A chevy issue

[Jucebox]

Ladies and gents, I require assistance

The Situation: 1997 Chevrolet K2500 5.7L

The Symptoms: Cold start, its amazing. Barely gets rolled over before the bang, but after its up and warm and you shut it off, the restart takes a lot of turning over and it barely catches.

The New so far: The fuel pump is new, and a delco, Ive been warned about alternatives for that part, filter obviously, ignition coil, rotor and cap.

Any other ideas? I was going to see if theres a pressure regulator like on the 5.3s. this fuel spider thing doesnt give me a bunch of confidense either. And Ive plugs and wires that just need to be installed.

[colroggal]

Seems like a simple solution, but try using premium fuel. Does it burn rich when it first stats?

What's the mileage? The timing chain might be stretching as well.

Gummy injectors and a few degrees retarded: computer can compensate for timing up to a point.

Thinking hard. It's been a few years since I had an older vortec.


Colin

[skidderman]

I read where one fellow had a similar condition. Turned out it was a wire connector that was barely hanging on. Check for exhaust pressure. Could possibly be a collapsed catalytic converter. Had that happen once and it was nasty.

[tullfan]

You need to determine if it’s getting too much fuel or not enought fuel when warm to make starting difficult. A coolant temp sensor will work as it should when cold and truck will start easily, like yours. If the sensor is bad it will still read cold and tell the warm engine to add more fuel, flooding the engine making it difficult to start.
If it is not getting enough fuel when warmed up then you have an issue in delivery and a fuel system pressure test would be needed to verify cold start psi and hot start psi.
Hard starting/no starting issues are easily corrected, its determining what element your missing that takes some time.
Good luck.
Tulfan

[sako1]

Injectors and or regulator are leaking. Can replace as a unit.

[ghostguy6]

My ford did the same thing, it ended up being a leaking injector that was flooding one cylinder.

[Jucebox]

Well, I shall look at the thermo switch first, as the regulator for this thing is in the intake manifold and sounds like an afternoon worth of love, fun, and gaskets. If I got that far, Im going to be tempted to just rip the spider out and add injectors, and thats pricy.

And the cats, Ill look that way. Can you delete them without much issue in that vintage?

[HeavyD111]

My truck (1998 5.7 k1500) does the same thing, and i bought the cfi to mpfi injector kit, new filters plugs yada yada. About to give up but was suggested to try fuel pump, which you have done already. Maybe the delphi injector kit will work for you? Bought mine at rock auto for half of what local guys wanted..

[HVA7mm]

Originally Posted by sako1

Injectors and or regulator are leaking. Can replace as a unit.

I agree, I had the same issue with a 7.4 Vortec (albeit MPFI). When trying to start warm, try putting accelerator peddle to the floor, if you have a leaker the added airflow should make it fire right away. It's a simple test if nothing else.

[tri777]

Originally Posted by Jucebox

Well, I shall look at the thermo switch first, as the regulator for this thing is in the intake manifold and sounds like an afternoon worth of love, fun, and gaskets. If I got that far, Im going to be tempted to just rip the spider out and add injectors, and thats pricy.

And the cats, Ill look that way. Can you delete them without much issue in that vintage?

Thing is though, if cat is bad, you should smell the rotten egg, I don't think your cat is bad if no smell. I have put
$1200 of new parts into my '96 since Aug now. It still does the very thing you describe yours is doing, cold start, instantly, then,
long turn over when hot..i am down to just Fuel Pump replacement now(already bought) then Spider after that.
I just threw new parts at it because it likely needed them shortly anyhow..thought for sure it was
gonna be the coolant sensor,EGR, coil,Distrib/Cap or the crank sensor though.

[sako1]

Originally Posted by tri777

Thing is though, if cat is bad, you should smell the rotten egg, I don't think your cat is bad if no smell. I have put
$1200 of new parts into my '96 since Aug now. It still does the very thing you describe yours is doing, cold start, instantly, then,
long turn over when hot..i am down to just Fuel Pump replacement now(already bought) then Spider after that.
I just threw new parts at it because it likely needed them shortly anyhow..thought for sure it was
gonna be the coolant sensor,EGR, coil,Distrib/Cap or the crank sensor though.

Stop throwing parts at the thing. Put a fuel pressure gauge on it. It needs at bare minimum 55psi to pop the injectors, usually closer to 60 psi.

[tri777]

Originally Posted by sako1

Stop throwing parts at the thing. Put a fuel pressure gauge on it. It needs at bare minimum 55psi to pop the injectors, usually closer to 60 psi.

LOL, you missed the most crucial part of my post,
My loved chevy is now 22yrs old, and with all the parts still original,
it is time for new to be put in anyhow, and as bonus, I now have 'still good' parts
for quick back up's..i'm happy to throw parts at it as the only thing that
has failed in it's 310,000kms life was the tranny in 2013.

