V85TT extreme cold start issues

[Hurk51]

My 2021 has had some cold start issues, meaning that when the engine is cold(sat overnight) or for a few hours it was extremely hard to start. I am saying upwards of 7-9 hits of the start button then erratic idle. Once the bike was warm it would start easy and run normal. Tried a multitude of things, valve re set, found throttle body was not aligned in intake manifold and was half cocked, moved wiring around thinking i had interference, changed out oil and head temp sensors, changed out air flow sensor in intake. Did static fuel pressure test and got 28 psi. Cleaned fuel injectors and fuel pressure bumped up to 30psi.

I asked my local bike shops and MG dealer for ideas to look at, they had nothing. I tried multiple MG dealers on what my fuel pressure should be for my bike, none could tell me a pressure even with serial number. I was getting told min 40psi possibly and maybe a 45psi static pressure. Compared to cars fuel pressure this still seemed not quite correct?

I pulled the fuel pump to see if anything jumped out and was noticeable. Found the regulator sealing oring was gouged and i thought that was my issue as it was probably passing out the gouge. Fuel filter looked dirty but could not source one locally. The KTM bikes run the same filter but they wanted $93 for the filter and two sealing clamps.... WTF?? Found the filter on Rock Auto for $9.47, so bought three. Flushed the filter as a long shot and put the bike back together until the filters arrived.

No luck on the starting issue..... still bad. Filters arrived. This time when i pulled the pump i decided to test each part of the system. I wanted to see what the pump full output was and if over 30 psi then on to the testing the relief pressure of the regulator. Rigged up a test stand for the pump compete with gauge and pinned power and ground to the correct pins on the connector. Started with dead heading the pump to check for full pressure output and thats when my problem became crystal clear. I had a cracked fuel filter on the top seam allowing fuel back into the tank. This crack could not be seen with the eye, it had to be under pressure. I had no fuel coming out me regulator at all.

I changed the filter out and did a new test. Pump system pressure came instantly up to 60psi and my regulator was now flowing fuel. This now told me that my pump was good, my regulator pressure setting is 60psi and my system pressure for the injectors was 60psi. Not 40, not 45psi. Tested the old filter with air to find the crack, had to use 20psi and a magnifying glass to see the plastic flex at the seam to locate position of crack.

Put the pump back in the tank. Bike starts up first crack of the button and can sit overnight, two, three days ( time testing for pump schrader valve leak back). Bike goes to fast idle and has no bobble or RPM jumping. My bike has always bobbled a bit on RPM from the day i bought it until it was warm.

I now know what my bike should be for fuel pressure and symptoms of a possible cracked filter in the future. It would be nice to be able to get a tin fuel filter to fit in the system but the filter holder and top plug in ( oring sealed) design is meant for the Mahle KL 97 filter. For the ease of changing this filter out i am now looking at setting up a PM to change this filter yearly.

The video i had of the filter failure is too large to upload so there is two screen shots. One with the pump off and no leaks out of the filter and one with the pump on and the filter spraying out liquid from the crack.

 

[MG02]

Hurk51
Very interest problem you had there. Thank you for letting us about that and something to remind us in the future. I have had my V85TT since September 2020 without any such issues. I live in the Snowy Mountains of Australia where it gets pretty cold and I run my bike regulary in winter to ensure the battery is ok. Luck had no petrol pump issues to date.

 

[FMerlino]

I have a 2021 V7. Before I remapped my bike with UpMap, I was considering fuel pressure changes to modify the fuel flow. My fuel pump has a sticker on it that says “400 kPa “, which is 58 psi, according to my calculations. My fuel filter looks like it is metal. I tried to purchase a new pressure regulator from my dealer, and was told that it was not available, and that I would need to purchase the pump complete for $$$$$. Thinking that I would look for a used one, I enquired about the p/n and pressure rating on the 750 compared to my 850. The 750 p/n was different, along with the pressure (40 or 45 psi, as I recall).

Now the confusing part: if you try to order the pump for the 750 bike, the p/n subs to the same p/n as on the 850. This is according to the parts manager at the dealership.

I posted a picture of the fuel pump sticker on an earlier post.

