Help....1999 BB Will Not Idle When Hot

Guys,

I am getting the problems sorted out with my good friend?s BB (1999 FI model) and have now eliminated the battery as part of the problem.

Here is where I am now at?

The bike will start with no problem and for the first 5-10 minutes will run and idle as normal. I can detect a somewhat rich fuel mixture as some smoke does come out of the cans and it smells of gasoline. But?.the engine apparently is running fine other than this. It does not stumble nor surge. Just a nice clean idle at 1500rpm as I have adjusted the idle knob on the left side of the engine to sit at this speed.

However, after I run the bike for about 10 minutes and get it warmed up to operating temperature, it will no longer hold the idle. When I come to a stop and let the throttle go?the engine will first go to the idle of 1500 and then in the next few seconds go below that point and stall. If I immediately hit the start button it will crank over and slowly come to life again ? but only if I have the throttle open. It will not come back to life if I simply sit there and not give it some throttle.

After I let it sit for perhaps five minutes it will start, but only with judicious use of the throttle. It will not hold the idle at that point and I must get it above 2000rpm or else it will stall again.

Help!

It seems that some kind of hot run sensor or switch is acting up as the problem only occurs after it has been warmed up. While cold for the first 5-10 minutes it starts and idles quite fine. Only after it reaches operating temperature does it die out. Also, after it dies and sits for a short period of time it will gradually start again?but barely.

Fuel is fresh and clean at 93 pump octane. Battery is a brand new Yuasa AGM 12V model. It fires and runs on all four cylinders when cold, but has this darn problem when hot.

What should I look for?

Thanks so much as always.

Bob in Arkansas

Need to review any fault codes stored in the ECU, believe there is a list on this site, if not get a workshop manual.. I am also assuming yours is an EFI bird ?. The way to check fault codes is quite straight forward.... Keep viewing this site others will probably post.

What condition is your air filter in? :dunno:
How many miles has the bike done? :dunno:

Answers to Questions

Yes, this BB is EFI and has 8,500 miles on it. It was in storage for about five years and thus this low a mileage. Air filter is brand new from the local Honda dealer and I just inspected it once again to insure it is truly new and not simply blown out with an air hose.

Inspection under the gas tank shows no leaks, wet areas, etc. which could indicate a fuel leak. All wires/plugs are in place and nothing looks amiss to my eyes.

Bob in rather sunny Arkansas

Might want to try pulling off all the connectors you can find to all sensors etc. It may be that you have dry joints and a quick wiggle of the terminals can help that.... or clean each one. (possible cause would be oxydised terminals). Get a workshop manual to locate them. Think cause - bike stood up for years, think what could have happened in this time. Dont forget you may have a sensor or moving part thats siezed through gummy oil/petrol etc. The best bet to elliminate sensors is via any stored ECU info as per previous info.

Have you checked the fast idle wax unit?. Might be playing up and sticking as it hasn't been used for a while, over choking the engine when it warms up.
Forget the ECU unless it is flashing a code at you, it covers a lot of the sensors and if you're not getting the flashing FI light they are probably OK, the wax unit isn't covered by the fault codes.

Codes and Wax Unit

Guys,

Some good advice is coming my way!

I have checked the error codes on the BB and got back 9 (IAT sensor), 13 (#2 injector) and 14 (#3 injector). I then went through the factory manual and did exactly what it said. The IAT came back good via all checks, and so did the two injectors. So I then zeroed out the error codes per the manual and took it for a ride.

It seemed to do better for a longer period of time (20 minutes instead of the usual 10) and then gradually went back to not holding the idle when at a stop. But....this time it did go a definite bit longer before stalling.

I got it restarted and then drove it back to my shop....and will check the error codes later today to see what new ones popped up.

The wax unit is also my next item to check....since error codes do not cover it.

Finally, I have read the article on the 1999-00 BB wiring loom issue and wonder if this could be related to that potential problem in some way? My gut feel is that it is not related as my problem occurs gradually as it warms up and not suddenly cutting out or backfiring.

Thanks for the ideas...they are getting me closer to home!

