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07 Ranger 700 losing fuel pressure as it warms up

8274 Views 15 Replies 5 Participants Last post by  Jerry1
Hello all, hoping you folks can shed some light on an issue I am having with my gf's grandmothers side by side that I have offered to look into for her. I'm new to the side by side world, but have done my share of work on dual sports I have owned over the years as well as my daily vehicles and some other toys along the way so I felt that I would look into it before her having to bring it to the dealer. A little background info.

She purchased the vehicle new in 07 from a local dealer. Had zero issues with it over the years, generally gets used as a utility vehicle for the land she owns behind her house (light use) She had no problems with it and had the dealer take it in this year for a general service (this was before I knew her). The dealer came back and said she needed a new motor - long story short after going back and forth she ended up paying for a new motor from the dealer.

She gets it back this summer and it runs as it should. Shortly there after it starts acting up, so the dealer sent someone out and they tried helping diagnose the issue and she was told it was most likely the fuel pump. She did some research and found a replacement pump online, ordered it, and a family member installed it for her. I am told this cured it and it ran fine for a few weeks of light use.

I now enter into the family and the gf and I take a ride on it and I notice that something doesnt feel quite right as I drive it. It feels like after half way on the throttle, if you push it more, the engine almost makes less power. It wasnt stumbling or making any bad noises though so we continued on in the woods for a bit as it wasnt even noticeable unless you really floored it. We had it out for another half hour or so, and it started getting worse, not making any power so we decide to turn around, hit the road and head home. ON the way back it was open field so we were able to just floor it and keep it floored, and that is where it really did not want to run correctly, just a total loss of power. We limped it back to the barn and parked it.

I then started searching through all the threads (there appear to be a lot about similar issues, but few with the actual fixes posted.) The three main things that I gathered to look at first are as follows

1. fuel pump issues
2. tbap sensor harness
3. tps sensor harness/adjustment

I decided to start with checking the fuel pressure. I borrowed my good friends snap on fuel pressure tool (hes a mechanic - tool it well taken care of). Get it hooked up, start it. Goes to 38/39 lbs as expected. Hop on the ranger and head out for a ride. Pressure starts dropping almost immediately. I bring it back and start researching pumps more and pull the pump assembly thinking perhaps her grandmother sourced the incorrect part. The pump she ended up putting in was a CNT 265lph pump that appeared to fit correctly. I did some searching and that particular pump was not one of the ones listed on the sticky on this site. I had read that people had tried swapping similar pumps only to find out that they were not suitable substitutes so i called her up and we agreed to try a pump that was listed on the sticky here in the website. IT should be noted that the fuel sock was replaced with the pump as well so i was looking at a clean and clear sock.

I ended up getting the Napa/Bosch Pump#N69128 listed on the sticky. Looked identical at all the critical areas. I headed back to the barn feeling that this was going to fix it. Put it all back together, transferred the clean sock to the new pump and got everything back together. I hooked the gauge up to the fuel rail again, turned the key and the pump cycled quickly but the pressure did not come up where it should. I turned the key off and on a few times to get teh pump to cycle and it came up to 39 psi. Started it, and it started right up...took it down the hill and out in the field. Ran great, pulled through the rpms as it should a def. improvement and all felt correct. I kept running it for a bit and noticed that the pressure was slowly starting to fall at WOT now, nothing significant, but slightly noticeable so I kept it out for a few more minutes, and sure enough after 5 minutes or so of running it, the pressure would start falling more and more, all the way down into the 20's where it would again have no power. I could simply let off the throttle and let the pressure build again and take off, and it would be normal for a few more seconds until the pressure went back down and started all over again.

Pulled it back in the barn discouraged. I checked out the harnesses for the two sensors. The look very clean, I'm assuming they were replaced with the new motor this late summer. It looks liek the newer tbap harness as well as it has the corrugated protection tube over it. I cant imagine its the tps sensor as the peddle position correlates to the engine speed while in neutral and there is no load on the motor (revs as it should in neutral/no load).

At this point I am really seeking input from anyone that has experienced this. I have found a number of threads with similar issues discussed, but no clear solution was posted. If it matters, the fuel tank is about half full, and it is COLD out here in New England, 20's and 30's. This appears to be directly related to temperature somehow. I measured the voltage at the pump pigtail before hooking the pump back on. There are three wires. One of them is ground, the middle one would go to roughly 5v with the key turned on, and the other would go to 12 v then right back down to 5v when the key is first turned on. This seemed odd to me however the vehicle started and ran correctly while cold for the first few minutes.

