Penny-pinching 258 TBI

For everything related to using Fuel Injection in an FSJ.
User avatar

Topic author
tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Penny-pinching 258 TBI

Post by tgreese »

Inspired by these articles from Will Marsh http://www.binderplanet.com/forums/show ... hp?t=53524 I decided to MegaSquirt (MS) my J10. I will keep close track of how much I spend, and try to keep the total cost down - within reason.

I could have done the bashed GM computer that seems to be popular here, but I didn't want to mess with the ePROM burning stuff that goes with that. Direct serial communication with the ECU seems more straightforward and accessible.

MS has intrigued me for years, so that's the starting point here. I was browsing eBay and came across a complete throttle body (TB) from a 4.3L Chevy V6, and that started the process. Unlike the Ford TB that Will Marsh used, this TB has a stepper motor idle air control (IAC) that is not compatible with the cheaper MS I board, so a MS II kit was ordered.

Here's the kit dumped out on my bench:

Image

Assembly is straightforward. The instructions are really thorough, and you won't have any trouble if you read through them first, then read through as you assemble. I found that I had a few parts left over when I finished - these were either unused optional parts, or a few from steps that I skipped reading down the list on my computer monitor. Might be better to make a paper copy and cross off what you've done. Also, there are two 8 pin DIPs that I mixed up, and I had to unsolder one (a pain). Except for the CPU, the kit does not comes with sockets, so that might be a useful addition.

The lettering on the parts is tiny and faint, and it helps to have bright light and magnification of some kind. The bags are labeled, but you need to verify the ID of each component before you install it.

You assemble and test the power supply, the serial communications, the CPU clock, the input section, and then the output section, testing each as you finish it. There's a testing circuit called "the stimulator" that provides a test signal for each stage. The site describes a V1/V2 stimulator based on the NE555 timer, and a V2.1 based on the AD654 voltage-to-frequency convertor. The V2.1 has a few more features, but the 555 is common as dirt and I could build that version from my junk box parts... so that's what I did. They sell a kit for the V2.1 if you want to go that way, but I saved $45 and used what I had. I bought nothing to make the stimulator - but if you don't have a lot of electronics parts already, you're unlikely to save money by building the stimulator from spare parts like I did.

So here it it completed, running from the serial port on my Shuttle computer and my junk box stimulator:

Image

If this were animated, you could see the LEDs flashing as each of the injectors fires.

You can see the inputs to the MS board - CLT (coolant temp), IAT (intake air temp), O2 (O2 sensor), TPS (throttle position sensor). The two potentiometers in the background are RPM, fine and coarse. The manifold air pressure (MAP) sensor is under the board, connected to the black vacuum tubing. I tested it with my MiteyVac, which can be seen at the edge of the picture.
Last edited by tgreese on Sat Jun 01, 2013 10:20 am, edited 3 times in total.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
User avatar

Topic author
tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Penny-pinching 258 TBI

Post by tgreese »

Additional parts have been purchased.

Image

The block of aluminum is a remnant I was given at work - the crude outline of the adapter I will make is shown. After some more precise layout, I will drill and tap the holes, and match the patterns with my die grinder. There's also a fuel pump, an O2 sensor with matching socket, and the base gasket to mate to my manifold. The fuel pump will go down in the tank, in a manner similar to the article linked at BinderPlanet.

Here's what I've spent so far:

Image

I already regret spending extra for the TB rebuild kit - I should have just spritzed it with carb cleaner, bought a new base gasket, and tried it (It's supposed to be from a running car). I could have spent less on the O2 sensor and the fuel pump, and scrounged the connector for the O2 sensor.
Last edited by tgreese on Sat Jun 01, 2013 6:33 am, edited 1 time in total.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
User avatar

Topic author
tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Penny-pinching 258 TBI

Post by tgreese »

Looking at what I've spent, I did a little editing of the parts list to see how little I could have spent if I bought generic parts.

Image

Here are a few links for anyone who wants to find out more about the posts above.

