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Fuel Injection woes.

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INSTG8R View Drop Down
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    Posted: 28 Jun 2021 at 05:09
Time to ask the brains trust as my googling and forum searching have branded no results.
I have a '99 California EV CafĂ© Racer project (sorry purists). Before work began it ran smooth as a Big Guzzi twin should. After pod filters and exhaust mod's she is not so smooth. I have had a custom 45mm exhaust made with crossover and db killers fitted. 
I expected it to run lean but I have quite the opposite.
Local Guzzi mechanic has set the Fuel Injection, tps, throttle controls, to factory settings but she still is not happy.
Idles nice, accelerates ok up to 1/4 throttle then gasps for air as it chokes on too much fuel. Black smoke and some coughing and banging ensue.
When trying to cruise over 1/4 throttle it surges. The mechanic who set it up said it is 8 Cycling, whatever that means, and couldn't work out why. All sensors tested with in parameters and the only thing left to test was the ecu, however the only way to test that was by swapping it our with a known good working one, which no one has.
One of my questions is will screwing the idle/air mixture screw out on the throttle bodies lean the fuel mixture out? and if so should I use a manometer when adjusting to keep the balance true?
Any other suggestions would be greatly appreciated.

The bike in question. Still unfinished.



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Guzzished View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Guzzished Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2021 at 07:09
Instg8r
No idea what '8 stroking' might be,
Is there any such thing ?
If there is someone will chip in.
In the meantime, it's obviously a fueling issue, leave the ECU alone.
Your twist grip directly and mechanically opens the throttle butterfly valve feeding the engine with more air as it opens wider, the throttle position sensor is operated by the butterfly spindle/pivot turning but the position of the sensor on the spindle is adjustable, ( two little screws underneath )
Allowing the sensor to be 'advanced' or 'retarded' in relation to the butterfly position, if too far 'advanced' the ECU will think the butterfly is wider open than it actually is and will therefore provide more fuel than is actually wanted resulting in massively over rich fueling as if trying to run on full 'choke' on a carbed engine,
Do you have a manual with your FI set up described in it ?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Guzzished Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2021 at 07:24
Plus, if I remember correctly there is a sensor in the original air box, and probably another under the tank on the original set up, what has happened to these, are they still connected, where is the one that was in the air box, (filter housing )
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Guzzished Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2021 at 07:27
I'll have a look at my manuals later when I get over to my workshop to refresh my memory and post again later unless you get some definitive answers in the meantime.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2021 at 08:04
8 stroking is when it runs very rich and can sometimes only fire every second firing stroke.

Guzzished, he said the TPS had been set to factory default.
Assuming this has been done correctly, it must be something else. The TPS woud have to be wildly out to get that much overfuelling.

Any adjustments to the throttle bodies in terms of idle mixture should always be done in conjunction with a manometer. However, the idle mixture could never be that far out to cause so much overfuelling.
Do you know the injectors are good, and not leaking/dripping?
Brian.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote andrewhush Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2021 at 09:29
Brother in law's recently acquired ballabio came with fuelling problems. Would start and idle, but very rich, stank of unburnt petrol. Would drive but not well. Turns out that the tps was not the correct type. Voltage from the signal wire varied upwards from 2.0v rather than from nearly zero. A new properly spec'd one and a standard setup sorted it.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Guzzished Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2021 at 10:33
Right,thanks Brian,
INSTG8R, says it ran well prior to the stripdown/rebuild. So I was assuming TPS would be original and injectors OK ( Andrew ) not necessarily guaranteed but reasonable assumption I thought.
( Just occurred to me, is the fuel fresh, not been sitting in the tank for yonks )
TPS setting seemed possible/likely because I recently acquired a 1100i Cali of similar vintage to INSTG8R's that was having similar problems though not quite as bad, that was supposedly set up by someone who was supposed to know what they were doing which was cured completely when I experimented by resetting the TPS according to the 'superceeded', obsolete, instructions for resetting. i.e. loosen screws, twist against spring loading and release, tighten screws. Wasn't perfect first go but vastly improved, addition of very fine reference mark for further minute adjustment using sparkplug colour as guide to go richer/weaker, like adjusting carbs, followed by fine adjustment of balance and tickover, bike is now beautiful, starts on tickover hot or cold, ( just a 'whiff' of raise on the tickover lever when stone cold ) runs clean throughout at all speeds and loads, and seems to be achieving about 60 MPG With good plug colour, was going to buy a digital meter, ( always preferred analogue before ) and do it according to the numbers but am so pleased with it as is, that I haven't bothered.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Guzzished Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2021 at 10:46
Thinking again, I think I've experienced 8 stroking in the dim and distant past, with stinking black smoke, coughing, spluttering and banging, and I'm sort of sure it was due to rotten petrol gone off in the tank.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nickst4 Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2021 at 10:57
8-stroking would be the logical term for a four-stroke that is firing on every other compression, just as 4-stroking was a very familiar term for a two-stroke that fired on every other stroke; something stinkwheels did/do as a matter of course during normal usage. All to do with needing a combustible mixture in the cylinder!

