Poor life choices - C4 content

In reply to Stampie:

Lol! The way this one is going I'm more likely to become an FI expert.

Well Pete... I hate to be the one to say I told ya so... But... maybe it wouldnt've been a bad idea to stay with FI on this pig... Just my .02.

In reply to Bill Mesker:

Naw I need him to learn Hollys first then Megasquirt cause I'll be needing that for a future project also.

In reply to Bill Mesker:

Hindsight being 20/20 I should have approached it as a car that sat for 15-years vs. one that sat for ~4, and just planned from the start to go through every system & replace/rebuild/refresh. However, from a performance standpoint I'm not sure I want the stock TPI regardless. It really is a restriction to the 350, and while aftermarket options exist they're either not cheap, or not bolt-on, so a carb seemed to be the quickest/easiest/cheapest route to get there.

Fuel miliage is a consideration (down to 2.07 today) and Idle/ start up, But HP is Not Comprimised with a carb, It is 100 year old tech though. For me it's a hands on thing and I can't come there now and October is a long way off, but we'll get it. Find the MOST Minimal Way to power the dist key to dist.(Google) mimic that.that will eleminate all but what is nessesary for now then add operating systems after it runs,I don't think it's electric but can't see what is happening even though you tell us.

In reply to Pete Gossett:

I can understand that. It's always interesting to try something new. Hopefully you get it figured out.

And Pete I apologise If I came off sounding like an ass. That was not my intention. I want to see this thing running and driving just as much as you do

In reply to Bill Mesker:

Not at all Bill! I've just spoken to way too many former C4 owners, and the TPI system was a major issue for most of them.

In reply to Pete Gossett:

TPI=Totally Primitive Injection

TBI is even more primitive, it's basically a fuel-injected carb. I remember when all the Chevy truck guys were jealous of the TPI motors with the L98 heads.

In reply to dj06482:

TBI=Toilet Bowl Injection, because they do kinda look like a toilet flushing when running.

BrokenYugo wrote: In reply to dj06482: TBI=Toilet Bowl Injection, because they do kinda look like a toilet flushing when running.

Then My C4 Must be a Public restroom. It has 2 Side by Side Hah!

TPI is pretty easy to sort and the super-long runners make for great torque. The downside is it isn't conducive to some time-honored hp tricks because they can cost air velocity. Headers in particular can cost power with TPI. As I understand it there is a pretty low top horsepower limit, say 270-275 or so without resorting to heroic measures. Other than sometime IAC woes and the occasional EGR hassle, TPI is pretty robust. The caveat may be that the 87/88-91 setup is better-sorted than the early years and that may be where you're getting some of the feedback from other owners.

All of which is moot because you committed to carb. If you end up going MS in the future the cheap setup is swap in a 92-6 LT1 intake and drill it to run a distributor. I had an 88 track car back in the day that made 375 hp to the wheels running a Holley Commander and a modded LT1 intake. The old TPIS mini ram, which was very well-regarded, is kind of an LT1 intake.

You've solved the carb/intake height problem, hang in there and keep the updates coming.

Reading this Hot Rod article on Holley tuning(SWMBO thoughtfully brought it for me) I see one thing offhand I've likely misadjusted - they state the idle mixture screws lose authority once the idle screw is turned more than 1.5-turns, which mine most definitely is. So I need to get it running, back the idle way down, then adjust idle mixture.

Hopefully I can investigate it this weekend.

In reply to Pete Gossett: Yes when they get Off Idle the Main's begin to feed it, that's what I was talking about builders not having to Set-up the Carb. and truely 1.5 rounds out is more than I will, use Half that is more likly.

OK....WE KNOW YOU'RE BACK IN BILOXI. UPDATE??????

In reply to Ovid_and_Flem:

Yes, I am...and I need more Holley advice.

I was attempting to readjust the float level tonight - after replacing the paper gaskets on the adjuster nut & set screw that disintegrated from fuel leakage during prior adjustment attempts - and discovered gas cascading out the top of the carb like a waterfall, even though the fuel level in the bowl is well below the screw hole.

Any idea what's causing that?

Yea the adj Gasket is Metal(black?) or Nylon (White) but not paper.

In reply to GTXVette:

I'll check again, but didn't see any that looked like the correct size.

In reply to GTXVette:

These are my options. The top 2 are the paper gaskets I thought were correct, based on size. The bottom ones are the only non-paper gaskets in the kit that look like they would fit, but are they wide enough?

Pete Gossett wrote: In reply to Ovid_and_Flem: Yes, I am...and I need more Holley advice. I was attempting to readjust the float level tonight - after replacing the paper gaskets on the adjuster nut & set screw that disintegrated from fuel leakage during prior adjustment attempts - and discovered gas cascading out the top of the carb like a waterfall, even though the fuel level in the bowl is well below the screw hole. Any idea what's causing that?

