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evilunclegrimace

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You may or may not need the adjustable FPR but it will give you the ability to fine tune your fuel at the TBI unit.

I run the same set up that PlayingWithTBI has pictured. My slightly modified 5.7 would ping under hard throttle with the factory set up. The adjustable FBR allowed me to turn up the pressure to 15.5 PSI and the ping disappeared.
 

Schurkey

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So I have a 1990 Chevy k1500 with the tbi setup stock.
Then added these
Chevrolet Performance 350 Vortec C.I.D. 330 HP Crate Engines 19433030 Summit PN NAL-19433030
WHAT TORSIONAL DAMPER and WHAT TIMING POINTER are you using? This came up in another thread a couple of days ago. Mis-matching damper and pointer can really easily screw up indicated ignition timing by 13 degrees. Find TRUE TDC on #1, verify that the timing mark on the damper aligns with the "0" on the timing pointer.

What are you using for a water pump on this engine? The coolant bypass on Vortec engines is different from the TBI engines. I don't know how the Crate Vortec engines are machined--I'd expect a blocked bypass just like the as-installed Vortec engines.

Spark plugs SPN ADO-1 (wires are just part store wires)
ACDelco "Rapidfire" #1 spark plugs? You have the wrong spark plugs to fit Vortec heads. If you HAVE to use ACDelco "Rapidfire" plugs, you need #14 not #1. But either way, they wouldn't be my first choice. Consider R44LTS (NOT R44LTS6) instead, at .044 gap.

Jegs intake manifold 555-513036 (with this we also did an EGR delete)
Is EGR deleted in the computer tune?

An air-gap manifold is totally wrong for winter use. Let me guess: You've also deleted the heated-air intake for the air cleaner, too.

Holley 670cfm TBI SPN HLY-502-6
WHICH fuel injectors do you have in that Holley throttle body? There's "Early" and "Late" styles. The "Early" style was discontinued for a reason. The early injectors have a rubber cap over the top to smooth airflow. Late injectors don't.

I've heard of folks having problems with the Holley TBIs. I own one, a 502-6 just like yours and with the "late" injectors, but I've never used it. One of my "projects" for this summer...maybe. I've had it for maybe eight years so far. Bought it burnt-up, had to replace the wire harness and some other parts. Clearly, it wasn't working-out for the prior owner.

Jet Stage 2 prom chip SPN JET-29005S
Not a lot of love for Jet PROMs. I suppose it could be worse. WHAT IS DIFFERENT between this PROM and the stock PROM?

we’ve set the timing to a lot of things with ecm disconnected properly between 0degrees and as far up to 12 degrees (it seems to like 10 the best which is what the motor booklet says for a vacuum distributor)
What does JET want for initial timing with their "Stage 2" PROM?


but no matter what it’ll hesitate, backfire out the throttle body and either stall or feel like it’s missing a good 100+ HP when it finally picks up we’ve tried different electronic distributors, even different gm ignition modules with different timing curves,
Those are symptoms of the fuel mix being too lean. What are your fuel trim numbers? What is the O2 sensor showing for voltage? Cross-counts?


What "GM ignition modules" have "different timing curves"?

and to make sure my esc module was good we took the one out of my dads truck,
Changing the ESC module does no good if the wire harness is faulty. Have you verified ALL the sensors, and ALL the computer outputs using the scan tool?

1. Ignition coil (I have a spare I just haven’t been able to get up to the shop to swap out)
TEST the coil before you scrap it. You'll need an ohmmeter, a spark tester, and a spray-bottle of water.

2. Vacuum advance distributor (bear with me here) we did some research and found out you can wire up the vacuum distributor to the ignition module so the computer doesn’t throw any codes from not having the ignition module. (We don’t have an extra laying around or we’d just try it)
OH, HELL NO!