 

[john zibell]

Fuel pressure should be 45 psi. Not sure if an Aprilla regulator would fit the assembly.

 

[Hurk51]

I have a 2021 V7. Before I remapped my bike with UpMap, I was considering fuel pressure changes to modify the fuel flow. My fuel pump has a sticker on it that says “400 kPa “, which is 58 psi, according to my calculations. My fuel filter looks like it is metal. I tried to purchase a new pressure regulator from my dealer, and was told that it was not available, and that I would need to purchase the pump complete for $$$$$. Thinking that I would look for a used one, I enquired about the p/n and pressure rating on the 750 compared to my 850. The 750 p/n was different, along with the pressure (40 or 45 psi, as I recall).

Now the confusing part: if you try to order the pump for the 750 bike, the p/n subs to the same p/n as on the 850. This is according to the parts manager at the dealership.

I posted a picture of the fuel pump sticker on an earlier post.

That's the thing I had issues with. How can the dealer not know what pump and pressure was installed with a serial number . Everything on that bike should be documented on installation. One told me until I pull the pump and look for a tag or markings then it's a crap shoot. Oh well... I know now

 

[GTM®]

How can the dealer not know what pump and pressure was installed with a serial number

Sounds like you are new to Guzzi. They are a TINY manufacturer, and parts supply comes down to what's available. For what you posted, BIG OEMs are this way.
The more frustrating one is when there's a left and right part, and they arrive labelled as such, but you get two of the same part in the bag. It's been this way for 25+ years that I've been involved in the brand.

 

[GTM®]

I had a cracked fuel filter on the top seam allowing fuel back into the tank. This crack could not be seen with the eye, it had to be under pressure. I had no fuel coming out me regulator at all.

Thanks for posting this. There's always more than one reason to NOT use plastic INSIDE of the tank submerged in fuel, but seems we can't get away from it. What part of the assy cracked? Hard to tell from your photos.

 

[Hurk51]

The fuel filter itself cracked. Cracked just under the seem that joins the top side and bottom body of the filter. Like JUST UNDER the seem on the 90 deg bend of the seem to the lower body. In your photos you can see the brownish seem of the fuel filter (top side). In my photo the liquid is pissing out toward the fuel gauge electrical connector.

 

[2WheelBuzz]

Hi All,

I’m having a similar issue but don’t seem to having any leaking anywhere I can see. My bike is a 2023 V85TT and only has 1700 miles on it. I bought it used but have only had it for a month, I’m only on my second tank of gas too. This issue only came on after it sat for a few weeks (on a trickle charger too) Plus my UpMap shows battery is fine. Weird this would come on so suddenly, so a couple questions:

I had some suggestions that I only use brand name gas, ie Shell V power. I have filled it twice with 92/93. Could this contribute?

I installed Battery Tender Jr leads on the battery so temporarily the bike was disconnected. Could this have reset anything like the TPS?

PT 2, to the last question, is TPS hard to reset/calibrate? Is it a dealership level service?

Thanks

 

[john zibell]

Surface voltage is not a true indicator of battery health. Have it load tested. Software is required to reset the TPS. See the Store tab under fueling for what you will need. I do recommend using top tier fuel as it will keep your fuel system clean. Also see this thread.

GTM E5 Fueling - V7-850 & V85TT E5

The long time vendor of the devices we sell is finally moving into modern times with their all-new device shown below. This says it will allow us to distribute our work via the cloud and bluetooth/phone app (including Diagnostic capabilities), similar to UpMap (which doesn't allow us to...

www.guzzitech.com

 

[GTM®]

I’m having a similar issue but don’t seem to having any leaking anywhere I can see. My bike is a 2023 V85TT and only has 1700 miles on it. I bought it used…

This comes up over and over and over… it’s all here for the reading. I’ll save you the time, this time only.
Almost NO bike gets delivered properly set up (PDI), valve lash being the big one, so the bike suffers. Has yours had the first service by someone truly knowledgeable? If yes, what was the lash set to?
John covered battery voltage. Listen to him.
TPS does NOT need to be reset with a battery disconnect, no. The fuel issue above is from INSIDE the tank. You will see no leak anywhere.
We have tons of info here on how to make the bike run better. Also see tip/evap and SAS posts here.