help me diagnose problem please?

[hondajt]

Here are the details.
2000 Interceptor
20k miles on bike

Sypmtoms:
Hard starts while cold
**Hard starts while warm/hot
**Power loss all over, but mostly above 4-5k rpms
**Feels like throttle is "behind" at 4-5k rpm's, then stays "behind". ("Behind" - refers to the sensation that I feel like im getting the power of only an 1/8th twist though I'm really giving it a 1/3 twist) It's REALLY noticable.
**Random deaths. - example: going down the highway, cruising at about 70mph in 6th gear. I'll down shift to 5th, and when I go to give it gas, it dies. I try to reestart it, but to no prevail. I'm not 100% sure it dies when I give it gas, or when I shift, or even if its a moment later, as I am always watching the traffic, not the bike :(. They also occur while driving down the road, after I notice that the throttle is noticably "behind". It feels like it is getting worse, then it dies.

I popped a stored code once, it was saying I was getting a poor connection to the MAF sensor. I tightened the connection, still problematic.

Thoughts? Should I buy a new sensor? Hope on dumb luck thats the problem? I only have a week to get this fixed and im on a limited budget (about $600).

_______________
(Hard Starts) refers to having to press the start button numerous times, sometimes as much as 10 times.
(**) refers to an itermittent problem

[Action]

Check the connection to the throttle position sensor. I didn't connect mine all the way last time I fixed a small leak and it acted the same as yours. Only diference is mine threw the code for the TPS. While you've got the tank up you might as well recheck all the electrical connections around the throttle body especially the MAF sensor.

Action

[TOE CUTTER]

If the code was cleared and you have no codes now the problem is one that the ECU is not monitoring. That may be your clue. Fuel delivery problem maybe? Just a stab in the dark from here.Good luck.

[hondajt]

thanks. Yeah, the fact that its not throwing a code is whats really getting me...

[motorhead1977]

Sea Foam. Worth a try anyway.

[KC-10 FE]

Start with the cheap & easy stuff. Change your plugs & fuel filter at your convienence. If you do the work yourself, it's less than $100 for these procedures.

If that doesn't do the trick, I would bet it's one of the throttle sensors or the oxygen sensors. The O2 sensors are eary to change but the throttle sensors, not so much.

KC-10 FE out...

[jobvfr]

A fuel issue? Does the pump sound ok? Low pressure or bad gas (water) can cause problems similar to your description. (I've done the water thing - not fun)
Sometimes you can unplug a sensor to put the pcm in back-up and see if that makes a difference - try the O2 if app. -- if the bike runs better, than you have a bad sensor causing the problem, finding it can also be a chore however.
I didn't know these bikes had a maf sensor! Sure it wasn't the map sensor? -- with a bad tps or map the bike will barely run.
Good luck with it -- sorry I couldn't help more

[hondajt]

It's a map, not a maf, my bad. I changed the plugs, no change.

Never thought about the fuel filter. I'll check it.

I will try unplugging the o2 sensor also.

[tinkerinWstuff]

Do you know the history of the bike or is this some project you picked up?

When was the last time it ran properly? What was going on before and after the problem started? Did it come on quickly or over time?

These are all important questions before throwing theories over the fence.

[02 VFR Rider]

see if someone in your area has same gen or year try his map sensor
unplug it on your car you will see same results as what it appears your bike has

[02 VFR Rider]

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR. The MAP sensor is mounted on or connected to the intake manifold to monitor intake vacuum. It changes voltage or frequency as manifold pressure changes. The computer uses this information to measure engine load so ignition timing can be advanced and retarded as needed. It performs essentially the same job as the vacuum advance diaphragm on an old fashioned mechanical distributor.

On engines with a "speed density" type of fuel injection, the MAP sensor also helps the PCM estimate airflow. Problems here may cause an intermittent check engine light (light comes on when accelerating or when the engine is under load), hesitation when accelerating, elevated emissions and poor engine performance. The engine will run with a bad MAP sensor, but it will run poorly. Some PCMs can substitute "estimated data" for a missing or out of range MAP signal, but engine performance will be drastically reduced.

MAP Sensor Strategies: Some MAP sensor problems are not the fault of the sensor itself. If the vacuum hose that connects the MAP sensor to the intake manifold is loose, leaking or plugged, the sensor cannot produce an accurate signal. Also, if there is a problem within the engine itself that causes intake vacuum to be lower than normal (such as a vacuum leak, EGR valve that is stuck open or leaky PCV hose), the MAP sensor's readings may be lower than normal.

[VFRBenny]

Ya, I'd try a fuel pressure test.

[hondajt]

with my MAP sensor unplugged, it runs much better, and I don't notice a power loss.

WTH?!?!?!?

[02 VFR Rider]

Originally Posted by hondajt

with my MAP sensor unplugged, it runs much better, and I don't notice a power loss.

WTH?!?!?!?

there you go it must be sending the op signal to computer.
the computer can compensate somewhat when it gives no signal.

[hondajt]

I am tempted to just leave it unplugged and ride it like this for a little while. Is that a bad idea?

Also, it seems it isn't as hard to start now.

[02 VFR Rider]

could foul plugs and would run rich.
if you dont have a cat on it your choice
I would replace it first

[hondajt]

All the part's diagrams are telling me we have two MAP sensors. WTH?

Also, after letting the bike get cold, it still had the hard starts. But warm it doesn't.

Odd...

[jobvfr]

I wouldn't run it without the map sensor. These bikes are a speed/density system, and unplugging the map could make it run very rich. Check for vac leaks, or try reversing the map sensors (if there are two - I haven't checked mine). Does it start better with the tps unplugged? (it won't rev, but the tps also allows the pcm to check map operation)
If you have a digital Volt meter you can check the map voltage: key on, engine off - one wire will be ground, one will be ref voltage (5v) and one will be the signal line 2.88v or so depending on altitude. Engine running the signal should be around 1v, but it willl be hard to read (it'll go up and down alot) You'll have to check this with the sensor plugged in so be careful to not damage the wires.
If unplugging a sensor makes a difference remember that the computer may not recognize a problem (no fi light) but will read a bad sensor as if it was ok. When you unplug a sensor you cause the computer to go into open-loop (or back-up) mode and it runs the bike off of a basic table of values and often runs better. This doesn't mean the sensor you unplugged is the culprit, just that the pcm won't operate in closed loop with a missing input.
Another thing to try is the ect sensor (coolant sensor), not the fan switch. If the pcm thinks the engine is hot (or cold ) when it's not, that can cause problems too.

Wow -- I'm really ranting!
Maybe you just need some new tires
or another fence to throw things over :)

[hondajt]

Thanks, I appreciate it. Yeah, we do have two map sensors.

I'll try plugging everything back in, checking the TPS, and I'll report back.

The one MAP sensor I could find, tested fine.