another di probiem 2000 gtx

[wolfie]

this is for all the di fans rebuilt top end of engine do to low compression over the winter. took the (2000 gtx) out on the water today to break it in and see what I had. she starts up fine and idles good. took throttle on the trailer in the water good. went for a ride and it would not give me over 3500 rpm. ran it for about 10 minutes and brought it back to the trailer and home. It never just died on me at all. Took a compression test both sides were at 145 psi. what I didn't like was my brand new spark plugs were black and dry. I don't think it is my injectors could there be low fuel pressure and I need to pressure check? I had taken the fuel pump out and changed both fuel filters over the winter and they were not to bad. I have good fuel and oil. will they run and idle with a fuel pump that has a little low fuel pressure? Any help and direction would be great. thanks in advance

 

[ski-d00]

not likely fuel pressure, the DI fuel pump typically either works well or not at all. what you describe is exactly how DIs run with a broken reed.

 

[wolfie]

ski-doo is there a test for a damaged reed or just take them apart and look at them. should it be easy to see when you take them apart.

 

[ski-d00]

just unbolt the throttle bodies and pull them out to inspect.

they don't normally break unless something has happened to the motor like sinking it and cranking it full of water.

another common failure is the voltage regulator that can keep it from revving up but typically will throw codes and/or limp mode.

you don't have any codes or messages or blinking red light do you?

 

[wolfie]

no codes first thing I was looking for have had the ski for 3 years no water intrusion or sinking this is something that has just happened after top end rebuild (not my first rebuild) will rev to 5000 on trailer with no problem. the black dry plugs would indicate a lean condition if I am not mistaken that was why I was thinking low fuel pressure or low air pressure. you are correct about the di pumps working or not I just had last week a 03 rxdi that would not start but had 140 compression. fuel pump was frozen up bought a used one from a local guy and it ran but would not pump fuel. fixed it by pressing in on the top of the pump by the rubber piece and it started working. was told if the pumps sit a while they can stick. have not had a problem since. so I should go for the reeds in your opinion?

 

[ski-d00]

does it idle perfectly? DIs will idle pretty well with one cylinder not running quite right or only running on one cylinder. does it throttle up from idle perfectly? if it's running a little rough, it could also be an air injector. do you have access to BUDS or CanDoo which is an easy test for air injectors?

I wouldn't start with reeds if you haven't touched them and there were no incidents. A new top end would make me think it is something that you took apart didn't get back together quite right. like the carbon seals under the air injectors or maybe even a rave valve. did you oversize pistons and cut the rave valves back?

 

[wolfie]

I do have a can doo I can use from work. how can that determine if the air injectors are the problem? it seems like on the trailer it is not a perfect idle like it is dropping a cylinder every once in a while. never have been impressed with the can doo system I have mercruiser and Yamaha systems and they give you so much more information to figure out where to go.

 

[ski-d00]

I have BUDS so only know that system but others have said it will do everything BUDS does. You can cycle test the air injectors on BUDS and hear them clicking. No clicking means not working, very simple.

When idling, I'd pull one of the spark plug boots off and see how much it changes for either cylinder. This will tell you if one of the cylinders has an issue if it doesn't change much. It should not stall when pulling one off. It will run a little rougher but DIs compensate pretty well and will idle on one cylinder.

 

[wolfie]

ok had some time to work on this di problem yesterday pulled spark plug boot off one at a time and seems to run rough when pulled but keeps on running. Runs smoother when boot goes back on that seems normal. took off air box and put piece of paper in front of it to see if any gas or oil was coming threw the reeds while it ran and all was dry. compression still good. ran ski and checked charging system seems to be charging at 13.4 to 13.5. after these tests I have to assume there is something up with fuel delivery or air supply.

 

[tkarvelis]

Before you did a top end, how was the ski running? Did you leak test it after. I would agree you are lean.