Bob in Arkansas

If its a 1999 Fi one whilst you have it apart do the job on the loom anyway. The connector block is of no use whatsoever and WILL eventually go wrong if it hasnt already. When it does go it can take out the reg rec which in turn (as Ianrobbo can confirm) takes you generator, clocks, lights, battery, fuses and some relays. I was lucky when mine went and the bike just died slowly. Its not a hard job and could at least remove one potential cause for the problems you are having. :beer:

Just a though - long shot.... could be HT lead breaking down, plug, coils, plug cap... I had a simular prob years ago. ie What can change when its hot.:dunno: Are all cylinders cutting out or just one or 2. Is it misfiring.

Did you fully drain down the fuel tank before refilling with fresh fuel ? Maybe some non volatile residues have mixed with your fresh refill. Just an idea. Even over winter here, my Bird ran rough on the first tank of gas, after that, it was ok.

Some answers to questions...and error codes

The 1999 EFI BB sat for almost five years with a tank full of gas. Yes.....this totally screwed up everything when it was put back into service by my friend. So, two Honda dealers and a local mechanic cleaned out the entire fuel system to the tune of a LOT (I mean a real LOT!) of money. Also, two fuel injectors were replaced by the second dealer.

The bike ran fine for about a week and then the problem started. It started losing power after it was warmed up - but seemed to run mostly OK when cold. You could detect a slight rough idle when cold but something which would not unduly worry you. But, when warmed up, it simply would not hold the idle at all.

The tank was totally drained down while at the dealers and absolutely fresh fuel is now in it. I put it in there myself along with the correct amount of fuel injector cleaner, too. In theory I should not need to put the injector in but figure it could not hurt. With five year old fuel there is always the chance some gunk is still slightly in there.

When it does does die out it occurs on all cylinders...you cannot trace or get any evidence that only one or two cylinders are going bad. All of them go bad at the same time. It simply dies out very smoothly when warm and wheezes to a smooth halt.

Assuming my friend approves the loom repair (he probably will because it should be done) I will then fix the loom while the BB is apart and it is easily accessible. I have already printed out the article on how to repair it and have already identified where the taped-over connector is at.

I will check the HT lead as that could be part of it...small chance, but, one never knows.

Per my earlier post, I had error codes of 9, 13 and 14 when I shorted the service plug near the ECM unit. Following the factory manual I went all the way through the repair procedures and all came back exactly fine. I then took the bike for a 20-minute ride and it died out as before. When I came back and checked the error codes again. NONE OF THEM had been reloaded into the ECM. This tells me that more than likely these three areas of interest are OK and the last dealer simply did not clear out the system when he finished "repairing" the problem. Whick now leads me to a non-code related sensor which is the wax unit.

For some reason the "First Idle Wax Unit" is catching my interest a lot since it loads no codes into the ECM but does control a key part of the warm up process. The more I read about it, the more this is becoming a focus.

What exactly does this Wax Unit do and what is the approximate cost to get a new one?

Thanks!

Bob in very windy Arkansas

Hehe, you will LOVE this... The wax unit simply holds open a set of CHOKES on each body, sorry, honda call them "fuel enrichment Jets". As the bird warms, the wax melts and the extra fuel jets get closed off. They were cheapskates and didn't put full engine management on the Bike. The FI VFR's even had a lever on the bars for cold starts.. :tosser:

Iwould try the connector problem first, just a look may tell you if you 'could' have a problem. The try the wax unit. Agree that the fault codes are old. Only two things will stop a combustion engine running, apart from altered settings which would casue uneven running most of the time... The 2 are fuel or spark. Earlier you said that the tickover was 1500 rpm, why?. if its to keep it running with no missfire would suspect fuel, also the problem only appears when its warm/hot. something breaking down. Hope thats of help.

Good news on the BB...Finally!

After test riding the 1999 EFI BB I came back into the shop and quickly checked for any new error codes...after zeroing out the three old ones. NONE!

So, I then took apart the Wax Unit and found it was totally grunged up with a thick greasy blackish-gray "goodge". Hmmm...this is part of the cooling system and the funk should not have been there. Regardless, the rest of the antifreeze looked good and in fact was freshly installed.

