Jump to content

Recommended Posts

Well I finally did it. I decided my 248 needed fuel injection. At leas I thought it did. O.K., I wanted it!!!! After a lot of research, I jumped in with both feet

All the EFI systems required 12 volts, so that was the first chore. Went fairly easy. I changed all bulbs, unhooked the heater, defroster and radio.

Bought an 84 amp alternator. post-59466-143141751927_thumb.jpg A small adjustment to the bracket and hung it in place.

I already had a volt meter installed, so I bypassed the amp meter. Really, just repositioned the incoming wire from the alternator to the amp meter to the amp meter out to starter. At the regulator, essentially did the same, thereby bypassing it.

The EFI also requires an electronic ignition. So a Pertronix was installed. All went smoothly.

Started up and ran on 12 volts. Ready for the EFI.

Ben

Link to post
Share on other sites

The EFI kit arrives!post-59466-143141752144_thumb.jpg Installed a couple of pressure gauges in the fuel line.Installed a return fuel line into the filler vent line in the gas tank. A bunch of laying on my back, standing on my head to hook up the wiring and I was done.

More later.

Ben

post-59466-143141752096_thumb.jpg

post-59466-143141752109_thumb.jpg

post-59466-143141752117_thumb.jpg

post-59466-143141752127_thumb.jpg

post-59466-143141752135_thumb.jpg

Edited by First Born (see edit history)
Link to post
Share on other sites

About all that was left to do was start it up and drive. Come on, START.. Must have done something wrong. No fuel pressure. Crawled under the car and low and behold, someone forgot to hook up the fuel line to the tank!! Wonder who? Took care of that little oversite and it fired right up.

A few adjustments were needed, but tech support is good.

I drove to Joplin and back and managed 17.4 mpg. Driveabelity is good. Cold starting is good. I am content. Summer hot weather will be the final test.

Nothing changed that can not be put back. I will keep the generator, fuel pump and carb boxed for any future owner. I will probably buy a water pump goose neck and generator bracket, as well as the access plate to the inside.

I forgot to mention, along with the Pertronix I did install a 12 volt , high output coil. 40,000 I believe. I have not yet, but will, regap the plugs.

Over all, I am satisfied. A bit pricey, but not as bad as some of the big brands. The scan port is there, so an OBD1 scan tool can be used. For you V8 guys, this would be a piece of cake. post-59466-143141754437_thumb.jpg

B en

post-59466-143141754424_thumb.jpg

Link to post
Share on other sites
I am really impressed! You are very skilled. And 17.4 MPG is very good for an old straight eight. Who is the supplier for the EFI kit?

Joe, BCA 33493

Joe, in post 2 can be seen the supplier name and web address on the decal. Their web site makes for some good reading.

Ben

Link to post
Share on other sites
That is really cool, Ben.

17.4?

Wow. What were you getting before?

Thanks Mike.

I got about the same on the trip to the Nats and back. But remember, the 4:1 gears have been swapped out to 3:4. That really helped. I had hoped to get a little more, but none of the kit suppliers promise more.

Ben

Link to post
Share on other sites
Driveability and dependability count. I may look into these mods for the wagon.

Good morning, Mike,

I think you would like it. And since the wagon is already 12v, it would be a simpler install. Throttle body would probably mate to the intake manifold easier, as well.

Ben

Link to post
Share on other sites

Good work, Ben! I'm glad you finally got it done and that it turned out well. This should eliminate vapor lock and carb slobbering on the manifold. It should tolerate ethanol better. Fuel mileage should improve with use.

Willie

Link to post
Share on other sites
  • 3 weeks later...

Why not run a flexible tube from the left fresh air duct, and into a box on top the EFI with a KN filter in it.

Might aid the mileage, MIGHT. I did that with my Limited, picked up approx. 1/2 miles per gallon, I think.......

Dale in Indy

Link to post
Share on other sites
  • 1 year later...

Been awhile since posting on this thread.

I drove to South Bend to the Nationals. Absolutely love the FI! No starting problems at all.

