Misfire on the Track Car...

[Ade T]

I got my 172 cup track car out of storage today and its been parked up since March.

It was running fine when I put it into storage so its strange that it has now developed a misfire.

Symptoms:

• Sounds like a Subaru when revved
• Loss of power
• Can here it popping out the exhaust
• Strangely it smells almost like firecrackers?
• No engine warning light

I have a track day next week so need to get it sorted asap.

 

[Nick172Cup]

My guesses is injectors.

 

[martynzs]

Mine is doing the exact same thing today.

Will be plugged into ODB tonight, gotta be coilpack/injectors I recon!

 

[DannyR]

Injectors 99.9%

 

[Greeny.]

I had this and it ended up being a faulty injector.

 

[Ade T]

Just tried a coilpack and still the same so that rules that out.

Got another set of Leads and 02 sensor to try tomorrow then last resort injectors. There is a strong smell of fuel so I suspect its going to be an injector.

What the deal with injectors btw, refurb? replace? How much is it gonna cost

Also is there anyway to diagnose an injector fault without having it plugged in to diagnostic equipment.

 

[MicKPM]

Engine running and disconnect the jets one at a time. If the engine note changes for the worse the injector was working. If you unplug one and it makes no difference... BINGO!

 

[CuppyDean]

Same symptoms as i had on my cup except i had the emission light on to, mine was a nackered injector

 

[Tony Hunter]

Just pull the fuel rail off, and get somebody to turn it over.

 

[MicKPM]

Just pull the fuel rail off, and get somebody to turn it over.

Involves removing x2 10mm bolts... effort!

 

[DannyR]

It's much easier to do that than test leads. And it's 4 bolts as you'll need to get the fuel rail guard off

 

[Tony Hunter]

Involves removing x2 10mm bolts... effort!

It's much easier to do that than test leads. And it's 4 bolts as you'll need to get the fuel rail guard off

​Still too much effort for some I suppose.

 

[DannyR]

Of course, but this is CS I'll ask for advice but I'll still do it my own way .net

 

[Steve]

How long has car been standing for?

​Fuel, our old petrol mower hated the fuel left in it

 

[Ade T]

Engine running and disconnect the jets one at a time. If the engine note changes for the worse the injector was working. If you unplug one and it makes no difference... BINGO!

Brilliant I'll try that tomorrow!

I've managed to borrow an Autel diagnostics reader so will give that ago as well.

Its bound to be a simple fix.

 

[Ade T]

How long has car been standing for?

​Fuel, our old petrol mower hated the fuel left in it

Since 1st March, half a tank of V power in it. Not sure if it can go stale in that time?

 

[MicKPM]

Injectors are wired in banks so I don't think they will show up as individually faulty on diags. May be better off with the methods above tbh

 

[Ade T]

Injectors are wired in banks so I don't think they will show up as individually faulty on diags. May be better off with the methods above tbh

Just tried it quickly, injector 4! Can they be cleaned up or is it a new one?

 

[DannyR]

Injectors are wired in banks so I don't think they will show up as individually faulty on diags. May be better off with the methods above tbh

They do, mine did using the Snap On Diags.

New injector, they're cheap new from Renault.

 

[MicKPM]

They can be cleaned/refurb'd but not worth the effort imo. The cost new is about £45 so easier to just bite the bullet and call GSF for one.

 

[Ade T]

I can get one on a staff sale from euro but I am suspect as to the quality for parts like this. I'll have a ring round tomorrow anyway, just glad its a simple fix.

 

[martynzs]

Any luck with this dude?

Picked up a new injector today ready to be fitted tomorrow - fingers and balls crossed it works!

 

[Ade T]

Just! £40 later and I found out in wasn't the injector! It was the HT lead hence why nothing changed when I pulled out injector 4. When I did my last track day back in march I checked the plugs after I had put it away and must have nipped the lead because its bridging. Now I need to get some new leads!

 

[Ade T]

Running perfect again

 

[martynzs]

Glad to hear it buddy!

Mine is now running on 3 constantly. I had all the plugs out and lead off which I think disturbed something as the misfire has gone from being intermittent to constant. Leads and plugs next!

 

[Ade T]

You might of trapped one of the leads under the intake like I did