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Author: Subject: R1 Locost misfiring
Sanzomat

posted on 17/4/21 at 08:57 PM Reply With Quote
R1 Locost misfiring

Hi All,
Been reading a few posts on here for a year or so. Back in Sept I bought a Locost R1 that had been laid up for over 5 years. I bought it sight unseen during isolation but at a price that I figured gave me headroom to sort out the inevitable issues.

I've done a lot of work on the suspension (separate story!) but my issue now that I've tried running it is the thing is misfiring dreadfully.

It is a 4XV lump and it has been converted at some point to run 5PW throttle bodies/injection. The spacing is different so the previous owner has altered the spacing of the TBs to suit the 4XV inlet ports and it seems the size of the inlet stubs are also smaller on the 4XV so some eccentric ali spacer rings have been added to each inlet stub with the 5PW rubber connector then installed over these. Seems a bit of a dogs dinner but I guess it must have worked at some point.

Before I start messing with the megasquirt mapping (again, assuming it worked before it was laid up) I'm ticking off the things that are likely to have suffered during storage.

Symptoms - Starts okay but idle isn't great and runs rich and fouls the plugs after idling for a while.
If you rev it it fluffs/hunts/stutters but will pick up and rev. With no load, in neutral it'll rev all the way but AFR is going really rich and popping back and making some black smoke at times. With load it won't go past 9000rpm and leans out. It pulls kind of okay from around 7k to 9k though. Rich below 7k and lean at 9k, too lean to go any further, like hitting a rev limiter.

I've cleaned the injectors and they seem to be firing okay and flowing about right.
Fuel pump has good pressure. Haven't tested the pressure regulator though. New fuel.
I've changed the spark plugs and coil packs (had an R1 bike in the past, 5PW, and it was very sensitive to old plugs), no real improvement.

I'm currently suspecting air leaks from where the 5PW TBs have been mated to the 4XV inlet stubs so my next task will be re-sealing these (looks like plenty of clear silicone type gasket goo was used to seal them previously and it has broken down a bit)

Do any of you guys have experience of 5PW TB's mated to 4XV and can it be made to work? Is this a common thing or a bad idea in the first place??

Any other thoughts?
Cheers, Dave

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adithorp

posted on 17/4/21 at 10:01 PM Reply With Quote
Not heard of anyone converting them. Sounds like you've covered everything I'd have normally suggested and I'd be looking at the tb to stub seals.





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CosKev3

posted on 18/4/21 at 09:11 AM Reply With Quote
Are they deffo 5PW ITBs?
I thought the heads were the same as the carbed R1.
5PW ones are the strange ITBs that still look like a carb with that float thing on them?

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sdh2903

posted on 18/4/21 at 09:19 AM Reply With Quote
We're the coil packs new or used that you swapped in? The 4xv I had was rough running on the 2 sets of coil packs that came with the engine. New ones cured it.
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Sanzomat

posted on 18/4/21 at 09:50 AM Reply With Quote
quote:
Originally posted by CosKev3
Are they deffo 5PW ITBs?
I thought the heads were the same as the carbed R1.
5PW ones are the strange ITBs that still look like a carb with that float thing on them?

Definitely 5PW TBs. I've looked on a few bike R1 forums that confirm there is a different spacing and different size to the inlet stubs on the head between 4XV and 5PW. I've got the original carbs in a box of bits that came with the car, a few bits have been robbed off the carbs though otherwise I would have tried swapping them back on and seeing how it runs on carbs. The diameters of the carb outlets where they mate to the head inlet stubs are definitely smaller than the 5PW TBs. I've also got a full 5PW TB assembly straight from a bike so with the spacing fixed by the fuel rail etc and the 5PW ones on the car have clearly been altered as the fuel rail is in two parts and is blue anodised versus the plain ali of the original one piece fuel rail. The actual TBs are the same though, as you say with the same vacuum sliders like carbs but no float chambers/jets.

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Sanzomat

posted on 18/4/21 at 09:53 AM Reply With Quote
quote:
Originally posted by sdh2903
We're the coil packs new or used that you swapped in? The 4xv I had was rough running on the 2 sets of coil packs that came with the engine. New ones cured it.

