Miss when cruising

[315TDSidewinder]

Just got this sled 2017 . Had a bunch of stuff done to it. It’s got TD dash flash265 285 295 315 hp, full fuel system, full header and exhaust 2.5 muffler, 3bar map, cold air intake, 196 studs 2300 miles. My problem is when I give it throttle it starts to miss or stumble. I changed the spark plugs and gapped them to .020 drained all the fuel added 91 with vp octane booster. Doesn’t matter what tune I’m on doesn’t matter doesn’t matter if I’m cruising and give it throttle or slowly work into the throttle, it stumbles every time. Running it’s got like 65psi koeo it’s got like 52 with the pump running and down to 47 when the pump turns off. Pulls like a train when it gets out of the miss. Any help would be greatly appreciated

 

[1nc 2000]

Map sensor

 

[315TDSidewinder]

Map sensor

This a common thing with these sleds.

 

[vmxrdr]

We have had a simpler solution to the exact same symptoms. Went through entire sleds fuel systems and swapped coils and map sensors to eventually find that the little fuel filter socks were screwed and wouldn’t let enough fuel in for acceleration even with full fuel system upgrade with bigger pump and direct power supply to pump. Got new ones from Pefi and never missed a beat since. We now keep a set in the shop. The filter socks looked fine visually but wouldn’t flow enough fuel for big tune, even washed em out with brake cleaner to no avail

 

[1nc 2000]

This a common thing with these sleds.

The gap map sensors do fail and cause run issues. Data logging will be able to see it.

 

[Fleecer]

At what speed and /or rpm does it miss?
Is header TD or another manufacturer?

 

[sideshowBob]

Does it have closed loop, afr readout, and data logging?
Monitoring AFR and data logging if installed will definitely help diagnose the issue.
65 psi fuel pressure key on sounds very high to me....it could be running too rich.

 

[Turboflash]

Agree. Static fp should be 44, not 65. Unless there's something we don't know.

 

[315TDSidewinder]

Agree. Static fp should be 44, not 65. Unless there's something we don't know.

It’s a TD header the rpm idk I will ride it tonight and see. the fuel pressure so I turn the key on it pumps up to like 52 when running its around 60. With the key on engine off the pump just shuts off it drops to 47. So I need to drop the fuel pressure with the pump running engine off and it need to be around 44?

 

[315TDSidewinder]

Does it have closed loop, afr readout, and data logging?
Monitoring AFR and data logging if installed will definitely help diagnose the issue.
65 psi fuel pressure key on sounds very high to me....it could be running too rich.

No afr or data logging.

 

[sideshowBob]

When you turn the key on but don't start the sled the fuel pressure will rise until the pump cuts out then it will drop a bit....its the value it rises to you are looking for to set the fp.
I would call TD and take their advice on FP with your specific equipment/mods.
JM.02 c...
With all the mods that sled has you should go a few more steps and install an AFR module, O2 sensor, AFR readout and closed loop.
TD can fix you right up and its all a seamless add on with the gap system TD and Hurricane use. LOL...its only money!

 

[315TDSidewinder]

Yeah, I was thinking the same thing when I bought the slide that I need to have the AFR and all that stuff. The problem is I just bought something from precision efi and getting charged another $122 to get my part because they’re in Canada really don’t wanna spend that right now so I’m thinking of a AFR gauge for now.

 

[Fleecer]

It’s a TD header the rpm idk I will ride it tonight and see. the fuel pressure so I turn the key on it pumps up to like 52 when running its around 60. With the key on engine off the pump just shuts off it drops to 47. So I need to drop the fuel pressure with the pump running engine off and it need to be around 44?

At 315hp you should be 45/46 lbs at idle depending on temperature. Above 30f 44# is fine.

 

[315TDSidewinder]

Just got off the phone with TD they said if it was a map sensor it would throw a code. I have one coming for it and will be putting it in just because. They told me to adjust the fuel and call back

 

[Turboflash]

It’s a TD header the rpm idk I will ride it tonight and see. the fuel pressure so I turn the key on it pumps up to like 52 when running its around 60. With the key on engine off the pump just shuts off it drops to 47. So I need to drop the fuel pressure with the pump running engine off and it need to be around 44?

Does it have a fuel return to tank fuel pump basket? Reason I ask is, fp should be lower with engine running compared to engine not running. You're saying fp is higher when engine is running. That's not normal. Either there's a problem with regulator itself, you might have a return line restriction. Way back in like 2018, the plastic return elbow fitting (front left corner of fuel tank) was changed to have larger opening, or some just drilled it bigger. It was restricting return flow. This was especially noticed when installing a larger fuel pump.
Unless there's something we don't know about the tune, the fp should be 43-44 lbs key on engine not running. This should be checked during the 2-3 second fuel pump run when key is first turned on.