tps evaluating for ii issues

[dave]

Update: I thoroughly re-cleaned the TPS connector last night and took the bike for a ride around town. 5 miles into the ride the low idle condition (700 RPM, slow return to 1,050 RPM, but no stalling) returned. So I thought really hard about what could have changed to bring on this condition, since the bike ran perfectly last Sunday, Monday evening, and Tuesday evening, and I think I have hit on something, and that is the gasoline. I refilled the tank Tuesday evening, putting 3.94 gallons in it. Wednesday evening, after driving almost 60 miles on the freeway, the low idle condition returned as soon as I exited the freeway (it may have returned earlier if it wasn’t for the freeway driving, where the problem does not occur). I most always buy my gas from name brand stations, but occasionally, like last Wednesday, I filled up at a 7-11 station, where there wasn’t even a name on the brand of gas. I always purchase the premium grade. Here in California we have what is called “summer blend” and “winter blend” gas, and the difference being the Reid Vapor Pressure. So on Saturday I am going to drain my tank and refill it with gas from a Chevron station, where I normally buy it in my neighborhood, and see what happens. Do any of you guys have any thoughts on this? I can’t think of any other variable that changed from Sunday, when the bike ran perfect, to today, with the low idle condition. Can you please post your comments? Thanks again for all your help guys!

Dave,
"AS" forget about this...it should be written ..."as" far as to PCSV....

>>>>>>>>>>>>>>>>>>>>>>>>>>
1* test condition:: on center stand, engine hot/normal operating temp and NORMAL RPM (1050)..if for any reason is not within specs, wait until it stabilizes within..
2* disconnect THICK/YELLOW vacuum hose end **that goes from PCSV to Th. body/intake manifold = this will create vacuum leak or as if PCSV were stuck in open position (normally closed) and register RPM change....it may very, so watch it for a while..
** careful, not to break nipple to PCSV
Unplugging the electrical connection will not be the same thing as removing the hoses (Popgun is perfectly correct)

>>>>>>>>>>>>>>>>
YELLOW SKINNY HOSES DISCONNECTION...might be more difficult to achieve , since there is less access to inner throttles ??? have a look..

Max is recommending that I disconnect the two EVAP ( skinny vacuum hoses/yellow & blue, linking each th. body, Honda calls'em MAP vacuum hoses) system hoses (hoses identified with yellow marks in previous post), and I assume that this is the same thing as the PCSV?(..generally, all seems to go to intake manifold) . This seems like a pretty simple test that I can do. If my bike is running fine (1,050 RPM, warm idle) and I pull off these hoses what should I expect = YOU SHOULD SEE RPM CHANGE...watch for a while what is happening with RPM...may go up, down...

Let us know, please... before next step as per Max/SportsterDoc/Popgun

pb

[pdedse]

Update: I thoroughly re-cleaned the TPS connector last night and took the bike for a ride around town. 5 miles into the ride the low idle condition (700 RPM, slow return to 1,050 RPM, but no stalling) returned. So I thought really hard about what could have changed to bring on this condition, since the bike ran perfectly last Sunday, Monday evening, and Tuesday evening, and I think I have hit on something, and that is the gasoline. I refilled the tank Tuesday evening, putting 3.94 gallons in it. Wednesday evening, after driving almost 60 miles on the freeway, the low idle condition returned as soon as I exited the freeway (it may have returned earlier if it wasn’t for the freeway driving, where the problem does not occur). I most always buy my gas from name brand stations, but occasionally, like last Wednesday, I filled up at a 7-11 station, where there wasn’t even a name on the brand of gas. I always purchase the premium grade. Here in California we have what is called “summer blend” and “winter blend” gas, and the difference being the Reid Vapor Pressure. So on Saturday I am going to drain my tank and refill it with gas from a Chevron station, where I normally buy it in my neighborhood, and see what happens. Do any of you guys have any thoughts on this? I can’t think of any other variable that changed from Sunday, when the bike ran perfect, to today, with the low idle condition. Can you please post your comments? Thanks again for all your help guys!

