Warm Idle Dropped to 700-750 rpms

11029 Views 32 Replies 10 Participants Last post by Magical-1, Dec 10, 2009

Thorns

Discussion Starter · Jan 9, 2006

I rode for over a 120 easy miles today in 40-50 degree outside temps, and towards the end of the ride I came to a stop light, which was probably the first stop in 40 miles, and the idle dropped down to 700-750 rpm on the tach. Engine sounded a little slower, but idled and ran ok(rev'd ok, but came back to 700-750 rpms). I rode about 2 more miles, and pulled the clutch in and the tach read the same, 700-750 rpm. Engine wasn't hot. I pulled into a gas station, needing gas, shut the engine off, filled the tank, restarted, and the tach read like normal, 1000 rpm, and idled at 1000 rpm the rest of the ride, another 20 miles. Anyone have this happen to them? 05 Low Rider EFI 95", 20,000 miles.

Thorns

1 - 20 of 33 Posts

BaggerDave

· #2 · Jan 9, 2006

This is happening to me too

I have a 05 FLHTCI. Same symptoms. Mine just has pipes, air cleaner and SERT. I found an oiled rear spark plug because I did not have the oil consumption issue fixed yet. That will be taken care of with the 95 build.

The two things I heard so far are intake leak and possible fuel line leak inside the tank resulting in low fuel pressure. One other thing to look at from an HD service note is a bad engine temperature sensor or problems in the ETS circuit.

I have been too busy to fix mine yet. I can still ride the bike and it otherwise runs fine. If you find it please post back to this message and if I find it will do the same.

David

Thorns

Discussion Starter · #3 · Jan 9, 2006

BaggerDave, I pulled my plugs and the are perfect, with a nice brown/gray fuel ring, and dry. You might be on to something, as I needed gas when this happened. I have a SERT, but no external cylinder head temp gauge, and I haven't really wanted to ride around with a laptop strapped to my back(winter rides), but if this condition continues, I will. I want to eliminate the fuel suspect before taking to the H-D dealer to check out the engine temp sensor or ETS circuit as if it isn't broke when they look at it, it will be returned as no problem found, and they will blame the SERT, and try to charge me for their time. I will keep you updated until problem solved.

Thorns

06RKCLASSIC

· #4 · Jan 10, 2006

Thorns said:
BaggerDave, I pulled my plugs and the are perfect, with a nice brown/gray fuel ring, and dry. You might be on to something, as I needed gas when this happened. I have a SERT, but no external cylinder head temp gauge, and I haven't really wanted to ride around with a laptop strapped to my back(winter rides), but if this condition continues, I will. I want to eliminate the fuel suspect before taking to the H-D dealer to check out the engine temp sensor or ETS circuit as if it isn't broke when they look at it, it will be returned as no problem found, and they will blame the SERT, and try to charge me for their time. I will keep you updated until problem solved.

Thorns

I've had the same problem with my 06 FLHRCI since it was delivered. Would really like to know what's causing this.

Thorns

Discussion Starter · #5 · Jan 10, 2006 (Edited)

Me too. I've been able to put on some miles(yesterday and today), but it hasn't done it yet, but I'm getting down where I will need some gas soon, so will let you know. I did have a cage problem once when the temperature dropped below 30 degrees, the ECM would malfunction.

Thorns

Thorns

Discussion Starter · #6 · Jan 22, 2006

Update: I was riding with a 3/4 tank of fuel, stopped for a red light, and the idle dropped down to 800 rpms, but engine was running good, no misfire, rev'd just like always(good), and was not overheating(45* outside temp). I pulled over, and shut the engine off, and turned the ign key to off. Then restarted, and the rpm was on 1000 rpm, and stayed there for the rest of the ride of about 60 miles before I shut the engine off. I don't think this is fuel related now, as I had plenty of fuel, and engine ran great. I have had this kind of situation happen in my line of work, diesel trucks, and as intermittent as this is happening, and resolved with the cycling of the ECM, it could very well be a logic problem, and difficult to solve unless the idle drops out and stays dropped out allowing more diagnostics. Cycling of the ECM tells me it could be a logic problem, and not a hardware issue. It's been too cold to ride with a laptop connected to the ECM recording data with the SERT. If anyone has more on this please tell what happened when the idle drop out occurred, and if cycling the ignition key cured the concern.

Thorns:hmmm:

See less See more

BaggerDave

· #7 · Jan 22, 2006

I have not been riding

I have not been riding much. I will try cycling the ignition when it happens again and let you know. I am thinking cylinder head temp sensor or logic problem or doing the wiggle test described in the diagnostic manual.

