NB engine cuts out (not EGI relay, not cam position sensor)

Magpie · Postby **Magpie** » Wed Feb 25, 2015 6:49 am

What about this http://aeromotiveinc.com/products-page/accessories-electronics/16306/fuel-pump-speed-controller/

The American · Postby **The American** » Wed Feb 25, 2015 6:53 am

Hi C-gazer,

I have tried cleaning the contacts, and they appeared to be misaligned in the original relay. The arm that the moving contact is attached to is both screwed and tackwelded to the body of the relay. I did not want to disturb the weld and cause damage, and so I did not remove the the arm and contact so as to have a good look at the condition of the surface. There is no obvious burnt appearance, and the plastic around the connections on the base show no sign of melting or discolouration.

AutomotivePlus supplied me with another relay, which I swapped out and the fault reoccurred. For this reason, I ruled out the individual relay as the root cause - but perhaps I've been unlucky enough get a second dud.

The car is currently with AutomotivePlus for some unrelated work, and then will be with the tuner for some fine tuning, so I wont have the car to try any further on this for a few weeks.

The American · Postby **The American** » Wed Feb 25, 2015 7:05 am

Magpie wrote:What about this http://aeromotiveinc.com/products-page/accessories-electronics/16306/fuel-pump-speed-controller/

that's another alternative! When I google outside of Mx5 circles, the problem of stressed factory fuel pump relays with upgraded fuel pumps is not unheard of. This product addresses a similar problem and appears to recognise the weakness of OME relays.

Are you making any changes to the fuel system for the E85 upgrade? Which pump will you be using/continuing to use? Others have suggested the pump I went with was overkill.

Magpie · Postby **Magpie** » Wed Feb 25, 2015 7:34 am

Hopefully Plus will have my at GT Auto as well this week.

Not sure what pump will be used for my E85 build, I'll ask. My concern is the amount of fuel that can be carried, however this will be dealt with later.

luzinit · Postby **luzinit** » Wed Mar 04, 2015 2:16 pm

Just want to add that one month ago I changed my coilpack to an OEM copy from Mania. I've dríven around 1000KM since then and so far my EGI relay is holding up fine. My previous brand new OEM relay lasted 1 day on the old coilpack before failing. I'm hoping this fixed the issue, only time will tell.

In regards to the fuel pump, my original one was replaced 1 year ago with an uprated DW300 pump.

Food for thought!

The American · Postby **The American** » Fri Mar 06, 2015 6:32 pm

Madness.
Apparently the decomposing remains of not one but two aftermarket immobilisers are lurking under the dash.
No evidence yet that either is the guilty party, but they've been seen at the scene of the crime.

bruce · Postby **bruce** » Fri Mar 06, 2015 7:57 pm

I hate that leftover electronic sheit.

manga_blue · Postby **manga_blue** » Fri Mar 06, 2015 8:01 pm

The American wrote:Madness.
Apparently the decomposing remains of not one but two aftermarket immobilisers are lurking under the dash.
No evidence yet that either is the guilty party, but they've been seen at the scene of the crime.

They're aftermarket alarms systems. They're both guilty of everything electrical that goes wrong with a car. That seems to be their main function.

The American · Postby **The American** » Thu Mar 12, 2015 6:41 pm

the good men of AutomotivePlus retrofitted another heavy duty relay for the fuel pump, but the fault persists, and they also had formed the view that the problem was not relay related.

The car has now been with the tuner for a week (they wired up the ecu) and while they have been able to observe the fault in action, they haven't been able to nail it down. I believe they dealt with the immobiliser issue and then the car didn't fault again for two days, and then did shut itself down again this afternoon.

speed · Postby **speed** » Fri Mar 13, 2015 5:40 pm

At least the fault occurs whilst in there possession. Hopefully only a matter of time now.

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The American · Postby **The American** » Fri Mar 13, 2015 6:39 pm

I just spoke with Tim from GT Auto Garage. They've been running the car at idle, waiting for it to fault. Today it faulted, and they observed the ECU power off. They then checked and there was still power to the ECU.

They borrowed a PS1000 from AutomotivePlus and ran the car with that for an extended period, and it did not fault.

Consequently, they want to send the ECU to Haltech to check, which will be a week or two.

The truth is now clear to me - I need a second Mx5 for those times when the first is in the care of others!

The American · Postby **The American** » Thu Mar 26, 2015 6:30 pm

Tim from GT Autogarage emailed to let me know that my brand new ECU has been repaired by Haltech, and it is on it's way back to Brisbane. I should have my car back soon. Hooray!

The diagnosis was a faulty 'polyfuse' which has been replaced.

I had found one or two threads on forums where other Haltech owners had similar symptoms to my car (ECU has uninterrupted power, but randomly cuts out) and that were eventually traced to the ECU, and subsequently to a faulty polyfuse in the ECU.

I'm not going to call it fixed until I've had it back and dríven it for a while, but it's sounding like it just might be solved.

What is a polyfuse?

speed · Postby **speed** » Thu Mar 26, 2015 6:53 pm

A poly fuse is a fuse made from polymer. It is a fuse that after it has 'blown' will self heal; that is after several days. It will almost behave as if nothing has happened.

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Caffeine · Postby **Caffeine** » Thu Mar 26, 2015 7:22 pm

speed wrote:A poly fuse is a fuse made from polymer. It is a fuse that after it has 'blown' will self heal; that is after several days. It will almost behave as if nothing has happened.

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Some of them can reset after seconds or minutes

The American · Postby **The American** » Thu Apr 09, 2015 8:20 pm

It's not clear to me exactly what was wrong with mine - it appeared to blow and reset, but blew too easily - or at least that would fit the symptoms I had. No issues since!