Random momentary cut-outs?

[dvs_dave]

For a while now my Mk.1 Tuscan has been having what can best be described random momentary cut-outs. The car has never completely died but it’s a bit of a pain and not right. It seems like the engine cuts out for a fraction of a second, accompanied by a flicker of the pod lighting and a click from the pod/footwell area that sounds like a relay switching, and then everything carries on as normal. No error codes, backfires or anything.

Has anyone else experienced this or have any ideas what it could be?

[Mustang Baz]

Dave - I have experienced this from time to time albeit the intermittant cut-outs are very quick indeed and barely impact the driving experience. Seems strange, but I have generally grown to live with it over 5+ yrs of ownership!

[nelly1]

It could be a number of things:-

• a loose earth or poor battery connection;

• a hairline crack in the 'other' 100A fuse (the one in the passenger's footwell);

• a badly crimped or dodgy soldered joint at the fusebox;

• a bad soldered joint on the ignition barrel or a dodgy switch therein;

• the power relay has a bad connection between it's contacts;

The fact that the engine and dash go simultaneously says it's a common power feed problem rather than just an engine one.

Happy hunting!

Edited by nelly1 on Monday 5th July 16:35

[YRRunner]

Check out the fuel pump relay. Even if it looks fine, it could have a hairline crack where the pin meets the block. Mine used to cut out momentarily (usually whilst overtaking in the fast lane) then cut back in. The fuel pump relay sticks out of the fuse board quite a bit and can easily be caught with your right toe.

[nelly1]

That wouldn't cause the pod to flicker though...

[dvs_dave]

I thought a dodgy pump relay resulted in the engine struggling to run and gradually dieing, rather than momentary cut-outs?

Would the pod not flicker due to the sudden current draw of something kicking out and back in? BTW it doesn't coincide with the the fans switching on/off.

[LeeT350c]

Dave, I get his on my T350.

Is it like you click the ignition off for a split second so loose engine, pod, everything then all is well?

I cleaned the terminals on my power relay and it seems ok now.

Cheers.

Lee.

[dvs_dave]

Yes, everything appears to cut out for a fraction of a second (maybe less than 0.1 second?), and then everything carries on as normal.

I'll check the power relay as that sounds a likely cause. Will probably just order a new one as it's easily got the potential to leave me stranded. Anyone know which relay is needed for a Mk1 Tuscan S?

[Arapo]

Dave - Had the flicking from the pod as well a couple of times, but no power cut outs when this happened.

Had power cut outs though plus the fuel pump has been playing up, so was thinking to get new relays as a precaution. Lets coordinate when ordering to get them together.

I also have a couple of spare 100 amp fuses, let me know if you need one.
Should be getting the car back tomorrow, so I will check what relays are required and give you a shout.

Costas

[dvs_dave]

Took the power and pump relays out and nothing seemed amis. Put them both back in and made sure they were properly seated and so far so good after a 200 mile drive today. Hopefully just the relays not properly seated.

[JamesSim]

nelly1 said:

It could be a number of things:-

• a loose earth or poor battery connection;

• a hairline crack in the 'other' 100A fuse (the one in the passenger's footwell);

• a badly crimped or dodgy soldered joint at the fusebox;

• a bad soldered joint on the ignition barrel or a dodgy switch therein;

• the power relay has a bad connection between it's contacts;

The fact that the engine and dash go simultaneously says it's a common power feed problem rather than just an engine one.

Happy hunting!

Edited by nelly1 on Monday 5th July 16:35

Sorry to hijack this post but I've also experienced this twice recently, although it was a complete loss of power.
I have only recently had to replace the entire fuseboard this was following the return of the dash from Paul, due to the headlight relay failing.
The car was running well when suddenly the speed, fuel and temp gauges failed, it was arranged that as I was going to be on the M6 Paul wanted to see the car for himself, when these 2 failures happened I didn't relish the idea of the 300 or so miles with the possibility of a cut out on the motorway.

kind regards,

James.

[TCat]

I experienced exactly the same problem to my Tuscan Mk1 last year. Matt at Silverstone Performance replaced both throttle potentiometers and the problem was solved.

[Lucozade]

Not sure if this is related, mines is experiencing huge idle drops to 0 before picking back up again. I've noticed it tends to happen when the outside temperature is warm.

[NCE 61]

Lucozade said:

Not sure if this is related, mines is experiencing huge idle drops to 0 before picking back up again. I've noticed it tends to happen when the outside temperature is warm.

I had a similar issue and found it was down to the air temperature sensor giving very high readings, would cause all sorts of AFR faults and high adaptive readings, particularly when ambient temperature was above 25 Deg.C

[Lucozade]

NCE 61 said:

I had a similar issue and found it was down to the air temperature sensor giving very high readings, would cause all sorts of AFR faults and high adaptive readings, particularly when ambient temperature was above 25 Deg.C

I've had the water sensor and both lambdas replaced so I guess I'm getting close.

Next stop TVR Power I think.

[Lucozade]

5 minutes at TVR Power and it was fixed - cheers Dom.

Laptop plugged in and lambda sensor reset. No problem now. In fact my air con is now behaving much much better.

Who would have thought eh !