Megasquirt II board kit from DIY Auto Tune: http://www.diyautotune.com/catalog/mega ... p-119.html

Top-level for Megasquirt site: http://www.megasquirt.info/

Assembly instructions for Megasquirt II: http://www.megamanual.com/ms2/V3assemble.htm

Assembly and discussion for the Stimulator using the NE555: http://www.megamanual.com/v22manual/v1stim.htm

In-tank fuel pump thread at Binder Planet: http://www.binderplanet.com/forums/show ... hp?t=49496

2/10/15 - NB! Almost everything regarding costs changes later on in the thread.
Last edited by tgreese on Tue Feb 10, 2015 2:48 pm, edited 3 times in total.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
User avatar

Stuka
Site Admin
Posts: 11789
Joined: Thu May 12, 2011 5:53 pm
Location: CA
Contact:

Re: Penny-pinching 258 TBI

Post by Stuka »

Not a bad price overall. Will be following this thread.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

ferox
Posts: 82
Joined: Wed Oct 03, 2012 10:43 pm
Location: Portland, Oregon

Re: Penny-pinching 258 TBI

Post by ferox »

This is great. Thanks for posting it up. I will be following with interest in doing it to my own 258.
'82 Wagoneer, 258, T176, NP208, D44, AMC20, Weber 32/36 DGV http://www.arkive.org/fossa/cryptoprocta-ferox/
User avatar

Topic author
tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Penny-pinching 258 TBI

Post by tgreese »

Finished the adapter.

Image

Fortunately I have an extra 2V 258 manifold to use as a jig. The countersunk screws are from Fastenal, at about $2 each. They will sell you one or a thousand (the bulk price is 41c).

I also had to buy a special burr for my die grinder that works with aluminum. The regular carbide burrs do not cut very fast, and load up with aluminum in about 30 seconds of grinding. So that was another $20 expense. http://www.amazon.com/gp/product/B00385 ... UTF8&psc=1 Cuts amazingly fast though.

Here's the throttle body on the adapter.

Image

The only issue here is the diameter of the countersunk head on those fancy screws. The screws need a 5/8" diameter countersink. The heads stick out into the TB venturi diameter slightly, and the throttle flap barely clears the edge of the screw head. Ideally you'd want a slightly smaller diameter head - maybe 1/2" or 7/16". Howell uses conventional socket head cap screws, as in this adapter

Image

as shown on this site - http://www.jeep-cj.com/bustedjeep/proje ... rdtbi.html - but supposedly they won't sell you their adapter by itself. And the cap screw recess needs some gasket cement to seal right. Affordable FI will sell you what looks like the same adapter for $175: http://www.affordable-fuel-injection.co ... 49-23.html

Another possibility would be to buy the adapter to a Holley 2V (Transdapt 2086? http://www.summitracing.com/parts/trd-2086) from Summit or Jegs, and another adapter from the Holley to the throttle body (Transdapt 2204 http://www.summitracing.com/parts/trd-2204) and stack them. Also, I believe that Hamilton Fuel Injection http://www.hamiltonfuelinjection.com/ (Bill usn-1 from BinderPlanet) will sell you an adapter. Or you could hunt up a piece of aluminum and make one. The aluminum stock is not cheap, so looking around for some scrap to use would be worthwhile, if you go that route.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
User avatar

Topic author
tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Penny-pinching 258 TBI

Post by tgreese »

So next step ... rebuild the throttle body. Here it is, finished:

Image

Image

Not much to it - if you've ever had the top off of a carburetor, it should be very easy. I submerged the body and hard parts in solvent (not carburetor cleaner) for a while, after removing the idle air control (IAC), the throttle position sensor (TPS), and the injectors. Scrubbed a little, then spritzed the parts clean with spray carb cleaner. The Advanced Auto carb cleaner was on special, and worked well. I've added it to the tally.

Here's the parts diagram that came with the kit. You can identify all the parts from this.

Image
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
User avatar

243
Posts: 740
Joined: Sat Mar 16, 2013 7:32 am
Location: Texas

Re: Penny-pinching 258 TBI

Post by 243 »

What is the advantage of the MS II over the 7747?
1978 Cherokee NT, 5.3/4L60/NP241 in Progress
User avatar

Topic author
tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Penny-pinching 258 TBI

Post by tgreese »

243 wrote:What is the advantage of the MS II over the 7747?

Mainly, you can program the Megasquirt with your laptop. The Megasquirt was conceived as a DIY system, so it's arguably more accessible than a factory system. There's still a lot to learn.

To program the GM computers, you need to burn an EPROM (electrically programmable read-only memory) and plug that in to the computer. You can do a lot with it, but basically you are hacking a factory computer that was meant for a single application. Some argue that the programming that the GM computer uses is more sophisticated than the Megasquirt - could be.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
User avatar

Topic author
tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Penny-pinching 258 TBI

Post by tgreese »

Some progress today on this project.

I haven't had much time to mess with this over the past year. However, I had pretty much decided to use my GM throttle bodies on ... something else ... and look for one of these for the J-10 258.

