My car has a Ford I4 RS2000 engine, 2.0L running on Kawasaki ZX6R carbs with megajolt ignition. It has a Innovate LC1 wideband fitted along with a AFR gauge.

Last night i noticed at WOT the gauge swinging around to around 16.5:1 which is obviously too lean. On further investigation today it seems to swing that way past half throttle ish. It didn't do this previously, it would maintain 14:1 ish to redline.

Ive had LC1's on other cars in the past and would say it probably needs a re calibration in free air, except the gauge reads "correct" or to put it better, what you would EXPECT it to read at all other times, cruise, around town etc so Id say its reading accurately.

Now I know nothing about carbs if Im honest (give me a laptop!) but was wondering what should be me first steps and is there anything to obviously check first? This could be the ideal time to get more familiar with them.

Thanks

if it was running well before with all the jets etc. set correctly and you've not changed anything then I guess something has got stuck / needs a clean...

has it sat for any length of time with old fuel in it ?


see here for some background on this style of carb:
http://www.gadgetjq.com/keihin_carb.htm



[Edited on 7/8/2014 by mcerd1]

Thats for the response/link

Well that was my best guess, something is blocked. Any advice on how deep i need to go in removing the carbs/stripping them to get to the jets etc?

Thanks

I've got these on my car and have done lots of setting up with them - they are great and really easy to setup.

First thing is get everything clean - blowing through is not enough! Drain the float bowls and remove them. Looking at the bottom you will see two brass jets near the middle.One is screwed into a hex adaptor - that is the main, just to the side of that is another jet - that is the pilots. Take both of these jets out and soak in a glass of carb cleaner for 24hours. Blowing through won't do it - I tried numerous times and even when 'clean' an enormous amount of crap came out when soaked.

When it's back together see how it goes. I found balancing the carbs was very important - my Pinto is quite sensitive to how well they are balanced.

Just what I was hoping, someone else with these carbs chipping in!

So you do this whilst they are still on the car? Or remove them from the block?

Thanks

No worries - I struggled for ages to get my carbs right but was a great learning experience - wouldn't call myself an expert but have learnt a lot about setting them up!

On my car, I can do everything with them on - i.e. remove all the jets, balance carbs and adjust the needles. Mine are close to the edge of the body, but there is lots of room below, so I put a mirror down and just check the screwdriver is in the jets properly. Be warned the float bowl screws are made of soft cheese, so if you have never had them off before you may want to do them on a bench and replace with some capheads - then they are easy to get from below.

How much setup have you done with your carbs?

Luckily I have a spare set of zx6 carbs right here for reference which is good. I assume the bowl is just the black outside cap thing?

I've done zero carb setting up/tuning. I bought the car a month ago and it was running well and AFRs were good.

The bowl is the aluminium cover on the bottom. This will be full of fuel so use the little 'nipple' on the bottom to drain them.

See this for view of the bottom -



[Edited on 7/8/14 by davidimurray]

quote:

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Originally posted by dmrider_10
I assume the bowl is just the black outside cap thing?

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Just to confirm, when removing the jets, the central one with the hex head holder, I'm only removing the flat he's screw part and leaving the hex holder in situ?

You only need to take the jet out, i.e the one with the screwdriver slot

Ok just to keep this up to date, I let the jets soak in carb cleaner for 48 hours, blew them out and refitted along with the cleaned out bowls etc.

Its now running like a pig :-(

Most of the time its idling at around 17/18:1 and is now more erratic during normal driving, generally leaner than it should be everywhere.

Does the choke on these carbs just add more fuel/richen the mixture? I tried to counteract the lean-ness by using the choke, the AFR gauge reacts and swings rich only to then go back to lean (with the choke left in the same position)?!

Ill investigate more tomorrow.

Thanks

Have you checked for air leaks on the inlet?


What manifold are you using?

Pretty sure it's homemade by the previous owner. The fact that I couldn't balance it with the choke said to me air leak actually

Well took the carbs off and at first I when I saw this i thought id cracked it!



But its not all the way through, will replace it anyways though.

Looking at this image, should these two ports be connected together at all?




Also decided to check the plugs to see if they told a story at all, interestingly 1 and 4 (fed from same coil) looked like this:



And 2 and 3 (the other coil) looked slightly but noticeably whiter:



This is the home made mani:



[Edited on 12/8/14 by dmrider_10]

[Edited on 12/8/14 by dmrider_10]

make sure you use fuel resistant hoses to attach the carbs


check the diameter but these should be what your need:
Silicone Hose 40mm Fluro Lined Bike Carb Kit BLACK

The pipes are part of a heater circuit used on the bike and aren't generally used on cars so no need to worry about them.