Dave,
"AS" forget about this...it should be written ..."as" far as to PCSV....

>>>>>>>>>>>>>>>>>>>>>>>>>>
1* test condition:: on center stand, engine hot/normal operating temp and NORMAL RPM (1050)..if for any reason is not within specs, wait until it stabilizes within..
2* disconnect THICK/YELLOW vacuum hose end **that goes from PCSV to Th. body/intake manifold = this will create vacuum leak or as if PCSV were stuck in open position (normally closed) and register RPM change....it may very, so watch it for a while..
** careful, not to break nipple to PCSV
Unplugging the electrical connection will not be the same thing as removing the hoses (Popgun is perfectly correct)

>>>>>>>>>>>>>>>>
YELLOW SKINNY HOSES DISCONNECTION...might be more difficult to achieve , since there is less access to inner throttles ??? have a look..

Max is recommending that I disconnect the two EVAP ( skinny vacuum hoses/yellow & blue, linking each th. body, Honda calls'em MAP vacuum hoses) system hoses (hoses identified with yellow marks in previous post), and I assume that this is the same thing as the PCSV?(..generally, all seems to go to intake manifold) . This seems like a pretty simple test that I can do. If my bike is running fine (1,050 RPM, warm idle) and I pull off these hoses what should I expect = YOU SHOULD SEE RPM CHANGE...watch for a while what is happening with RPM...may go up, down...

Let us know, please... before next step as per Max/SportsterDoc/Popgun

pb

Dave, while I can't answer the question, I can report on my last 5-6 weeks with my bike after I had cleaned the TPS connection.

Before doing the TPS cleaning, I had taken the bike into a dealership and they were trying to help with a few ideas before I committed to letting them have a go at finding the problem...which I never gave them the chance to do. The service tech said try the highest grade gas at Chevron for a few fills to see if that would help. He said that it wouldn't be the first time that idle issues that he sees from time to time were alleviated by better quality gas. Till that point I had filled wherever was convenient and cheap. So I switched to higher grade gas at Chevron at the same time the TPS was cleaned, and as I've mentioned before, the problem didn't return for 8 half-hour to two hour rides with exception of two dips to 900rpm, then back to 1000 with fully warm engine.

At times I'm sorry I didn't stick with the bike just for wanting to find out what it could be, but I got tired of the mental "high/lows" as well as the idle's.

What I find perplexing is that some members here report that their idle issue simply "went away" after some time...and never came back. If there is a defective TPS, ECU, IACV or whatever alphabet part, why would someone's issue "go away" unless it were something simple like loose / bad TPS connection, loose hoses, or.... "inferior" gasoline? So strange...but others more knowledgeable will chime in.

Continuous "get well" wishes for your CB.

[dave]

What I find perplexing is that some members here report that their idle issue simply "went away" after some time...and never came back. If there is a defective TPS, ECU, IACV or whatever alphabet part, why would someone's issue "go away" unless it were something simple like loose / bad TPS connection, loose hoses, or.... "inferior" gasoline? So strange...but others more knowledgeable will chime in.

Continuous "get well" wishes for your CB.
[/quote]
Hi Paul. Thank you for your feedback, and well wishes. I am not giving up! Thanks to all the support from several different forum members, between all of us we will get to the bottom of this.

[max]

some pictures to clarify

Just to show how easy these outer skinny hoses are to get to i included three pictures.
Only pull off one outer hose on each side as shown in the pictures marked yellow, do not pull off any more, the blue skinny hoses are for the map sensor and need to stay in place.






I have difficulty in expressing which hoses to pull off at which time ,let's just say that you should have two skinny very outer vacuum hoses disconnected at the time of the test as per the picture, not four.




The hoses were a little stuck at first so i put them back halfway to make it easy to pull them off.

