TBI For the 74

[slammed427]

Came across a few good craigslist deals this morning, I picked up an edlebrock aluminum tbi manifold and a stick shift pcm. I then ordered a new 20gal tbi tank from Oreilly.

I've decided to swap out my qjet for injection, now with the parts I listed above, can anyone give me a hard parts list, of what else I'm going to need? I'd like to get the rest of my parts together and get this swap done over my thanksgiving data off from work.

I was going to ls swap this truck, but this engine just runs too good to rip it out. And my 88 got sold this morning for double what I had into it, a hard deal to say no to.
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[Jonboy]

The TBI fuel sender is a little pricy; I would use an inline pump and cancel your fuel tank order. The fuel neck is also larger on the later tank, makes for a PITA to adapt that to your existing neck. I would also look into getting a new stand alone harness, I got mine from www.fuelinjectionconnection for $245, and you don't have to worry about the connectors being old and brittle. Make a pick a part run and score a throttle body, ESC module, distributor and coil, throttle cable and brackets from a 350 TBI truck or van and you should be good.

[slammed427]

What about o2 sensors? Should I find a set of manifolds while I'm there?
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[Jonboy]

I just took the truck to a muffler shop and had a bung welded in to the driver's side down pipe. Do it before you do the conversion and thread the O2 sensor in. Done

Something else I forgot is the VSS. I used a VSS from Stealth Conversions, the 2 PRS. It senda a 2000 pulse per mile signal. You will also need to change out your neutral safety switch for an '87 one that has a Park/neutral signal as well
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[slammed427]

Do I need the vss deal right away? I was planning on swapping in a 5 speed at tax time and converting to a electronic speedo then.
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[Jonboy]

You will need it right away. The nice thing about the stealth part is that it goes in line with the speedo cable. You can keep your original gauges.
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[Desert1957]

Originally Posted by slammed427

What about o2 sensors? Should I find a set of manifolds while I'm there?
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My 87 only has one 02 sensor, its one wire that's all you need. makes it a little easier.

Desert

[C-10 simplex]

Even though it may be debatable if the mpg increase would be worth the change, suggest calling these guys for one stop shopping, expediency, and advice:

http://howellefi.com/

[MalibuSSwagon]

Your MPG increase may not be much, but the driveablity of EFI is worth the change all day.

[C-10 simplex]

Generally agree as i have a tbi car.

However, my next conern would be ease and cheapness of diagnostics and repair. My nod would go to carbs and that's why i prefer them.

[Firebirdjones]

Originally Posted by C-10 simplex

Generally agree as i have a tbi car.

However, my next conern would be ease and cheapness of diagnostics and repair. My nod would go to carbs and that's why i prefer them.

Carbs are my prefered choice as well, however I do enjoy some of the detailed tuning ability of a newer fuel injection setup. TBI however I would not get excited about, software for tuning is less obtainable, old system, very primitive software that not many people at all mess with anymore. Fine for a bone stock engine, limited on power and tuning potential though.
I much rather prefer an OBDII system MPFI, faster computer, better fuel control, etc..

In any case, I'd can the inline fuel pump idea. They only last so long and eventually will die at a most unexpected time They tend to run warm, fuel pressure can and will fluctuate, it will also be a source for heating the fuel, and you get to listen to the noise all the time.
An in tank pump cooled by the fuel will last much longer, run much quieter, stable fuel pressure and will be much more dependable in the long run. However fuel pump changes (even though much less frequent) require dropping the tank (not that big of a deal) Just some things I've experienced. Up to you...

[C-10 simplex]

RE: Inline vs. intank pump:

What gm part #'s are available for the intank; My main concern is dependability as good as the original; Mine has lasted over 300,000 miles.

If not, what are some good aftermarket models available?

[MalibuSSwagon]

Still plenty of people out there using the older OBD1 systems, TBI is very popular for budget conversions of almost any carb'd car. Software and hardware is very easily obtained, and the knowledge is out there, just gotta read it all!

