Trottle body Sync not adjusting with Morgan Carbtune

OK . . . . Here's the deal. :angry:

The bike has ran great since the start of summer and suddenly once it has been riden a couple miles and the motor is hot the idle goes to crap when stopping, like its missing and doesnt want to stay running. This is weird cause when its cold and started in the garage it purrs like a kitten and sounds smooth as silk. Then I go for a ride 5-10 miles and stop and it sounds like a diesel when idling, but while its running at high speed there are no noticable problems, but maybe I just cant hear the problem over the wind and noise.

I do a throttle body sync with a hot engine with my morgan carbtune and number 3 cylinder is several bars (2 inches) below 1, 2, and 4 at 1000 and 3000 rpm and will not adjust up or down with the screw full in or out. The other cylinders will adjust with no problems. I unplug and replug the injector wiring to number 3 injector and no change in the carbtune levels or the sound of the rough idle at 1000. Very perplexing indeed. :blink:

Got to be fuel delivery or lack of spark I'm assuming to cause this problem . . . plug wires/wiring breaking down with heat ? Bad injector ? Bad TPS ? I'm running a tank of gas with some injector cleaner through it but no change has been noted and I'm not confident this will fix it. This bike has low miles and not had the TPS R&R as far as I know but I cant see a TPS affecting one injector/cylinder this way.

Has anyone experienced a problem like this or have a suggestion before riping it apart or taking it to the shop at 80 bucks an hour. :angry2:

Thanks, Chief

Alaska,

If I understand you correctly, you did swap out injectors...and it did not work? Well I have had a similar problem on my '03 where #4 would not sync for nothing or change at will. I just got my bike last week from the shop and it was found to be the Throttle Body Assy. Everyone refused to believe this Assy. could be the problem, but when it was replaced, it Synced right in and nows idles better than ever.

We had to order the Assy. from Japan which took about 2 weeks due to Customs, etc.

The shop replaced/swapped injector, coils, wires, plugs, ecu, head....and ultimately the Throttle Bodies were the culprit and they don't seem to code and I sure wish they did!

Hope this helps.

03HiYoSilver said:

Alaska,
If I understand you correctly, you did swap out injectors...and it did not work? Well I have had a similar problem on my '03 where #4 would not sync for nothing or change at will. I just got my bike last week from the shop and it was found to be the Throttle Body Assy. Everyone refused to believe this Assy. could be the problem, but when it was replaced, it Synced right in and nows idles better than ever.

We had to order the Assy. from Japan which took about 2 weeks due to Customs, etc.

The shop replaced/swapped injector, coils, wires, plugs, ecu, head....and ultimately the Throttle Bodies were the culprit and they don't seem to code and I sure wish they did!

Hope this helps.

Click to expand...

03HiYoSilver,

Mine is an 03 as well and what you describe sounds like a very expensive ordeal if it was out of warranty . . . . man. . . . I hope that's not my problem. What I did was to unplug the number 3 injector electrical plug that fires the injector and did'nt notice a significant change in idle sound or movement on the carb sync tool. Maybe its a screwed up injector but the motor seems to run fine when cruising along at all speeds other than sittiing at a stop light, then it struggles to to maintain idle at 1000-1100 rpm. The idle adj knob works and moves the idle up and down but I'm bothered by the fact I cant sync the bike and have a smooth engine. I worry that there is still somthing wrong with the number 3 cylinder/injector and its just being masked by the noise and wind when going highway speeds. Mine is not under warranty so I'd like to avoid the stealership if at all possible.

Alaska,

The best way to reduce the problem is to Swap out a good injector for the evil one and see if there is any change to the evil cylinder performance. This way you can eliminate the injector side of things out of the equation.

In addition, have you changed plugs, checked the plug wires/boot and one thing often overlooked is this:

https://www.fjrforum.com/forum//index.php?s...st&p=267606

Hope this helps and you find a cheap solution.

How many miles do you have on it? (Valves Adjustment Check?) There is a possiblity that #4 has some carbon build-up that may be keeping one of the Valves from closing completely. The other way is to do a Compression & Leakdown test.

By the way, even when I had all these problems, the FJR still ran at speed pretty good. Just did not get the most optimal gas mileage as should have.

Usually when a injector goes bad it will not spray a fine mist but a squirt and it will make you idle rough but normal driving will be fine with a reduction in pep. You will usually have backfiring when accelerating slowly in higher gears.

The problem appears to be isolated to the number 3 cyllinder so I'm going to focus on the #3 injector and trottle body boot seal, and second troubleshoot the plugs and wires since it runs fine at highway speeds. I'm about halfway through a tank of injector cleaner and so far NO change in symptoms. . . . runs fine at speed. . . idling like crap. The carbtune tool clearly shows close to a 50% decrease in vacum on that cyllinder compared to 1, 2, and 4. Just out of curiousity whats the price of a new injector and how hard is it to replace ?

Thanks, Chief

That no.3 is either flooded or not injecting fuel at all. Check for black rich exhaust at idle for flooding, too much of a squirt. If there is no fuel it will still pull vacuum but not near as much. At higher speeds or hard acceleration if it is squirting too much the engine can handle it better. This is just some observations I have made on my own cars and trucks with fuel injection. When they get bad or real dirty the injector cleaner won't help. A machinest who does injector rebuilds told me to use seafoam. I just read on this forum that the 03s had a tps recall because of erattic idle. Of course I don't believe it would cause just the no3 to act up.

Alaska,

I bought an extra injector for this purpose last year. If I recall correctly, it was around $75.

How many miles are on the FJR?