Truck Starts Hard at Times

[davbell22602]

97 K1500 5.7L. Replaced wires w/napa, plugs w/ac delco, dizzy cap w/napa and rotor button w/napa. Checked gap on plugs and were already pre gapped to .060 according to the sticker on the radiator support. Fuel filter was already changed 7200 miles ago/March 2011. Idles rough at times too. It hard to start more when in the sun and idles rough at times too. Its was cloudy and rainy on yesterday with no hard start issues. Plus when parked or idling I have strong gas smell but its not raw/lean/rich smell. Fuel tested at 52 running and 60 when turning key forward. Tested from that plug in with the black cap thats on the intake. Put it on the Modius Snapon scantool and all was fine except for clearing a misfire in cylinder 2 that I had before the tune up. All Data says fuel pressure is supposed to be 55-60. Mileage is 123,***.

So which is it fuel pump, fuel pressure regulator, or spider? Or what else could it be?

 

[89Suburban]

I haven;t onwed anything newr than an '89 so I will just sit back and watch and learn on this.

 

[foamypirate]

Leaking injectors. I believe it's a pretty common problem on the Vortec 5.7s.

 

[davbell22602]

Leaking injectors. I believe it's a pretty common problem on the Vortec 5.7s.

I can smell the gas odor on the drivers side from front fender to the gas door on the truck bed.

 

[oneluckypops]

97 K1500 5.7L. Replaced wires w/napa, plugs w/ac delco, dizzy cap w/napa and rotor button w/napa. Checked gap on plugs and were already pre gapped to .060 according to the sticker on the radiator support. Fuel filter was already changed 7200 miles ago/March 2011. Idles rough at times too. It hard to start more when in the sun and idles rough at times too. Its was cloudy and rainy on yesterday with no hard start issues. Plus when parked or idling I have strong gas smell but its not raw/lean/rich smell. Fuel tested at 52 running and 60 when turning key forward. Tested from that plug in with the black cap thats on the intake. Put it on the Modius Snapon scantool and all was fine except for clearing a misfire in cylinder 2 that I had before the tune up. All Data says fuel pressure is supposed to be 55-60. Mileage is 123,***.

So which is it fuel pump, fuel pressure regulator, or spider? Or what else could it be?

Dave theres alot more to it then just hooking a scanner to it and checking codes.

You say you had a cylinder #2 misfire BEFORE the tune up. Well what were the misfire counts? Sorry to say but it would seem that you have fallen into the statistics of wasting money on parts to fix a problem, when you should have diagnosed it before you bought anything.

If your smelling a gas smell I would reccomend to have the EVAP system smoke tested, even though you dont say anthing about a code for evap. Could very well be a small leak, as they sometimes dont trip codes. Large leaks will trip a code 7 out of 10 times.

Also Fuel PSI chould be 60-66 with KOEO and 50-55 with KOER. Pressure looks ok but is it holding pressure or does it bleed off quickly? I would suggest doing a injector balance test.

If the truck isn't having the symptoms when your trying to trouble shoot your going to have a difficult time.

 

[davbell22602]

Dave theres alot more to it then just hooking a scanner to it and checking codes.

You say you had a cylinder #2 misfire BEFORE the tune up. Well what were the misfire counts? Sorry to say but it would seem that you have fallen into the statistics of wasting money on parts to fix a problem, when you should have diagnosed it before you bought anything.

If your smelling a gas smell I would reccomend to have the EVAP system smoke tested, even though you dont say anthing about a code for evap. Could very well be a small leak, as they sometimes dont trip codes. Large leaks will trip a code 7 out of 10 times.

All it said on the misfire was #2 cylinder and on right side think it had 2 but not cant remember. But the counts were less than the 10 though on the #2 cylinder.

Also Fuel PSI chould be 60-66 with KOEO and 50-55 with KOER. Pressure looks ok but is it holding pressure or does it bleed off quickly? I would suggest doing a injector balance test.

If the truck isn't having the symptoms when your trying to trouble shoot your going to have a difficult time.

The Snapon Modius said the evap was off and the evap container was off. I needed the tune up anyway. Plugs were fried, rotor button was black, and cap has corrison on it. Fuel pressure dropped to nothing when getting 60 on turning the key. When starting the truck up it drop to 52 from 60.

 

[89Suburban]

 

[oneluckypops]

The Snapon Modius said the evap was off and the evap container was off. I needed the tune up anyway. Plugs were fried, rotor button was black, and cap has corrison on it. Fuel pressure dropped to nothing when getting 60 on turning the key. When starting the truck up it drop to 52 from 60.

Ok lets go slowwwwwwwwwly.

Hook your gauge back up to the test port on the intake, turn the key on and off to cycle the pump untill max pressure is observed. Record you readings, then time how long it takes for the pressure to bleed off.

Next run an injector balance test.

Evap off doesnt mean anything, you need to smoke the system to check it for leaks.

 

[89Suburban]

.....you need to smoke the system to check it for leaks.

Can you explain how this is done?

 

[Irishman999]

Can you explain how this is done?

I totally forgot about those!

Its this machine that creates smoke, it has a hose and a nozzle you can plug into a vacuum line to check for leaks. Very kick ass tool.

 

[89Suburban]

I totally forgot about those!

Its this machine that creates smoke, it has a hose and a nozzle you can plug into a vacuum line to check for leaks. Very kick ass tool.

That sounds neat, is that a special, expesnive tool/machine?

 

[Irishman999]

It looks like they are upwards of 1k online, but I am reading about a guy building his own for 35 bucks.

The only thing cooler than the smoke machine I played with was this box that had a shitload of alligator clips that were microphones. You could put them on different parts and run the wires into a switchboard you keep in the car. There was a dial you could turn to different microphones so you could locate a sound.

You just drive around with headphones on listening to stuff until you find your problem.

 

[89Suburban]

Haha, thats neat.

 

[davbell22602]

It looks like they are upwards of 1k online, but I am reading about a guy building his own for 35 bucks.

The only thing cooler than the smoke machine I played with was this box that had a shitload of alligator clips that were microphones. You could put them on different parts and run the wires into a switchboard you keep in the car. There was a dial you could turn to different microphones so you could locate a sound.

You just drive around with headphones on listening to stuff until you find your problem.

Thats a suspension/steering mic for finding noises in the steering/suspension on a vehicle. Not all repair shops have those cause the cost of it.

 

[Irishman999]

Thats a suspension/steering mic for finding noises in the steering/suspension on a vehicle. Not all repair shops have those cause the cost of it.

This one did not look that expensive, my high school auto shop owned it. I was just screwin around with it and put one on the valve cover and one down on the oil pan, as well as some on the transmission and started driving around with the headphones on. All the sounds were way different, you could put the mic's on any part. It was not just for suspension parts.