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FYI DooTalk will be Read Only for the rest of the day. We won't be seeing any updated posts until the new software upload is completed, hopefully Monday.
 

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2007 Mach Zx
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Discussion Starter · #42 ·
Hi. The new site seems nice. Just reading the service manual for the Z and have been checking it all over. Sure looks good. Not many parts to replace. So that’s good. I was thinking on having the injectors tested any thoughts? Also I should source a high pressure t-fitting and guage for some monitoring.
 

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The site does look good. The shop manual is a good read for sure. Just me mindful of any errors like torque specs in 2005 manual and DooTalk faq, and incorrect table for one of the sensors in the 2006/2007 manual. It is the air or coolant sensor - I am not sure, but cross reference with the 05. The min torque for the monoblock and head is shown at the end of the technical specs of the 05 manual.

Injector testing can be done using different setups. The sled is already fully equipped with pump, regulator and rail, so that's another possibility.

Having a fuel pressure gauge is a personal choice. I personally don't enjoy having to disassemble any fuel lines to remove the gauge cluster, nor having to back out the fuel tank to remove the airbox with pods. If this is what it means to gain reliability, then I'm not doing it. But I did enjoy riding with a fuel pressure gauge on RX7MachZ' primary and secondary sled.

I have seen a local Mach Z fail because of a LP pump and it had no pressure gauge to show the problem before it was too late. But it also had injector flow problems at the beginning of the season which made things worse with less tolerance.

RX7MachZ' #3 sled has no additional gauges other than a volt gauge which we have both reached the conclusion that it is a necessity including any other sled. The way he did this was by finding a LP pump that survived without a glitch. It did take years to figure out it was reliable. He is the only one that I know personally who has used the Airtex pump, and since I have ridden his main sled since 2012, I have no choice but to piggy back on his experience. I do believe there are other similar LP pumps like the AC Delco that are not prone to failure, but I cannot say from actual experience. All that I know is that I will not run a vane pump if it is below the bottom of the tank, nor a Posi-Flow for any kind of reliability with bad gas.

I wish that I knew more and could validate everything, but it's not going to happen. I don't have the resources for objective testing over a 1000 sleds. However, what I do know is once you have reached a recipe that does work, then most gauges become less important. In my opinion this is the key to the 1000 SDI. This is what RX7MachZ and I have been working on since 2012 to prove that once the build, setup and maintenance is solid, then monitoring gauges are not needed more than an E-TEC, with exception of the volt gauge.

To reach the point of having confidence in the 1000 SDI is where it gets tricky. Unless that I know the failure history of a particular sled - SDI, P-TEK and E-TEC alike - there is no way that I will work on someone else's sled without plugging my Wideband and EGT. I always carry a multimeter and can easily check at stops like I do with plug reading, so that's a non issue. But if I am putting $3K of someone else's money on a rebuild and everything that goes with it, I need to know it is working 100%, not 80%. I even do a quick 5 min ride with my fuel pressure gauge routed through the panel closing to make sure it holds pressure at wot.

Since you have a 2007 and that you know the history, that alone takes away over 80% of my concerns. I focus on making sure the electrical connections and battery are up to snuff, no coolant leaks, no pressure in the coolant bottle, and the injectors are cleaned no more than a couple of weeks prior to the first ride of the season. There are other things to check, but I need to make sure those things are covered.
 

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I do check spark plugs. In early afternoon I make a/f adjustment on my chain saw because it was out of power. Easy to do, but I need to make sure the plug is not overheating. I did risk cutting for 20 min without checking, but I am used to the saw. Although I did just check and it is a little too off-white for my liking. The saw is sitting next to me on my scaffolding while I am writing this. If the plug on a 1K showed that much white for trail riding, I would be nervous. For a race setup then I would be looking for even leaner. The 1K can run crazy lean for a race, like an E-TEC.

The thing with this saw is that is getting old and does not hold good compression, hence why I need to lean it out to get any decent power. Ideally I would buy a new cylinder and piston/ring for it. It is out of power because there is too much blow-by the rings. This also means excess heat from the combustion reaches the crankshaft. I am currently running it at 45:1 , but with the leaner adjustment I should be running at least 40:1 for the additional oil. It won't survive too long running this way, so I will be adding a little more oil to reach 35-40:1 .