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Post Options Post Options   Thanks (0) Thanks(0)   Quote iansoady Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2021 at 11:54
I have to ask - if it was running well why make the mods? I would replace standard and see if it returns to running well. It does sound as though the air / fuel map is not compatible with your current setupand to properly correct that you would need to change the map in the ECU but I have no idea whether this would be possible on your bike. A dyno would be a good way to find out what is actually going on.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gianni Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2021 at 12:32
Guessing here but how about this for an explanation...

You have replaced the air filter box with pod filters. The air temperature sensor (ATS) is now either disconnected or hanging somewhere and, as a result, is sending mis-information to the ECU.

It is not essential that the ATS is mounted in the air filter box though that does give the most accurate reading. On the early Quotas the ATS is mounted in free air just behind the front frame down tubes.  However the standard mounting can mean it gets an overhot reading when stationary or at low speed due to the proximity of the exhausts so some owners relocate it up and away.

This Guzzi FI manual may be of use to you: https://dpguzzi.com/efiman.pdf

I would also check the operation and closing of the injectors and the fuel pressure relief pop-off valve.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2021 at 16:05
Very good point, and also reminds me of the engine temperature sender. If that misbehaves (or not connected) it will also cause rich running as the ECU will think the engine is very cold.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Guzzished Quote  Post ReplyReply Direct Link To This Post Posted: 28 Jun 2021 at 17:00
Good points Gianni and Brian, and things I was wondering about cos I have another 1100i that will have to be extensively rebuilt due to condition and won't be going back together as original, slight remodeling, the air box will have to go to make space for the suitcase sized ECU to allow remodeling of seat and rear end, (not going the cafe racer route though ) and I was wondering about relocating that ATS, also on this bike there is an ambient air temp sensor mounted to the top r/h frame rail under tank.
Good point re engine temp sensor fooling ECU.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote INSTG8R Quote  Post ReplyReply Direct Link To This Post Posted: 29 Jun 2021 at 04:05
Thanks Guys for all your input! Thought I would right 1 reply to all rather than individual.
Firstly to Guzzished and Brian) Man if you saw the state this bike was in when I acquired it, dropped several times, hand painted by brush and fire damage to the left hand side. She was not pretty and never going to be a restoration project, but I digress. I mounted the Intake Air Temp Sensor to the same bracket as the the Ambient Air temp sensor, so they are side by side. Mario the Magician from Thunderbikes Western Australia tested all sensor values (Air, engine temp, tps, timing signals and voltage regulator) both engine cold and varying temps and they are all with in factory spec. 
Tank was cleaned and fresh fuel with injector cleaner added as the old original tank did have stale fuel when I removed it although it ran well.
Andrew- Guzzished has assumed correctly the TPS and Injectors are original. I did remove the injectors to test open and close operation but not spray patter or leakage, Thanks Brian for this tip. Now on the list of checks.
So apparently 8 Cycling is where the ecu is telling the injectors to dump more fuel every 8 revolutions of the power stroke causing it to run rich. One of the reasons Mario tested the voltage to the ecu as I have replaced the voltage regulator (the old one was causing voltage drop) and I am now running a Lithium battery.
iansoady- Sorry there is no going back hahahaha. The air box and intake fittings were damaged by the previous owner when the bike was dropped. I agree, the current fuel map is not ideal for my set up. So Mario the magician tried a Power commander to over ride the ecu and adjust the fuel mapping, made no difference. This is what lead him to think maybe the ecu is faulty as it appeared not to talk to the power commander.
Gianni- There may be something in what you said about the fuel pressure relief valve. Originally it was screwed directly to the underside of the tank. I had to remove it and retro fit it as an inline fitting to work with the Suzuki tank. Visually it inspects ok but I haven't put a fuel pressure gauge on the system to see if it is actually working correctly.

My to do list after chatting with you fine gentlemen.
1. Check Fuel Pressure/ Regulator function
2. Study FI Manual as provided by Gianni (Many Thanks!)
3. Check Fuel injectors for leaks and spray pattern.

Should the above not resolve my issue I was wondering if smaller volume injectors might work?
If I cant increase the Air surely this would reduce the fuel in the equation? 
         
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 29 Jun 2021 at 08:28
If you have had Mario on the case, then I would suggest you follow his advice. Few in Aus know more than him.

8 stroking is when the engine is getting too much fuel and so only fires every second firing stroke. It happens on carbed engines too. It's not the ECU telling the injectors to do anything.

If the pressure relief valve isn't working correctly you could be getting much higher pressure in the fuel line, which in turn will mean far more fuel injected. If you have moved it and done anything to it, that would be my first thing to investigate.
Have you checked the fuel relief line back to the tank and made sure that's clear, if that's blocked the exess fuel pressure will build up anyway. It is a mechanical pressure relief valve I believe.


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