NOW SORTED - K Series Engine Build - Won't Start - Any Ideas?

[revilla]

Just finished building up a spare engine, K-Series VVC 160.

 

Bit of background - the engine is mounted on a trolley/frame with all external plumbing, wiring, ECU, 5AS, fuel tank and pumps, gauges and switches etc. necessary to get it running.

 

Trying to fire it up this morning for the first time and I have two problems.

 

i) It won't start. It makes all the right noises when the ignition is switched on (fuel pump priming, IACV chatter as it resets). It cranks over strongly and there's fuel coming back to the tank from the return line so plenty getting through. It is however just popping and banging occasionally from the exhaust and chuffing out plenty of black smoke. It seems to be firing and kicking back against the starter at times. After cranking for a bit, all exhaust primaries feel a little warm and there's a strong smell of exhaust fumes rather than petrol, so I think I've got good sparks and burning fuel in all cylinders.

 

ii) NOW RESOLVED Checking over OBDII, the ECU reports a coolant temperature of 140C (the engine has not run yet, so it's not hot!). As the coolant temperature sensor is a resistance that decreases with increasing temperature, this suggests a short circuit across the sensor, however if I pull the plug off the ECU and check the resistance across pins 7 and 33 (which are the correct pins according both to the Caterham wiring diagram and the Rover MEM3 documentation) I get about 4000 ohms, which is exactly what it should be at 10C - which seems reasonable. By reading the resistance from the ECU connector I would have thought this would eliminate both sensor and wiring problems, however swapping in another ECU (the one from my car which reports a sensible temperature when installed in the car) still doesn't resolve the problem, it still reports 140C. Does anyone know if any other wiring issues could lead the ECU to reports off-scale high temperature?

 

I've used an external Bosch fuel injection pump, and I think this may be the problem. The injection rail pressure as I understand it is supposed to be 3 bar. My logic when I bought the pump was that I would need one rated a bit higher than this in order to allow the regulator to bleed fuel off from the rail into the return line to regulate the pressue down to 3 bar, so I bought a 4 bar unit. I'm now wondering if I should have bought a 3 bar unit and the 4 bar unit is completely overwhelming the capacity of the regulator and pumping the rail pressure right up, flooding it. I was slightly alarmed when the pump arrived to read that it was rated for up to something like 500bhp!

 

Does this theory sound reasonable, and does anyone have any other ideas to try?

 

I've done all the "usual suspects", the ECU and 5AS are matched up, the keys match the 5AS and the immobiliser is disarming, done the throttle reset procedure, tried unplugging the lambda sensor, pretty sure all the belts were timed up correctly when I built it up.

 

Thanks for any advice ...

 

Edited by - revilla on 22 Dec 2013 10:37:43

 

Edited by - revilla on 23 Dec 2013 21:49:24

[Tony Whitley]

I had similar symptoms which I eventually traced to the cam timing being way out because I'd fitted the sprockets wrongly (No damage fortunately!)

 

The ECU ought not to try to run the engine if it thinks the coolant is at 140C but I have no idea whether such protection is built in. That yours is firing at all suggests that there isn't any.

[revilla]

Tony - Thanks, I will recheck!

 

The temperature issue is now resolved, but still don't understand it. I now have two temperature sensors which read almost identically on a resistance meter, but when I plug one into the ECU it reads 140C and the other reads 12C! Checked and double checked my readings. Oh well, I'll use the one that works and call it solved.

 

Still not starting though

[Grubbster]

I had slightly similar symptoms when I had an EU3 MFRU connected to an EU2 engine, but I assume all the bits you have have always been associated with this particular engine?

[revilla]

No the parts have not always been together, I've converted then engine from an MG ZR 160 block and head plus other bits sourced from here and there but I'm pretty sure that everything is EU3 160 throughout. The engine block and head are definitely from a 160 (pistons are stamped "160") and the coil packs were on the plug tops as for an EU3 VVC.

 

One thing that does occur to me - converting from a ZR of course I had to change the flywheel for the smaller 1.4 unit to fit the Caterham bellhousing. From memory, different flywheels have different crank sensor trigger patterns. I was fairly careful to identify the correct one, but I may have got it wrong and if I have an EU2 trigger pattern on my flywheel I guess it won't like it. That maybe why you got similar symptoms with an EU3 ECU on a EU2 engine as it would have had an EU2 flywheel.

 

Does anyone have any pictures / diagrams of / info on the crank sensor trigger patterns on EU2 and EU3 flywheels please?

[Tony Whitley]

All Caterham flywheels are all the same size but the 1400 has a different crank sensor pattern to the 1600/1800 - 2 missing teeth vs. 4 but I can't remember which is which. EU2/EU3 isn't a factor AFAIK. I think that with an Emerald the "crank sensor OK" LED doesn't light and you get no spark but MEMS may be different and you'll get a mis-timed spark that fits your symptoms.

