pm

Unscrew the oil pressure light and connect a gauge in its place. No point in speculating without hard evidence.
Oil level sensors can get clogged. Take the sensor out (it's just above the normal oil level) and clean it repeatably in petrol. I think it's in the wiki.

Post Tue May 06, 2014 10:08 pm

Brianmoooore wrote:Unscrew the oil pressure light and connect a gauge in its place. No point in speculating without hard evidence.
Oil level sensors can get clogged. Take the sensor out (it's just above the normal oil level) and clean it repeatably in petrol. I think it's in the wiki.

Thanks for the reply Brian.

During the rebuild I thoroughly cleaned the sump and oil sensor in petrol. I think it was submerged for a couple of nights aswel. I'll have a play around with the actual connector if no luck I think I'll replace it with know working unit.

Regarding the oil pressure do you have a link for further information in how to check this? Not to sure in how to go about connecting a gauge?

Post Tue May 06, 2014 10:14 pm

You'll need a connector with the same thread as the oil pressure switch, a length of tube that is good for 100 PSI or so, and a pressure gauge that reads from zero to 60 or 100 PSI to connect to the tube.
My gauge comes from my oil boiler testing kit, and the pipe is something I made up years ago.

Post Tue May 06, 2014 10:38 pm

Brianmoooore wrote:You'll need a connector with the same thread as the oil pressure switch, a length of tube that is good for 100 PSI or so, and a pressure gauge that reads from zero to 60 or 100 PSI to connect to the tube.
My gauge comes from my oil boiler testing kit, and the pipe is something I made up years ago.

Ahh got you.

I've just seen some kits on eBay for around £15, but just before I buy I'll aak around if a can borrow one.

Out of interest what reading should the gauge give?

Post Tue May 06, 2014 10:53 pm

Autodata says 7 - 28 PSI (0.5 -2.0 bar) at idle, and 57 - 85 PSI (4.0 - 6.0 bar) at speed.
Note that 7 PSI is about the pressure that the switch turns on at, so a flickering oil light at idle can be considered normal, but I don't think I'd be buying any engine that does.

Post Tue May 06, 2014 11:04 pm

It's a strange one just to reiterate, on start up the light stitches off. After a little while it flickers back on constant and when you rev it the light switches off for a few seconds.

Just had a thought could it be down to the oil I'm using; 15w-40 mineral.

Post Tue May 06, 2014 11:07 pm

Idle pressure will always be lower with hot oil than cold.

Post Tue May 06, 2014 11:09 pm

Brianmoooore wrote:Idle pressure will always be lower with hot oil than cold.

Thats interesting... On initial start up (stone cold) the light was off, when the engine got to normal temp that's when the light started to flicker on?

Post Tue May 06, 2014 11:57 pm

It's normally an indicator of worn main bearings on the crankshaft causing reduced oil pressure, but you may be lucky and find it's just a dicky oil pressure sender.

Post Wed May 07, 2014 7:25 am

Oil.when cold,is thicker,thus giving a higher pressure reading.
I found that my M20 did not like 10/40,it blew it out of the breather,but is quite happy on 15/40.

These engines were designed at a time when 20/50 was the norm!

Post Wed May 07, 2014 11:36 am

The general rule of thumb for oil pressures (and choosing the correct oil for your engine) is (when warm) ~ 75 PSI at 6000 rpm, and to gain 10 PSI with every 1000 rpm.

What oil are you using?

Post Wed May 07, 2014 1:31 pm

Speedtouch wrote:It's normally an indicator of worn main bearings on the crankshaft causing reduced oil pressure, but you may be lucky and find it's just a dicky oil pressure sender.

I really do hope it is as simple as a sensor or wiring as I used new big and main bearings. I lost sleep lastnight thinking about it.

I did notice when I replaced the oil pressure sensor yesterday the old one was covered in black sludge. I thoroughly cleaned the block prior to building it but may have missed this area. Tonight I am going to take the new sensor out and see when it covered in the black stuff again and run a pipe cleaning brush to clear some of the sludge....

capnmchl wrote:
What oil are you using?

I'm using 15w 40 mineral oil for the initial break in period.

As Brain mentioned the gauge will be the best bet to establish what's going on.

Post Wed May 07, 2014 1:58 pm

Did you fit an oil filter with the non-return valve in?

Also could be worth checking the pressure relief valve isn't sticking.

Post Wed May 07, 2014 3:54 pm

Speedtouch wrote:Did you fit an oil filter with the non-return valve in?

Can you elaborate on this Speedtouch? Not sure what you mean by this?

Just to note I have a oil cooler installed with the oil filter housing.

Post Wed May 07, 2014 4:15 pm

OEM-spec oil filters have a non-return valve built in, to prevent oil draining back into the sump when the engine is switched off.

Cheap filters sometimes don't have the valve fitted, which can cause problems with low/no oil pressure on start-up.

Post Wed May 07, 2014 4:36 pm

Speedtouch wrote:OEM-spec oil filters have a non-return valve built in, to prevent oil draining back into the sump when the engine is switched off.

Cheap filters sometimes don't have the valve fitted, which can cause problems with low/no oil pressure on start-up.

I normally tend to use BMW oil filters but this time around I used an ECP filer (Mann). How can I tell whether this filter has the valve fitted or not?

Post Wed May 07, 2014 5:15 pm

I imagine a MANN filter will have one, according to their website:

https://www.mann-hummel.com/en/mann-fil ... er/spinon/

Only one way to find out for sure though - either remove it and inspect it, or phone up MANN's technical department and quote the part number and ask them about it...

Post Wed May 07, 2014 9:40 pm

Out of curiosity if the oil pressure lower then expected would it be the oil pump at fault?

Post Wed May 07, 2014 9:50 pm

Worn pump, blocked/leaking intake pipe, leaking excess pressure valve, blocked filter, worn engine.

Post Mon May 19, 2014 11:47 am

This has now been resolved!

Thought I post up the fix for anyone searching on the topic in future.

I carried out a Oil pressure test and indeed the pressure was low as expected (dont have the actual psi reading to hand).

After searching for a number of months I managed to get hold of a brand new oil pump of a private selling on ebay.

So this weekend I dropped the sump, replaced the pump and changed the oil to 20w 40 mineral as per 15w 40 previously.

No oil pressure issues at all! After the first start up I left the engine running for around 20mins and had no issues.

Was driving around in the sun yesterday and not issues at all!

Hopefully if I can borrow the oil pressure unit i will check the psi!!!

Post Mon May 19, 2014 1:55 pm

SilverShadow wrote:Hello zoners,

So today I done all the final bits to get my newly built m20 fired up today.

Most of us would expect 'newly built' to incorporate a nice new oil pump!

Post Mon May 19, 2014 2:08 pm

Brianmoooore wrote:
SilverShadow wrote:Hello zoners,

So today I done all the final bits to get my newly built m20 fired up today.
Most of us would expect 'newly built' to incorporate a nice new oil pump!

Yes agree but I tried everywhere to get one at the time of the build process and no one seem to have them in stock or order them in.

BMW GBR/DEU, ECP, GSF, FAB, Frtiz etc They still don't have them and I was lucky that there was a private seller on Ebay who had one brand new.

So I continued hoping the one I had would be OK! Anyway all sorted now!

Thanks Brain for your help on this!