K-Series powered 7 – won’t start

K-Series powered 7 – won’t start

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Discussion

BertBert

18,953 posts

210 months

Sunday 26th March 2017
quotequote all
So you know you have sparks.

Are they at the right time?

Do you have fuel coming out the injectors?

Do you have compressions?

Bert

BertBert

18,953 posts

210 months

Sunday 26th March 2017
quotequote all
Could you borrow an emerald to try?

dave7

Original Poster:

21 posts

274 months

Sunday 26th March 2017
quotequote all
Hi Bertbert

Yes, that's right I have sparks at each plug, and fuel seems to be getting into each pot (each plug is wet when removed).

What I don't know is the timing of the spark and the injectors - I guess with a standard MEMS ECU there is no way to tell without the Rover diagnostic equipment?

I've not checked the compression, but there's no reason why it shouldn't be at least good enough to get it running, as the engine didn't go bang - and I think it would at least try to fire on a couple of cylinders if not all 4. I also know the history of the engine, as I've had it from new and it's always looked after.

I don't know anyone with an Emarald unfortunately.

upsidedownmark

2,120 posts

134 months

Monday 27th March 2017
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Is it possible that the sensor ring (I'm assuming a slotted disk type arrangement on the crank) could have moved - again I have no k-series specific knowledge. A simple timing light should allow you to verify the spark is happening at the right time?

Logically I'd think that the remaining options are a mistimed spark, or sufficiently too much fuel that it's not combustible (given the plugs are wet).

Peanut Gallery

2,418 posts

109 months

Monday 27th March 2017
quotequote all
Sorry for throwing ideas at you!

Right, you mentioned distributor cap. I (my mom) used to have a 1995 mazda 323 - from S.A. It had carbon HT leads that failed, were replaced by copper HT leads, this then lead to the condensor within the distributor failing. After ages we figured out what it was, and replaced the leads and condensor, all sorted!

If I remember correctly there was a small spark, but not enough to fire.

(Comment about cambelt / compression removed, you have checked cambelt.)

Are you getting a smell of petrol out the back?

Not ideal, but I have had success tow starting a car that was being a pig to start, 2nd gear at 30mph tends to get things moving!

No blown fuses? Anti dieseling cut-off valve working (delete that if fuel injection)?

JRA

9 posts

100 months

Monday 27th March 2017
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I'll put my money on a dead crank position sensor as its this that tells the ECU when to send sparks. The distributor only sends it to the correct plug. Good luck.

ben5575

6,216 posts

220 months

Monday 27th March 2017
quotequote all
Silly one, but have you checked that the inertia switch hasn't popped and needs resetting? Did you happen to drive over a big bump/jolt before the engine cut out? Mind I think that cuts the fuel pump which you say is running, but worth a check for the sake of 10 seconds.

Thread below might have something to offer (inertia switch & crank sensors etc)?

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

As before, if it doesn't start with easy start etc then it's not a fuel problem.
It cranks over without munching the engine so it doesn't sound like a timing/mechanical/hydrolic'd problem
I take it the tb butterfly opens and closes so you're getting air to it?

Fuel, air and spark all present with a decent battery but doesn't start. If it is sparking then even if it doesn't start, you would still get some coughing if you took the air filter off and sprayed easy start into it . Fuel/air/spark = bang regardless. And you say you've tried this? If it doesn't bang then it's the spark as you have fuel and air (unless it is being flooded for some reason)

All four HT leads would need to fail at the same instant for it to be them (if it were one or two then your would get a misfire rather than a dead engine)

Sensor inputs are:

Throttle pot
Air temp
Water temp
Oil temp
O2 sensor
Crank sensor

Engine will start/run (albeit not well) with most of those not functioning. Apart from the crank sensor.

For the crank sensor to work you need a functioning sensor and a powered up ecu. Check - fuse/ignition circuit/alarm/immobiliser/proper earth and then the circuit completing to the spark plugs.

Pin 8 on MFRU output plug is ecu power supply, Pins 1 on MFRU input plug is ecu relay control. All of the other pins deal with fuel/starter.

If you pm me your email I can send you the electrical section from the manual of you don't have it.

battered

4,088 posts

146 months

Monday 27th March 2017
quotequote all
K series are very unfussy, if they have sparks and timing they will start if you just throw fuel in the air intake. I did this when my 7 (1.4 kss) dropped its fuel pump, it started perfectly and ran for a second or two until the fuel ran out. At least then you know it is fuel that's at fault.

dave7

Original Poster:

21 posts

274 months

Friday 31st March 2017
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Thanks for all the replies.. smile

I bought a can of ‘Easy start’, and it still wouldn’t fire. I guess that rules out a fuel or injector switching problem.

Yes, I’ve checked the inertia switch.

I was driving on a smooth road when it cut out.

Yes, the butterfly opens fine.

ben5575 said:
If you pm me your email I can send you the electrical section from the manual of you don't have it.
Thanks, I’ll send you a pm..

I’m now thinking maybe it is the ECU is on the blink – causing it to spark at the wrong time. I do have a spare, but as the ECU and alarm module need to be matched, I’ll have to get it reprogrammed.


Edited by dave7 on Friday 31st March 12:31

battered

4,088 posts

146 months

Saturday 1st April 2017
quotequote all
I think it's garage time. 60 quid will sort it, it doesn't sound like you have the diagnostic gear or skills to DIY, no disrespect, but modern cars don't lend themselves to fixing by part substitution.

ben5575

6,216 posts

220 months

Saturday 1st April 2017
quotequote all
Dave, got the pm. Will email tonight.

dave7

Original Poster:

21 posts

274 months

Saturday 1st April 2017
quotequote all
battered said:
I think it's garage time.
Yes, I think so too.

ben5575 said:
Dave, got the pm. Will email tonight.
Thanks Ben smile

And thanks everyone else for all the suggestions..

Eric Mc

121,776 posts

264 months

Sunday 30th April 2017
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Any developments?

dave7

Original Poster:

21 posts

274 months

Tuesday 2nd May 2017
quotequote all
Hi Eric

No – unfortunately not.

I’ve been really busy restoring an old Series 1 Land Rover so not had much time to look at the Caterham. frown

BertBert

18,953 posts

210 months

Tuesday 2nd May 2017
quotequote all
And here we are on the edge of our seats, dying to find out what the problem is biggrin

dave7

Original Poster:

21 posts

274 months

Tuesday 2nd May 2017
quotequote all
Sorry, me too!

I was thinking about a crossflow conversion - might be easier to diagnose faults wink

battered

4,088 posts

146 months

Tuesday 2nd May 2017
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That would do it. "What's wrong with it, Bob?" "I've been all over it. I know the fault, that's easy. It's a Crossflow."