Has anyone have this happen?

[90 Silverado]

Anyone know how much AutoZone charges to rent a fuel pressure checker?

Doug in P.R.

 

[Doughnuts]

Should be free, if you return it within the 90 days or whatever it is. But yeah that's what I would be checking for, especially with all the symptoms the fuel filter showed . There's a bunch of YouTube videos of people hooking up the testers by the filter. There is also away to get one hooked up to a tbi, though a bit more involved it's something to do if you're ever taking it apart to rebuild or the tbi mods to it.

And no I don't think any gmt 400 was built with corn fuel in mind lol.

 

[90 Silverado]

Did the propane test, no changes. AutoZone wants $179 deposit to rent the fuel pressure tester. Probably buy the test fitting online and get a gauge off EBay.
Cleaned up the grounds, idling better with the map sensor line plugged.

Doug in P.R.

 

[Doughnuts]

You could get one of these and buy a cheap gauge from harbor freight or online.

https://www.summitracing.com/parts/ANM-01800001465

Buddy of mine has one and it's one of the fastest way to troubleshoot the fuel system.

I still think it's your fuel pump though. I had a suburban that had the exact symptoms, but I never suspect the fuel pump becuase it would still run. Just any throttle use would instantly kill it .Wound up giving up and took it to a mechanic and the first thing he asked me if it's the original fuel pump. And yeah with 25 years and 170k miles under it's belt it finally gave up. I was sure glad I had them do it cause it was a hefty 35 gallon tank on that girl that you couldn't just pull the bed off .

 

[90 Silverado]

Thanks for all the help and the link. What pump did they get for you? Delphi or Delco or some cheap brand?

28 years old and only 106 k miles.

Luckily I can tilt the bed ,mines a 34 gallon too.

Wife drives it cause the a/c works.... Sunbird needs some parts still.

Doug in P.R.

 

[Knuckle Dragger]

Did you check to see if the EGR is stuck partially open?

 

[90 Silverado]

Yes no change either with it unplugged or plugged in.Cleaned underneath also. No change with propane test either.

Doug in P.R.

 

[Doughnuts]

I believe I just used a cheapie at the time . unfortunately that's been a couple years, and i don't recall . And I didn't really have it long enough afterwards to find out , a deer made sure of that.

I'm planning on installing an ac Delco pump in my 91 when I can get a couple guys together to help me lift my truck bed off lol.

Here's a really good article of a guy installing a pump into his truck .


https://www.thirdgen.org/forums/tbi/612473-tbi-fuel-pump-upgrade.html

There's a bunch of info on that site so if it's and electrical gremlin you're after then I would go searching over there . I mean our trucks are essentially giant Camaros really, lot of the same electrical systems. Same engines and transmissions .

I have also seen a bunch of write ups on replacing the fuel pump on this website too. So do a bit of searching and you'll find it .

 

[90 Silverado]

Thanks for the link, you only have to lift the front of the bed up , not off. ( Did it on my S10 in Arizona)

Just used a rachet strap and an engine hoist and a 4x4 chunk of wood for safety.

I'll also have a headache rack and wires to deal with on my bed.

Probably change the hoses to ethanol safe ones also.


Doug in P.R.

 

[Doughnuts]

Well unfortunately I don't have access to an engine hoist. But I was also gonna go ahead and do the old rust prevention and removal. Salt is a bit cruel around here in the winters and I'd figure that I might as well get two birds with one stone . Let us know if you ever figure out what the issue is, like I said I'm pretty sure it's just a bad pump.