I will replace my fuel pump if any readings below 57psi.
(and Ac-Delco or Delphi pumps only)

[pgavey]

Had the same problem with my 98 454 replaced the injectors with a set of Bosch from ebay now click boom.Injectors were leaking fuel and flooding the cylinders.

[Jucebox]

I wonder if I just poured a bunch of seafoam in the fuel system if it would clean the injectors enough? Definitely a cheaper alternative, if nothing blows up.

[Mayhem]

I would first determine and confirm it is a fuel system related problem instead of throwing parts at it. Partsource will loan you out a fuel pressure tester free of charge and there is a schrader fitting right on the supply line before it enters the metering body. Vortecs are finicky when it comes to fuel pressure.


PM me, I can walk you through the tests.

[Suzukisam]

That year is notorious for leaking fuel pressure regulator. Goggle it and follow the diagagnostic chart before replacing

[RandyBoBandy]

Maybe you should plug in the block heater and see if that works..NO?? Maybe touch the battery cables together.. I heard on the innernet that works too

[does it ALL outdoors]

Originally Posted by skidderman

Could possibly be a collapsed catalytic converter. Had that happen once and it was nasty.

That would be my guess also, I had that happen and the symptoms sound the same. I cut mine out, bashed out all the junk with a huge spud bar and welded er back in place. Thought it was the crappy fuel spider and swapped it out for nothing

[brslk]

I don't have a lot of experience with older Chevys but one of the things I'd be looking at in that situation would be the evap purge valve.

[pikeman06]

I got tons of experience with 5.7 and 6 liter chevy. At a glance it's fuel pump. The Napa one is cheap but it's one every 60000 km once the factory one is replaced. They give you an "upgrade" on the wiring harness with the new pump. Never did a pressure check, probably should have but just changed the pump and I was golden. Never touched an injector or sensor or frigg all. Use my trucks for work and 400000 plus on a couple of them and the new fuel pump always fixed the problem. You can hear it getting weak.

[Dean2]

You have done a lot of things already. I did not see these on the list.

Check and clean MAP sensor using the proper MAP cleaner and do NOT touch the wire. Check Oxygen sensor for proper operation. Also, locate grounding strap from motor to chassis. Remove and clean real well. Surprising how often the ground strap ends up being the issue on older vehicles and hardly anyone looks at them.

[Mayhem]

Originally Posted by Dean2

You have done a lot of things already. I did not see these on the list.

Check and clean MAP sensor using the proper MAP cleaner and do NOT touch the wire. Check Oxygen sensor for proper operation. Also, locate grounding strap from motor to chassis. Remove and clean real well. Surprising how often the ground strap ends up being the issue on older vehicles and hardly anyone looks at them.

I think you mean the MAF sensor?? The MAP is not serviceable and the grommet should be replaced if it is removed from the I/M.

It's a speed density system...unpluging the MAF sensor will default to generic values so might give you an indication if that is an issue.

[Dean2]

Originally Posted by Mayhem

I think you mean the MAF sensor?? The MAP is not serviceable and the grommet should be replaced if it is removed from the I/M.

It's a speed density system...unpluging the MAF sensor will default to generic values so might give you an indication if that is an issue.

True! Looking to check and clean the Mass Air Flow Sensor. Bad typing on my part.

[Jucebox]

Originally Posted by tullfan

You need to determine if it’s getting too much fuel or not enought fuel when warm to make starting difficult. A coolant temp sensor will work as it should when cold and truck will start easily, like yours. If the sensor is bad it will still read cold and tell the warm engine to add more fuel, flooding the engine making it difficult to start.
If it is not getting enough fuel when warmed up then you have an issue in delivery and a fuel system pressure test would be needed to verify cold start psi and hot start psi.
Hard starting/no starting issues are easily corrected, its determining what element your missing that takes some time.
Good luck.
Tulfan

Replaced the temp sensor this weekend, and it seems to have resolved the problem. Thanks again all! Im sure Ill be back for more things... It is a chevy.

[marlin1]

Originally Posted by Jucebox

Replaced the temp sensor this weekend, and it seems to have resolved the problem. Thanks again all! Im sure Ill be back for more things... It is a chevy.

its a chevy so it will last if maintained . I like these troubleshooting threads . Some good techs here in the shadows

[tullfan]

Glad your problem was resolved. Onward and upward.
Tullfan

[Jucebox]

Most of my chevys Ive found break simply and economically. Nothing is like, even a head gasket level. (Aside from when I had a 4L60) Just a little sensor here, a fuel pump there. The parts are incredibly cheap, as far as truck parts go, and easy to replace. I mean the wheel hubs only took me a pair of hours each on my 99, which I thought was fairly awesome. I dont look forward to when I egoboost decides it wants a complicated relationship.

[RandyBoBandy]

Originally Posted by Jucebox

Replaced the temp sensor this weekend, and it seems to have resolved the problem. Thanks again all! Im sure Ill be back for more things... It is a chevy.

Outstanding diagnosticians here...Hell it only took a month..but heck..mission accomplished ..Well done