Jump to content

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

at a loss... cranks but won't fire


Recommended Posts

Ok, so I've started to prepare my boat for summer. Backstory is that its been sitting covered for a few months with a battery tender trickling over.

Boats never had any issues and normally fires immediately. Today i tried to fire her up and she cranked but wouldn't start. Started with the plugs (changed them out) - old ones were looking pretty tired.

checked for fuel pump priming, no issues there. battery running at the correct voltage.

Figured i may have some stale fuel, (less than 1% in the tank) so I grabbed some new fuel (granted i didnt drain the old fuel but i figured it wouldn't hurt as i was filling the other 99% with new fuel)

changed the fuel filter just for good measure too.

Still no go....

Checked the injectors to see if they were gummed up and they were all spraying consistently and the rails we filling with fuel.

Fuel, spark, air - check but still no go.

Its never had the safety lanyard connected so that cant be the issue.

Sprayed carby cleaner straight into the intake and she will fire enough with that in it, just wont continue to run which would lead me to believe its a fuel issue (although i cant see why)

i can only think its bad fuel still in the lines so i cranked it several times while a mate held the schrader valve open to clear the line.

I was thinking about taking my in tank fuel pump out and sitting it in a bucket of new fresh gas to see if that fixed the issue, but i cant access the fuel pump to get it out which is a pain..

Does the fuel line have to be under pressure or would i be able to gravity feed fuel through the line in order to test that theory?

any help would be greatly appreciated

07 VLX btw

Link to comment

have you run through tvano's no start faq?

re the safety lanyard, do you get gauges on key-up? If you do get gauges to come up, then probably not the lanyard.

do you hear the fuel pump prime on key-up?

Link to comment

If you have close to the correct fuel pressure at the Schrader valve at key up then your fuel pump is good enough to start the engine.

suggest checking basics, (mistakes I have made)

Neutral, ?
Coil wire connected?
Firing order correct ?
Safety lanyard ?

Edited by Bozboat
Link to comment

You never said that you actually put a pressure gauge on the fuel rail. What is the pressure?

You say it fires on cleaner but won't run. That means you most likely do have a fuel problem. Fuel pressure while cranking is the first diagnostic. If it is good, you may want to check the connections at the temperature and oil senders. The engine needs a lot of extra gas when cold, so it will has to know the temperature to calculate the needed enrichment.

While you are at it, go ahead and check the grounds at the engine (probably on the back of the head near the distributor).

A MEFI reader would make this diagnosis go much quicker....

Link to comment

+1 for justgary's recomendation to use a fuel pressure guage. Fuel injected engines need the right fuel pressure to work.

Also double check that you didn't cross the plug wires. This is a common mistake that will, if you are lucky, keep your engine from running. Had a buddy destroy a starter when the engine turned backwards due to crossed plug wires.

Link to comment

Plugs are in correct firing order. Firing with good spark. Gapped correctly. Definitely not a lanyard issue (boat doesnt require it to run)

Pump primes, gauges all in working order.

Ill get a will get a fuel pressure gauge to check Im getting enough pressure, as its along the same line as im thinking is the issue.

do the fuel pressure regulators stuff up often? i would of thought it was a pretty robust part.

Link to comment

Plugs are in correct firing order. Firing with good spark. Gapped correctly. Definitely not a lanyard issue (boat doesnt require it to run)

Pump primes, gauges all in working order.

Ill get a will get a fuel pressure gauge to check Im getting enough pressure, as its along the same line as im thinking is the issue.

do the fuel pressure regulators stuff up often? i would of thought it was a pretty robust part.

If your switch has been jumped check to make sure the wires are still connected. (Mine no longer requires a lanyard to run either however if the wires come disconnected it won't run)

Sounds like a fuel issue, usually the fuel issues are gummed up fuel pumps (inlet screen) and fuel filters.

Good Luck

Link to comment

Plugs are in correct firing order. Firing with good spark. Gapped correctly. Definitely not a lanyard issue (boat doesnt require it to run)

Pump primes, gauges all in working order.

Ill get a will get a fuel pressure gauge to check Im getting enough pressure, as its along the same line as im thinking is the issue.

do the fuel pressure regulators stuff up often? i would of thought it was a pretty robust part.

High fuel pressure usually means a bad fuel pressure regulator

Low fuel pressure is usually a bad pump or a clogged filter

Link to comment

What year boat? How long you had it?

If the safety lanyard has never been connected it must be "jumped" right? Prob because it's a got a bad connection or switch. Check that lanyard to make sure it's still "jumped". Boat won't start without it. Yours must be hot wired.

Link to comment

As i mentioned before the boat is sending out spark. My understanding is the lanyard kills the spark (and gauges wont fire up), add to that for the 4yrs I've owned it the lanyard has been bypassed and had no issues. I'm now pretty sure its a fueling issue

Edited by Sm0Ke
Link to comment

As i mentioned before the boat is sending out spark. My understanding is the lanyard kills the spark (and gauges wont fire up), add to that for the 4yrs I've owned it the lanyard has been bypassed and had no issues. I'm now pretty sure its a fueling issue

I think the lanyard kills the fuel.

Link to comment

Check your cannon plug connection. A loose one has similar symptoms of a lanyard issue. And I think your cannon plug is near the distributor, you may have bumped it just right while messing around in that area. It's worth a try.

Link to comment

tried the cannon plug connection - shes all tight. pulled the injectors to make sure they're spraying and they do, so it is getting fuel. just waiting on a pressure gauge to see if its getting the correct amount.

I'm a little concerned that when i bleed the valve its not the most pungent smelling fuel (just filled the tank) I cant see how water would ingress into the tank but that is a fear. I may drain the tank again (even after putting the new fuel in) and start again fresh

Link to comment

undertook the painstaking task of draining the fuel tank as I was still not convinced the fuel was right. took 1/4 of a tank out, reconnected the fuel line and she fired straight up.. All along it was fuel! - i guess water ingress is an issue with these boats, Not really sure why people say you can't put a water separator in line (fuel pressure issue?) - but may be something i try out next

Link to comment

Congratulations on the fix! Just curious, do you use fuel stabilizers like Sta-bil marine? I use them with every tank to help reduce problems like yours, but I'm never sure it does anything.

Link to comment

undertook the painstaking task of draining the fuel tank as I was still not convinced the fuel was right. took 1/4 of a tank out, reconnected the fuel line and she fired straight up.. All along it was fuel! - i guess water ingress is an issue with these boats, Not really sure why people say you can't put a water separator in line (fuel pressure issue?) - but may be something i try out next

How did you drain the tank?

Link to comment

I drained it by grabbing some old garden hose, running it to a bucket and holding it in place (where the fuel filter goes into the tank) and just allowing the fuel pump to prime with each key turn. (had a 2nd bloke helping me out)

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...