My bet is an air leak developed over time. Incidentally even your original 14:1 is lean for loaded conditions - should be aiming for low-mid 13 AFR's.

Those hose clamps don't look ideal and as said make sure the silicone hose is fluoro lined fuel resistant otherwise they will break down.

[Edited on 13/8/14 by FASTdan]

Yeah Ive got some new flouro hoses on order and clamps although I think those existing clamps are better than they appear really.

Im just hoping on reassembly, balancing and adjusting that everything is normal.

Another possibility is the fuel filter? Probably worth changing that too.

[Edited on 13/8/14 by dmrider_10]

Just got a carbtune pro of a mate in work to balance the carbs.

Am I going to be able to use these as I dont recall any vac ports to plug them up to?

Not if youve no vac pipes
Best use one designed for webers etc that check vac at carb mouth
Set mine up fine with one
If you think theyre miles out you can check 99% with mig wire under each butterfly as a feeler gauge
Adjust master carb ( with the throttle cable attached to ) by the idle cable,then set others to match
Start and reset idle and tps

quote:

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Originally posted by dmrider_10
Just got a carbtune pro of a mate in work to balance the carbs.

Am I going to be able to use these as I dont recall any vac ports to plug them up to?

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Ok so for the second time Ive had the carbs in bits, and rebuilt them up. I found one of the idle adjustment screws was missing a O ring and a washer, and another just missing the washer. Luckily having a spare set of these carbs I've now replaced them.

Ive also got new fluoro lined silicone joiners to the manifold and clamps.

I cleaned everything, blew everything out, inspected the diaphragms, jets etc and re assembled.

Has it resolved anything? No :-(

I set the idle screws each to 3 turns out. Ill be honest, I haven't balanced the carbs, but nor have I touched the screws since the car worked properly so that doesn't really concern me.

AFRs are still all over the place :-(

Seems to be running around 14:1 for normal driving but its very random at higher revs/load.

Im really fed up with it now its doing my head in!

Sorry to hear your having trouble with the car. The engine was tuned from WOT backwards to cruise. So the needle positions and jet sizes where chosen to give a 12.5-13 on WOT. Then tweaked for cruise. The ignition timing from the Megajolt can affect the mixture, so it would be worth plugging a laptop into it and making sure its reading all the engine sensors correctly. As if it can't read sensors it can't progress through the table. Adjusting the carb needle positions by just one notch will richen/lean up the mixture considerably. All this should be done with the air filter on, as removing the filter leans up the engine lots.

quote:

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Originally posted by dmrider_10
Ok so for the second time Ive had the carbs in bits, and rebuilt them up. I found one of the idle adjustment screws was missing a O ring and a washer, and another just missing the washer. Luckily having a spare set of these carbs I've now replaced them.

Ive also got new fluoro lined silicone joiners to the manifold and clamps.

I cleaned everything, blew everything out, inspected the diaphragms, jets etc and re assembled.

Has it resolved anything? No :-(

I set the idle screws each to 3 turns out. Ill be honest, I haven't balanced the carbs, but nor have I touched the screws since the car worked properly so that doesn't really concern me.

AFRs are still all over the place :-(

Seems to be running around 14:1 for normal driving but its very random at higher revs/load.

Im really fed up with it now its doing my head in!

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Ok, so, after a busy week in work I got around to installing boot camp on my mac, installing windows 7, downloading the megajolt software and plugging it in. I was met by this:



Now Ive never used a megajolt before, but Ive mapped a megasquirt or two (albeit a few years ago) and that says to me theres no map on there?!

With just the ignition on the advance reads 7 and at idle reads 18, which seems a bit high?

From what the previous owner said to me, (deezee^^^) the car should run ok with the megajolt unplugged even and just running on the EDIS.

Can anyone make sense of this?

It's been a while since I used it so I can't remember the exact command but once you have communication between the MJ and your laptop you have to 'load' the map from the MJ.

Looking at your image I think it us one of the buttons with the little blue up / down arrows. One uploads the map from your MJ to the software. The other downloads a map to the MJ.

Stu

quote:

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Originally posted by whitestu
It's been a while since I used it so I can't remember the exact command but once you have communication between the MJ and your laptop you have to 'load' the map from the MJ.

Looking at your image I think it us one of the buttons with the little blue up / down arrows. One uploads the map from your MJ to the software. The other downloads a map to the MJ.

Stu

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I actually realised this myself after posting grrr.

Ignition looks fine, TPS working as it should etc.

