Help please - won't start!

[Fishy Dave]

Hi guys,

 

I'd had a great weekend blatting around Exmoor, right up until the point the Seven died on me. I could really do with your help diagnosing the problem (I only have limited time to get it running again before the MPH show next week).

 

I was just exiting a roundabout when the engine just cut, I dipped the clutch and frewheeled to the side of the dual carriageway. Fearing a belt had gone I took off the bonnet but all looked fine. Turning off and on the electrics I couldn't hear the fuel pump, so sure enough when thumbing the starter button then engine turned over fine but wouldn't fire.

The AA man arrived and confirmed their was no voltage to the fuel pump. Checking this wire in the engine bay at various point showed their was power (white wire with purple), we checked the fuses and found one 10 amp fuse on the top row had gone (standard Rover fuse box afaik). Replacing the fuse then brought power back to the fuel pump. It still wouldn't start though.....

A spark was being produced at the plugs, but the plugs were dry of fuel.

 

This is ther point we draw a blank. His best guess was an ECU fault preventing the injectors from functioning? The flat bed truck operator (that arrived over 5 hours after initially breaking down!!) thought it was a fuel air lock?

 

I now have the car back in my garage, so, what do I check next? Please treat me as a relative novice.

 

Thanks, Dave

[Frying Pan]

Check the inertia switch (usually on the bulkhead behind the battery - black rubber top) hasn't tripped. Press the rubber button to reset.

 

What immobiliser do you have?

 

Guy

 

-----See some pictures of the build here. 13000 miles completed!

[Peter Carmichael]

1. It isn't a fuel air lock. Doesn't happen with an immersed high pressure pump. If you've got fuel in the tank and a running pump, you will have fuel at the fuel rail.

2. It isn't the inertia switch, because the fuel pump is running

 

3. Check all plug connections on the sensors on the engine

4. It could be the immobiliser has got confused somwhow during the fuse blowing incident. Needs four/five set/unset cycles on the keyfob

[Sheds Moderator]

The fuel pump is new so unlikely to be faulty. Try the batt isolator(Red FIA switch), it's from 2002 and it caused me a few breakdowns then which were a sod to trace as it was an intermittet fault. Yes the starter will turn when the switch is faulty.

 

The check is to bridge it across with a bit of wire, then run the engine.

 

They are known to be poor quality and unreliable. ☹️

[Fishy Dave]

Thanks guys,

 

Yes, forgot to mention we bridged the wires from the inertia switch, so know that wasn't the problem.

 

Thanks for letting me know about the fuel pump Steve, didn't know it was new

 

Also good to know it won't be a fuel airlock.

 

I bought a spare FIA key, and was using the new one. Will try the old one and have a fiddle with the isolator too. Would that have caused the fuel pump fuse to have blown though?

 

We checked every connector we could find was connected on the engine. Most we removed and reattached too, just in case of a dirty connection.

 

The AA guy also thought an earth could be to blame, but every earth point we found seemed fine. Where does the black earth lead that exits the ECU actuallu earth to? We couldn't find as it is lost in the loom. He was expecting to find another main earth point?

 

Thanks again.

[Fishy Dave]

Hello,

 

Ok, I took the fuel hose off the fuel rail and primed the electrics and got no fuel out, although I could hear the fuel pump whir for a couple of seconds. I rigged up my multimeter and detected 12v for those couple of seconds.

Working my way backwards I disconnected the fuel filter and tried again, nope, still no fuel (apart from any lost through gravity).

So, am I right in thinking it's the fuel pump, or is that a bit too obvious?

 

[CageyH]

Or a blocked fuel line...

 

Only dead fish go with the flow....!

[anthony1956]

or an empty fuel tank .. +faulty guage..

[S47zz]

I had a similar problem on my S4 which has an 'in the tank fuel pump', the pump pickup pipe had fallen off the pump[inside the tank] and so was not picking up any fuel even though the pump was working [making a noise]. I'm not familiar with Cats fuel pumps so don't know whether this may be a possible cause on your car 🤔.

[Fishy Dave]

I have blown through the fuel hose, so know it's not blocked. When I removed the fuel pump I had to drain out about 15 litres of petrol from the tank, so it's not too little fuel. Their were some deposits on the fuel pump filter (firmly attached), but not enough to have really impeded the flow IMO.

I will try to connect up the pump to a 12v source now it's out of the car and see what happens.....

 

I have searched on here for possible sources of fuel pumps (other than CC), but apart from the Rover tomcat pump being suggested, I can't find out which model of Rover the standard pump comes from?

[Paul Deslandes]

I don't know what type of ECU you have but depending on how they're wired, the MBE units only supply power to the fuel pump for a couple of seconds when the engine isn't turning over. Its a safety feature so that in a smash, if the engine stops the pump cuts out after a couple of seconds. Personally I prefer the impact switch cut out but this might explain why you pump stops after a couple of seconds. Can you see if there are volts going to the injectors? Is there a relay in the injector supply that could have failed or have a loose connection? +12V goes to the injectors via a relay and the ECU switches to ground on MBE setups. Other ECU types may well be different.

 

 

[Fishy Dave]

I think they call it a MEMS unit? Standard rover type ECU on my 1400 supersport?

[Paul Deslandes]

Ah! Others will no doubt be along to tell you more about this unit. My comments re MBE ECUs almost certainly don't apply unfortunately.

 

Best of luck.

 

 

[Fishy Dave]

Ok, my last update on one of my other threads was that we tried a 12v connection direct to the fuel pump and it whirrs into life. A bit annoying as I was hoping in a way the fuel pump was the problem. Scratching my head a bit and reading more advice here, I decided to check that it was actually pumping, and not making a noise.

So, I connected the pump only, up to the original wiring. I carefully lowered the pump into a container of water about a cm from where the wiring goes into the top of the pump (to avoid shorts) and turned on the ignition. The pump whirrs into life but no expected fountain. In case of some sort of air lock I shook the pump and tried this procedure a further 10 times, but not even a dribble of water from the outlet.

So, am I right in thinking something has broken inside the pump?

 

 

New owner of BOSS

 

[Stationary M25 Traveller]

Sounds like the impeller has fallen off the motor ?

 

7 related photos

[rgrigsby]

Hmm yup does sound like a dead pump, not sure whether it's something you really want to pull apart and repair as they are a fairly sealed unit if I remeber correctly.

 

Rob G

www.SpeedySeven.com

[Fishy Dave]

Hi Rob,

 

Please can you contact me asap on 07718 368173 re. your fuel pump you have available. :)

 

New owner of BOSS

 

[Fishy Dave]

Well, I ordered a new pump assembly from Caterham, and with good service (at a financial cost) they got it to me Thursday morning. To cut a story short it worked!

 

It was such a relief the car started, so it must have been the impellor or internals of the pump that had broken.

 

Thanks all for your help and advice everyone, it really made a difference having my car on the stand at the MPH show. I'm also filming at Brands next week so am happy to be able to resume chase car camera duties again.

 

New owner of BOSS

 

[Sheds Moderator]

Glad it's sorted Dave, but I am a bit p*ssed off on your behalf as that pump is at best only 12 months old. I think it had done about 100 miles before I sold it to you, and bearing in mind the price ex CC I don't think that's very bloody good.