05 kingquad 700, 9300 km's, stock

a couple months ago our KQ quit on my dad, no power then stalled and backfired, was hard to start but restarted and has started and ran fine ever since,
she quit on me again yesterday but we had to tow it, it started in the driveway when we got back. runs like crap and stalls when you rev it up but it idles great.

we found a mouse nest in the airbox the other day, but that's cleaned out and obviously not the issue. it ran fine with that crap in there surprisingly.

just wondering if anyone else has experienced a similar issue? just looking for the right direction to start looking for the issue. seems strange for a fuel pump to act up intermittently. but it sure seems like its starving for fuel to me. sucks because this thing quit last fall and needed an ECM and wiring harness...... not good luck with Suzuki for me, been a good bike but getting expensive in her old age.

thanks in advance.

 

If the fi light isn't flashing for an electronics fault, it could be the pump, or just the fuel filter, but most likely is the fuel filter in the injector. This is a regular job for me. A KQ runs badly or not at all, I remove injector, carefully poke out dirt from the injector inlet, then blow out with an air line to reveal a tiny tubular filter screen. Put injector back in, start up, and the bike runs like new. If it doesn't, then you have to take the tank off and change the fuel filter, giving the inside of the tank a good clean at the same time. In theory a pressure test would show if it needs a new filter, as it should be over 40psi. The filter is the biggest pita to remove from the pump too, best of luck with that one, as the metal pump needs to be separated from the plastic housing first.

 

thanks a lot man! glad to hear it isn't likely to be another ECM problem. will look into this and post results. hopefully its as simple as that.

wouldn't you think they'd put a finer fuel filter on it? thought a fuel filters purpose was to keep the dirt out of the fuel system? seems like a poor design to me....

 

The fuel filter is fairly fine, but is in a very inaccessible place and, as I wrote above, extremely difficult to change. In fact, when the 700 came out (same pump & filter) Suzuki didn't sell filters, you had to buy the whole pump/filter/sender unit if the filter blocked. We were fitting Mitsubishi Evo3 filters which didn't fit in the "tray" too well, until Suzuki relented and started selling the filter on its own. Why they can't use the set up on diesel vehicles with a large, easily changed filter unit, I don't know. All makes seem to be the same, though the ones with pump and filter in a separate canister below the tank, are a bit easier to get at.

 

or a simple inline fuel filter like other quads or my old Chevy half ton pickup..... that's too easily owner serviceable I guess.

just a thought: why would such a thing as a plugged injector cause it to act up intermittently? it acted up 2 months ago then was fine until last week. kinda came and went like a ghost... i'd think dirt in an injector would just cause her to quit?

we haven't had time to tear into this thing yet, but have moved it out of the way a few times while revamping our garage/shop. it has run fine at low revs/slow speeds. starts right up and idles fine. will hopefully take a look next weekend.

thanks

 

started to check things out today.

we have a solid fuel pressure reading of 42 psi key on engine off and 44 psi engine idling, as well as proper fuel volume according to my service manual. the injector looks visibly clean, the little tubular screen is not plugged up at all. but it appears to only spray from 2 of the 4 orifices in the end when engine is cranked. will pick up some good carb cleaner and clean it out.

will get the tank out and check out the filter next weekend hopefully.

still curious as to why it would have stalled in October, started then ran fine till it quit new years day, and now runs but poorly, when the cause seems to be a fuel issue. guess some things are just a mystery.

 

I never use any cleaner on injectors, fuel is a good solvent. Just blow through with an air line, and they work afterwards. Only takes a few seconds to check, you don't need the airbox back on, though the sensors need to be connected.

 

did some work this weekend.

pulled tank, filter looks fine.

cleaned injector, reinstalled, took it up the road and it quit again, waited a minute and it restarted and rode back.

fuel pressure is still the same, 42 psi while pump is running and 38 or so after it kicks off. but now the pressure fluctuates while engine is idling but smooth when riding it down the road???? 40-45 psi ish, hard to read because it fluctuates with the engines rhythm. don't remember it doing that last weekend. also, she seems to be running rich to me, stinky slightly smoky exhaust when we revved her up in garage.

let it idle till it was up to temp today. rode it around and it ran fine, revved all the way to rev limiter and no stalling or rough running of any sort. unplugging the ECT doesn't change anything.

we feel this is a sensor issue and not a fuel issue, please let us know if we're barking up the wrong tree.

noticed something weird with the TPS: it doesn't always settle back to normal adjustment after releasing the throttle. usually does but not always, thought i'd ask because its hard to just throw a 150 dollar part at something.

intermittent issues always give me the gears, atm it runs fine leaving nothing to diagnose...... thanks in advance

 

We did once fit a new TPS on a 700 as we couldn't get the three C--- marks right on tickover. Not entirely sure it was the TPS but it ran better afterwards. Also had a faulty engine temp sensor, it put up the FI warning light on a 450, ran like crap so we fitted a new sensor and still got the warning. Turned out to be the wire broken where it went into the plug on top of the sensor. After that we got quite a few the same, the wire couldn't stand the shaking it gets as the engine moves in those soft mountings, but that was sending a fault code. I have also had throttle body butterfly spindles stick, not on 450 to 750 but on the 400KQ which has a different fuel injection system. If you take the cover off the cable quadrant, you can check if it drops back onto the stop when you throttle back. It was the spindle sticky, not the TPS on these 400s.