David

GRock

· #8 · Jan 22, 2006

You guys have a common issue with these EFI systems. The re-start absolutely solves the problem (TEMPORARILY) as the IAC (idle air control) sets itself to the correct number of steps for start up and you are good to go. For some reason the TPS (throttle position sensor) seems to be set right on the borderline edge of the correct readings for reading from the idle tables and sending the info to the IAC and, whether bacause of thermal expansion or just jumping out of the correct idle voltage (.35 to .45 millivolts is the correct range), when this happens the IAC will fall out of idle range with it. If you can get a handle on the voltage from the SERT or dealer analysis, a simple 1/4 to 1/3 turn of the throttle blade will fix you up. If you are on the upper range of the voltage turn the butterfly stop screw OUT, if you are on the lower end of the voltage range, turn it IN. BE SURE THAT YOU KNOW THE FINAL VOLTAGE READING AS BEING OUT OF RANGE FOR IDLE WILL HAVE THE ENTIRE MAP READING WRONG AT ALL THROTTLE POSITIONS!!!!!!

See less See more

Thorns

Discussion Starter · #9 · Jan 22, 2006

Thanks GRock for the explaination. I will let you know what I find.

Thorns

BaggerDave

· #10 · Jan 23, 2006 (Edited)

Thanks GROCK

How would I find the IAC voltage? Warm bike fully, hook up SERT in data logging mode and look at the Throttle position voltage setting?

Thanks for the help.

Thorns, I just noticed that you are in MD too. I am in Reisterstown.

David

Vetteman

· #11 · Jan 23, 2006

BaggerDave, you are correct, use your SERT in data mode.

Cheers,
Frank{salute(

BaggerDave

· #12 · Jan 23, 2006

Thanks Frank

Frank,

Thanks for the help. Does the bike have to be having the issue when I hook up the SERT or do I just look for a value that is close to being at the top or bottom of the range?

I have been so swamped, I have not even been riding in the mild January weather in MD. Soon, I hope to be jumping back in to fix the problem.

David

Thorns

Discussion Starter · #13 · Jan 23, 2006

David,

Havre de Grace here. Born in PG hospital. Lived in Riverdale, East Pines, Landover, New Carrollton. Lived in Chicago suburbs for 27 years, and moved back to HDG, Maryland on 9/10/11. Drove all day, woke up, and all hell had broken loose. My wife is from CA, and could believe how pretty the Maryland countryside is, or how wide the swing is from the poor to the rich. But, the motorcycling is great here in northern Maryland, Pennsylvania, and Delaware.

Thorns

Vetteman

· #14 · Jan 23, 2006

David,
No, just hook the SERT up in data mode and as GRock said in his post, look to see the value of your TPS and follow his directions if needed.

Another method to help troubleshoot is using the Twinscan 88 tool. This baby will hook up to the bike's diagnostic port and will gather and store sensor data while you ride. Then, when you get home, download the data to your computer for review.

It's really small and collects alot of data:

www.daytona-sensors.com/Twin_Scan.html

Cheers,
Frank{salute(

See less See more

BaggerDave

· #15 · Jan 29, 2006

I have the TS88 tool

I have the TS88 and have the log file from when the problem was happening. What value do I look at in there? The TPS is a % not mv as GROCK stated. I have not had time to do the SERT hookup. The TS88 has 12 monitorable values:

RPM
VSS
MAP
BAT
TPS %
ET
IAT
IAC
Front Advance
Rear Advance
Front inj
Reat inj
Front knock
Rear knock
ARR command
AFR WEGO

Thanks.

David

See less See more

Vetteman

· #16 · Jan 29, 2006

Dave, use your SERT data mode to look at the voltage for your TPS.

Cheers,
Frank{salute(

BaggerDave

· #17 · Jan 29, 2006

Thanks Frank

I will try it.

David

WVULTRA

· #18 · Jan 29, 2006

Dave: As Frank pointed out, the SERT will record both:

Throttle Position

The throttle position is displayed in Volts (0 to 5.00) and in percent open (0 to 100 percent). See Also: TP - Throttle Position

:cheers:
Ben

Thorns

Discussion Starter · #19 · Jan 30, 2006

GRock,
Yesterday, I connected my laptop running the SERT Data mode and checked the TPS voltage at idle. It is .47 Volts at 0.0%, and the idle rpm was 1000. I haven't had idle dropout happen for a while now. The last time was about 800 miles ago. Do you see anything that might promote the idle drop out?

Thanks,
Thorns

BaggerDave

· #20 · Jan 30, 2006

Mine is .49

I hooked up the SERT in Data mode and after messing with the damn USB to serial converter for about 15 minutes, I found that my TPS voltage is .49. I will do as above and get the voltage in the middle of the range so that when it heats up, it is still in the range of normal.

I will report back with more data.

David

1 - 20 of 33 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.