Top view and ...

Image

bottom view.

Image

This is a throttle body from a 1985 Ford LTD or Marquis - not sure which, since the PO had stripped all the badges and primered the car, before wrecking it. The markings said "40K miles" and the throttle body looks pretty fresh. The engine in this car is a 3.8L Essex V6 http://en.wikipedia.org/wiki/Ford_Essex ... anadian%29 which, as I understand it, is a pretty unremarkable engine. However, there were a lot of them made, and in the mid '80s they got Ford's CFI - "Central Fuel Injection" which is a throttle body injection (TBI) system, like the GM cars got for several years. This throttle body is notable because it has the same base pattern as a Motorcraft or Holley 2V. My J-10 has already been converted to a Motorcraft 2100 using the Transdapt TRD-2086, cheap from Summit: http://www.summitracing.com/parts/trd-2086

So this TB will essentially bolt on, and keep my overall costs down, in the spirit of making this project as inexpensive as possible. And it's somewhat more of a challenge than the GM 4.3L TB. (Pricing all this is a bit of a sham, since I'm buying all this stuff and only including the cost of what I use. But you-all will get the story of how to do this at minimum cost ... and I'll have the fun of pinching the pennies - at least on paper).

The 3.8L has about 120HP in factory trim, so this throttle body should be fine for my 258. This TB also has an external stepper motor that performs a similar function to the idle air control on the GM throttle body ... I'll have to sort out how to control that with Megasquirt. The Megasquirt board has the capability to control several styles of idle stepper motors. Otherwise the TB pretty conventional - same type of injectors, a throttle position sensor (TPS), and an adjustable (!) fuel pressure regulator.

If you want to use this TB, they should be fairly easy to find in the yards, and cheap (this one was $25 - I pulled it). The 3.8L is not a popular engine (though Ford made a lot of them), and this TB is kind of small for V8s, so there isn't a lot of demand. Should not take much looking to find one - I found this one at the first yard I went to. Here in the NE, there aren't a lot of cars of this age in the pick-n-pull yards - they have all rusted away.

I also looked on car-part.com, and availability is good in the full-service yards, though you may have to pay a little more.

Also got the matching air cleaner at a different, nearby yard ($5, but I really had to dicker).


Image
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
User avatar

Lumpskie
Posts: 1320
Joined: Wed May 14, 2014 4:33 pm
Location: New Hampshire

Re: Penny-pinching 258 TBI

Post by Lumpskie »

Hey Tgreese,

Any updates since August? I'm thinking about MegaSquirting my 360 and have been wondering what you impressions are...
1989 Grand Wagoneer - Rebuilt 360, 2" Alcans, 10" travel Gabriel Guadian shocks.
1996 Land Cruiser - 1HD-T Diesel, Gturbo (23psi), Wholesale Automatics 442f, F/R ARBs, 35" Duratracs, ARB Rear Bumper, OME 2" lift, home built sliders and aluminum belly skid
2000 Honda Civic - Integra GSR engine, transmission, shift linkage and axles, 200hp, 33 combined mpg
2006 Mitsubishi Lancer Evolution 9 - 437hp/447ft-lb
User avatar

Topic author
tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Penny-pinching 258 TBI

Post by tgreese »

Sad to say - I have not had much time to work on this project. Maybe soon.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
User avatar

Topic author
tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Penny-pinching 258 TBI

Post by tgreese »

Okay, a little progress.

First order of business was to figure out how the big solenoid on the side of the Ford V6 throttle body operates. It's called the idle air control (IAC) motor by Ford and it works in closed-loop mode with the Ford computer. The connector has four wires - red, black, yellow and purple. NB these may not be the same on what you get from the junkyard - Ford identifies these wires by the color going to the car (into the plug), not into the motor. Check the following manual page I got from a post on the 4-eye Ford forum (not a great transfer, but readable):

Image

There are 4 leads from the car to the connector - ISC+ (white or white with light-blue trace), ISC- (yellow with black or red trace), ITS (light green with white trace) and SIG RTN (black with white trace). The various plug styles are also shown. My ISC motor has the early style pluggage. On the ISC motor (not to the car), the color code is ISC+ red, ISC- black, ITS and SIG RTN yellow and purple.

The idle tracking switch (ITS) tells the computer that the throttle arm is against the idle stop, and that it should calculate whether to adjust the idle speed. The ISC motor also acts as a dashpot, extending fully at cruise and pulling back slowly when the throttle is closed. The ITS uses the ITS and SIG RTN wires.

