Hard start hot or cold!?!

Hey guys got an issue here. My 00 4.3 has progressively been harder and harder to start. I bought the truck needing an lower intake gasket(nightmare) in may of 2011. I cleaned everything! Replaced the plugs wires etc. you get the idea. Ok about 3 months ago in noticed that its was a little hard to start,later that week of the same stuff when I open the fuel cap it had suction(whoosh of air) ok. So redneck remedy: sit cap on don't click cap. It worked somewhat. Sparattic startability. Well,let's just say the holidays are a bad time to actually buy parts. Anyways when I turn it over now sometimes it will backfire. Got to tinkering around with it today and replaced the fuel filter and it started up good. When I took the filter loose it sprayed hard! The fuel pump was put it a month before I bought it ( less than a year).i need a starting point. Oh yeah truck runs great! Just getting it started it nerve racking.

you say truck runs great is it when you go to start it i'll just keep cranking over and over and not start? when you said the cap had pressure when removing it sounds like a vent blockage somewhere or maybe just try replacing cap first. as for it starting dose it seem to start harder in the rain or snow? also maybe they never replaced fuel pump rite?

Yes truck runs good when it finally starts. It has never not started it just wants to act a fool while doing so. I went outside a few hours after I installed the fuel filter and it started up fine which is..odd I just can't believe that filter was that bad I mean I could blow air through it? Firestone put the fuel pump in. And I do know that it got sent back because of heavy fuel smell. Do tanks still have vents tubes? Or are they vented through the cap? I am monitoring closely the next few days keep the ideas coming! Thanks. Mike

Hey guys got an issue here. My 00 4.3 has progressively been harder and harder to start. I bought the truck needing an lower intake gasket(nightmare) in may of 2011. I cleaned everything! Replaced the plugs wires etc. you get the idea. Ok about 3 months ago in noticed that its was a little hard to start,later that week of the same stuff when I open the fuel cap it had suction(whoosh of air) ok. So redneck remedy: sit cap on don't click cap. It worked somewhat. Sparattic startability. Well,let's just say the holidays are a bad time to actually buy parts. Anyways when I turn it over now sometimes it will backfire. Got to tinkering around with it today and replaced the fuel filter and it started up good. When I took the filter loose it sprayed hard! The fuel pump was put it a month before I bought it ( less than a year).i need a starting point. Oh yeah truck runs great! Just getting it started it nerve racking.

you should have a slight suction at times when removing the fuel cap. slight//////If too much this may be the cap as defective or wrong part.

measure the fuel pressure . new pump is not meaning good !

squirts good means nothing. back fire on cold start sounds like low pressure.. not sure on your 4.3L what the exact fuel pressure spec is.

post what you get , and a member should have this info.

fuel pressure cold start 60-65 psi ...after engine starts will drop to about 55-58psi.....

venting is done by control valves and vapor goes to the charcoal cannister. if the broke vent tubing ya it will smell .

if the broke the fuel pump pickup tube and rubber connector in the tank the pump will not work good or at all.

Thanks J. Now I have some direction on this issue.

My 2000 2.2 ltr was being stupid like that only after the first start of the day and I checked everything. Fuel pressure is good, changed ICM. All new plugs , wires filter. Finally I was told to hold the throttle to the floor while cranking. Damn thing starts right up like that. I always believed a fuel injection system should start without any pedal and it should as far as I'm concerned but this works and I'm tired of fighting with it. I'm thinkin computer issue.
Let us know what you find.

Is there a base timing on this truck? Some of. Older trucks you set the TDC then unplug a wire and set with timing light. Does this truck have similar setup?

I also forgot that I have a egr code that is on.

I also forgot that I have a egr code that is on.


if the egr is stuck open this acts like a big vac leak.

Today i had to keep it floored to get it started. I thought i had it beat. I ran some lucas through it and its been starting wonderful until today. I guess i shall break down and buy a pressure checker. now is there anyway to check the return line? How does the return work anyways, i mean what governs the fuel to be returned and how does the system hold pressure if fuel returns the tank? dont get me wrong i know what the supply and return is, i have never cared or needed to know the details until now. Thanks guys

ok fuel pressure is fine. so i went the fuel pressure reg. route. and since i was in there i cleaned the poppet nozzels 2 of them were quite dirty so its been a day without any troubles no problems starting and i reset my ces light and it hasent came back on if anything else happens in a week or so, i will post.

ok fuel pressure is fine. so i went the fuel pressure reg. route. and since i was in there i cleaned the poppet nozzels 2 of them were quite dirty so its been a day without any troubles no problems starting and i reset my ces light and it hasent came back on if anything else happens in a week or so, i will post.

I would repalce the fuel filter again like after several hundred miles on it.

cut open and see how much debris in it. could be from pump or fuel supplier.

I use purolator or ac filters.

Ok so its been a week and the truck has started EVERY time as it should. Now,i do not know if it was dirty injector nozzels or the pressure regulator the reason i replaced the regulator is because i opened the upper plentum again(didnt want to do it again) and 40 bucks is a piece of mind. I honestly thought i cleaned the injector nozzels when i replaced the upper and lower manifold gaskets. And for that matter if anyone that has the 4.3 like mine and has to do a lower manifold gasket. it would be wise to go ahead and do what i did before they put it back together. costs a little more but it beats the crap out of more hassle. So, I hope this helps someone out there, thats why we are all on here! Mike

I would repalce the fuel filter again like after several hundred miles on it.

cut open and see how much debris in it. could be from pump or fuel supplier.

I use purolator or ac filters.


Thanks JCAT, will change at my next oil change.

the vehicle is 11 yrs old rubber parts like this need replacing now.

what you did is good preventive maintenance. do it while your in there.also anything else that looks beat.