It isn't a sled, but the principals remain. While I am pushing an old piston/ring/crankshaft, I need to be smart about it. I won't let it reach too high rpm and I won't let it overheat. To prevent overheat, the exhaust needs to be free flowing. If I have the muffler right against the log for too long, it will overheat the ring. I can run it lean, but not lean and with an excessively hot exhaust and a too little oil like a 50:1 mix, and with old parts.

The compression is important. With too little compression the sled or saw will be more difficult to turn over and start and to keep a steady idle for any period without fouling a plug. Hopefully this gives some hints with how to use your own experience to put things into perspective.
 

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2007 Mach Zx
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Discussion Starter · #45 ·
Thanks for the sound advice. I think I’ll just not be concerned about cutting and splicing fuel lines. Just going to do the proper maintenance and ride it. Like you said it’s very easy to get paranoid with monitoring everything. Once you get to know this machine you realize where most of the attention needs to go. I believe since it has run well I will simply get to know it more this upcoming winter. Looks like the machine will need a new battery/ a few bearings/ new secondary rollers / a new LP pump for preventative and flow test the injectors. Also I will clean the RAVE valves and check adjustment. I will check the oil pump adjustment as well. I believe you said 15mm is a target. Thanks for all your advice
 

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Discussion Starter · #46 ·
Hi Daag. If I replace the OEM LP pump that is under the motor do you still recommend the Airtex E8012s that you used previously? Where have you mounted yours? Thanks again
 

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I have the original diaphragm pump to setup high on the steering column. Either that or I deleted the LP pump. 15mm is a lot of oil unless the engine is going though break-in. It all depends how much oil you want to give it.
 

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Discussion Starter · #48 ·
Ok good info. Thanks. Maybe 16mm is closer to the amount. I must confess I have to measure where it is at now. I was just curious. Had to work on my sons car last few days do not as much time to check more on the Z.
 

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Same here, been really busy getting things done around the house.

I can't really tell you what is the best LP because I believe we were led astray the last time that happened with the Carter vane pump. It is important to note that all these pumps work. My main concern is the conditions that stop them from working and the number of times that they have needed to be replaced. If we could look at the warranty claims for the Posi-Flow pump, the number would be surreal. I had to do my own research to figure that one out with reasonable degree of confidence. This meant asking original owners until I hit a hundred.

In comparison I had very little data to go on for what came of the Carter vane pump that was first introduced on this forum in 2009. One of the first things that I leaned when joining this forum is this vane pump was the end all be all answer to all LP pump failures. As years went by I began to see owners report failures of these vane pumps. There were not many, but there were supposed to be none. This led me to call the Carter support line and ask what they thought about having this pump located below the fuel tank where water or Ethanol could collect. This is the main reason I have never suggested installing the pump that low. I never imagined I would become the next one to suffer a failure of that pump below the fuel tank level.

Now I can say that I have personal experience with LP failures of the Posi-Flow, Carter vane, and the original diaphragm pump. This subject is in my opinion mostly about fuel issues, and the main reason some owners had problems while others did not. I may not know what is the best pump, but I am reasonably certain fuel issues was the downfall to Posi-Flow, and the oil was the downfall of the diaphragm pump. It could have been both for the diaphragm pump, but this I do not know.

To find the most reliable fuel pump system, consider that all the snowmobile manufacturers for the past 10 years have used a single pump system, and far away from the engine, brake and muffler. BRP did something unique for Ski-Doo. They managed to keep the fuel sump that was derived from the SDI, and use only one pump as a supply. This is not something that can be easily done and it is not worth it for the SDI. But it does give a choice. In other words, pick the easiest fuel system, or change to the easiest one to adopt. If I cannot find the fuel system from a 2004 SDI, then I am sticking with a dual pump and choosing one the more reliable LP pumps that I know of.

You are in an excellent position to determine what works and may not have anything to change. However it does require testing the flow of the LP pump which is a dangerous test with a flammable fluid........ Relocating a LP for the 1K has ominously meant next to the muffler and in line to the brake rotor that constantly sparks. Higher up means an additional leakage failure point near/above the engine. It is a no win situation when it comes to safety.
 

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Discussion Starter · #50 ·
Thanks as always for the insight
Gained from your years of experience. What has me confused a bit about the LP pump is the location. I guess what I mean is all of our older snowmobiles dating back to who knows the 1970’s all of those Mikuni round and rectangular pulse pumps were all below the tank. Some under the motor like the Z and some mounted just off onto the drive axel bulkhead. I’m sure bad fuel/water plagued some of those but it seems our poor Z’s have. Experienced the worst. Interesting.
 

