Bronco Forum - Full Size Ford Bronco Forum banner

1 - 13 of 13 Posts

·
ate lug
88 + 96 broncos, 96 F250
Joined
·
8,577 Posts
Discussion Starter #1
Posting this here because I figure you guys would know best.

Yanked half of a blown Mass Air 302 out of a 96 bronco. Dropped a SD 351 in on Monday, and wiring it up to stay Mass Air.
The 302 did not use an Evap Canister Purge (CANP). My 351, which came out a 97 F250 did, altho that is mostly irrelevant. I am staying Mass Air (using the 302's harness because that's the only mass air harness I have). The 351 will be run by a 96 351 PCM, code TIN 1.
My question is, does this PCM require a Canister Purge? My 96 EVTM shows it for both the 302 and the 351 but my 302 cleary didn't have it (no connector for it in the harness).
My goal is to make this motor swap as 'stock' as possible, so if it needs one i need to know so i can take the harness back off the motor and add it.
 

·
Charlie don't surf..
'92 Ford Bronco XLT
Joined
·
14,965 Posts
Remind me again, was the MAF 302 from the '96 OBDII, if so that may account for why it's missing the CANP..Having said that, the 351 EEC is definitely going to be looking for the CANP, but it should only trigger the code in memory and not set a check engine light. so in theory I believe you could leave the CANP off..Are you certain that 351 EEC is MAF friendly..
 

·
ate lug
88 + 96 broncos, 96 F250
Joined
·
8,577 Posts
Discussion Starter #3
Remind me again, was the MAF 302 from the '96 OBDII, if so that may account for why it's missing the CANP..Having said that, the 351 EEC is definitely going to be looking for the CANP, but it should only trigger the code in memory and not set a check engine light. so in theory I believe you could leave the CANP off..Are you certain that 351 EEC is MAF friendly..

Yeah the 96 bronco was MAF 302 (OBD-II), just that the top half of the motor was removed prior to my acquiring it, so im kind of in the dark as to how everything is supposed to go together (pieces missing, etc). Don't know much about the OBD-II EFI system, and i don't know the vacuum routing for '96 for either motor, which is complicating things.

The 'new' PCM is from Lifted Ford's bronco. Its also from a 96 bronco, but one that had a Mass Air 351 (OBD-II).

So youre saying the CANP wasn't used on 302s, but was on 351s? So in order to make it 'stock', id have to add the pigtail for it to the engine harness.
 

·
Charlie don't surf..
'92 Ford Bronco XLT
Joined
·
14,965 Posts
I see so both the 302 and 351 were MAF OBDII..got it..Regarding the CANP, I'm just going off of what you said about the '96 302 not having one. or did I misunderstand?
 

·
Charlie don't surf..
'92 Ford Bronco XLT
Joined
·
14,965 Posts
here are the vacuum diagrams...actually from one of your threads...you can see they both have the CANP (vapor management valve)..



 

·
ate lug
88 + 96 broncos, 96 F250
Joined
·
8,577 Posts
Discussion Starter #6
So that means that that sensor over the driver valve cover is the canister purge. Which means that the SD and MA motors use a different sensor. So that's why I can't find it, I'm used to the cylindrical one that literally just hangs off the vacuum line right next to the throttle body, but that one must be SD only.

Never owned a mass-air bronco before; it is surprising to me the number of sensors that are different from a SD motor to a MA one. This whole project would have been a lot easier if the 302 had still been together when I bought it.
 

·
ate lug
88 + 96 broncos, 96 F250
Joined
·
8,577 Posts
Discussion Starter #8
My 97 351 has that one near the throttle body, but that's a SD motor out of an F250. So I guess just the OBD-II broncos got the one that's over the driver valve cover. So weird.
 

·
Charlie don't surf..
'92 Ford Bronco XLT
Joined
·
14,965 Posts
yeah, they obviously moved s**t around..
 