The ISC motor has four states - running out, running in, fully extended or fully retracted. Fully extended or retracted it draws no current. So to move it in and out fully, you only need to switch the polarity between ISC+ and ISC-. When running, the motor draws about 250 mA with no load, and takes maybe 1-2 s to go from stop to stop.

Using this with the MegaSquirt (MS), it's too complicated to try and use the intended closed-loop mode. So I'll use the MS fast idle (FIdle) on and off mode. There is a FIdle pin on the DB37 connector, pin 30, that goes low (ground) when the coolant temperature is low enough to trigger fast idle, and then floats (does not conduct) above that temperature.

I'm abandoning the ITS functionality, so I removed the ITS and SIG RTN pins from the original socket, leaving only 2 wires coming out ot the connector (IAC+ and IAC-). This is easy to do on the Ford plugs - just pull out the red plastic block in the plug that's held with a couple of springy plastic detents and carefully pry the connector shell away from the pin to be removed.

The fast idle will work by extending the pintle completely at fast idle, and withdrawing it completely at curb idle. There is another idle stop screw on the throttle body that can be used for curb idle. Note that the pintle moves about 1/4" stop to stop, which is way more than you need for fast idle. So the pintle, when fully withdrawn, will be too far from the throttle arm to affect the curb idle.

Note that the FIdle on a FI system only affects the amount of air available for running when cold. You still have to make a fuel map that accounts for the change in idle during warm-up.

Next big task - design and build my relay board. Here's the schematic:

Image

[ 2/16/15 - Diagram modified slightly so that the fast idle connection only powers one relay coil. The relay coils have a fairly low resistance (75 ohms) and pin 30 is only supposed to sink a maximum of about 500 mA of current. Running two relay coils from that does not leave a comfortable safety margin, so I changed the wiring slightly so that the coil of RY4 is grounded by the contacts of RY3, along with the IAC Motor Negative. The 2A fuse should be ok, since I've measured that the IAC motor uses about 250 mA running, and that plus the relay coils 2 * 13.4 V / 75 ohms = 357 mA is less than an amp. That's more than 2x margin and should be fine. ]

I'm using two of the standard automotive SPDT relays to change polarity on the IAC motor. I looked for a suitable DPDT relay, but did not find one. A single device would be better, but this should be fine - nothing bad will happen if one of the relays hangs up.

IAC+ to positive and IAC- to negative fully extends the pintle. So the default state (pin 30 floating) is retracted.

Next up - building the relay board. Should be an afternoon's work; if I get all my parts by Saturday there will be an update soon.
Last edited by tgreese on Mon Feb 16, 2015 8:23 am, edited 2 times in total.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
User avatar

Topic author
tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Penny-pinching 258 TBI

Post by tgreese »

Here's the relay board:

Image


Image

The main things I had to buy for this were the fuse panel (eBay seller http://www.ebay.com/itm/231311276482 $15.99) and the relays (2 @ $2.38, 2@$1.48, Parts Express), and some connectors. Parts Express has very good prices on crimp connectors - the insulated push-on connectors are 16c each, which is considerably less than any type of socket that you can find for the relays (34 connectors, $5.44 for the whole board). I could have soldered the wires directly to the tabs of the relays, but that would pretty much rule out replacement of the relays in the field. Replacing a relay without the socket would take a few minutes, but I expect the relays to last the life of the truck.

The rest - wire, heat shrink, hardware, G10 board - came from my junk box. I really didn't need to buy the fuse box... I have plenty of fuse holders for the glass AGC fuses, but then I would have had to rig a weather cover of some sort, and the footprint of the board would have been larger. With the plastic weather cover that came with the above fuse holder, I can mount the board on the top of the fender without any other weather protection. A junkyard fuse holder would also have worked, but it's hard for me to find time to prowl the junkyards every time I need another part. So the eBay part seemed a good option.

Re the fuses, I bought packs of fuses from Parts Express (36c each). They don't have the 2A fuses that the plan calls for ... so you have to go to a more expensive source like RockAuto, Mouser, Digikey, etc.

I also didn't use any kind of ganged connector on the board. You can see that the wires just hang off the edge of the board. When this board is in place, the ignition, power and ground will connect directly to the Prestolite ECU and starter solenoid, adjacent to the planned board location. The rest will have bullet connectors inline, which I have on hand. There are only about a dozen wires to connect to the board, and I don't see the need for some kind of ganged connector. Really, you could skip connectors altogether. Mechanical connectors in the wiring are the prime source of wiring problems. The car manufacturers use all those connectors so they can build the car quickly on the assembly line, not because of service issues or to make the car better or more reliable. Automobile electrical would be much more reliable without all those connectors.