Just changing fuel filter and pump now

Little update. Changed fuel filter and tested pump, all seemed fine. Didn't actually pressure test the pump but as its only running at 2psi anyway I figured the car wouldn't even run if the pump was only half working etc. No change.

Went to my mates to use his trumpet type balancer...... couldn't get cylinder 1 to balance. When I looked into the trumpets with a torch, for cylinders 2/3/4 I could see fuel being dribbled out at idle, at cylinder 1 there was nothing!

So tomorrows job is to remove the carbs AGAIN and strip cylinder 1 down to see whats what

Ok problem is certainly to do with the idle circuit.

Once again had them in bits, cleaned everything, checked everything, reassembled.

No change. And at idle cylinder 1 (or 4 dunno which) isn't getting any fuel. AFR is 17:1. Raise the revs and fuel visibly comes out and AFR drops to 14:1.

But for the life of me i can't clear whatevers blocking it :-(

Is sticking the whole assembly in the dishwasher and then an ultrasonic cleaner recommended!

Really doing ones swede in now

Glad your making some progress - a few things to check / try.

Have you checked the float heights are similar across all the carbs?
Try removing the idle screw and blowing car cleaner in from the bottom.
Do the diaphragms lift when you rev it?

Just a thought, you say you can't get no.1 carb to balance with the others? looking at the photos it looks like the throttle cable is connected to no.1 so that is the master carb that you need to balance the others to not the other way around. I suspect you have got that one shut and have lifted the other butterflies.

Latest:

Yes checked float heights, all the same.

Diaphragms all look to move the same when revved yes.

As far as the balancing goes, please remember this setup was working fine beforehand. When adjusting the screw between cylinders 1+2, adding more bias to cyl2 by screwing anti clockwise raises the revs, visibly more duel comes out from the needle. When turning the bias more towards cyl1 (the problem cylinder) your basically making TWO cylinders run lean as your reducing fuel in cyl2, so the engine will eventually stall. All the while, zero fuel is evident in cyl1 mouth.

Took the car to a mates garage and did a compression test (dry) and all cylinders were good. Thought maybe one was running weak and providing less suck or something so was worth ruling out.

Ordered another set of carbs off ebay now, will change the jets over and see if the problem persists!

[Edited on 2/9/14 by dmrider_10]

Hi everyone, still no luck with this car :-( Just looking for any old wild suggestions now!

To recap, ive:

Confirmed main jets are all 1.6mm
Pilot jets are standard
Float heights have been checked to 7mm
Carbs are balanced
Had manifold off, new gasket
New fluro silicone joiners and clamps
New fuel pump
Jets etc ultrasonically cleaned
Re calibrated LC1 in free air
Changed lambda sensor to another used one, re calibrated
No diaphragm rips/tears
Needles raised by one click
New plugs
Idle screw currently at 4 turns out

AFR gauge now reads 18:1 at all times while driving?!

[Edited on 19/9/14 by dmrider_10]

[Edited on 19/9/14 by dmrider_10]

quote:

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AFR gauge now reads 18:1 at all times while driving?!

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Obviously I also thought this as the car seems to run ok, no coughing and spluttering, no missing, no jerking etc.

But obviously i darent boot it when the gauge is telling me different.

Im booked in at blink motorsport next week for a RR sesh which will hopefully confirm/deny whether the sideband is reading correctly.

Problem Solved :-)

Well after trying bloody everything and systematically ticking off everything it could be causing this, doing some of it 20 times etc, I decided to get booked in on the dyno to check the AFRs against my LC1.

Went down to runcorn to see Chris at EFI parts, comes highly reccomended and I can only add my own reccomendation to that as he was brilliant. Got the car on the rollers after discussing the issue with him, him agreeing that he finds it hard to believe the car would even have made it down to him if it was running the constant 18:1 the gauge displayed. Sure enough, the fuelling was spot on!

Turns out the Lambda sensor for the LC1 is goosed, as is the spare (used) one that I had changed to, we plugged Chris' own bosch sensor into my controller and the gauge read correctly :-)

I was so relieved! I really didnt think that would be the outcome as having already changed the lambda sensor I assumed both sensors couldnt be broken and therefore took that it was reading correctly.

Just goes to show if your saying to yourself "I really dont think that gauge can be reading right, but will assume it is" then sometimes It pays to get it checked!

I can actually now start enjoying and tinkering with the car to improve it, instead of removing the carbs every other day!

Great news and annoyingly simple

On the bright side, at least you know your carbs are in top condition now!

The whole fuel system is minty fresh!

Thanks for the help though everyone.

The car made 155bhp at 6500rpm but was still making power and I think the rs2000 boys up the rev limit to 7k on these engines so I think ill be looking into that :-)