SEI Intermiient Surging Problem and Solution

[neoracer]

for about two years have had an intermittent surging problem at times when on an extended hi-speed (65-75mph) trips which seldom coded but would surge for maybe 5-20 secs and then maybe correct iteslf and run fine,once it coded that the air temp sensor was faulty but was checked and tested ok,replaced anyway and it ran fine for several weeks,normally this was hot weather related but recently noticed that when it surged the travel computer would show that the mpg were dropping from the 40 range into the low teens meaning the fuel system was going rich,usually this might occur for 5-10 secs sometimes longer but would cease if i slowed down and traveled slower
thinking this was related to either a sensor or a sticking fuel pressure regulator i changed out the fpr with a spare and thought it was fixed because on my next short 70+ run for about 40 miles it ran fine,on the return trip on a straight 70+ mile trip at 65/75mph the surging started intermittently and then continued until i turned off the highway since i couldn't keep up with traffic,sitting at the next light the bike set a code and ran home fine,code this time was for a coolant temp sensor,finally something made sense
next morning was determined to find problem,so set out for a way to check sensor other than the standard test for the sensor as outlined in honda's sei supplement,measured sensor resistance cold and checked computer voltage to sensor cold with key on,both readings within factory specs,still not satisfied decided to test voltage when bike was warming up and when hot,hooked two posi-taps into sensor lines and got these readings
engine cold sensor resistance @ female sensor line connector 2.4 K ohms (w/i specs)
sensor connected and key on engine cold 2.41 volts, connector disconnected key on computer side 5 volts, within specs per honda
all below readings at idle
at 1st temp bar .91 volts (turn on voltage)
at two temp bars .87 volts ( same as above)
at 3 temp bars .78 volts (same as above)
with engine fully warmed up .45 volts, everything seemed fine,

talking with wingsam41 he said sounds rpm related,scoffed at the idea but when i revved engine to 3000 to 4000 rpms i saw the voltage ,momentarily jump to 5 volts showing that either the sensor was malfunctioning or problem in the connector at the sensor,when this happened the computer coded for a malfunctioning coolant sensor,turned off bike and checked sensor resistance 278 ohms (within specs),tore the air valve off to get to the coolant sensor connector ,not easy considering the location,hondas solution to get there is to pull the throttle body assembly,no way
PROBLEM with intermittent connector found someone has been there before and when they put the connector back on the retaining clip which locks the connector on like the air temp sensor was lost and although connected must have been intermittent at higher temp and engine rpm situations,thanks wingsam41 for your suggestion

final results were that at normal running temp the sensor is reading approx .35 volts vs .45 before which if i'm correct will lean out the bike slightly,regardless,.... if the intermittent condition is corrected i will be a happy camper :YMAPPLAUSE: :YMAPPLAUSE: :YMAPPLAUSE: :YMAPPLAUSE: :YMAPPLAUSE:
now to find an 85+ day to test this out might be another problem in the near future

[ghostrider52005]

Maybe you will be able to come to the rally without coming half way and going back for the other bike this time bro :lol:

[Burnout]

Sounds like you probably found the culprit. As primitive as the injection system is on the LTD /SEI's are, the voltages and resistance values are critical. Is there any inner city, heavy traffic, stop and go, in your area? Get it good and hot down in there to try and simulate the problem?

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[85GL1200I]

I sure hope you found the problem. I know that thing has been drivin you nuts.......

Might get a good hot day in July, can try it out then :d

[neoracer]

happy to report over 400 miles on SEI in last two days,with most 85+ temps ,no problems noted even with prolonged 70mph + stinks,no problems,even gas mileages seems up 1 or 2 mpg over normal
at least this problem is put to bed

[ghostrider52005]

:YMAPPLAUSE: \:d/ :YMAPPLAUSE:

[Burnout]

Good news NEO !