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The older sleds didn't escape the fate of bad fuel or excess storage oil. The large 1000 cc has the added disadvantage of consuming a remarkable amount of gas nearing 18 gph. The amount of fuel/oil mix that gets sucked into to the pulse line used to actuate the pump does impede the amount of gas it can pump. The sump provides a good amount of gas, so this is normally not an issue as the excess oil is worked/pushed through the pump.

On a 1K, poor a half quart of oil into each hole for storage and it will likely be impossible to start at the opening of the season. The 600 SDI with a diaphragm pump mounted on top of the bulkhead (over the tunnel) have a greater chance of working ok over those that have the pump placed under engine.
 

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Discussion Starter · #52 ·
That’s true. I suppose that’s why they went from the pulse type on the Z. Like you have found too much oil in the pulse line to sink down to the pump. I like the traditional engines with the constant gas/oil mix through the crankcase.
would have been quite interesting to see how this engine would have been had it been designed to scavenge gas/oil mix like the traditional types.
have a nice day. Sure is pouring rain at my place.
 

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I am looking forward to the oil pump cable measurement. It might already be set fine and not worth changing until you get a long enough ride to measure the fuel vs oil consumption. You can also mix the tank at 100:1 to complement the oil injection system.

Oil cable stretch is a common thing that I noticed with any SDI or carb that were up in mileage. Of those there were the odd ones with only one or two strands left and they were getting way too little oil.
 

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Discussion Starter · #54 ·
For sure I will post it. The previous owner did have the dealer set the pump after his rebuild. Like you said. This is a good runner now so the perfect time (and warm summer weather ) to check and make good observations of everything.
 

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I saw one adjusted by the dealer for a rebuild and it was set high. They were told to do so by the BRP Remanufacturing center. It might be the same with you sled. Still raining here.
 

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Discussion Starter · #56 ·
Wow talking sleds and we are in a heat wave. What do you think about the Quantum LP from Royal Disributing. ?
 

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It's a vane pump similar to the HP pump in the sump and to the Carter vane. It's not my preference as explained earlier, but many choose these as a LP pump and locate them under the battery tray.

Quantum fuel system parts for the Mach Z 1000 SDI
 

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Discussion Starter · #59 ·
Hmm. Well it’s tough now. So it am lifting the motor to clean around everything and check hoses/wiring etc. I will flow test the posi flo pump that is there. If it was your Z would you just replace it (was installed in 2009) or if it passes a flow test relocate it and use it.
 

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Hmm. Well it’s tough now. So it am lifting the motor to clean around everything and check hoses/wiring etc. I will flow test the posi flo pump that is there. If it was your Z would you just replace it (was installed in 2009) or if it passes a flow test relocate it and use it.
Fire Hazard

You have asked the right question which was the foundation to my previous post #49 that essentially provides the explanation behind why I don't really know. Yet I know enough to side-step certain setups that I have reason to believe do not hold a good enough advantage to make it into any sort of <reliability campaign>.

In your particular case, I am suggesting to learn the setup through flow testing the LP pump, and only then start thinking about the setup and pump. However, the risk of a fire and death is real. BRP has a number of fire hazard recalls that range from setups with loose fittings that lead to leaks, to the fuel hose itself that did not meet the electrically dissipation requirement. If you follow through, you do need to understand the risks are real in effort to take the necessary precautions. Those in our team who work high up as arborists live by a creed - if we are not scared then it is time to quit and change jobs. The following is the best explanation that I have regarding the risk.

2008 Safety Recall (bulletin 2008-17) to replace fuel hose
Usage of none electrically dissipative hose on listed model may lead to fuel tank explosion and potentially cause serious injuries or even death if the vehicles are exposed to the following conditions. Under extremely cold and dry weather (temperature of less than -30°C (-22°F) and less than 50% relative humidity), electrostatic charges may accumulate on components within the fuel tank when the engine is left idling. At a certain level of accumulation, charges could dissipate suddenly, sparking in the vapor space volume of the partially filled fuel tank, igniting a combustible mixture of gasoline and air and therefore causing an explosion.

Normally the air/fuel ratio of the vapor space of a fuel tank is overly rich in fuel thus inhibiting ignition of the mixture. Usage of fuel inappropriately stored or stored for long period can have the effect of lowering the vapor pressure characteristic of the fuel and therefore allowing the vapor space mixture in the fuel tank to reach the ignitable air/fuel ratio range, which became a significant factor in the explosions possibility.
 
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