 

[wolfie]

I did the top end because the ski would not give me more than about 6200 rpm and I took a compression test 1 cylinder was about 90 lbs and the other was around 110. figured it was time for a top end rebuild only has 135 hrs. I am going to work a little on it tonight see if I can find anything. I did not do a leak test do not have the equipment.

 

[tkarvelis]

You don't need much to do a leak test. I was able to get some aluminum sheet to block the manifold where it attaches to the pipe and made two plugs for the throttle bodies. It was fairly easy.

 

[ski-d00]

I don't think I'd worry about a leak test at this point. If it idles well and your compression is good most likely it is not an air leak situation. If it's not going over 3k rpms, it is a bigger problem.

When the airbox was off, did you look through the throttle bodies to see the reeds? Just hold open the throttle and use a mirror and a light. Make sure they are all there and there are no broken corners.

Did you clean your raves and do they open easily when you suck on them? Is your rave solenoid hooked up properly?

 

[wolfie]

yes I cleaned my raves and no I have not looked at my reeds to any extent yet. while working on the ski tonight this is what I have found. when I start it up and let it idle it stays at 1420 to 1460 every once in a while it will raise to 1580 to 1600 rpm and then go back to 1420. while I was listening to the engine I seen some water droplets around the head gasket by where the spark plug ground posts where between the raves. So I shut the engine down and removed the post and put the bolts to the raves back in started it up and turned the water back on. I have never heard of or seen this before but I am certain after checking it several times the water is coming from between the head gasket itself. can I assume the head gasket is no good and could this be what might be going on. has anyone ever seen or heard of this before ??

 

[wolfie]

no thoughts on what I found?? will be taking head gasket of during the week

 

[ski-d00]

Yes, head gaskets can leak if not installed properly. Water can leak into the cylinder and keep it from revving up properly and not making good power when under load. Head gaskets can't be reused so you will need a new one. Did you check the head for flatness? Was everything clean and in pristine condition? Torqued properly per sequence?

 

[wetwaterskier]

Wolfie,

I have a 2000 RX DI with similar issues.... did you ever figure this one out?

 

[wolfie]

wetwaterskier, hi, I have taken the reeds out for inspection and found a piece of sand in one of the flappers holding it slightly open. Have no idea how that might have happened. as far as the head gasket leak I have not had a chance to take the head off yet (been a very busy season so far at the marine) but the person that I did the machine work for the jugs and pistons told me that next time I have to use a small amount of sealent between the head gasket material because it was not a factory head gasket and that might be the reason for the leak between the gasket. he was nice enough to send me another one free of charge. hope to get back to this some time next week season is short around here. if you find out what is wrong with yours let me know.

 

[wetwaterskier]

Thank you for the followup! I have replaced the fuel pump and have another set of fuel injectors and regulators for troubleshooting. I have not looked at the reeds at all .... looking at that now for sure! Thanks again, and I'll let you know what I find

 

[drew.66]

Hi, I am having the same exact issue with my 98 GTX RFI. Has anyone had any success on a fix?

 

[wolfie]

hey wetwaterskier, have you had a chance to fix the ski yet let me know I put a fuel pressure gauge on mine and I am running between 107 and 110 which I believe is good

 

[wetwaterskier]

Hey Wolfe, I havnt totally got it figured out..!? I have a perfect 27psi with key cycle, but looks like only 90+ish when running. Wouldn't that be an air issue?!? The pump isn't going to create any more pressure itself...12v is 12v. The air compressors 80psi + the fuel pumps 27 = the 107psi required, right? Not sure what I need to look for. Weird too that mine won't always start without removing plugs and dropping 2 eye drops of fuel in cylinders and then starts and runs.....!?!?

 

[wolfie]

you are correct you need that 107 psi of fuel pressure if you are getting it from the fuel pump you need to check the air pump. I have 107 to 110 running. if I have the same issue after I change the head gasket I will check fuel pressure under load and see what I come up with.