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454xli flooding when warm

T

TWSLPS

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HEY ALL, I have 96 model crusader 454xli that i have a problem with engines flooding when starting while warm. engines start & run perfect
when cool, can run for a couple of hours with no problem, stop & anchor
for a couple of hours & can not restart motors. thought i had vapor lock
problems, but have rulled that out. engines getting fire, but open throttle body & can tell they have flooded. using manual i have tried to find problem, but just can't. i have cleaned injectors, not leaking, replaced both cts sensors, did not help. fuel pressure good. one engine started this
last year, while trying to fix that problem, now the other engine has started doing the same. any ideas will be greatly appreciated.
found a couple of threads with others having this same problem, but no
responses as to what fixed their problem.
 
Guess you have no scan tool?

There are only two other sensors that are on the suspect list - TPS and MAP. I'd also check the Throttle body for leaks...the injectors may be ok but what about the rest of the TBI.
 
i do not have scan tool, but had mechanic check out about 4 weeks ago,
no codes set. i rebuilt both throttle bodies, new gaskets, orings, and pressure regulator. no leaks.
did not know if mapp & tps sensor would cause this or not. what about
air valve. with both engines doing the same, makes it hard not to be able
to swap parts from engine to engine.
any way to check mapp & tps?
thanks
 
The air valve provides an alternative path for air, around the throttle plates. In essense, it controls rpm, not the air fuel ratio, directly.

The TPS is nothing more than a variable resistor with its "know" tied to the throttle shaft. One leg of the resistor sees +5 VDC, from the computer and the other leg sees ground. The wiper moves from the ground side to the +5VDC side as the throttle opens so the voltage will increase with throttle setting.

The MAP sensor works in a similar fashion and provides a varying voltage based on the absolute pressure present at its port. The mantra from school was higher pressure = higher voltage. At see level, acceptable ranges for the MAP output are 3.8-5.5VDC. A vacuum pump is handy for lowering the pressure at the port. A vacuum gauge is also handy to assess the plumbing to the sensor.

When you changes the CTS's, did you make sure the harnesses and connectors were ok?
 
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how would you check mapp. engine running? or just switch on, and pull vac. and check voltage. this voltage correct with engine warm or cold.
would i check the tps with just switch on and move throttle?
also, something i tried sunday when engines did this, put throttle levers in 60% open, started cranking, and about 2 seconds of cranking pulled throttle to idle & engine started up & ran smooth. without doing this they would start & stumble
thanks for the replies, really appreciate the info.
terry
 
For the map, you can use the engine. I prefer a hand pump for two reasons: 1) you don't add to the summer heat & 2) you can control the vacuum applied. Whether you keep the key on is determined by what you are trying to measure

Most ECU are programmed to have a "Flood Clearing" mode during starting. This is activated by advancing the throttle at least 75% open. It shuts off the fuel from the injectors until the engine starts.
 
Missed the last line on prev. post. yes i looked at connector on cts. looked good, but did not check other ends. will do that fri.
going to try to check map fri. too, if can understand correctly how to check. if map is bad should there be a code set?
i have vac. pump i can use to check map. can you explain exatly how to peform check.
thanks again, i really appreciate the help
 
The code for the MAP sensor will only set if the error is 'gross'. This usually means a connection is bad or the sensor is totally out-of-bounds. Same for CTS.

The MAP check is to verify the +5vDC reference and ground leads are intact and stable. Ground is the A terminal and the reference goes to the C terminal. The sensor output is the middle -B- terminal. at sea level, the range for the MAP output shows as 3.8 - 5.5VDC (nominal 4.9VDC). If you hook up the vacuum pump to the sensor and pull the vacuum down, the pressure drops and the output should drop, too. At idle, on a 'new' engine, the MAP will show ~ 1.5VDC.

