383 Vortec/TBI Build Thread

[Daveo91Burb]

Got my 383 started in the rig today! Running awesome (at least as far as idling and back and forth out of the shop. Haven't driven it more than 10' yet tho. Got it started after a few false starts (main battery is dead even tho showing charged - aux batt OK) Started right up with very little cranking. Pretty out of time at first and then I got it timed with light, but had forgotten to unplug tan advance wire. Retimed with it unplugged and now it sounds good. No SES light, either!

Remaining issues:

Fuel pressure is low, under 10 psi. Might have to consider different spring or making my regulator adjustable.
Idle is a bit high 800-900.
Need to flush cooling system. Just water in the radiator now.
Need to get the hood on - buddy coming over tomorrow.
Then...on to tuning. Hopefully going to do some datalogging with TunerProRT this week.

Short vid:

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Getting an engine to run that you built isn't quite on par with your wedding day or the day your kids were born, but it's close!

 

[Daveo91Burb]

Longer video:

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[yevgenievich]

Looks/sounds good

 

[4WDKC]

Here is the spring I used
http://www.top-downsolutions.com/spring-for-gm-17113186-vafpr-(vac-adj-fuel-press-regulator)

 

[skysurfer]

You might consider ditching the 0-100 fuel gauge. A 0-30 liquid filled gauge is easier to read and can register an increase of less than 1 psi when you're using an adjustable regulator.
I've been using the Jegs house brand gauge for about ten years without any issues.

 

[Daveo91Burb]

Here is the spring I used
http://www.top-downsolutions.com/spring-for-gm-17113186-vafpr-(vac-adj-fuel-press-regulator)

Thanks, I might try that - seems like a good spring to use if I go adjustable.

One other question for you, since I think you have a similar setup.....my throttle cable seems too long. It has to loop up by the firewall before it connects to the throttle lever and I think it's causing it to bind. Thoughts?

You might consider ditching the 0-100 fuel gauge. A 0-30 liquid filled gauge is easier to read and can register an increase of less than 1 psi when you're using an adjustable regulator.
I've been using the Jegs house brand gauge for about ten years without any issues.

Thanks, definitely going to consider changing that fuel gauge. Totally agree the 0-100 gauge might not be appropriate for this application and may be my problem.

 

[4WDKC]

Thanks, I might try that - seems like a good spring to use if I go adjustable.

One other question for you, since I think you have a similar setup.....my throttle cable seems too long. It has to loop up by the firewall before it connects to the throttle lever and I think it's causing it to bind. Thoughts?



Thanks, definitely going to consider changing that fuel gauge. Totally agree the 0-100 gauge might not be appropriate for this application and may be my problem.

Thats how they were from the factory, you may check the cable see if its binding but the loop was definitely there on mine.

 

[Daveo91Burb]

Thats how they were from the factory, you may check the cable see if its binding but the loop was definitely there on mine.

Ok cool, good to know. I didn’t think I changed the distance that much. Thanks


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[Daveo91Burb]

Got her on the road this weekend! Running good, driven less than 10 miles, but no driveability issues so far. Working on data logging so I can get the tune going. I'm working out a deal with Dave W of Old School EFI. I'll do my own data logging and burn the chip (I bought a Moates Burn 2 and have the ALDL cable) but I think I'm going to pay him to crunch my data logs and hopefully come up with a BIN file for me. Or at least tell me what I need to do to get it right. Just not sure I have the skill set to determine what's right for the spark and air/fuel tables.

You might consider ditching the 0-100 fuel gauge. A 0-30 liquid filled gauge is easier to read and can register an increase of less than 1 psi when you're using an adjustable regulator.
I've been using the Jegs house brand gauge for about ten years without any issues.

Good suggestion! Bought a Jegs 0-30 psi and installed - now my pressure shows about 10 or 11 when it's running.

 

[4WDKC]

Got her on the road this weekend! Running good, driven less than 10 miles, but no driveability issues so far. Working on data logging so I can get the tune going. I'm working out a deal with Dave W of Old School EFI. I'll do my own data logging and burn the chip (I bought a Moates Burn 2 and have the ALDL cable) but I think I'm going to pay him to crunch my data logs and hopefully come up with a BIN file for me. Or at least tell me what I need to do to get it right. Just not sure I have the skill set to determine what's right for the spark and air/fuel tables.




