5.7 efi (tbi) starting crank time

Strecker25

Strecker25

Well-Known Member
SILVER Sponsor
Nov 20, 2014
4,931
Rochester, NY
Boat Info
2002 410DA
Engines
Caterpillar 350HP 3126
Hi all, a little bit of paranoia I'm sure but I have a question on starting crank times on a cold throttle body EFI 5.7. In the beginning of the year until last week both motors would fire from cold in about 2-4 seconds of cranking. Recently the port engine fires in that same timeframe but the starboard engine needs to be cranked for about 5 seconds, let off the starter, then another couple seconds to fire. They both run perfectly fine afterwards and will fire instantly once warm.

Anything I should look at? Or it is normal? It has been quite warm here recently and approaching upper 80s-90 with high humidity.
 
Solving any mechanical issue starts with a complete tuneup including fuel filters
 
scoflaw said:
Solving any mechanical issue starts with a complete tuneup including fuel filters
Click to expand...

Thanks. Plugs are new, have the fuel filters in hand so those are next. Seems like a silly question but given the relatively high pressures of the fuel system, how do you depressurize (or do we need to) prior to taking the old filter off. Not looking to spray fuel all over the engine room. Thanks!
 
Strecker25 said:
Yes just the old spin on. Thanks
Click to expand...

Nothing to depressurize....just spin it off and have a bucket under to catch the fuel that will spill and to place the old filter in. Don't worry if you spill some in the bilge because it will evaporate very quickly. Spin the new one on then turn the key to the first click without starting the motor and listen for click in the engine. Turn off and repeat 5-8 times to prime the filter.

As for the start time -- could your starter be going bad? Mine is going but will get me through the season.
 
Great, I'll take it off tonight. I suppose the starter is possible, but it seems to crank properly. Oddly enough if I crank it for a couple seconds, back off the switch, then crank it again it fires right up. If I simply hold the ignition switch it will continuously crank and not start. I'll probably change the filters and if no results there have someone put a computer on it, maybe one of the sensors isn't initializing properly on first crank.

I thought maybe IAC since it's so common, but the engine runs perfect after it fires so that doesn't sound like the issue.
 
One other thing I've never bothered to ask but what's the proper starting procedure on an EFI TBI motor? I always hit the switch until the buzzer stops to give time to pressurize the fuel system, then I crank it. Would. Pump of the throttle be necessary on these motors? I've never seemed to need it under normal circumstances.
 
With fuel injection moving the throttle does not pump fuel into the intake like a standard carb does
and it always helps to add a bit of throttle
 
Almost sounds like you aren't getting fuel pressure up to the TB.
 
Gotcha. Went to the boat tonight and replaced the filter on the engine in question. I turned the key to the first notch 4 or 5 times to prime the filter and then fired it up. It started normally that time, except it idled for about 30 seconds and died. I fired again, it cranked and fired idle went up a bit and then it died, then she wouldn't start

figured it may have flooded as I had given it throttle to try and keep it running so let it sit for 20 minutes. Next time it fired up and stayed running with no issue. Maybe it sucked the filter dry and needed a couple good cranks to get the filter can filled up?

Only thing i notice with this motor is a whining noise while running, hard to tell if it's alternator whine, ps pump, or fuel pump.

Here is a video of it at idle. Unfortunately the belt whine is louder than the sound I'm talking about so not sure how much you guys can get from this

https://www.youtube.com/watch?v=JDdfkiso_fk
 
Last edited:
Sounds like an idler pulley, bearing squeal. Take your belt off and give all your pulleys a spin
 
I have the same motor but a 97 and I have a sound that is strange to me. It is the same sound I hear on the video except no squealing,I have had many carbed 5.7's and never made that sound. This is my first fuel injected 5.7 and not sure if it's normal or not. It starts and runs great.
 
Ill give the pulleys a spin this weekend as well.

@twomad -- do you hear the higher pitched noise continuously while the motor is running? Where does it seem to be coming from? About 10-15 seconds after the motor starts I hear that second high pitched whine, which is why I thought maybe fuel pump kicking back on after initial startup pressure drop. I will fix the belt first to isolate any other issues.

The second part of this story is I went to the boat today, fired up that motor with no issue (no cranking delay) and she ran fine. I'm hoping the fuel filter replacement was the ticket for the hard start condition
 
Strecker25 said:
Ill give the pulleys a spin this weekend as well.

@twomad -- do you hear the higher pitched noise continuously while the motor is running? Where does it seem to be coming from? About 10-15 seconds after the motor starts I hear that second high pitched whine, which is why I thought maybe fuel pump kicking back on after initial startup pressure drop. I will fix the belt first to isolate any other issues.

The second part of this story is I went to the boat today, fired up that motor with no issue (no cranking delay) and she ran fine. I'm hoping the fuel filter replacement was the ticket for the hard start condition
Click to expand...

Sounds like it was the issue and it makes sense...if it was dirty it would struggle to get the fuel through on the initial crank. Fuel filters should be replaced at least annually and wouldn't hurt to do it mid-season if you use ethanol fuel.
 
Yeah, especially when the dealer claims they replaced them at the beginning of the season. Not to be a cynic, but we've found some questionable work so I wouldn't be surprised if the filters weren't ever changed.

Anyways, thanks all. Simple fixes are good.
 
You must log in or register to reply here.

Forum statistics

Threads
113,247
Messages
1,429,229
Members
61,125
Latest member
Bassinbradw
Back
Top