Don’t seem to be getting fuel

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stutaeng

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I picked up a pressure tester on my way home from work. I had to get under the truck to listen, but was able to hear the pump whirring. Got somewhere around 62-63 pounds on the gauge, almost dead in the middle of what the specs call for.

I’ll be checking fuses soon. Thankfully this isn’t my primary vehicle, so I can totally afford to take a shower and veg out in front of the tv this evening. I have other stresses that are driving me crazy, but that’s too long a story and it ain’t the time or place.

Jay, can you go into a little more detail about your problem with the security system and how you fixed it? The previous owner had gotten into the steering column at some point, left it all zip tied back together.

Great start. A lot of guys will unfortunately just change fuel pump without even checking for pressure, believe it or not.

Anyway, did you also check to make sure fuel pressure holds? Turn the ON, without cranking and it's fuel pressure, then comeback 10-15 minutes and it should be within a few psi.

If that checks okay next would be to check for spark... check a few of them and report back.
 

SHC286

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Y’all…

My new TPS came in the other day. I went ahead and swapped it out. Figured “meh, let’s see what happens”. Same thing. It’d turn over like crazy, but no start.

I pulled fuses one by one when I got home from work today. They were all good but I did kind of wipe the blades while examining them. Then I checked the battery to see if it still had some charge. It checked out good.

Then I just left it alone because, well, I didn’t replace any fuses so there shouldn’t be any change, right?

A few minutes ago, just on a whim I decided to see what would happen, damn thing fired right up. And of course with the new TPS the check engine light turned off.

Can a faulty TPS cause this sort of issue? Could wiping the fuses down be what fixed it?
Or y’all reckon it’s something else?

I’m kinda still wondering if it could be the security thing because I’ve seen similar behavior out of a car I had when I tried to start it with a spare key that didn’t have a chip. But is that something that could come and go?
 

alpinecrick

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1998 C1500 5.7 ext cab with 4l60e.

Attempted to start and engine would turn over and act like it was going to start. It would make a huffing noise and shut off.

Shop diagnosed it was a defective Passlock VATS security module ACDelco 19352768, but they have been discontinued by GM.

It doesn't throw a code when that happens?
 

alpinecrick

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Y’all…

My new TPS came in the other day. I went ahead and swapped it out. Figured “meh, let’s see what happens”. Same thing. It’d turn over like crazy, but no start.

I pulled fuses one by one when I got home from work today. They were all good but I did kind of wipe the blades while examining them. Then I checked the battery to see if it still had some charge. It checked out good.

Then I just left it alone because, well, I didn’t replace any fuses so there shouldn’t be any change, right?

A few minutes ago, just on a whim I decided to see what would happen, damn thing fired right up. And of course with the new TPS the check engine light turned off.

Can a faulty TPS cause this sort of issue? Could wiping the fuses down be what fixed it?
Or y’all reckon it’s something else?

I’m kinda still wondering if it could be the security thing because I’ve seen similar behavior out of a car I had when I tried to start it with a spare key that didn’t have a chip. But is that something that could come and go?

Did the weather dry out by the time this all took place?
 
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alpinecrick

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Yes, but It’s not driven in the rain and not really messed with in the rain. So if it’s moisture related, reckon it could be humidity?

It could be distributor cap and rotor are getting condensation inside during wet weather. Especially aftermarket cap and rotor.
The rubber weatherstripping over the cowl can also become compressed over time and leak—almost invariably right on top of the distributor.

The only time I’ve seen this happen is on initial start in wet weather and usually the motor will hit on a few cylinders, then clear up after a moment. Sometimes though there will be enough moisture in the cap the truck won’t fire on any cylinder.

AC Delco or Delphi cap and rotors. Other caps often work well initially but have short lifespan before the problems start.

If it happens again check the inside of the cap for moisture.
 

SHC286

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It could be distributor cap and rotor are getting condensation inside during wet weather. Especially aftermarket cap and rotor.
The rubber weatherstripping over the cowl can also become compressed over time and leak—almost invariably right on top of the distributor.

The only time I’ve seen this happen is on initial start in wet weather and usually the motor will hit on a few cylinders, then clear up after a moment. Sometimes though there will be enough moisture in the cap the truck won’t fire on any cylinder.

AC Delco or Delphi cap and rotors. Other caps often work well initially but have short lifespan before the problems start.

If it happens again check the inside of the cap for moisture.

The original cap on these were round, right?
This one has one I’ve seen people call a “spider” style. Instead of wires arranged in a circle on top of a round cap, it’s got a cap with four wires coming out of each side. I’ll definitely pull the cap next time it rains and check it out. Thank you.
 

SHC286

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What was the code?

A bad TPS reading going to the computer can cause headaches with starting.


Sent from my iPhone using Tapatalk

Heck if I know, the scanner said “throttle position sensor” and it’s a quick, easy and cheap swap so I just swapped it. New AC Delco part for $45, took about five minutes.
 

alpinecrick

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The original cap on these were round, right?
This one has one I’ve seen people call a “spider” style. Instead of wires arranged in a circle on top of a round cap, it’s got a cap with four wires coming out of each side. I’ll definitely pull the cap next time it rains and check it out. Thank you.

All the caps look like this:

https://www.rockauto.com/en/moreinfo.php?pk=1323386&cc=1303647&jsn=3673

The hot ticket here on GMT400 are brass contacts with a vent to let the ozone out (which means there is a hole somewhere in the cap which can let moisture in). But I may try one of these next time:

https://www.rockauto.com/en/moreinfo.php?pk=1991918&cc=1303647&jsn=3678
 
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