 

 

[Englishmaninwales]

1400 has 2 missing slots in the trigger pattern

[Grubbster]

That maybe why you got similar symptoms with an EU3 ECU on a EU2 engine as it would have had an EU2 flywheel.

 

No it was because they are wired differently - but it did seem to fire a couple of times and back fire a lot. Fitted the right MFRU and it worked first time.

 

I replaced an EU3 1800 (running with an Emerald) with an EU2 1800 complete with its Emerald - I just forgot to swap over the MFRU and assumed they were the same.

 

Edited by - Grubbster on 22 Dec 2013 18:26:37

[revilla]

The flywheel I bought for it was stamped with WFM1972 although this part number doesn't show up in Rimmer's list. I bought it through eBay, the original listing has now ended but the same seller has another one which I believe to be absolutely identical here. Even the description is identical to the description show in emails for the one I bought, and I'm quite sure that it had the same trigger pattern, i.e. four missing teeth grouped in two pairs of two. The description does however refer to it being for a 1.4 or 1.6, 1996-2002 (i.e. EU2?). So now I'm really confused as I thought the 1.4 was different to the 1.6, and that the 4 missing teeth model was correct. In short I don't know if I have the right flywheel or not! Can anybody confirm whether this should work on an EU3 VVC 160?

[Bricol]

I fitted replacement cams, set up the ECU for sequential injection and could not get it to fire properly.

 

Finally, at around midnight one day, in bed, nearly asleep, I had to get up and leg it down to the garage to check something . . .the cam position sensor works from a reluctor on one cam . . and my cams didn't have one.

 

Changed to non-sequential, and it fired immediately.

 

Bri

[Slipper man]

I had a similar problem, but my issue was a much more stupid one. The p;ug for the crank sensor is the same as another plug (it might have been the throttle pot - I can't remember). I got them the right way round. When I swapped them, like magic the car started.....

[revilla]

Thanks for all the helpful input.

 

So far tonight ...

 

Removed both front and back cam covers and checked cam timing mark alignment. Everything aligned exactly, no off-by-one-tooth errors. Sprockets appear to be fully home on their locating pins, and the VVC has one flat and one domed sprocket (to fit over the VVC mechanism) at either end, so not possible to fit them in the wrong positions. Belts (new) all look healthy and everything turns freely.

 

Double-checked the flywheel trigger pattern, it is as I thought as shown here and from researching on Google, this appears to be the right pattern unless anyone can tell me otherwise. I did find references to Rover (not in a Caterham context) flywheels with four missing teeth but phased differently (different positioning of the crank sensor?) but on mine with the crank pulley timing mark lined up at TDC, the crank sensor pin was exactly central between the two missing pins shown on the lower left of the linked picture, which I think is correct.

 

Confirmed the MFRU internal wiring is as per EU3 requirements. I'm fairly familiar with the MFRU working after having dug into in detail to write the K-Click MFRU replacement article for Low Flying.

 

Can also confirm that I am running standard MEMS3 rather than Emerald and standard cams (in fact engine standard throughout), so no possibility of switching between sequential and batch mode injection, but also shouldn't be a problem with cam sensor. Have also checked and a faulty cam sensor should still allow then engine to run in a limp mode.

 

Have swapped the ECU back into my car and confirmed it runs the other engine fine, so not an ECU fault.

 

Have checked all of the critical wiring I can think of with a resistance meter, working from the actual pins of the ECU plugs. Cams sensor and crank sensor 1200 ohms as per spec. Injectors all 14-15 ohms. Coil packs both about 1.2 ohms. Injector and coil pack power feeds all OK. Verified that the injectors, coil packs and crank and cam sensors are wired the right way around to the correct ECU pins with the correct wire colours throughout. Coil pack wires and injector wires are not exchanged.

 

Verified that the main relay in the MFRU is correctly feeding power to the engine electronics when operated by the ECU.

 

Have replaced the crank position sensor with a spare I had in my box without effect.

 

Have finally verified that the cam and crank sensor plugs are not exchanged.

 

Can't imagine that even if my fuel pump is a bit over keen it would overfuel to the point of being totally unstartable.

 

... but still it just chuffs out black smoke rings and the occasional spectacular pop from the end of the exhaust when cranked! Stinks of soot, so quite sure it's getting both fuel and sparks, but obviously not in the required quantities or not at the right times.

 

Really don't know where to go next, would very much appreciate some further help!

[revilla]

Last two things I tried tonight:

 

Removed flying spark plug leads, one from each coil pack, and connected to spare spark plugs resting on head. Decent sparks from both when cranking. So it looks like it's sparking as it should (but I guess I knew that from the puffs of smoke).

 

After fuel pumps primed, but before cranking, removed fuel pump fuse, thinking that as the pressure died away in the fuel rail it might just fire normally for a second or two if the problem was indeed the pump over pressurising. No difference. Just puffs of black smoke each time it cranked over.