·
Registered
Joined
·
49 Posts
Hopefully you chase it down. I just had my motor tuned and have been going round and round about if there's a can-p or not going from the 1990 sd 302 bronco to a computer from a 1993 mustang gt hooked up to my new 351. I've decided to say screw it and let ecu continue to throw the code because I can't figure it out.



Sent from my iPhone using Tapatalk
 

·
ate lug
88 + 96 broncos, 96 F250
Joined
·
8,577 Posts
Discussion Starter #11
Ok so digging into the vacuum system has pretty much answered my own question. I don't have a CANP, because I don't have one. Instead it uses a VMV (vacuum management valve), which is located over near the heater box. Does more or less the same thing I think. Just got to figure out how it was plumbed. I have a rough idea, I'll figure it out when I get back to it Monday.
 

·
Super Moderator
Joined
·
25,337 Posts
Yo rept,

Ports shown, but I believe the vacuum hose goes to the emission plastic vacuum tank; couldn't pull spiral wrap off due to fragile hoses.

As you know, The vapor management valve (VMV) replaced the canister purge valve used in EEC IV; it is located on passenger side firewall, high in our 96 5.0L

151994
pic by edaminski in his 96 5.8
...
Overview; "...Non-enhanced evaporative systems use either a Canister Purge Solenoid or a Vapor Management Valve to control purge vapor. These systems are tested differently as described below.
The Vapor Management Valve (VMV) output circuit is checked for opens and shorts internally in the PCM by monitoring the status of the duty-cycled output driver. When the output driver is fully energized, or de-energized, the feedback circuit voltage should respond high or low accordingly (P0443). The VMV functional check uses the idle airflow correction for the IAC solenoid to check for adequate purge flow. The VMV is a source of engine airflow at idle, therefore, a change is VMV airflow will produce a corresponding change in IAC airflow. The IAC airflow correction is checked while the VMV is normally open (> 75%), then checked again after the VMV is commanded closed (0 %). If the difference in IAC airflow corrections is too small,
it indicates inadequate VMV flow (P1443)..." by Ford motorcraftservice.com

btw the 96 Bronco F Series Workshop Manual does not address the VMV except; "The 5.0L engines utilizes a fuel vapor management valve (VMV). The vapor management valve (VMV) functions in a manner similar to that of the evaporative emission canister purge valve. " Figure Ford built the 96s with the VMV since the parts were available for 97 run.
See http://www.diesel-dave.com/vehic/manual/stj/stj3d006.htmfir for the CanP overview.
...

Will try to post pics of the hoses if I can get outside today.
EDIT, ADDED FOLLOWING pics and diagrams

96 Bronco 5.0 Vacuum Diagram
VMV vacuum small hose is green unless replaced.
...


Item Part Number Description
1 9A220 Fuel Vapor Tube from Fuel Tank
2 9G271 From Purge Control Valve
3 9D653
Evaporative Emissions Canister, 1400ml (1.48 Qts.)
4 Fresh Air
5 9D653 Evaporative Emissions Canister, 925ml (0.98 Qts.)
...


Item Part Number Description
1 9C987 Fuel Vapor Return Hose and Valve Assembly
2 9D653 Evaporative Emissions Canister
3 N-S2 Screw, M6.3 x 1.81 x 16.0
4 9A220 Fuel Vapor Return Hose Assembly
5 10A812 Battery Tray Support
6 9E926 Throttle Body
7 12A581 Wiring Assembly
A - Tighten to 5-7 Nm (44-62 Lb-In)
...

Attachment pics;
vacuum hose from VMV has small red tie wrap; goes to throttle body.
My much better-half couldn't snap pics of the cannister.
 

Attachments

·
ate lug
88 + 96 broncos, 96 F250
Joined
·
8,577 Posts
Discussion Starter #13
You are correct. I got it all sorted out when I ran the vacuum lines for the motor on Thursday.

I have the diagrams for the 96 5.8 now, which helped me sort out which hose went where, since I wasn't the one who took it apart. Its basically the same as the 5.0.
 
1 - 13 of 13 Posts
Top