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Grahaml

engine just stopped

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Sorry. No progress. I've been distracted by my mini cooper s.  Had a burst coolant hose, overheated enough to blow head gasket, replaced head gasket, still leaking coolant into oil, take head to be checked and skimmed to find it is cracked. Replacement head collect Monday.  At least it is something I feel I'm making progress on eventually. 

 

I can't get any info from running engine as I can't get it to start now.  I will just need to follow the various suggestions and work through to find and repair the problem. I might get a chance later today to have another look. 

 

I will update as soon as I can. 

Graham

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I had a bit of time looking at the Lotus this afternoon.

looking over the circuit diagrams (I have a set of workshop manuals) based on advice here I strated to track the circuit.

Fuse - OK

Relay = I was reluctant to take apart so I found one the same (there are lots as it tuurs out) and I swapped the one from the A/C compressor circuit into the fuel pump & injector circuit.  Imediately I got an extra bit of whirring and the car started on the key.  Sorted!!! - I though - it was the relay all along.  I shut it off and restarted several times and it was fine.  I was in an enclosed garage so didn't want to run the engine for more than a few seconds anyway.

However when I opened a door in the garage for air, started the engine and it ran for 12-13 seconds and cut out.  This happened every time (I timed it).

Also the whirring sound remained - even with the ignition off.

As far as I can tell it is the fuel  pump running - circulating (and recirculating) fuel along the fuel lines and back again.  I'm thinking that my problem might be the pump not giving enough pressure to keep the car going.  I will get a pressure tester (there are lots on eBay) and test it.

But - does anyone know if this would give the other symptoms I'm getting - like the pump continuing to run even when the ignition is off.  I had to remove the fuel pump fuse to stop it when I left it tonight.

I also found that fuse B7, 7.5 amp (ignition controls) was blown.  I didn't have a 7.5 so put in a 5 amp for now but I couldn't see any diifference.

I'm wondering if the fuel pressure needs to be higher to actually cut off the pump (even with ignition off??) - sounds a bit strange to me.  Or could there be a wiring problem elsewhere causing that?

I'll do a bit more digging myself - I already found the thread about the fuel pipe as part of the pump splitting and reducing the pressure - that will be one to check anyway)

At least I had it running again (12-13 seconds at a time) !!!

Graham

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I don't think the pump should be running with the key off. Something is wrong there. So that gives you another point to look at.

Personally I would start there as that sounds odd.

The fact that it starts and then cuts off after a certain period of time seems to suggest that some sort of sensor is providing a signal outside the parameters that the ECU would allow, so shuts the engine down.

That is a wild guess mind you.

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If it were a parameter thing from the ecu - it would log a fault code for sure.

that fuel pump primes before you crank the car and give a dose of fuel into the lines ready to go. The fact it's cutting out after a set time would highlight fuel supply issues to me. The pump should only run with the key inserted and turned - it won't run otherwise - or shouldn't !!

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I would have expected a fault code as well, but with some of the weird things that seem to be going on here who knows?

Could it be the MAP sensor that is showing up in the logged codes in the initial posts?

The pump still running is weird as well. Since pulling its fuse stopped it, it is either being fed directly from somewhere which doesn't make sense as it would always be running and would have been heard before. Or there is an issue with the ignition switch itself possibly?

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well - good news.

Having a think and doing a bit more research I'd come across someone who'd had a problem with a sticking relay. So I swapped the relay with another one and it all worked fine.  The fuel pump stopped running when I switched off and the car kept running when I started it.  I'd already ordered a couple of new relays when I discovered the faulty one yesterday.

I've had the car running for probably an hour, stopped and restared several times - sorted I think...

I didn't have any more time today so I will check the relays later to see what the faults are.  What I think ..

  • The original one that was in position C (primary fuel pump and injectors) just wasn't working.
  • the one I swapped into position C was from position G (A.C. Compressor) did open the circuit but stayed open ( probably permanently making a circuit)
  • the one I put in today (from position D (ignition) worked fine (I put the one originally from the A.C. slot into the ignition slot)

As you might expect the relays have been replaced at some point previously in the car's history and the one that had been in the fuel pump/injector slot was a seimens (as was the one from the ignition slot that is working now).  The rest are Bosch.

The replacements I have ordered are Bosch too but that's just because I found them first at a decent price.

I'll be back on the road in a couple of days as soon as I refit the boot floor.

Easy eh :) ................

