Auto start/ stop; Surging after engaging

[Rabel376]

2017 Raptor SCREW, 36K
Bought used and had for 3 months. No issues with Start/Stop but did have hard downshifting when driving. Found on the threads here the TSB regarding a transmission reprogramming. Dealership addressed and HUGE difference in being more smooth. Was informed that trans would learn my way of driving for next few weeks. (Only mentioning trans programming in case its relevant)

About 3 weeks after that noticed hard "surge" from a stop when Auto Start engages. Prior to this when driving I would stop at a light, truck shut off, then while releasing the brake the truck would start and accelerate smoothly. Now, as i take my foot off the brake the truck surges/ lunges forward. Think neutral dropping an old hot rod but not as violent.

Anyone else have this OR has had it happen? Its too rough to be normal but not sure if its something that I can address before it going back to the dealership.

Thanks guys!

 

[smurfslayer]

I’ve never had that and it’s definitely not right. No mods?

also, when you are disengaging the brake and the truck starts, are you still holding the brake pedal; that is, you lift the brake only enough to get the engine to restart, OR, are you just totally releasing the brake?

if the latter, I can understand how this could happen.

When restarting, the truck needs to be ready for action immediately, in case the driver needs to accelerate quickly.

I disabled default engagement of stop start after upgrading my stereo. the start up would draw enough voltage to scram my amps, so I just disabled. I will turn it on if I’m at a series of long lights, etc and listening to news or something that doesn’t tax the amps.

 

[Rabel376]

Went back to the dealership, this time on a Monday instead of a Friday. Tech found "Auto Start/ Stop Transmission engagement solenoid" had failed on the side of the transmission. So, in case this happens to anyone else on here....there you go!

There's my weak ass contribution to this group. I need to step my game up!!

 

[smurfslayer]

Auto Start/ Stop Transmission engagement solenoid" had failed on the side of the transmission.

Interesting. Got a part number?

There's my weak ass contribution to this group

FIFY ; very good info!

 

[isis]

2017 Raptor SCREW, 36K
Bought used and had for 3 months. No issues with Start/Stop but did have hard downshifting when driving. Found on the threads here the TSB regarding a transmission reprogramming. Dealership addressed and HUGE difference in being more smooth. Was informed that trans would learn my way of driving for next few weeks. (Only mentioning trans programming in case its relevant)

About 3 weeks after that noticed hard "surge" from a stop when Auto Start engages. Prior to this when driving I would stop at a light, truck shut off, then while releasing the brake the truck would start and accelerate smoothly. Now, as i take my foot off the brake the truck surges/ lunges forward. Think neutral dropping an old hot rod but not as violent.

Anyone else have this OR has had it happen? Its too rough to be normal but not sure if its something that I can address before it going back to the dealership.

Thanks guys!

Did you ask someone about this on Jalopnik? It sounds familiar.

 

[Rabel376]

I did not post on Jalopnik. After being told what the problem was I researched it a little more. Tends to be a fairly standard part that goes bad BUT since most people turn off/ tune out/ by-pass the Auto Start/ Stop function its possible that the pump has failed but never noticed since its no longer needed. Got the truck back after having it replaced and everything is back to normal.

 

[isis]

Ok. Somebody there asked me about this exact thing a few days before you posted here. Maybe was a friend of yours? I’ve never heard of anything like this otherwise so I thought it was strange.