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mj22 10-30-2012 05:06 PM

JRSC just will turn over but won't idle
Hey Everyone,

I have just finished up installing a JRSC kit on my car.

I went to start the car for the first time this morning and have run into a problem.

When I start the car it turns over as usual with the indicated revs jumping to 1500 rpm or so and then they quickly drop down as used to be the case when starting the car. My problem is the revs continue to drop quickly until the car stalls. It is not as if the car is spluttering and the revs are slowly dropping until it stalls, they drop quickly.

I tried to correct the problem by applying some throttle when I start the car. This made no difference. While I could get the revs to climb a little higher at start up by applying about 10% throttle, no amount of throttle will stop the rpm dropping - if anything applying the throttle seems to make the car stall more quickly.

Can anyone offer their thoughts on what they think may be the problem?

I will do the usual checks for vacuum leaks once I am home tonight however given how quickly it is stalling this seems like it may not be the problem. Most people seem to just have a really rough idle with vac leaks. Could be a massive leak somewhere [:p]

Is it possible it could be the tune? I have an Xcal 3 and only have a base tune loaded on their which the tuning will be adjusting once the car is running. I've heard mention of custom tunes not supplying enough fuel for start?

Any help would be great!



ah1f39 10-30-2012 05:36 PM

Sounds like the fuel pump isn't switching from start to run. Check the fuel system. Relays, fuse, lines...ect.

1turbofocus 10-30-2012 06:54 PM

A base tune is just that a base tune , you need to get your car tuned properly to get it to run right ,


mj22 10-30-2012 07:42 PM

Thanks Tom. I appreciate what you are saying.

I'm chasing advice as to what I should be looking at myself prior to discussing the problem with the tuner.

I will definitely check the fuel system once I am home tonight.

BigRed03 10-30-2012 08:24 PM

is your maf installed correctly?

idle air control set correctly?

mj22 11-01-2012 05:22 AM

Hey again Everyone

So I did a datalog and the car is reading 0 fuel rail psi. So I make the assumption this is a fueling problem.

The fuel system appears to prime just fine. Possibly this is what is providing me sufficient fuel to kick the car over and let it run for couple of seconds.

I also took the return line of the fuel rail (Australian Focus have a return fuel system) and attached a hose to the return feed for the fuel rail then to a bucket. Turned the ignition key and had plenty of fuel was coming through the fuel rail as the fuel system ws attempting to prime.

My question now. What does everyone think the likely cause is for the fuel rail to be reading 0 psi?

I have checked all the fuses and relaya (switched the relays around with others of the same type), all of the various connectors are connected/clipped up properly.

Could it be an issue with the vacuum line between the fuel pressure sensor and intake manifold? However I assume the fuel pressure sensor is seeing vacuum on start up as it is t'd into the same line as my boost gauge which shows vacuum on start up. I followed the vacuum line configuration advised by OJ as mentioned discussed in a couple of threads over on FJ

Alternately could this be tune related? ie. tune is setup for different injectors by error or something along those lines?

Anything else anyone can think would be causing the problem?

Again any help would be great as I am very keen to get the car back on the road.



1turbofocus 11-01-2012 10:33 AM

Do you have fuel psi why cranking ?


ah1f39 11-01-2012 10:37 AM

That's exactly what I said the problem was. You need to recheck your vacum lines and make sure that they are set up the way JR sugested.

When you engine fires and runs it creates vacum wich makes the fuel pump relay switch to the "run" circuit.

If it was an injector mismatch problem it would run but would have a rich/lean mixture.

mj22 11-01-2012 03:42 PM

Hey Tom

The car reads 0 fuel psi even when cranking.

However, like I said there is definetely some fuel there to get it started.

I also checked a datalog that I completed prior to installing the JRSC kit and it was reading fuel pressure. ie. the datalogging does work with Australian delivered focus.

If you have anymore thoughts that would be great.


1turbofocus 11-01-2012 05:17 PM


Originally Posted by ah1f39 (Post 4434380)
That's exactly what I said the problem was. You need to recheck your vacum lines and make sure that they are set up the way JR sugested.

When you engine fires and runs it creates vacum wich makes the fuel pump relay switch to the "run" circuit.

Im not sure I understand what your saying , the Focus will start and idle with no problem even with no Vac lines hooked to anything ?


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