Archived Runs, but HARD HARD to start!! Help

[nevinst]

Fueled up this morning and headed to Tallahassee. Got there and shut off the engine for lunch. Couldn't start it after lunbch. I had noticed it "missing" a bit while in traffic earlier, but didn't think anything of it. Anyway, had plenty of fuel pressure, cracked an injector line at the head and cranked for a while before fuel came out and truck fired up great. Still ran rough though and as soon as I shut it down a few minutes later, it did the same thing. Had to crack a couple more lines and it took quite a bit more cranking before I got it started again. Drove it back home with no problems except at idle, when it ran rough. Got home, shut it off, and it wouldn't start after only a couple of seconds being shut off. Changed the fuel filter. (Old one was dirty and had been a while since it was last changed) Primed the cannister and it started right up! Drove it around the block a few times. Seemed to run better, but still not quite right. Pulled in the drive, shut it off and wouldn't start again! I'm thinking bad VP44 or an air leak on the fuel high pressure side? Any other thoughts? Is bad fuel a possibility? First time I ever fueled up at that station.



HELP! HELP! I need my truck this week, 'cuz I have family visiting and we need the transportation!!!

 

[Casey Ray]

Sounds like air getting into the system. I'd check fuel lines from the tank all the way to the vp for cracks. Probably not the fuel if it ran fine driving home from Tallahassee to Panama City and the filter didn't seem too bad for not being changed for a while. But sounds to me like an air leak.



Good Luck,



Casey

 

[nevinst]

Could a leak on the low pressure side cause this as well as on the high pressure side?

 

[B.G. Smith]

Could a leak on the low pressure side cause this as well as on the high pressure side?

A leak anywhere up to the banjo fitting where the fuel enters the VP can cause hard start/no start problems. Inspect the lines and the filter, especially the fittings on top of the filter for signs of leak, (if it's wet with fuel it's leaking) a small fuel leak under lift pump pressure will allow air into the lines during shut down. You could have a leak in the fuel pressure gage setup also? bg

 

[rkressg]

A leak on the fuel return line can also cause hard start conditions. Have you recently done any work under the hood? Check the T-Fitting on the fuel return line (back by firewall). They are sensititive (compression fittings), there could be a fitting back there that has come just loose enough to let air in, but not fuel out. You can tighten up the fitting to see if this helps.



Also, check the engine for any codes. If you do not have a scantool, go to your local AutoZone (I see you have a 98. 5, so the normal way of checking will not work).



What is your fuel pressure during startup. The LP should shut off during cranking. With that K&N, you might want to invest in a new MAP sensor.

-Rich

 

[nevinst]

I will have to wait until later this morning to check the lines for leaks. I appreciate all the recommendations so far.



My fuel pressure has always been around 10-12Psi at idle and 6-8 at WOT. (Still is) I never paid attention to it while cranking, but will when I get the chance. I have noticed that when I bump the starter, the pressure runs to 12Psi while the pump is running, but as soon as it stops it drops to zero. It has always done this since as long as I have had the gauge though. Is this normal?

 

[fox]

Your fuel pressure is normal, maybe a little low.

For the next 12-15 starts, first bump the starter so the LP runs a full cycle, then start it. If this cures it then it is losing prime from a leak.

 

[nevinst]

Went out to check FP while cranking (8Psi). It started right up! When I left it last night, I had just run it after changing the fuel filter (Still warm from the trip to Tallahassee) and it would not start, no matter how long I cranked it. It maybe fired once or twice, but would not even think about starting. I gave up without doing anything to it. This morning it fires right up. What is going on? If it were a leak in the fuel system, wouldn it still be a problem this morning? I am confused. I don't trust it and know it will leave me stranded if I don't find the problem.

 

[rkressg]

Just to get this correct, the hard start condition occured when the engine was hot? I know there was a TSB reflash for hard start conditions while hot, but I think it was for Autos (I can't remember). A hard start while warm can also be a sign of a potential future failure of the VP44.

 

[fox]

Was the truck sitting nose up or down when it was hard to start? If I recall correctly, with a fuel filter leaking air, and the truck sitting nose up, it becomes hard to start.