I thoroughly cleaned the internals of the wax unit until it was spotless. Also, I took out the small steel rod in the unit and used a pipe cleaner to carefully clean out the channel it rides in. Also, the spring had this thick crust on it and I cleaned it up, too. All was carefully reassembled and the bike buttoned up for another test ride.

Now, I have maintained since the bike came back from the Dallas dealer (who fixed the messed up fuel injectors the previous wrench had wrecked) that the best "fix" would be to run plenty of fresh fuel - with a good injector cleaner mixed in - through the engine on long high speed drives.

The friend did this last night for about 40 miles on the freeway and brought it back into the shop. It seemed to run fine the entire time and now holds its idle at 1100rpm!!!!!

I think this might have finally solved the problem. God Willing. It now appears that after the battery was replaced with a new AGM Yuasa item, and the injectors were replaced after being screwed up, and all the sensors were tested (codes 9, 13 and 14) and then the First Idle Wax Unit was totally disassembled and cleaned...then a good amount of fresh fuel was run through the engine...it may be on the road to good health.

I will keep you all informed as this board has clearly been a MAJOR help in getting things to this much happier point.

Bob in Arkansas

Head Tomcat said:

Guys,

I am getting the problems sorted out with my good friend?s BB (1999 FI model) and have now eliminated the battery as part of the problem.

Here is where I am now at?

The bike will start with no problem and for the first 5-10 minutes will run and idle as normal. I can detect a somewhat rich fuel mixture as some smoke does come out of the cans and it smells of gasoline. But?.the engine apparently is running fine other than this. It does not stumble nor surge. Just a nice clean idle at 1500rpm as I have adjusted the idle knob on the left side of the engine to sit at this speed.

However, after I run the bike for about 10 minutes and get it warmed up to operating temperature, it will no longer hold the idle. When I come to a stop and let the throttle go?the engine will first go to the idle of 1500 and then in the next few seconds go below that point and stall. If I immediately hit the start button it will crank over and slowly come to life again ? but only if I have the throttle open. It will not come back to life if I simply sit there and not give it some throttle.

After I let it sit for perhaps five minutes it will start, but only with judicious use of the throttle. It will not hold the idle at that point and I must get it above 2000rpm or else it will stall again.

Help!

It seems that some kind of hot run sensor or switch is acting up as the problem only occurs after it has been warmed up. While cold for the first 5-10 minutes it starts and idles quite fine. Only after it reaches operating temperature does it die out. Also, after it dies and sits for a short period of time it will gradually start again?but barely.

Fuel is fresh and clean at 93 pump octane. Battery is a brand new Yuasa AGM 12V model. It fires and runs on all four cylinders when cold, but has this darn problem when hot.

What should I look for?

Thanks so much as always.

Bob in Arkansas

Click to expand...

not too sure how to sort out your problems..but one thing i do know is that the idle speed is 1100 RPM..NOT 1500 RPM as you have done.probably not the cause of your problem,but thought you should know.

DOH......

should have read ALL the posts relating to this thread c7u8 :bang: :bang:

























sorry peeps :blush: :blush:

CONGRATULATIONS and CELEBRATIONS.... Sounds like you've cured it. Its always the sticky gungy stuff that blocks the hole....:yo:

SilverFox...Good One!

I got a good laugh out of your short retort. My friend cannot figure out where this thick greasy funk came from in the Wax Unit but since it had sat for five years before we got to wrenching on it....it just happened.

My personal feelings are to change the fork oil and essentially replace all fluids whether they are fresh or not. Just start all over again with new...if you will.

I do know the front fork oil is original and suspect the brake/clutch fluid is too. With the speeds this BB can do, common sense says to change it all as soon as possible. Brake pads are fine, but a new rear tire is definitely in order.

Just a thorough overall wrenching and nice cleaning is necessary.

Bob in Arkansas

Head Tomcat said:

My personal feelings are to change the fork oil and essentially replace all fluids whether they are fresh or not. Just start all over again with new...if you will.
Bob in Arkansas

Click to expand...

The only way to go. Then you know everything is as it should be. glad you got the problem sorted