RX DI won’t start

[Billy Prause]

Hey everyone, I have a 2003 SeaDoo RX DI that I recently bought. (it wasn’t running because it needed a new air compressor) I replaced the air compressor (and compressor head) in it and now it makes psi but the machine seems to flood with fuel every time I try start it.
It has a strong spark, the fuel pump obviously works, I tried different injectors, it has compression and timing and it still won’t run and I’ve run out of ideas
If you have any idea what could be wrong please let me know
Thanks

 

[etemplet]

Since you say it is flooding I'd look to the MPEM but make sure all your lines are connected properly. Make sure you don't have the injector wires swapped as some electrica lplugs are easy to confuse.

You can remove the fuel rail and determine if the injectors are firing properly. I'm not a fan of this but I had a ECM that fired and held the PTO injector wide open. I couldn't believe how much fuel came out of the small hole. LOL I could have jet blasted the bilge easily.

Just for general information, the guy I used to clean the injectors told me the air injectors cause more problems than the fuel injectors.

If you have access to a Can Doo you can do a lot of checks on the DI.

The RX DI is a bad azz ski when running correctly. I have one in the yard and restored one last year. Good Luck !! Post some pictures. I had a 2003 Red that I restored last year and have a Blue and Gray sitting in the yard waiting on and engine.

This pic is when I first got the ski. I put on a new seat and polished it up.... it was beautiful and fast. Hit 58mph on the GPS which ain't bad for my area.

 

[WaarrEagle]

What makes you think it is "flooding" with fuel? Have you checked fuel pressure? Fuel pressure must be absolutely perfect for DI's to run. 107 PSI when cranking/running, 27 psi with just the key in.

 

[Billy Prause]

What makes you think it is "flooding" with fuel? Have you checked fuel pressure? Fuel pressure must be absolutely perfect for DI's to run. 107 PSI when cranking/running, 27 psi with just the key in.

If the plugs are dry and I go to start it it just turnes over and never fires then I check the plugs and there soaking wet but if the I dry the plugs then pour a little fuel in the cylinders it fires and runs for a second.
I talked to the mechanic that worked on it last year said he replaced the fuel pump with a “high quality” one

 

[Billy Prause]

Since you say it is flooding I'd look to the MPEM but make sure all your lines are connected properly. Make sure you don't have the injector wires swapped as some electrica lplugs are easy to confuse.

You can remove the fuel rail and determine if the injectors are firing properly. I'm not a fan of this but I had a ECM that fired and held the PTO injector wide open. I couldn't believe how much fuel came out of the small hole. LOL I could have jet blasted the bilge easily.

Just for general information, the guy I used to clean the injectors told me the air injectors cause more problems than the fuel injectors.

If you have access to a Can Doo you can do a lot of checks on the DI.

The RX DI is a bad azz ski when running correctly. I have one in the yard and restored one last year. Good Luck !! Post some pictures. I had a 2003 Red that I restored last year and have a Blue and Gray sitting in the yard waiting on and engine.

This pic is when I first got the ski. I put on a new seat and polished it up.... it was beautiful and fast. Hit 58mph on the GPS which ain't bad for my area.

I checked the wires and hoses and I’m positive that there hooked everything up right and I have already turned it over with the fuel rail and ingectors off and they seem to fire properly.
FYI I checked the fuel and it’s clean and not watery
My dad has an near identical perfectly running 2001 DI that I can steal some parts off of for diagnosing. ( I’ve hit 64mph on that machine!)
I would like to think it was an ignition problem but like I said it has a strong spark and the timing is fine.
And I’ll look into checking the MPEM

 

[etemplet]

It's not likin somethin. If you think it is flooding hold the throttle wide open and try to crank it. It might just shut off the fuel flow. Good Luck !

 

[WaarrEagle]

If the plugs are dry and I go to start it it just turnes over and never fires then I check the plugs and there soaking wet but if the I dry the plugs then pour a little fuel in the cylinders it fires and runs for a second.
I talked to the mechanic that worked on it last year said he replaced the fuel pump with a “high quality” one

Aftermarket fuel pumps are generally not recommended for DI's. Most fail, a couple folks have had success but it is very hit and miss. Even when they "work" they often draw more current than the charging system can deliver which causes other problems.

Your next step should be to verify fuel pressure. You have a fuel issue of some kind, and an aftermarket pump is a glaring red flag.

 

[Billy Prause]

Aftermarket fuel pumps are generally not recommended for DI's. Most fail, a couple folks have had success but it is very hit and miss. Even when they "work" they often draw more current than the charging system can deliver which causes other problems.

Your next step should be to verify fuel pressure. You have a fuel issue of some kind, and an aftermarket pump is a glaring red flag.

I don’t have a fuel pressure gauge but I “tested” it by disconnecting the fuel line at the fuel rail and put the phob in and measured how much fuel came out and it was the exact amount that came out of my dads DI
( I’m using a jump pack to run it off of so it has plenty of juice)

 

[Billy Prause]

I decided to mess with it a little bit today and I was able to get it to fire and sort of run. And the only way I was able to see life in the machine was if I disconnect and remove the rear plug and turn it over it fired and sort of ran.
I don’t know how that works but if anyone has any idea lmk

 

[mikidymac]

First off, never ever use a jump pack as there’s a good chance of frying the computer, you will be the next in a long line of people that have.

You need to measure fuel pressure, flow isn’t the same measure or indicator. Exactly 107 psi or it won’t run.

 

[Billy Prause]

Alright so after messing around with it for a while I still haven’t tested the fuel pressure. But I figured out that the compression is extremely low (90-95) so I took the head off and the cylinders look perfect but head gasket looks a little bit iffy but I don’t think that’s where I’m loosing all my compression. If I take the jugs off how can I tell if the rings are bad? Also as you can see in the pictures the pistons are black I know that means something but I forgot what.
Please let me know what you guys think I should do next

 

[mikidymac]

You need to have the cylinders and pistons professionally measured to find the wear and clearance to see if it’s within spec.

My guess is when you pull the cylinders you will see a lot of piston scuffling with that low of of compression.

 

[etemplet]

The rings are likely very worn but that won't verify you cylinder is good. Simply remove a ring off the piston, place it in the bore and measure the end gap on the ring. Almost all new rings measure .018" to .020" or there abouts on the WSM Rings I use. Measure the bore... it's probably gonna be at the end of the tolerance for the piston size. You can cheat and hone but if you got everything apart you may as well do the bores as well. If you bore you are gonna have to trim the raves as well. Good Luck !!

Cylinders in these pictures are good for a Zombie attack or similar escape but they need to be bored.

 

[Billy Prause]

I took the jugs to a mechanic friend who checked the bore and said that the top measured 6,000ths bigger than the bottom the top measurement was just below that “lip” which he thought was actually where it was worn down.
There’s a local parts DI for sale that has jugs listed for $200 it seems like a good deal but I would like confirmation that the jugs are where the compression is being lost
Thanks

 

[etemplet]

You're likely going to need to bore the cylinders on the engine you plan on buying. You may as well rebore yours. All of these old engines could use a new top end. The compression loss is a combination of piston, ring, and cylinder issues. I have a couple of 951 cylinders that are just at the top of the usable range and they look good but I wouldn't use them without a rebore.

I'd suggest that if your cylinders are in good condition other than the bore and IF you have enough metal left for a clean bore, I'd simply get them bored. Good Luck.

 

[mikidymac]

Don't forget that any 951 that needs a top end also needs a fresh crankshaft and balancer shaft.