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!