 

Is there any easy way to check that the injectors are injecting sensible quantities of fuel, short of taking the top manifold off, unbolting the rail and withdrawing the injectors to see if they will spray fuel when cranking? Because at the moment it looks like its got sparks and fuel in reasonable quantites and decent enough compression (certainly feels like it's compressing nicely enough to at least fire) which just leaves timing. It's as though it is firing at completely the wrong point ... but the cam timing looks spot on and all the timing-related electrics seem to check out!

[Mankee]

Interesting project, Andrew.

 

Are you running everything using a "normal" charging circuit (alternator, 12v battery etc.)?

 

The fuel pressure regulator should cause the non-starting. At worst, it will just overfuel as the rail is pressurised to 4 bar instead of 3 bar. The FPR is after the pump and rail, so will keep the pressure at the injectors and rail at the specified rating. Might be worth swapping it over with a known working regulator in case it is a duffer and jammed shut.

 

Did you check the timing of the VVC mechanisms? They are a bit of a mystery to me, but I'm sure DVA wrote an article on retiming and resyncing them if they've been apart.

 

Get a temperature probe to see if all the primaries are heating up all the same when you are cranking.

 

Good luck!

[revilla]

Mankee,

 

Yes everything "normal", I've replicated those systems from the car needed to support the engine on the test trolley so alternator and battery circuit is as per the car.

 

I too would be surprised if the fuel pressure caused a total non-start unless the plugs are just wet with fuel. Will have a look at them. In the meantime I'm goint to get myself a timing strobe and see exactly what point each is firing at, might give some clues.

 

The VVC head came from a 14K miles MG ZR and when I took it off it was absolutely immaculate, so I didn't bother stripping down the VVCs, just cleaned everything up thoroughly but mechanically left well alone, so I would imaging they are set up correctly.

 

Will keep on the case but maybe not so much over the next few days, think the kids would be a bit upset if I spent Christmas in the garage!

 

Will post anything I find, any ideas still gratefully accepted.

[Bio]

Could the plug leads be in the wrong position ?...failing that try a squirt of Easystart into the induction, if it then runs it must be fuel related.

[Self-appointed Club Pedant]

This is what you need:

http://www.nulon.com.au/files/images/aerosol/SYB350-small.jpg

[revilla]

SORTED! - IT'S NOW RUNNING LOVELY!

 

I built my own engine loom from scratch to the specs in the published Caterham Wiring diagram for EU3 models. Before I started I had to correct a whole load of errors in the diagram. For example if you look at the ECU connector the pin layout does not match the plug either in a front or rear view, it's as though the smaller pins are drawn from one side and the larger pins from the other. SEEMS LIKE I MISSED ONE MORE CATERHAM COCKUP ...

 

The Caterham diagram shows ECU pin 52 driving coil pack 1 for cylinders 1 & 4 and ECU pin 26 driving coil pack 2 for cylinders 2 & 4. THESE ARE THE WRONG WAY AROUND! Cross checking with the diagrams in RAVE, these show the correct connections. Interestingly though the wire colours White/Black and White/Orange shown in RAVE are the other way around to those in the injection loom on both of my engines. It seems as though Caterham have then corrected this error in their diagram but at one end only, leaving the wires crossed over.

 

I rigged up a timing gun as I said I would earlier, and the ignition timing when cranking was about 90 degrees advanced (or 90 degrees retarded as it's wasted spark, so you get a spark every 180 degrees). This was obviously never going to run. If the cylinder managed to fire on to fire on the advanced spark it would kick back against the starter and if it fired on the retarded spark it would fire straight into the exhaust! This pretty much exactly matched what I was seeing. The leads for the coil packs are different lengths so I couldn't swap them over but I moved the long wire from coil pack 1 onto coil pack 2 and it started and ran on two cylinders, so I knew I was on the right track.

 

To avoid having to redo chunks of the loom, I've cut the White/Black and White/Orange just short of the injection loom plug and spliced them together crossed over, and it runs a treat.

 

My intention after initially correcting the diagram was to publish it on here for everyone. I will further correct it for this error and then do so. I have already corrected it for the differences found in some cars around the main relay wiring in the MFRU found following my article in Low Flying. In addition to the information in the official Caterham diagram, mine contains full specifications for all wire thicknesses cross referenced against RAVE and original supplier part numbers and sources for all the connectors, so it's got the information you need when making up a new loom. I've also done it as a Paint Dot Net document with all the different options in different layers, so by ticking layers on and off you can get a diagram customised exactly to the wiring in your particular car.

 

I can now relax for Christmas.

 

Merry Christmas everyone and thank for your input as always.

[Tony Whitley]

Excellent news

[revilla]

Finally got round to posting the updated wiring diagram here.