The replacement coil packs are new ones. Made no difference at all.

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perksy

posted on 18/4/21 at 10:00 PM Reply With Quote
TPS been checked?

Checked for air leaks with carb cleaner or similar?

[Edited on 18/4/21 by perksy]

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Sanzomat

posted on 19/4/21 at 07:09 AM Reply With Quote
quote:
Originally posted by perksy
TPS been checked?

Checked for air leaks with carb cleaner or similar?

[Edited on 18/4/21 by perksy]

I plugged the laptop into the megasquirt and the TPS dial moves smoothly from zero to 100 as the pedal is pressed down so seems fine.

Spraying carb cleaner around the inlets during idle didn't seem to change anything but the idle was pulsing a bit anyway.

I'm going to give everything a good dose of sealant next and try that.

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ragindave

posted on 19/4/21 at 07:53 AM Reply With Quote
Are they balanced correctly worth checking.
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blue2cv

posted on 19/4/21 at 05:48 PM Reply With Quote
Surely if its making black smoke its running rich
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Sanzomat

posted on 19/4/21 at 08:18 PM Reply With Quote
quote:
Originally posted by blue2cv
Surely if its making black smoke its running rich

Yep - its rich up to around 7k rpm, well, the AFR is all over the place but generally rich. There seems to be a sweetish spot between 7 and 8k where the AFR is around 14 and then above 8k it leans out so that by 9k it the AFR is around 18 and it won't rev any higher. It has a wide band lambda with a digital AFR read out so I can see this (assuming it is reading right as I expect the lambda has gotten quite sooty)

My theory (possibly half baked) of what is happening is air is leaking in at the inlet joints. The Megasquirt is seeing the effect of this from the lambda and is increasing the fuel (assuming it can do this??) but if the air coming in is inconsistent then the fuelling adjustments can't keep up in real time so the fuelling is never right. At around 7k the air leaking in is matching what the injectors can provide at full flow so it comes on song. As the revs rise further and more air is sucked in, the injectors are already at full flow so can't give any more fuel so it goes lean.

What my feeble brain can't work out is how the amount of air sucked in through a leak can be anywhere as much as would come in through wide open throttles so then that theory breaks down. Or is it the location of the rush of incoming air, further down the port from where the injectors squirt, that is messing up the high end???

Anyway, my brain is hurting!

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Sanzomat

posted on 8/5/21 at 12:21 PM Reply With Quote
Thanks for all the responses. A bit of an update. I resealed the throttle body to head joints and no noticeable difference. I ran a log through a warm up cycle and that has given me some really useful information. The coolant temperature on the log graph was showing at -18F and other than a few odd spikes it stayed there throughout. The coolant temp gauge on the dash went up as expected and the fan came on at the right temperature but the sensor the ECU sees stayed at-18F. As such the warm up enrichment stayed at max. Removing all warm up enrichment made it run better straight away but the lambda AFR readings are still all over the place so I'm guessing all that rich running has contaminated the O2 sensor, maybe permanently.

I'm now hunting around trying to find the temp sensor. I can only find one, near the thermostat housing, and that is driving the gauge and doesn't seem to be connected to the Megasquirt. I think I'll have to locate the pin-out and follow it from the box to see where it goes!

Anyway. definitely some progress.

[Edited on 8/5/21 by Sanzomat]

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adithorp

posted on 8/5/21 at 06:07 PM Reply With Quote
The O2 sensor won't have appreciated that. The problem with that is the carbon crud build up on it "insulates" from the gas and it and it see's weak irrespective of the true mixture and will continue to richen the fueling.
If you take it out and get a blow lamp (or even gas cooker flame) on it and burn it off it can overcome that. Be careful not to get it too hot; cherry red at most.

The R1 only has one temp sensor (near the stat housing) so if your megasquirt is seeing a different one it must by a modification)addition that's been done. The other possibility is the MS is spliced into the standard one and theres bad connection somewhere in the loom causing a high reading.

[Edited on 8/5/21 by adithorp]





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