In the engine compartment of my 92 F150, I have a black coffee can looking thing with two vacuum tubes going into it, they are red and black.

What is this canister used for? And how important is it to a MASS Air system?

Thanks.

 

if its on the pass fender it is the vacuum canister. it stores vacuum for times when you engine doesn't produce enough to keep all of the vacuum dependent systems running.

look like this? (post 13)

https://www.ford-trucks.com/forums/1...l#post10782077

 

Yup. That's the one. If one of those lines is plugged or if the canisters is not working properly would that affect a mass air system?

 

I don't think so, but your brake pedal wouldn't have the same pressure. Short of a hole rusted through it which would probably maek a sound, you should be fine. Theres not an easy way for anything to get in those lines, as stated they are vacuum lines, so there is literally nothing in them. Check for obvious damage, other then that you should be fine. Are you have any issues that make you think its bad?

 

It shouldn't affect the MAF system particularly. It can affect other things though. It should be replaced if there is obvious damage.

 

I was asking because I removed it years ago. Back then the truck was an SD system and last year I converted it to a MASS Air system. Since the conversion the truck hasn't run and I was wondering if this could be a reason why. I was troubleshooting the converted system with the company I bought the new computer from and we couldn't determine why the motor won't run. The only theory is that the leaky head gaskets I have are bringing air into the motor that doesn't get measured by the air sensor so it was throwing off the mixture.

 

maybe you should give us the run down of what you did to convert from SD to MAF and the diagnostics you have done since to try and figure out the problem.

The only thing that comes to mind is that there is 2 spark plug wire configurations for the 351w and I have read from a couple posts that they had to re-rout the spark plug wires so the engine fires in the right order... THIS IS ONLY WHAT I HAVE READ!!!! I'm making full note that i'm not a MAF expert and this is just past reading i've done in other threads... I'm just suggesting maybe you want to check with the computer manufacturer to make sure you have the right firing order on your engine. Just a thought...

The vacuum can just stores extra vacuum pressure so i don't believe that alone will keep your engine from at least starting and idling...

 

Well, it was a kit that I ordered from a company called IST. I bought the Truck Mass-Air Kit from here: IST Products

The instructions were pretty clear: I first had to remove some wires from the existing EEC connector, I then had to move some wires to a new position, then I had to add new wires into existing connections on the EEC for the fuel injectors to fire individually under the MASS Air system. I also welded in a new O2 sensor as my truck only had 1 previously.

With that all said and done, the truck would barely run because something was off. It was firing maybe one or two cylindars for each revolution and the timing was way off. I don't remember doing anything with the distributor or wires other than checking to make sure that everything was in the right position.

I talked to IST about this during troubleshooting and verified, about 3 times, that each wire was in the correct position and that the connections were all good.

I also bought that MASS Air adjuster that you see on the top of that page and I would adjust the setting but it made no difference. At this point I have forgot what the readings were because that was about a year ago, but I have them written down somewhere.

The other puzzler is that once or twice when I had started the truck and was troubleshooting, the behavior changed from barely running to revving so high that the engine almost blew. I have been trying to figure out what situation I am in where the truck would barely run then almost blow itself up (I wasn't stepping on the gas at all, it was just the system that did it).

I went round and round so much that I just had to move on thinking that there was air getting into the engine another way and causing the system to not run properly. I know the engine in the truck is old and has had problems but it was running fine (with a supercharger) on an SD system. I almost have the new motor installed but am not confident that will fix the issue.

Thanks for any help or advice you can give...as you can tell I have been working on this for a while and am still kinda stumped.

 

hmmm... I'm probably no help on this one so I will leave it to Paul or other Ford guys more experianced with MAF and the electrics than I am...

I'd check with Lazy K, EPNCSU2006, or Conanski...

Also you might attract more guys if you change the post heading to "SD to MAF problems"

 

I'll probably do that but will wait until I get the new motor in so I can have something to troubleshoot with. Today I got out the old motor and I can finally see the area where I had a head gasket leak...I don't see that as being the source of the problems. Sure, it's leaking but it isn't that bad to cause the problem.

Thanks.

 

Rikil,

Hmm, It ran ok before the conversion. Mechanically it must be ok.

Have you tried to run it without the super charger hooked up?
***Have you tried to remove the IST air adjuster from the MAF circuit? ***
Have you traced each wire end to end thru the new harness? Not just at the connection point.
Are you sure that the pins were reset properly after you moved them in the old harness?
Check and make sure that you have the right controller PCM by checking the FORD number (not IST). If you have a standard tranny, you should have a 92-93ish Mustang computer. Check that. I can't speak to the proper computer if you have an automatic. There is ONE Ford truck PCM model that could work for a standard tranny truck. I am not aware of it being used. I tried it then went to the Mustang PCM.

I don't know why IST would have you swap wires on the existing connector. They could do that internally on their new harness.

Don't worry at this point if the injectors are firing in the wrong order, the engine will still run ok. The order can be fixed later.

It is easy to adjust the "Air Adjuster" so that your engine won't run or run very poorly. Ask me how I know!

I would do those things before I tore apart an engine. It won't take that long to check out the harness end to end.

I have read here (not my experience) that having two Oxy sensors has confused the PCM (351, 302, 302HO firing order differences). Each sensor would be regulating two of the injectors on the wrong ex manifold. I don't know the firing injection order on your cam and in your PCM. Try to hook up both PCM Oxy sensor leads to one Oxy sensor. It works for me!

You can check your wires against wire connector charts that have been put here ( I know of Paul's and mine) and the ones at FordFuelInjection.

I've built one from scratch for my 302/AOD and it has run for four years that way. Not bragging, just stating my credentials.

I assume you are located in Colorado. If you are in SoCal let me know.

 

Deleting the canister will not affect the air meter as long as you remove/plug all of the associated vacuum lines. Any leak after the MAF will affect the way the motor runs. I've had mine deleted for many years and no problems to speak of.

 

Yes, tried both of these, no change at all.

I haven't traced wires from the harness to their connection points.

I did an in-place upgrade...meaning while the motor and everything was still in the truck. I didn't take apart the whole wiring harness, just left the non-used wired loose (I did cover up the ends so they don't touch anything JIC).


maybe because of the in-place upgrade I did?

I asked IST about this and they strongly suggested I use two O2 sensors. They never mentioned that I need to get the right connector going to the right sensor. But the motor is out now and maybe only a few weeks before I put in the new one so I can test with that when I get there.

This is my truck, my baby...one day I know she will be running again and maybe with your help...I appreciate it.

 

Today I took off the air charge temperature sensor; there is no way this thing could have been working properly. The main element was completely covered in dirt/oil. I see this in my MASS Air diagram bit not sure what part it plays in the system.

 

The ACT sensor is used by the ECU to increase or decrease spark advance at a certain charge temperature.