Hi Pete (and guys),

New to the forum here - I gave up hot-rodding cars years ago to pour all my money into sailboats (ha, pouring money into a hole in the water!). I cut my teeth on Holley and Rochester Q-jets back in the day when fuel injection was for exotic Italian and German sports cars. I did own an '85 Corvette (had a '72, '73, '85, and most recently an '04) with the TPI but kept it mostly stock then. I also did about 15 years of circle-track racing (most fun ever!)

I keep thinking you are having too much trouble and are focusing on float level as the cause of your trouble. I don't ever remember needing to do more than set the floats once - then forget them until the next carb rebuild. So, why the trouble? I think you might be having an excess fuel pressure problem. Regardless of what your fuel pressure gauge is saying, remember that the needle and seat are dependent on the float, using fuel level, pressing the needle into the seat with enough pressure to stop the fuel from forcing its way past the seat. So if the fuel pressure is too high, no amount of float adjustment with cause the float to have enough force to stop the fuel flow into the bowl.

On initial startup everything may be ok, but given a few minutes the fuel pump will overcome the float's ability to regulate the incoming fuel under pressure. So, how to check this?

I say, take a trip the the local (generic) auto parts store and pick up a basic low pressure electric fuel pump - 5 gph-ish. Find a (clean!) bucket and put a couple of gallons of gas in, hook up the generic fuel pump, isolated from the car's current system, plumb to the carb and drop the feed line into the bucket. Start, check and set the float level (try setting the level just below the sight glass/level port, it will still work) then run to see how the carb functions. I'm guessing your primary culprit is an overly aggressive in-tank pump.

Also, as has been said just previously, there's not an intermediate circuit on Holleys (if I remember correctly). Check your throttle plate angle - if it's more than a few /32nds (should be stated in the adjustment literature) you're tapping the main fuel circuit, but it's getting a bad/weak vacuum signal and can't feed properly (seen as raw/non-atomised fuel dumping from the venturies). An easy way to check for this is with the idle set screws. With a properly functioning idle circuit, turning the idle adjustment screws closed will kill the engine. Sometimes only one closed will kill the engine unless your cam is aggressive and the vacuum is low to begin with. But no matter what, closing both idle screws should kill the engine. If not the carb is trying to feed from the main circuit.

Having said all that, I hate Holleys! Give me a Q-jet any day - I can still make them purr!

Cheers,

Mark

Pete the two on the right look right for the bottom and the left for top of the Adj.nut, the hole in the center of course must fit over the needle housing,you also must Have two of each.

His Idea is good but like I also said just leave the sight plugs out If the floats are right at the bottom of the Hole it won't leak. and not super tight but tight on those washers

Welcome Mark & thanks! The idle screws do kill the engine if they're too far in, I've verified that. Although I definitely had the idle too high for a while, but I've since backed it down. You may be onto something with the fuel pressure though. Both gauges are within 1/2-psi of each other(6 & 6.5), but that doesn't mean either one are accurate. Since Holley recommends 5-8 psi there's not much room for error...or inaccurate gauges. I still think there may be crud in the carb though. If I can't get anywhere with it this week I'll probably pull it back off & go through everything again.

John, I'll give those gaskets a try tonight & hopefully won't have fuel spraying all over when I adjust the floats.

A regulator that needs rebuilt can work fine but "creep" up in pressure so unless you're seeing those numbers while it's misbehaving don't trust them. Working alone you could temporarily stab a jumper in the fuel pump relay socket (so it just runs constantly) and watch the pressure gauge to test this.

well there IS fuel Because they are Loose,but Manageable, Nothing New For you Right. Remember .... the screws in the Jet/ Metering Plate are Air bleeds and DO affect the Idle Quality But Not Idle Speed, the one that raises RPM Is By the throttle arm and that screw is down low right side right by the throttle shaft. Back it off until it isnt touching the arm.. gently screw the two airbleeds in until they stop.then back out 3/4 turn.

now look into the front Venturi with a light /Choke open are the butterfly's completly Closed? If No Find out why (Still Touching Screw/)get them closed. while Looking into Front venturi with Good Light,turn screw in Until It Touches Arm...turn 1.5 turns more you should see the Idle fuel SLOT..T. blades in Middle area Of SLOT any farther you will see the High speed HOLES and that is too FAR,adj blade to Mid slot area,after running Set RPM HERE.

Look In ReaR venturi's Just a Hairs Breth Open 1/32 Maybe, too far open and you will flood because then they want to Act like 4 corner Idle and they are NOT meaning you can screw around with it But you won't WIN It will Beat you up. you just want some Air getting through but the front's control things Dude, You Got THIS. Timing light Vacuum Gauge, long skinny flatblade screw driver,,pocket size for air bleeds. We can't tune air bleeds with RPM UP OVER 1200 or. so really 650 to 700 idle and watch timing @12 deg idle speed then watch Vacuum Gauge Turn Air bleed to Highest Vacuum then do the other side,may back off the first one a touch when both sides are done, IS IT STILL RUNNING Idle down to 600-650 with screw, check timing

sight plugs out!