My tuning setup cost me under 250. Free laptop from a friend, Moates Ostrich for realtime tuning for 170, and an ALDL to USB adapter for datalogging for 40. TunerPro RT software makes it all work together, pulling codes for diagnostics is easy.

You can pickup AC Delco parts on Rockauto or almost any parts store for a reasonable price.

[slammed427]

My plan being for the tbi swap is the reliability, plus when coupled with a 5 speed, and the 3.42 rear end I have in the truck, should see some fuel mileage increases. The 5 speed will come with my tax return, and I'd like to have the tbi done before then.
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[Firebirdjones]

For in tank pumps I use Bosch or Walbro, which are used in some of your OEM high end cars like BMW's etc..

Alot of your performance aftermarket in tank pumps like Racetronix for instance, are Walbro pumps.

Then you have Aeromotive, Edelbrock, Mallory, all who make very good pumps as well.

Here is a short video by Airtex (another good pump) that explains the differences between pump designs. I will say that most of your aftermarket pumps now that I have listed above have gone to the Girator design mentioned in this video, that basically works like an oil pump (2 gears meshed together to create pressure) since this design has proved most reliable over the others and has been proven for many years now.

What's Inside An Electric Fuel Pump? -...

Notice at the end he talks about the fuel bucket. This is the expensive part of the system that I believe Jonboy above was talking about being too pricey. But this is the key element to keeping that fuel pump surrounded in fuel at all times (even when fuel level is low) which helps to keep the pump cool and you get a much longer life span from the pump. Not unusual for these OEM style setups to go 150,000 miles or more without a pump change. My fathers 91 TBI he bought new has 285,000 miles, did a pump change at 190,000 several years back.

An inline pump won't however. The last inline pump I used for a fuel injection retro swap setup went 15,000 miles and then started showing signs of failure, spiratically dying when getting warm. I had to pull over for several cool downs to make it home but that's another story. It's now an intank pump Hope this helps.

[slammed427]

And I agree about the inline pump, our gets too hot here in Tempe to not use an intank. Thats why I ordered the efi tank, sender will be next.
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[Firebirdjones]

Originally Posted by MalibuSSwagon

Still plenty of people out there using the older OBD1 systems, TBI is very popular for budget conversions of almost any carb'd car. Software and hardware is very easily obtained, and the knowledge is out there, just gotta read it all!

My tuning setup cost me under 250. Free laptop from a friend, Moates Ostrich for realtime tuning for 170, and an ALDL to USB adapter for datalogging for 40. TunerPro RT software makes it all work together, pulling codes for diagnostics is easy.

You can pickup AC Delco parts on Rockauto or almost any parts store for a reasonable price.

Yep, I used the Tunerpro many years back with Moates software. My point was that it's outdated software and very primitive, seems burning chips is a thing of the past. Most of your pro tuners don't even bother with it anymore. I sold my tuning software off many years back knowing I wouldn't have any customers (nor would I own another) with this style system.

The other issue I have with it (and this may not matter to others) is that the TBI system is limited in power potential, and I'm the kind of guy that can't leave anything alone I'm always striving for more power and better fuel economy, and I constantly tinker to find more. OBDII is much more advanced software with more tuning ability. Since fuel injection has become so advanced over the years, why not take advantage of it if you are going to make the change?
I know TBI is cheaper for a retro swap, I can understand that, but it leaves alot to be desired (from my point of view) TBI isn't all that much of a step up from a carb. Very reliable system however with very few components to complicate things which makes it cheap to adapt. I think that's the main attraction for the do-it-yourself guys.

[Firebirdjones]

Originally Posted by slammed427

And I agree about the inline pump, our gets too hot here in Tempe to not use an intank. Thats why I ordered the efi tank, sender will be next.
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Yeah, I seemed to have more issues when I made trips to Phoenix

[Desert1957]

Originally Posted by C-10 simplex

Even though it may be debatable if the mpg increase would be worth the change, suggest calling these guys for one stop shopping, expediency, and advice:

http://howellefi.com/

I strongly disagree with this statement about the mileage, I can tell you from practical experience my Duallys that had carbs got 5-6 MPG, and my TBI engines got 10-12. That makes it well worth it at $4.00 a gallon IMO.

