1990 EFI to Carb conversion

I began this conversion of removing the EFI and computer, as well as all emissions devices in engine compartment.  The attached pic shows only the new intake and carb mounted.  The distributor is coming out, and being replaced with a non-computer controlled model.  I still have to remove the air pump and find a belt that will fit without it in place.

My question is:

Does anybody have an idea on how I should wire up the AC pump now that there will be no computer installed?

This is going to be $$$$, but I cannot wait to finally get rid of all the JUNK in the engine compartment, and that computer that has been replaced twice over the years.

Rod

Hey Max,

I'm assuming by AC pump you mean the AC compressor.  The easiest way is to ad a dash switch to activate the AC. (most foreign cars have this ) run the switch to the AC pressure switch. Pressure switch to a relay under the hood. Relay to the AC compressor. Don't forget to put a fuse in the line from relay to compressor. 

If you don't like the separate switch, use the power wire that is activated when you turn the climate control to AC. and run that to a relay 

(I'll try to find my wiring diagram and send that info to you later.)

Good Luck

Thanks!  Any schematics would help.  The truck is a 1990 Eddie Bauer w/ 5.8L in case that is important on the schematic choices.

Rod

Yo,

Smog Pump Delete:

in an 89 5.8; NAPA Belt Part # 060825

Source: by Cucamongan (Scotty) at http://www.supermotors.net/registry/15996/70029

in an 89 5.8; "...Got a 91" belt and it fits perfectly, the pointer on the tensioner was right in the middle of the range area..."

Source: by moz_21

Wiring Diagrams in 90 Bronco 5.8, samee as in Ford evtm

http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=17378

http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=57156

Hey Max,

Thanks to M5s diagrams, (Thanks AL.) You need to do nothing for the AC to work. The controls are independent of the comp. so no extra relay needed. If the wiring is there use it.  

Thanks Ron.

I will continue to update this post as the next week or two progresses until completion.  I will add all actual part numbers of components, and steps that were required to successfully convert this beast.  I would add some part numbers now, but I want to make sure they actually work first!

I would be embarrassed to say how many tens of thousands I have spent on this truck over last 20 years.  After the first tens of thousands, it became a freaking challenge that I was going to win in the end.  Now I am so deep financially, and in love with the machine, I cant stop.  And this conversion will undoubtedly add about $6K more I figure when I am done.

Rod

I can add right now that I went with the aforementioned Edelbrock RPM Air Gap intake manifold due to its cooling effects, and a Holley 4160 4-barrel carb, which will provide 600cfm.  When I finally find a way to blow this 351 engine up, I can use both on the next 427 stroker block that will replace it

This conversion is taking a bit longer than I anticipated.  But yesterday we got the engine fired up with the new intake manifold and Holley carb, and timing set.  Sounds powerful, but cannot test drive until I get the tranny controller mounted on the dash, run the wires through the dash, and program the controller.  Should just be a few more days to completion.  I did have to install a lower pressure fuel pump in the vehicle to replace the higher pressure EFI pump.

I should be able to do a write-up on the conversion, components, and steps required after completion.

Regards,

Rod

Also, for the E4OD tranny control, I have chose the Baumann "Quick 4" transmission control system in tandem with the Holley 534-202 Throttle Position Sensor for the new carb.  Hope it works.

Yo Rod,

Thanks for the update. Looking forward to the pics!

Carb conversion turned out to take about 2 weeks longer than expected.   Lots of wiring had to be traced out after removing computer control.  Mounted the fuel pump under the hood for easier access.  Mounted the tranny controller on the dash.  Removed both catalytic converters and all the emission control junk.  It is drivable now but still programming the tranny controller for best performance.  Vehicle is truly loud and obnoxious now, and clearly shows more power.  Still ripping out unused stuff from under the hood that is not needed anymore.  Lots of room in engine compartment now!  Pics to come later this week after cleaning up the engine compartment.

Yo,

Great!

I am interested in pics of how the harness passes into cab.

Thanks!

Well, I can only tell you guys that converting a 351 EFI to carbeuration is no small task. 

1)  Found out that the starter had to be replaced with a non-stock heavy duty model, because after removing the computer, the original starter was overheating.  Reason?   Apparently Ford programmed the engine computer to ****** the timing while starting in order to make it easier on a smaller, cheaper starter design.  With no computer, the original starter just couldnt handle the necessary torque without a timing change.

2)  As if that wasnt enough, the camshaft in the EFI motor has to replaced as well with one designed for a carb intake system.  I did suspect that this would be a problem from the beginning, but hoped nonetheless.  So a new stage 2 camshaft is being delivered monday.  Of course this means that in the meantime we must remove the radiator, etc.  And since it is out, may as well replace the water pump and put on a new timing belt.

After all, as you say, Its only money.....

Will update you all next week after camshaft is installed.

Yup! That is why I usually don't participate in discussions about removing emission controls from the 88 and up EFI engines.  Years ago, I got tired of explaining why the controls were needed to prevent damaging the EFI engines and how Ford used the computer to compensate for some, shall we call them, cost savers. The older 351s were a hardier engine.  Enough said before I get up on my, "Soap Box"  b-( .

Glad to see you are progressing well.

>-

Moderators:

I have finished my EFI to Carb conversion and have about a dozen pics to post to my gallery.  What are the maximum size pics you allow to be posted in a members gallery on each picture?  I will resize to the recommendation.

Rod

For the conversion to be complete, the task was not simple. 

1)  Removed all emission controls, catalytic converters, computer, EFI intake, etc.

2)  Installed Holley RPM Air Gap manifold, and Holley 600 CFM carb

3)  Replaced distributor with Summit Machined Ford V8 Distributor

4)  Replaced cam with Competition Cams #CL-35, 218 Lift, 268 Duration *with new lifters*

5)  Traced out and rewired numerous wires to reactivate tach, AC, etc, after computer removal

6)  Replaced fuel pump with lower pressure model, and installed a backup in engine compartment

7)  Installed Baumann Quick-4 tranny controller with US Shift software, and tuned with laptop

8)  With radiator removed for cam replacement, went ahead and replaced timing chain and water pump too...

9)  Replaced starter with Ford SB Denso starter (original will not start a carb cam engine)

Overall, I would not recommend this conversion for the faint hearted.  It is very detailed, and time consuming, especially the wire tracing.  But having said that, I had no idea how much power was lost to emission controls and the EFI.  The power this engine puts out now is unbelievable.  The engine sound is throaty and obnoxious.  My chrome Magnaflow exhaust tips have already turned from silver to gold from the higher exhaust heat after the 100 mile test.  Details may be provided upon request.

Rod

Also, Fred posted on 27 Sept in this topic that only the older 351 engines were capable of handling removal of emission controls, and that doing so could damage some components on later model engines such as this one.  I need to point out that this short block is an ATK high performance block that I replaced the original with years ago.  I do not know if that changes what Fred mentioned about later models being sensitive to such conversions, or if he was referring to the long block components.  If you are reading this, Fred, could you be specific as to the possible damage to original blocks that attempt this conversion, Sir?

I posted some pics of the completed project and tranny tuner.

Rod

Sorry...had to post the pics in the gallery because I dont know how to post them within this topic