Please...somebody....anybody...tell me there is hope... thank you!
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Rob, that kind of narrows it down to either the fuel pressure regulator above the pump or the 10 micron black canister filter partially plugged (fuel pressure regulator plugs into this) or the lack of voltage to the fuel pump as it requires a minimum of 7 volts. On some '06 and '07 700's, I have had to actually drill out the 10 micron canister filter (and add a external fuel filter) to keep constant flow of fuel through it. They would start up fine but in a short time, flow would be reduced causing the typical low fuel pressure symptoms.
From what I have read, that pressure regulator is not sourced easily if at all as a separate item. I hate to keep spending money on these parts if we end up just having to buy the entire assembly. I have to pull the assembly again anyways so I will take a look at the black canister that you are talking about. I remember seeing the regulator but not a filter - I am thinking if the filter was plugged that it would not run correctly all the time, not just after the engine warms up. I can try and hook up a wire to the pump plug to try and get a reading while we are driving of the voltage supply. Any idea which of the two wires needs to have a minimum of 7 volts. Thank you for the input.
The black canister is the fuel filter. Red/Black is the hot wire for the fuel pump. Just FYI the ECU cuts power to the pump if the vehicle is not running . I have hooked up the entire fuel assembly to a pump outside the tank and watched the pressure drop off from an obstruction inside the canister filter. When I cut the pressure and let it sit a few minutes, pressure would return to normal for a few....................
Check your vent line to the tank. If it's plugged it will do what you are describing. When the Ranger starts dying open the fuel cap and see if air rushes in. The 5 volt line is probably the fuel gauge line. Make sure that regulator isn't plugged, it does happen.
The corrugated tube over the tbap wires is factory and isn't an indication it's been repaired. I'd check those wires at the connector that is where they go bad. It can be very difficult to find a bad wire as it usually breaks inside the insulation.
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Jungleman, I appreciate the help on this. I am looking at some pictures I took during dis assembly and see the black canister you are referring to. If I take this apart again will it be self explanatory how to drill out the filter? From my pic it does not look like the inlet and outlet ports are inline? Where would you suggest adding the external fuel filter? I have dealt with plenty of in line filters on carb setups, but I would imagine a fuel injected setup might require something different than the cheapo in line filters I am picturing. Again...thank you!
Curt - vent line is clear. I blew threw it and it had no restriction - its clear(transparent) as well so I am fairly confident that is not the issue. I can certainly try cracking open the fuel cap as an easy check as well next time I have it out.
Jungleman, I appreciate the help on this. I am looking at some pictures I took during dis assembly and see the black canister you are referring to. If I take this apart again will it be self explanatory how to drill out the filter? From my pic it does not look like the inlet and outlet ports are inline? Where would you suggest adding the external fuel filter? I have dealt with plenty of in line filters on carb setups, but I would imagine a fuel injected setup might require something different than the cheapo in line filters I am picturing. Again...thank you!
I would check the fuel tank vent hose for a blockage as Curt suggested . The canister can be drilled at an angle to line up the entrance and exit and then you need to clean it out very thoroughly. You can also replace the entire canister filter with a 3" piece of SUBMERSIBLE fuel line. I have a Yamaha mini 10 micron fuel/water separator bolted to the frame adjacent the fuel tank but a conventional inline metal fuel filter made for high fuel pressure will work. Just plug it in after the tank.
I appreciate the help guys, this will give me a few things to mess with this weekend before the snow hits. I'll run it again and open the gas tank cap to see if things improve. If not I'll pull the fuel assembly again, try drilling the filter out and cleaning it good. I can pickup a standard metal fuel filter it sounds like. Can these just be put inline with regular hose clamps? Sorry for all the questions, but the fuel injection on toys is still new to me. Thanks again.
I appreciate the help guys, this will give me a few things to mess with this weekend before the snow hits. I'll run it again and open the gas tank cap to see if things improve. If not I'll pull the fuel assembly again, try drilling the filter out and cleaning it good. I can pickup a standard metal fuel filter it sounds like. Can these just be put inline with regular hose clamps? Sorry for all the questions, but the fuel injection on toys is still new to me. Thanks again.
If the gas tank vent hose is clear, removing the gas cap will not help. As long as the fuel filter is rated for at least 45 psi, it will be fine and regular hose clamps will work. The '05 700's had this same external filter with clamps that we are talking about. No worries on to many questions as these Po's can really throw you curves that the Service Manuals don't even come close to have fixes for...............
These guys have you on the right track.