For ****'s sake, DO NOT screw around with a vacuum-advance distributor. Some nut-job on another forum posted about running both the OEM electronic-advance HEI module in combination with a 4-pin HEI module. I helped straighten-out the wiring diagram so that it had a chance of working. It's still a horse-shiit "solution" to the problem of computer tuning; you've already installed a "Jet" tuning PROM. The Jet chip is likely nowhere close to what you need, but vacuum advance would be even worse.



it WILL NOT backfire, hesitate, or act any sorts of funny IN PARK, as soon as it’s in gear it’ll hesitate and backfire, it also doesn’t want or even attempt to spin the tires. It also normally acts up more in park when it’s up to temp. I have not tried driving it cold to see if it is fine before it reaches operating temp. It’s very inconsistent
All of that points to a lack of fuel. I'm not saying it couldn't be something else...but excessively lean mixtures can do OK until they're under load.
 
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LosDoritos

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Don't listen to Holley, they're saying 14 PSI for a stock engine (or almost stock) I've run my stock TBI injectors as high as 28 PSI. The 18LB spring replaces the stock one in the Holley throttle body. That's what regulates your pressure. Now, I'm not sure what to say about the Holley setup, I have heard bad reviews about it.

Here's what @evilunclegrimace is talking about on a regular 220 style TB. The threaded rod with the red thumb wheel adjusts tension on the spring inside the regulator. The gauge and adapter can be found online too.
You must be registered for see images attach


Here's mine running with an 18 LB spring set at 20 PSI
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Im gonna move on the fuel pump and spring next. the fpr might have to wait till I get paid again, but do I need the sending unit for that fuel pump or can I use the one in the truck now and just get the pump. Also would that unit fit without having to mess with the lines?
 

PlayingWithTBI

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Im gonna move on the fuel pump and spring next. the fpr might have to wait till I get paid again, but do I need the sending unit for that fuel pump or can I use the one in the truck now and just get the pump. Also would that unit fit without having to mess with the lines?
The ACDelco EP381 is a direct replacement for the TBI pump but, it is fairly expensive.
www.summitracing.com/parts/ado-ep381

 

LosDoritos

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The ACDelco EP381 is a direct replacement for the TBI pump but, it is fairly expensive.
www.summitracing.com/parts/ado-ep381

I found one on AutoZone for 60 https://www.autozone.com/external-engine/fuel-pump/p/acdelco-fuel-pump-ep381/963537_0_0

For the spring I could only find an 18lb on amazon but I’m very weary ab ordering car parts on Amazon, I had some really bad experiences with it but this is it https://a.co/d/6jlqa91
 

PlayingWithTBI

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That sounds too good to be true.

For the spring I could only find an 18lb on amazon but I’m very weary ab ordering car parts on Amazon, I had some really bad experiences with it but this is it https://a.co/d/6jlqa91
I seem to remember buying stuff from them before. You need to confirm your Holley regulator uses the same size spring as the Rochester 220 TB, IDK if they'll cross over.
 

LosDoritos

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That sounds too good to be true.


I seem to remember buying stuff from them before. You need to confirm your Holley regulator uses the same size spring as the Rochester 220 TB, IDK if they'll cross over.
I did some research and found this forum https://www.thirdgen.org/forums/tbi/191442-holley-670-fuel-pressure.html it’s quite old but it states the Holley fuel regulators can be adjusted just through drilling and the regulator can hold 18psi. I figure if I do this and either can’t adjust it or it won’t give me 18 I could do the jet adjustable and at that point pull the spring out and check em. That way I only have to wait on a pump (gpas shop is starting to get PACKED with customer cars)
 

SlowZ71

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I was going to suggest getting an ep381 from rock auto, but it appears they’re out of stock. I had to get a larger diameter fuel hose for the sending unit in my 88, as the feed line inlet in the tank was larger than the pump IIRC.

MAKE SURE YOU USE SUBMERSIBLE FUEL INJECTION RATED HOSE
 

LosDoritos

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I was going to suggest getting an ep381 from rock auto, but it appears they’re out of stock. I had to get a larger diameter fuel hose for the sending unit in my 88, as the feed line inlet in the tank was larger than the pump IIRC.

MAKE SURE YOU USE SUBMERSIBLE FUEL INJECTION RATED HOSE
I’m doing the fuel pump this weekend but now I just wanted to know. Those pumps run at 50-60psi would I need anything to lower that or does that regulator do that then return what’s unused
 
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