[Houtman_imp]

I ALWAYS buy top tier gas ( 90 % of the time Shell) and the 93 grade.
Many riders are probably buying cheaper gas ( name/ no name )but so far all my 3 CB 1100 's run perfect all the time , the extra money I pay is worth it.
It might have nothing to do with the idle problems but could be related to some of the issues.

[Cormanus]

Can't speak for the quality of gasoline in the USA, but I always put standard petrol in the CB because that's what Honda says it's designed to use. No problems to speak of with running, although I did notice the other day that, when the bike was really hot after a long run and I came to a stop, the RPM dipped to about 900 and then climbed back up to normal. When I think about it, this has happened before, but only very occasionally and it is not enough of an issue to worry me. Should it be?

[dave]

Bikes sold in America are built to meet different emission standards. I asked Honda to remap my ECM with a map used in Europe (because someone from Europe had posted that his ECM was remapped by Honda and it cured the problem) and Honda responded that they could not do this because of the U.S. emissions standards. At one time the Japanese bike manufacturers sold bikes that were 48 state emissions compliant, and bikes that were 2 states (Ca and NY) compliant (cars also). My 1998 VFR800 is like this, but I don't believe this is the case with the CB1100. Ca and NY had (may still have) stricter emissions standards than the rest of the country. We also use a "Summer Blend" of fuel, and a "Winter Blend" of fuel. I am going to drain the "no name" fuel I purchased at the 7-11 station and refill if with Chevron fuel to see what happens.

[peterbaron]

I ALWAYS buy top tier gas ( 90 % of the time Shell) and the 93 grade.
Many riders are probably buying cheaper gas ( name/ no name )but so far all my 3 CB 1100 's run perfect all the time , the extra money I pay is worth it.
It might have nothing to do with the idle problems but could be related to some of the issues.

+1 or better as already stated im my posts.....

pb

[Cormanus]

Dave, are the US emission standards stricter that the European one the CB1100 complies with?

And, yes, the CB1100 is a 50-state bike.

[dave]

Update: Drained the fuel out of the CB yesterday and rode it immediately to the Chevron gas station about 1 mile from my house, where I filled it up with premium (luckily I didn’t end up pushing it). I proceeded to ride the bike around town to test my theory that the gasoline is responsible for the reoccurring low idle issue. As the engine warmed up over the first ½ mile the normal cold idle speed reduced to 1,050 RPM at the first and second stops. At the third stop, the RPM dropped to 700, but worked its way back to 1,050 RPM, similarly to how it acts when the low idle condition exists. At the fourth stop it dropped to 700 RPM, but this time it worked back up to 1,050 RPM quicker than it normally does. At the fifth and sixth stops the RPM dropped each time, but each time it returned to 1,050 RPM very quickly (much quicker than I have ever seen it). From there on the RPM never dropped to 700 again, and I continued my ride for 12 miles, making one stop to turn the engine off for about 15 minutes and then restart it. I can’t say that a similar scenario where the low idle condition ever “cured” itself while riding like this has ever happened before or not, I just don’t remember exactly. I plan to ride the bike this morning to run some errands and I will report back on the results.

Since I purchased this bike about 75% of my fill-ups have been at the same Chevron station, which is located about 1 mile from my house. I have just over 17,000 miles on the bike now, and I have never used anything but premium grade fuel whenever I have filled the tank. I always look for name brand stations when I fill up, but occasionally, either out of necessity or convenience, I will fill up at a non-name brand station. I have never paid any attention to when the low idle condition occurred with respect to fill-ups, but based on the results described above I will now use only Chevron fuel at all fill-ups, unless forced to do otherwise.

Chevron uses an additive called Techron, which is a detergent based on PEA, polyeter amine. I won’t go on describing what I learned about Chevron fuel in this post, but for those of you interested please look it up. Is it possible that the ECM in my bike has learned how to operate on Chevron fuel with the Techron additive, and that using different fuels cause the low idle condition? I can’t answer this, but I am sure some of you guys out there can offer your insight (Max, Doc, popgun, peterbaron). Gentlemen - please post your comments!