 

[nevinst]

The truck has been sitting fairly level each time I have had trouble with it. I went out a little while ago and checked connections and looked for signs of leaks. Nothing significant to note, however I did tighten up the connections at the "T" fitting that rkressg mentioned. They seemed as if they might have been a little loose, but I didn't tighten them too much. Then I started it up to let it run for a while. It started right up (after sitting all day) but it stumbled a while, then picked up OK and idled for about 30 minutes just fine. All the while I was looking for leaks or any evidence that something was not working right. Couldn't find a thing. Shut it off and let it sit for 5 seconds and it will not start at all!! It seems to be symptomatic of air in the system, but I don't understand why it fires up when cold. I am becoming more and more convinced that it is related to the VP44. Is there any chance that I have some bad fuel that is foaming real bad? Anything but the VP44!!!!

 

[J.Keith]

Hate to say this but I think you VP44 is toast.

My truck did EXACTLY the same thing, and after numerous other thing were replaced it ended up being the VP44.

Hope this helps

Joe

 

[nevinst]

OK, I am back to work on this problem. I've had to let it sit for the last couple of days because of work, but tonight I had a chance to look into it some more. I took and put a section of clear tubing in-line after the filter before it goes into the VP44. I am definately getting good fuel flow and no air being introduced from that direction. After I shut it off, I see no fuel movement and no air coming from either direction. I checked every fitting from the VP44 back to the tank and back up to the pump. I replaced the fuel filter again, and I eliminated my fuel pressure gauge as a source of air. After all that, the truck still will not start after it is shut down, even after only a second or two. It runs great once it is started, but won't start without cranking it forever. I think there are only a couple other things to eliminate before taking the big plunge for the VP44.



What does the starter have to do with this problem? I have read about some people finding their batteries or cables or starter causing the problem. Is there a minimum RPM it must reach before it will deliver fuel? I also read that the Crank position Sensor could cause similar problems, but don't know how. (My tach registers while cranking, so I think the crank position sensor is working, but I don't know if that is a good enough test) Any other things I should eliminate before going for the VP44? I need to get this thing going by the weekend so I am going to have to start looking for a pump soon, if I can't find anything else as the cause.

 

[J.Keith]

It wouldn't hurt to check the starter and crank sensor.

I replaced both in my quest to fix this and neither one was the problem.

I'm not saying that you don't have a problem with one of these things it's just not fun to spend a bunch on stuff that dosen't help.

You can pull the starter fairly quickly and take it to the parts store and get it checked. It's usally free except the time for R&R.

 

[rashwor]

I had the same problem on my '99. Replaced the VP44 and all was well again. I had the exact same symptoms you do. Hard start when warm.



Dealer done the TSB for hard start when warm (it ain't just for autos) and it did not help a bit. What it did do was stop the lift pump from running so long when you turn the key on. The reasoning on this is that the VP44 sometimes does not like to see high input pressures when you are trying to start the truck. This is not a problem for all VP44s, but some are really picky (mine obviously did not care). The other thing the TSB did for me was prevent my lift pump from running at all with the "bump the starter" trick. This made it so that you could not prime the canister after changing the fuel filter. The P*sser is that you can't undo a TSB. Solution? Pour clean fuel into the filter inlet bleed screw opening until full. Cranked every time after a fuel filter change with this little trick.



Sorry for the bad news, but I think it is the VP44.

 

[nevinst]

Got my rebuilt VP44 in this afternoon. Won't be able to start on it 'till Tomorrow afternoon. Will post how it turns out.

 

[nevinst]

I'm BACK!!!

Oo.



Swapped out the VP44 and it is back to normal. Starts right up, every time! Everything went very smooth and it took less than 4 hours.



One problem I noticed was that my number one injector was fouled around the outside with a black carbon-like gunk. The fuel side of everything looked good, just around the outside of the injector and the fuel line and the inside of the connector that joins them. All the others looked great. I'm attaching a picture. (I think?) Is this a problem or an inidication of a problem somewhere?





Thanks to all who helped and provided advice. It saved me a bunch of time and money. I appreciate it very much.



Thanks,



Troy