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Zetec intermittent running issues


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Hi everyone,

I am after some suggestions for what may be causing some very intermittent running issues on the SVT Zetec in my Caterham.  When I first start the car after it has been unused for a few days, it starts 1st time, settles to a smooth idle and will cycle through the fan coming on and off when the car is up to temperature.  Apart from different cams and lighter flywheel, engine is stock and has been used regularly without issue for several years.  This was originally a Rocky Mountain built and supplied car that I purchased from the original owner several years ago.

 

However, recently, if I drive to the gas station or a destination, and then turn the car off, when I restart the car it frequently either won't start, or will start and then sounds like it is running very poorly, won't rev cleanly, and frequently cuts out.  Repeated attempts to restart are typically unsuccessful, but if I leave the car for some time - more than 30 minutes or so, the car will start again and run normally.

 

I am not particularly mechanically minded, but have some enthusiastic helpers!

 

Has anyone experienced anything similar, or has any suggestions for how to determine root cause, or in what order to start replacing things?!

 

Thanks for your help,

James

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This sounds like a typical vapor lock in the fuel lines. If it is, the solution is to insulate the fuel lines from the heat of the exhaust or any other hot parts of the engine, or possibly reroute them so they a further from how objects.

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Vapor lock is a possibility.  Has anything under bonnet changed that would impact airflow, heat generation, or fuel line routing?  If not, and given this sounds like a new issue, I'd be more inclined to look for an electrical issue, and likely start with the coil pack.  As they age, heat soak can cause internals to expand and either break electrical connections or reduce contact area thus increasing resistance and performance.  Next time it happens, check for spark.  Over the years, I’ve had one coil pack, one TPS, and one engine loom all fail with similar results to yours.  The only difference is that when the engine loom failed the issue slowly morphed and was no longer limited to poor running after the car had sat for 5-10 minutes on a warm day.

 

-John

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Thanks guys - no recent changes to the fuel lines or under the hood, but not ruling that out!

 

I've just ordered a new coil - I'll let you know how that goes...

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BTW if you have the ability to do data logging with your ECU, it's worth doing.  It might help you narrow down the issue (e.g. if the TPS load site keeps changing rapidly under steady throttle, then you know that sensor circuit is an issue.)

 

-John

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46 minutes ago, JohnCh said:

BTW if you have the ability to do data logging with your ECU, it's worth doing.  It might help you narrow down the issue (e.g. if the TPS load site keeps changing rapidly under steady throttle, then you know that sensor circuit is an issue.)

 

-John

Thanks John - I am not sure - I believe it is a stock Ford ECU, and I do have an OBD port, but not sure if that means data logging is feasible.  I will research, unless you happen to know?

 

BTW - I see you are in 'Seattle-ish' - I was just there with the wife, absolutely gorgeous.  Rented an airbnb above Alki beach with the most amazing sunsets over the water.... must be why even a small place is 7 figures!  Your 7 must be fun in those hills!

 

James

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jFGW, first thing I would check is the Fuel filters, my S1 has one in the very back near the fuel tank and a micron filter in the engine compartment..  Hope you sort it out..

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Unfortunately, I don't know anything about the Ford ECU, so I'm not sure if you can even access a live events view, let alone log.  Someone here might know.

 

I used to live in West Seattle and would run down the back roads to Alki.  Lots of fun, but crowded.  I'm now closer to the foothills East of Seattle.  Less traffic, more corners :) 

 

-John

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If you have an OBD 2 port you can data log, I use a OBDLink MX+ Blue tooth adapter. It syncs up well with the https://racechrono.com/ app I use. You will be able to log all the OBD parameters, not everything, but a lot of interesting stuff. Engine temp, throttle position, coolant temp, IAT, speed... 

 

Graham 

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Just some clarification.   Zetec and Duratec Caterhams usually have a J1962 plug that is the same as OBD2 cars.  However, Caterhams are not OBD2 with one exception.  The J1962 plug will give CAN data out for a Caterham but that is not OBD2.  You will need something like Easimap or an AIM Solo II to read the CAN data.

 

The one exception for a Caterham with OBD2 is some regular Zetecs and SVT Zetecs used the Ford Oak model ECU.  This was just a regular black box, no labels - at least not on my former yellow SVT zetec. This would give OBD2 results off a scan tool albeit with faults e.g. emissions, fuel tank, etc. Best way to find out is try @fastg Graham's suggestion with a scan tool.  

 

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  • 2 weeks later...

If you think it might be vapor lock, one way to test is with running a tank of race fuel.  It could the pump gas formulation might have changed in your state, based on season, etc.  Race fuels almost always have a lower RVP and are more resistant to vapor lock.

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dallasdude - that's a good suggestion too, thank you.  Still awaiting the replacement coil, which was just shipped to me yesterday.  I'll update after that.

 

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  • 2 weeks later...

the saga continues...

 

I received the new coil, installed it and the car would crank but not fire.  I tried the old coil again and same result.  I tested the plugs for spark and all were good.  I bought new ones and installed anyway.  Still would crank but not fire.  I connected jump leads as battery was running out of juice - same result.

 

I disconnected fuel hose at injector rail and cranked, no fuel!

 

My fuel pump is in the tank I believe, on the lower right hand side as you stand behind the car.

 

I am working on running a wire from battery into the first connector block on the cable from the fuel pump (it has a brown and blue wire).  Brown to +ve, blue to -ve terminals?  This will tell me if pump will run.  There’s so many cicadas here in Ohio that i honestly can’t tell if the pump runs, I’m 95% sure it is not running.

 

I have an inertia switch which is depressed, I could bypass that.  Car also has the typical immobilizer chip that’s zip tied to ignition column, and no amount of wiggling makes a difference, and I believe it will let the car start and then will shut down.

 

Next plan is to pump fuel out of tank and then remove the side panel to get the pump out.  Does fuel tank need to be removed to do this?  I have a full cage and I’d rather not remove the cage to get the tank out!

 

Any thoughts gratefully welcomed!

 

James

 

 

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Does your tach show revs when you're cranking? My crank position sensor went bad, well the wiring to it. Was missing after a drive, parked it, and then wouldn't start a day or 2 later. Would crank, but not fire. I have a Zetec, and my basic standalone lets me fire the coils for testing. That checked out. Noticed no RPM readout when cranking, followed the CPS wiring, and the insulation had either chafed or been chewed on, exposing the conductor. 

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