4x4squid

Hey folks...Been wrestling an intermittent problem for a couple years and am looking for ideas for permanent fix.

Symptom: truck will periodically (a few times a year) crank, but not start. Doesn't correlate to being warm or cold, and ECU has thrown no codes. When it finally starts it runs perfect, just like the rest of the time. I'm running 31x10.5x15 Mud Terrains and get a consistent 17MPG, so all indicators are the engine is running great.

Here's the kicker: When truck pulls it's non-start trick, all I have to do is pop the hood, loosen the clamp on the fuel regulator return hose, pull the hose off the nipple coming from the regulator and stick it right back-on and tighten hose clamp...Whala...truck starts perfect after this action.

Thoughts? What am I doing to the system when removing & reinstalling the fuel return hose that's fixing the problem?

I'm a pretty savvy engineer and experienced mechanic, but this one's got me stumped.

Thanks!

Warm regards,
Squid

bone collector

What kind of shape is the vacuum hose that you pull off? Is it cracked? or clogged? When you pull the gas cap is there a big whoosh of air? When is the last time you changed that pesky fuel filter?
without more information my guess would be a residual vacuum issue. Like your charcoal canister need cleaned or replaced or the fuel filter is starting to get clogged. I would run a can of seafoam in the tank and put another can into the vacuum system thru the brake hose. this will really clean out the fuel and vacuum systems. and change the fuel filter if you haven't done it recently. good luck

scope103

I don't think there's a connection, other than time. You might have a bad Fuel Pressure-Up VSV (on the apron; just follow the vacuum line from the FPR). That VSV sometimes raises the pressure in the rail (by eliminating the vacuum to the FPR) during cranking to avoid vapor lock. You might be getting vapor lock; the truck won't start, and in the few seconds you're messing with the FPR the vapor lock clears. So I think it is just the delay that's doing it for you.

Having a good fuel filter is always a good idea, but that would be very unlikely to cause a "start" problem (more likely a "run" problem). Personally, I think SeaFoam is just so much voodoo, but Bone Collector and others like it, so what do I know?

bone collector

Vapor lock is the term I as looking for just couldn't think of it at the time. Thank you to Scope. I have used seafoam to clean my vehicles systems but usually when I first get the vehicle and never again. I do believe it to help the vehicle, but I can also see where people think it can cure every problem with the vehicle.

4x4squid

Bone...Thanks for the great reply...answers below:

-- Fuel filter is fairly new...no running problems indicate to me fuel is flowing well.
-- Vac lines in good shape...I check for leaks periodically and pretty sure I could tell if I had a vac leak.
-- to be clear, I don't touch the vac line to get it to start. I actually pull-off, then re-install the fuel return line off the FPR.
-- I did run a can of SEAFOAM through the tank about 5 months ago, and problem didn't reappear until last week.
-- Interested in your comment on charcoal filter...I'm orig owner and I hate to admit it, but I've never touched mine unless moving it out of the way to accomplish some other repair. Is there a cleaning procedure or some check I can do to see if it's clogged??

Very helpfull...thanks much!

W/r
Squid

bone collector

http://forum.ih8mud.com/60-series-wa...procedure.html