So, I have $30 in this board, not counting the stuff that came from my junk box. The official MegaSquirt B&G relay board kit costs $73 http://www.diyautotune.com/catalog/mega ... -p-31.html and won't work with the fast idle needs of this throttle body. If I wanted to use the B&G relay board with this throttle body, I'd abandon the IAC motor and use one of the idle air bypass valves that the MegaManual suggests. http://www.megamanual.com/ms2/IAC.htm Then I could wire the FIdle relay on the B&G board directly to the fast idle air valve.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
User avatar

Topic author
tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Penny-pinching 258 TBI

Post by tgreese »

Image

Ok, so here's where the new throttle body (TB) will go. This truck has a Motorcraft 2100 from a'76 360 Cherokee currently, with a manual choke.

Image

Comparing the 2100 and the TB, you can see that the 2100 has a bracket that converts the pull-back throttle linkage to a pull-down to match the original BBD's linkage. There is a ball stud that the linkage clips on to (the nut on the back side of the ball stud is seen). I'd like to convert this by adding a similar bracket to the TB using the existing linkage. There's not much to attach to though... the 2100 had a couple of extra holes available.

Image

Here is the throttle body set in place. Looks good there - fits without changes on the existing carburetor adapter.

This pointed out a couple of issues ... my Ford Mustang air cleaner that fits the TB won't fit the J10. The brake booster and the wiper motor are in the way. The TB has no ported vacuum, so the EGR would have to be under computer control, if I keep it. I could also control the manifold heater (that keeps the fuel vaporized in cold weather) with the computer - I expect it could be on while the fast idle is on. Another fuse and another relay.

This points out that I'm already running into stuff that I would like to add now or eventually. Starting with more fuse capacity would have been good ... as it is, I have all 8 slots in the relay board fuse holder filled.

Image

I have a couple of 258 air cleaners. The nearer black air cleaner is the original air cleaner for the J10. The galvanized housing is for a V6 Mustang. Looks like I can cut a circle out of the base of each, put the housing from the 258 and mounting ring from the V6 together, and the new air cleaner will fit and clear the wiper motor. Needs more careful measurement before I start cutting though.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
User avatar

Stuka
Site Admin
Posts: 11789
Joined: Thu May 12, 2011 5:53 pm
Location: CA
Contact:

Re: Penny-pinching 258 TBI

Post by Stuka »

The factory TBI setup used a solinoid that would open and close to allow vacuum to the EGR. Solenoid is controlled by the ECU.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ
User avatar

Topic author
tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Penny-pinching 258 TBI

Post by tgreese »

Stuka wrote:The factory TBI setup used a solinoid that would open and close to allow vacuum to the EGR. Solenoid is controlled by the ECU.
Which TBI, on the 150? Not the 4.0L ... both Renix and Mopar are MPI. Maybe you mean the Mopar MPI?
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
User avatar

Stuka
Site Admin
Posts: 11789
Joined: Thu May 12, 2011 5:53 pm
Location: CA
Contact:

Re: Penny-pinching 258 TBI

Post by Stuka »

tgreese wrote:
Stuka wrote:The factory TBI setup used a solinoid that would open and close to allow vacuum to the EGR. Solenoid is controlled by the ECU.
Which TBI, on the 150? Not the 4.0L ... both Renix and Mopar are MPI. Maybe you mean the Mopar MPI?
Sorry, was talking on the factory GM TBI engines.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ
User avatar

Topic author
tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Penny-pinching 258 TBI

Post by tgreese »

Stuka wrote:
tgreese wrote:
Stuka wrote:The factory TBI setup used a solinoid that would open and close to allow vacuum to the EGR. Solenoid is controlled by the ECU.
Which TBI, on the 150? Not the 4.0L ... both Renix and Mopar are MPI. Maybe you mean the Mopar MPI?
Sorry, was talking on the factory GM TBI engines.
Mmm. Standard VS12.

Image

Looks like an on-off switch, venting one end to the atmosphere or the vacuum tap.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
User avatar

Stuka
Site Admin
Posts: 11789
Joined: Thu May 12, 2011 5:53 pm
Location: CA
Contact:

Re: Penny-pinching 258 TBI

Post by Stuka »

That would be the one.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ
Post Reply