Desert

[slammed427]

Originally Posted by Desert1957

I strongly disagree with this statement about the mileage, I can tell you from practical experience my Duallys that had carbs got 5-6 MPG, and my TBI engines got 10-12. That makes it well worth it at $4.00 a gallon IMO.

Desert

I can attest to that, my 91 gmc dually and my 92 dually, both 454's pulled 10-12.

I'm forecasting,18-20mpg with the swap and a 5 speed. We shall see as things progress.
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[Firebirdjones]

You can make the carbs do better than that guys. I've said this before but it's worth mentioning again,,,,you can't dial in a carb properly without a wideband to read the AFR's.

99.9% of people throw a carb on and go,,,if you are lucky,,,,they "MIGHT" use a vacuum gauge to set the idle mixture but that's the extent of tuning for most everyone.

I get them in here all the time, running fine, idles nice, but I hook up the wideband and find them idling with a ~12.8-13 AFR (because they used a vacuum gauge) and cruising around they are as rich as 12.5-13.5 AFR, and it's killing the MPG because it's simply running richer than it needs to be. So people are picking up MPG with a TBI swap because the computer is programmed to run stoich right off the bat (14.7 AFR) with anything that doesn't require PE mode. So naturally they gain another 2-3 mpg,,,,well of course they will, the carb was running too rich to begin with.

Using a vacuum gauge to set idle mixture for highest vacuum reading will give you a richer than optimum AFR. It works fine but isn't always ideal. I've routinely picked up 2-3 mpg with carbs I've tuned if I can spend a couple days with it. Everyones been pleased with the results.

You really can't tune anything (carb or fuel injection) without a wideband, you're just shooting in the dark.

[355bullet]

Here ya go man!
Hope this helps https://www.affordable-fuel-injection.com/

[Desert1957]

Originally Posted by Firebirdjones

You can make the carbs do better than that guys. I've said this before but it's worth mentioning again,,,,you can't dial in a carb properly without a wideband to read the AFR's.

99.9% of people throw a carb on and go,,,if you are lucky,,,,they "MIGHT" use a vacuum gauge to set the idle mixture but that's the extent of tuning for most everyone.

I get them in here all the time, running fine, idles nice, but I hook up the wideband and find them idling with a ~12.8-13 AFR (because they used a vacuum gauge) and cruising around they are as rich as 12.5-13.5 AFR, and it's killing the MPG because it's simply running richer than it needs to be. So people are picking up MPG with a TBI swap because the computer is programmed to run stoich right off the bat (14.7 AFR) with anything that doesn't require PE mode. So naturally they gain another 2-3 mpg,,,,well of course they will, the carb was running too rich to begin with.

Using a vacuum gauge to set idle mixture for highest vacuum reading will give you a richer than optimum AFR. It works fine but isn't always ideal. I've routinely picked up 2-3 mpg with carbs I've tuned if I can spend a couple days with it. Everyones been pleased with the results.

You really can't tune anything (carb or fuel injection) without a wideband, you're just shooting in the dark.

Very good point, well explained also.

Desert

[Firebirdjones]

Thanks Desert, and I don't mean to sound like I'm trying to deter anyone from a TBI swap or make it sound like carbs are better. TBI would be a worthwhile swap to anyone that just doesn't like to fool with carbs and wants what should be trouble free operation. There are alot of advantages with electronic fuel injection, and coming from me that says alot

I think you'll find most of your gas mileage maintaining a certain rpm, with either an overdrive, gear swap, tire height change etc...and if you can get in there and tinker with a slightly leaner than stoich AFR,,,say 14.9-15.2 for light throttle cruise and/or idle on top of that, you'll enjoy and very gas friendly truck.

Probably a welcome addition as I hear folks in Cali are paying over $5 a gallon for the cheap stuff right now.