Good suggestion! Bought a Jegs 0-30 psi and installed - now my pressure shows about 10 or 11 when it's running.

Pretty sure he is going to tell you to get the pressure up to 18 psi, IIRC thats what is needed for WOT and will be different tune than you have now.

 

[Daveo91Burb]

Pretty sure he is going to tell you to get the pressure up to 18 psi, IIRC thats what is needed for WOT and will be different tune than you have now.

Maybe, but every time I've talked to him about fuel pressure he insists that stock pressure is sufficient for what I'm doing. I've been looking at my data logs and I'm actually on the rich side by quite a bit, but I haven't gotten anywhere close to WOT. I talked to him on the phone yesterday and we agreed to a hybrid option of tuning where he would look at my logs and provide guidance/advice/training, but I'd do the actual file manipulation and chip burning. (I bought a Moates Burn 2 and some SST 27SF512 28 pin chips - and my ECM has already been modified to plug and play those).

HOWEVER, I still have pressure concerns. I put the new Jegs liquid filled 0-30 psi gauge on and it shows 10 psi when cold/first started, but goes down over time to about 8 psi - which is below the recommended 9-13 range. So I'm going to order that spring you recommended and convert to adjustable regulator, so I can at least get it up to the high side of the OEM range.

 

[Daveo91Burb]

Working through some issues still, besides the tune. Some solved, some still lingering.

1. Leaking coolant at thermostat housing - SOLVED, upper rad hose clamp was just a little loose.
2. Binding accelerator cable- SOLVED, accel cable was hooked to the cruise control post on the throttle ass'y, not the main accelerator post. Much smoother throttle control now.
3. Starting issue - NOT SOLVED. This thing has started easy every time since I got it running except once. About a week ago, I took it on a test drive/data logging, then come home and washed it, then took it on another test drive. When I tried starting it for the second test drive, starter did not want to engage and cranked slow/hard. But it did start. Then after I came home, I parked it in the shop, shut it off, and tried to restart it and nothing. I could hear the solenoid click, but nothing else. Headlights did NOT dim when I tried to crank, just clicking. Next day I started it no problems - starter engaged easy, fast smooth spinning, and engine started right away. Thoughts? I have not been able to duplicate it since, even after a fairly long test drive/data logging yesterday.
4. Temp gauge issue. There are two temp sensors: one in one of the cylinder heads with one wire and one in the intake manifold by the thermostat with two wires. The two wire one controls the ECM, and fortunately that one is working fine. My data log sessions show a very consistent 175-185 deg f after it's warm. But the one in the cylinder head controls the temp gauge on the dash and it is wonky. It'll be pegged hot at one minute and show 190 the next. And I don't see any consistency. It's a new temp sensor so I'm thinking I might have bought an incorrect one. I believe I have an OEM sensor that I can put in there so I'm going to try that and see what happens, but if anyone has any ideas, let me know.

More bugs to work on besides these, but that's enough for now!

 

[theblindchicken]

For your starting issue, load test your battery when it's hot. If still good, then check the battery cables and for any bad grounds. Mine at the firewall above the trans would wiggle loose from time to time.

I've also heard that a hard hot start has to do with a timing issue as well.

Hope that helps get ya on the right path.

 

[yevgenievich]

I have a similar starting issue on 87 suburban that sat for years. I am suspecting actual starter in my case.

 

[Daveo91Burb]

I have a similar starting issue on 87 suburban that sat for years. I am suspecting actual starter in my case.

Yeah, the starter is what I'm afraid of. It's a high torque unit from an early 70s truck, cast iron nose. I rebuilt it with new drive gear and brushes, but there definitely could be an intermittent problem. I have a more modern unit with aluminum nose and enough parts to rebuild it as well - I'll swap them out if I keep seeing problems.

For your starting issue, load test your battery when it's hot. If still good, then check the battery cables and for any bad grounds. Mine at the firewall above the trans would wiggle loose from time to time.

I've also heard that a hard hot start has to do with a timing issue as well.

Hope that helps get ya on the right path.

Pretty sure it's not the battery - it's brand new (even though that can sometimes be the cause!) and starter is acting like it's not taking a load at all - headlights don't dim one bit. But it definitely could be a ground issue. I'll be looking real close at that next time it happens. Not timing related - it won't crank at all.

Thanks, all!