97 k1500 hard start issues.....

[1997chevydriver]

Ok guys...... Before i start throwing parts at this thing i would like your opinion.

Ok, so probably about 60% to 75% of the time the truck will start normal. Other times it has to crank for 2 seconds or so and stumbles for a few seconds once it fires then it will even out. Sometimes when it does this I will press the gas pedal (i know its a on FI vehicles) and it will fire up and idle normal.

Now for a while i have had a miss/shake at idle 90% of the time that goes away at about 1200-1500rpm.

I tested fuel pressure yesterday and this is what i got.

Key on eng off

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Running

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While it's running if you stab the gas it will rise to about 53-55psi.

I have found conflicting info on correct fuel pressure specs saying I'm within limits or i am low......

Other ideas?

Plugs, wires, cap, rotor, distributor new within 6-8 months.

Sent from somewhere in MN

 

[1997chevydriver]

Copied from FSC. Anyone else heard of this before?

Just to give a final answer, I finally called Standard Motor Products tech support line, who is the supplier for the part # FJ504 conversion spider, and they confirmed the conversion spider should show 61-66 psi key on engine off. They said my 55 psi key on engine off indicated a bad fuel pressure regulator, because my fuel pump and filter are brand new Delco/Delphi parts. That would explain my hard hot starting. Not thrilled about getting what looks like a bad-out of the box FJ504 unit but I have the replacement on the way under warranty from the company I purchased it from. I will update this thread when I install the replacement unit and check the pressures again. Crossing my fingers.

Sent from somewhere in MN

 

[97SilveradoHD]

bump.
I think you and I are having similar issues

 

[volunteerff21]

Make that 3 of us.

 

[1997chevydriver]

bump.
I think you and I are having similar issues

Make that 3 of us.

Completely random and if you push the gas it starts?

Sent from somewhere in MN

 

[volunteerff21]

Yupp. Just does it every once in a while. When I start it up it acts like it wants to die. Push the gas in a little and it comes right to life.

Our FI trucks seem to think they're carbureted lol

 

[1997chevydriver]

Yupp. Just does it every once in a while. When I start it up it acts like it wants to die. Push the gas in a little and it comes right to life.

Our FI trucks seem to think they're carbureted lol

some days it makes me wonder

Sent from somewhere in MN

 

[volunteerff21]

Copied from FSC. Anyone else heard of this before?

"Just to give a final answer, I finally called Standard Motor Products tech support line, who is the supplier for the part # FJ504 conversion spider, and they confirmed the conversion spider should show 61-66 psi key on engine off. They said my 55 psi key on engine off indicated a bad fuel pressure regulator, because my fuel pump and filter are brand new Delco/Delphi parts. That would explain my hard hot starting. Not thrilled about getting what looks like a bad-out of the box FJ504 unit but I have the replacement on the way under warranty from the company I purchased it from. I will update this thread when I install the replacement unit and check the pressures again. Crossing my fingers."

Sent from somewhere in MN

I've done the MPFI upgrade to my truck, along with a new pump, sending unit, and filter. I'm getting similar fuel pressure readings as you 1997chevydriver. It sounds like I could've gotten a bad fuel pressure regulator out of the box.

Now when I took my truck into get timed a few months ago, the tech said that the MAF was giving out all sorts of weird readings when the truck would first start, but it never did this hard start when it was in the shop. I cleaned the MAF using special MAF Cleaner after he told me this, but it didn't seem to make any difference. Truck has done this starting issue since I've cleaned it.

 

[1997chevydriver]

I have done the upgrade and filter too but not the pump. I have thought about cleaning the maf but haven't yet

Sent from somewhere in MN

 

[BHBurban]

I'm going with the FPR