Now, almost two years later, got a burr under my saddle. Had to do something else. Last summer, 2014, I replaced the six volt starter after stripping the drive gear. I bought a mini from Tom Telesco in MA. Works real good. I have now replaced the distributor with a computer controlled HEI. Used an Olds v8 one, modified by Evan Ritter to fit. I had the internals modified by Affordable Fuel Injection so all advance is controlled by the computer. So far , so good. Did a 50 mile run today . I THINK it improved a lot. I KNOW from 1800 rpm to 2800 rpm is livelier. Time will tell.

Now , I need to learn how to "tune" it.

Ben

Link to post
Share on other sites
  • 5 months later...

(Wondering what kind of "map" protocols they used??  IF there's a real map or if the detonation sensor is the limiting factor on full advance and such?  Plus how different the Buick 8 is from a GMC 6?) 

 

NTX5467

Link to post
Share on other sites

(Wondering what kind of "map" protocols they used??  IF there's a real map or if the detonation sensor is the limiting factor on full advance and such?  Plus how different the Buick 8 is from a GMC 6?) 

 

NTX5467

 

  Willis, I do not know the answers to your questions. Wish I did.

 

    There is no detonation sensor. There is a MAP [ vacuum] sensor.

 

   I wish I knew how to play with and tune it. So far, I have not found any one to help with that. It runs good, but I would always like better.

 

  Ben

Link to post
Share on other sites

    There is no detonation sensor. There is a MAP [ vacuum] sensor.

 

   I wish I knew how to play with and tune it. So far, I have not found any one to help with that. It runs good, but I would always like better.

 

  Ben

\

 

So they are just doing a fuel map, using the MAP sensor to detect "engine load" without a TPS, It appears, which is what the earlier GM systems did.  The detonation sensor was part of the distributor module situation, back then, even being "free-standing" on the pickup trucks when it was first used there in the middle 1980s.

 

Back when Chevy TPI engine were "the rage" for street rods, the more basic swaps used only a MAP sensor to detect engine load and mixture lean/rich needs.  Not sure if they used an oxygen sensor or not for those deals, back then.

 

As you have an HEI distributor, the detonation limiter can be added easily, if you can find an "Electronic Spark Control" Chevy pickup truck with a V-8.  The "box" is located behind the instrument panel "glove box".  It takes a module specific to that system.  The sensor screws into (on the Chevy V-8s) the rh block drain plug hole and has one wire going to it.  If that wire should short to ground, the system gets a "full retard" mode and "no power".  I think we also had an ECM to run the throttle mixture solenoid in the carb by that time, too? 

 

Thanks for the information.

 

NTX5467

Edited by NTX5467 (see edit history)
  • Like 1
Link to post
Share on other sites

Thanks for that additional information, Ben.

 

Detonation limiter would, in some cases, allow the timing to increase until "a rattle" was heard, then back it down until it didn't happen, which would mean that ignition timing (once base timing was set) would remain optimized at all times . . . in theory.

 

The way it's checked is to tap on an engine part (as exhaust manifold) to see if the engine rpm changes.  If the tapping continues, the timing will retard until the engine stops running.  Similarly, a bearing knock will do the same thing, resetting when the ignition is turned off, so it'll restart and then die again.

 

I read in a Buick 3800 performance website, where it advocated the use of super premium unleaded racing fuel (during drag racing), it mentioned that once the ECM hears the rattle, it'll retard the timing for a good while, then let it return to the normal map, progressively, the longer it goes without hearing a rattle.  End result, the higher octane fuel results in more horsepower and better racing results (hopefully).  BUT . . . if the advance curve in the distributor (vacuum and mechanical) is well-tuned for the vehicle, advancing the base timing until a rattle is heard, then manually decreasing the setting until the rattle is minimized or stops, would accomplish the same thing, just in an analog manner.

 

Take care,

NTX5467

Link to post
Share on other sites

Old-Tank, what is the total timing advance which is optimum for the earlier Nailheads and possibly the straight8s?  Just curious.

 

 

Thanks,

NTX5467

About 30°...mechanical advance=12°; vacuum advance=10.5° and I set the initial timing at 7° BTDC (55 nailhead...no specs on straight 8)

Link to post
Share on other sites
  • 3 years later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...