Thanks for all the advice guy - hopefully this little tale might help someone else in the future...

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OK - a little bit of digging showed up what might have been the issue with the relays.

while I was looking at the relay in preparation to test them I noticed there was a slight difference in the circuit diagram between the grey Bosch relay and the brown siemens relay.  Digging a bit more I see that they are different and I need the brown Seimens type for the fuel pump.  The grey Bosch ones keep part of the circuit completed - which I trhink is why the primary fuel pump kept running and the fuel kept being recirculater from the tank - around the fuel rails and back to the tank.

Apart from my own ignorance the thing that threw me about the relays is that they all have the same Lotus part number  - I spotted that the different relays hasd been mentioned before on the V8 parts cross reference thread which I spotted last night @Günter 

 

I've attached some copies from the wiring diagram relating to the fuel pump and injector circuit and from the parts diagram and list.  I also checked online on the dereure website and they are still listed as the same part number.

http://www.deroure.com/diagrams.asp?TBL=1480&MAK=1&MDL=15&SMA=0&SMO=0&ST=&SC=0

 

you will see that the grey relay has contact 87a connected and 87 unconnected when the relay is "off" whereas the brown Seimens one both 87 and 87a are unconnected when off and both connected when on.

Anyway - I hope this makes sense to you and can help in the future.  O've found the correct brown relay is also used oin Landrovers and more easily (and cheaply - probably) got.  I've not found another equivalent one.  As Gunter stated in the cross reference thread - and when I looked through the wiring diagrams it seems that the primary fuel pump and injector relay is the only circuit that needs the brown relay 

I've not actually tested them on a meter yet but it looks logical to me  ands is why the grey bosch didn't work properly - it kept the fuel pump on when not activated but cut the fuel off when activated and the car would only run for a few seconds until the fuel in the fuel rail was used up.

It does seem to be a pretty drastic error in the parts list though?

 

 

IMG_20171029_142358.jpg

IMG_20171030_121616.jpg

IMG_20171029_142342.jpg

IMG_20171030_121640.jpg

 

fuel relay wiring diag.jpg

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I'd bet the grey relay was put in to a circuit that doesn't use the 87a pin, so it made no difference to THAT circuit. However, it does make a difference in the fuel pump relay circuit!

Also note the Grey relay (Bosch) is not a twin 15A one as per the parts list.

I expect the parts list is correct, but the grey relay is the dog in a manger (or something).

The Grey relay is odd-most of the relays that have pins 87 and 87a connect them both together to the positive terminal (30)when operated. 

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I see what you mean - they are described as double contact whereas the Bosch relays just switch the continuity from 87a to 87.  As you sad though (as far as I could see) all the other circuits that the relays serve don't use anything on the 87a terminal so are effectively off until activated - then the circuit switches to the 87 terminal as required.  The part of the circuit diagram I uplaoded shows that on the secondary fuel pump relay.

Out of the 8 relays in the rear box 6 of them are grey Bosch relays and two were the brown siemens (AMR1088) ones.  When I was looking for replacements it seemed to me that these are a very common type - I couldn't find any (except for the ones) I bought that have the twin contacts.  If I've missed them somehow and you know where to get them at a good price let me know.  My searches found the brown ones used in Landrovers.

Car's working though which is the main thing for now - and I've learned a wee bit more...

 

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On 28/10/2017 at 11:24, Grahaml said:

Sorry. No progress. 

I can't get any info from running engine as I can't get it to start now.  

I will update as soon as I can. 

Graham

any results - or was thr car sold in parts ?

 

shortcut on O2 sensor "pre heater" wiring , or on sensor heater (internally) can harm your system ..as it was mentioned in one of the comments

so was there any outcome with this sitation ?

 

*****(

..ahh - now I can see other replys - as this story was still in my inbox over here in TLF

 

so its running and a cut-oof on relais was the cause - good that you could fix this

Edited by Günter

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yes all was well - not using the car much but I will have a couple of issues to see to over the winter.

1. Cam belts: - I plan to do them myself.  Rather than spending £322 on a crank/cam locking and tolerance pin set I have had a set made up by an engineering firm.  I plan to do the job with the engine in-situ - no rush although an american guy on Youtube does it in a few hours - I'll take MUCH longer.

2. I need to replace the catalytic convertors.  I made up a set myself last year using sports cats (taking your advice Gunter) but they barely scraped through the test this year (thanks to a VERY obliging tester) and I will need to have it fixed properly for the next test in April.

 

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