Cylinder 2 Lean R400 K-series

[sam919]

Hi,

Cylinder 2 is pretty lean, thought it was injector, swapped with cyl 1 and still the same. Engine gets to around 6800-7000 then sounds like its hitting the soft rev limiter although that light doesnt come on. With this engines getting power loss and generally not good to drive, have to shift earlier to use torgue.

Any ideas why the cylinder is getting either not enough fuel or too much air, checked o-rings on injectors and injector seems fine, nightmare.

[Peter T]

How do you know if it is lean?
Have you checked it?

[sam919]

The rest of the plugs are sooted up, its got caterham rollers and it runs pretty rich. The plug in cyl 2 came out clean.

[rj]

Hmmm


Blown headgasket?

Or could it be one of the wires to the injector that's dodgy?

[sam919]

Yeh it has been mentioned, no white deposits on the oil though, might run a compression test to see if its mechanical valve or rings. If i fill up the cyl with some solvent white spirits or something make a dip stick leave it then measure it later to check the level. If it doesnt change then it could be the exhaust valve, make any sense!?
Will chekc the wiring from ecu, could piggy back the signal to an oscope and refference the shady one against the other ones.

[Peter T]

More likely to be head/gasket fault rather than an injector/wire fault.
Mind you it sounds like the whole engine needs a complete re-map if it runs rich as you say??

[Pete H]

Have you checked the balance of the throttle bodies ? I chased what I thought was a misfire on my R400 till I spotted the balance screw was missing. I guess I would expect something odd on number one as well though, but your symptoms sound very familiar.

Edited by Pete H on Monday 15th September 21:33

[fergus]

sam919 said:

might run a compression test

you're better off with a leakdown test rather than a compression test!

[sam919]

Ok thanks for the input, in off to have a look and tinker now.Keep you posted

Edited by sam919 on Tuesday 16th September 12:27

Just done a compression test, its was easiest and 16 quid for the tool. If this had shown any drops i would have gone and done the suggested leakdown test.
Anyway not that there all about 150psi, took all injectors off had a look down the rail, checked all o-rings, checked the input voltages across the inj all around 7.65v. Dont know if this will change at high revs though.
Off to look at balance screw altough all the rollers seems to come around at the same time and with equal openig distances.

Edited by sam919 on Tuesday 16th September 12:32

[rj]

If it was the balance of the TBs it'd show at low opening.

If it's a faulty wire it has to be under vibration it fails as it's at max rpm your engine is missing power.

No, I'd think it was the head gasket. :-(

[sam919]

Number 3 cylinder and exhaust manifold doesnt seem to heat up as well as the rest. 350-390 deg for all the rest 160-170 for number 3 measured at manifold.
The lean cylinder 2 after changing plugs doesnt get lean any more, although it hasnt been used at race conditions just idling and a quick blast up the lane.
Changed all connectors to injectors, no joy.
Head gasket, so it would either, let oil into the water or water into the oil?

[OJ]

Sounds like a coil pack

[rj]

Can't be a coil pack if it's a genuine R400 K-series.

This will have only one coil and one distributor :-P

Further it would not seem lean if it was a misfire, would it?

[sam919]

Just come back from the rolling road, the misfire etc happened at lower revs due to the load from the rr, last thing in spares box was a coil, sorted got just under 200 bhp at 7100 and 152 lbs.ft torque at 6150. Still had 700 till soft limiter so still rising when test stopped.#

Thanks all for your input of to Croft next weekend!

[OJ]