A restriction in the in-tank filter is pretty likely. never replaced a fuel pump that it wasn't packed with dirt.

I can't help but wonder what kind of replacement pump was used when the fuel pump was replaced previous to this?

If it was a Airtex, I could be very likely that the fuel pump is indeed no good. They're a garbage fuel pump IMO, and never known one to last. Might not hut to look at the fuel in the tank next time you have the fuel pump out. if you see debris, water, or anything but unleaded, you should unbolt the tank (4 bolts that are accessable from the rear) dump it and fill it up with good gas. dirt, water, or sand in a fuel tank will eat a fuel pump up in no time.

Get the Bosch replacement pump if you decide to replace it again. PN- N69128 (napa)

Not sure is polaris offers a "fuel pump only" replacement for the 07 without buying the whole tank? I know they do for later models.
I pulled the in tank assembly again and took things apart a bit further. I have the black plastic piece removed that the pump gets inserted to. This is the part that you guys said has a filter in it that may be clogged. Looking down in it is not what I expected to be drilling thru. There looks to be two metal plates on both ends. Is this what I should be drilling thru? I was thinking I would be drilling thru filter material and trying to connect the inlet and outlet holes. I tred pulling the pressure regulator out as well but can't seem to get it out of its casing.
yep, that's the filter you've got there. I've never had one apart, but it does have a steel plate on both ends. Don't know what kinda stuff's in the middle. I'd try and clean it out first with brake cleaner (or solvent) and compressed air. I never saw one I had to drill...

Don't think there's anything you can do for the pressure regulator.
FIXED!!! - Thank you all for your input.

I ended up drilling through the in-tank filter. I tried cleaning it, but didnt want to chance it either not being clean "enough" or just giving me problems in a short time again anyways. I drilled diagonally through the filter, connecting the holes and blowing out as best I could. I then reassembled the in tank assembly, cut the fuel line from the tank to the fuel rail and added in a metal fuel filter a few inches after the tank elbow.

Started up once the line was filled with fuel again and took it for a cold rip through the field. All seems fixed! Hopefully others will be able to find this post should they have the same issue. Sounds like its fairly common. Manual calls for the fuel filter to be replaced every 100 hours. Unfortunately its not a replaceable/serviceable item by itself.
fixed!!! - thank you all for your input.

I ended up drilling through the in-tank filter. I tried cleaning it, but didnt want to chance it either not being clean "enough" or just giving me problems in a short time again anyways. I drilled diagonally through the filter, connecting the holes and blowing out as best i could. I then reassembled the in tank assembly, cut the fuel line from the tank to the fuel rail and added in a metal fuel filter a few inches after the tank elbow.

Started up once the line was filled with fuel again and took it for a cold rip through the field. All seems fixed! Hopefully others will be able to find this post should they have the same issue. Sounds like its fairly common. Manual calls for the fuel filter to be replaced every 100 hours. Unfortunately its not a replaceable/serviceable item by itself.
on the road again.............
My wife has a 2004 Ranger 4X2 we use on the place. I had similar problems that absolutely drove me crazy. The issue was, it was starving for fuel which I figured. After checking several things, cleaning carb, etc. I pulled the gas tank and the suction tube was deteriorating. I replaced it and it ran good for a short time. It sits more than it is used. A few months later, I cranked it up and it had the same problems. After going through all the same procedures, I finally checked the suction tube again, and again it was deteriorated and the fuel pump was not working. I cleaned the carb, blew out the fuel pump and lines and this time replaced the suction tube with poly tubing (5/16" I.D.) It has been running great since then. The problem (at least down here in Texas) is that we have up to 10% ethanol in our gas and it eats everything up. The poly seems to be the exception. I now plan to replace my gas lines on my motorcycle and mowers with poly tube. Hopefully this will help.
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