To get the +5VDC reference, the ECU will need to be powered on.
 
update, just spent 10days vacation on boat, very nice. had mechanic come look at boat. spent 1 full day checking things out. scanner showed no codes on either engine, everything was same on both engines, everything normal. changed all fuel filters, fuel pressure good. went out and ran with gen. running, backed in slip waited 30min tried to restart, neither would start. checked fuel pressure, showed 0psi. let set & cool 30 min both started right up, good pressure. checked all connections, relay, volt to pump good, pump running but no pr. when hot. decided to put 1 new fuel pump on, but did not help. has to be heat related. engine room getting to 150 degrees when sitting on hook with gen & blowers running. going to install 2 extra blowers & see what happens.
seems like getting vapor lock, but where.
any ideas
thanks
 
I just checked the installation manual. Turns out 150 F is the max temp for the engine room and that is without the blower running. They want air to be circulating. On top of that, they want the fuel temp, at the pump's inlet, to be less than 105F. Both restrictions apply for an hour AFTER shutdown.
 
thanks for the reply. looks like engine comp. getting a little too warm. i actually took temp readings from several locations. bottom of bilge 128. midway up between engines 150, very top 160.
thinking of installin 2 more 12v turbo blowers. putting them on the intake hose pulling air in, and having the other two pulling air out.
do you think that config. would help?
thanks
 
The crusader spec is 150, max, one inch above the top of the flame arrestor.

I wouldn't but anything in the inlet lines as it really won't help. I'd use 4" ID stuff if you have the room for it. Assuming normal temps, I'd route the inlet air "low", to the level of the fuel line. I'd put the blowers in so they are exhausting (removing) the air from the top (hot) region of the compartment. Use the shortest runs possible.
 
I do have 4" blowers & hose. the inlet are just in front of engine, exhaust in rear drawing from bottom of bilge. is it ok to move exhaust hose to top, i thought i needed them in bottom for fumes.
also gen set just in front of engines, in middle. right in front of all fuel lines!!
still guessing how to get lot more air flo
thanks
 
I suggest adding a separate "heat removing system". Leave the vapor purging system (existing blowers) alone. Yes, they still need to remove the air from the lowest part of the bilge.

I'd add the heat removing components so they can exhaust the Hot air from the upper region of the engine compartment. The other thing you need to remember is you need to provide a path for inlet (cooling) air to enter the compartment, so it can remove the heat.
 
update, last week added 2 blowers, plus plenty of intake air. dropped engine room temp to 110 at bottom and 119 at very top of engine room. outside temp was 98 so did pretty good at cooling engine room. this was with gen running, on anchor. after about 2 hours tried starting, did same thing as before. only this time i was able to re prime engines & they started up, after priming couple of times.
what should i look at next?
thanks
terry
 
Priming, as in cycling the key a couple times?

Maybe that's the fix.

It is also possible that the factory has "learned" some things after your engines were delivered. It is not uncommon for them to recommend a change in the programming of the ECU for numerous reasons. May wanna check with the factory and see if they issued any "reprogramming Tech Service Bulletins" for your particular model. Let them know all the hassles you've had lately...they may have an alternative 'fix' .
 
yes, by cyling ign switch several times. mechanic said he did call crusader dist. to see if any bulletins were issued, but told him no. maybe i need to contact carver & see if they have issued any.
do you think the temps i now have are in line, or do i need cooler?
thanks
 
I think your temps are in the recommended range. This is based on the 2007 install guide. Those are reasonable temps though it is possible that the 'current' blend for gasoline may like it cooler. I'd suspect if Crusader doesn't have any bulletins, this isn't a known (or recognized) issue yet.

I doubt carver would have anything engine specific unless Crusader sent it to them - no harm in checking.

I'm just a little baffled why the fuel pressure checked ok but the 'priming' is required..??..?? Anyhow, glad you have made some progress.
 
Problem solved i think. i have the 2 new blowers pulling air in, added 1 more pulling
air out around gen. left the 2 org blowers pulling out. engine comp staying with outside temp, which right now is around 100. engines starting up good.

as to fuel pressure, it checked out good when engines running, cold or hot. pressure
only dropped to 0 after getting eng room hot, and letting set awhile. now checking good after setting.

makomark, thanks for all your replies and help
terry
 
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