86 Mystery Mods Progress!

[Slobin3d]

Throw that one in and see how it runs. I'd reset the ecu and then install.

The larger MAF with 55 mm electronics is probably telling the ECU you are seeing less airflow that you really were. Probably why it was idling up.

Don't chuck the larger MAF though. You just need to find the sensor with the p:n I listed and install it on that.

Running the 55mm MAF with 65mm TB is probably costing you 1-2hp. I wouldn't swear it. Get car running right and then upgrade later

The mismatched diameter was my main concern, but when I originally started looking at it, I thought the TB was smaller then the MAF, not the other way around. Lol

It's worth a shot, I already have it. And I can always resell it later.


As for the cutting out at half throttle under heavy acceleration, it did that before the MAF conversion. Still haven't sorted that out yet.

 

[Noobz347]

Explorer MAF will not work on a Mustang. The MAF transfer function is not correct.

..without a digital tune of the EEC.

The biggest problem I see with mismatched housings and sensors is that there's no way for you to get the transfer function correct without a flow-bench machine.

You guys may already have covered this. I only skimmed through.

My advise would be to do some simple math calculations for air volume and purchase a new meter complete with 30 point transfer function (for later tuning if necessary) and to buy it in the size needed for the injectors and EEC that you plan to use.

It really is the path of least resistance.

Again, sorry if this has already been covered. ( I'm currently searching for DBS spoilers )

 

[Slobin3d]

You need a factory paired MAF sensor and housing. Can't swap electronics. That small bore the wires sit in is critical to how it calculates airflow.

So with 19# injectors you either need to track down a stock 55maf housing, or the correct electronics for that housing. The part number for those electronics is F2VF-12B579-A2A.

@Mustang5L5 I found a used one on eBay, but I'm having trouble crossing the PN for a new replacement. Is that meter out of a 94-5 5.0 mustang? Or a 4.6 car? Or Lincoln of some sort?

 

[Mustang5L5]

Here's where you can find it

1995-94 Mustang 3.8L F2VF-12B579-A2A,
1994-92 Crown Victoria 4.6L F2VF-12B579-A2A,
1995-94 Mustang GT & Mustang Cobra 5.0L F2VF-12B579-A2A,
1994-92 Town Car 4.6L F2VF-12B579-A2A,
1994-92 Grand Marquis 4.6L F2VF-12B579-A2A,

 

[billison]

Incase it was missed, I would trash metal intake tubes that have rust in them like that. Rust will flake off and do god knows what.

 

[Slobin3d]

Incase it was missed, I would trash metal intake tubes that have rust in them like that. Rust will flake off and do god knows what.

It's all going away. It's too small anyway. I'm guessing the PO bought some cheap kit and made it work.

 

[Slobin3d]

I swapped in the smaller MAF. It improved the surging idle quite a bit, not 100% gone yet, but close. Now I need to get the idle down below 1000 rpm.

Iirc isn't it, that you pull the throttle position sensor plug, and with it running set your base idle screw?

 

[Mustang5L5]

Pull the IAC plug, set base idle screw with IAC unpluggged, then you need to reset the ECU (unplug battery 30min).

Hook it all back up and restart. Idle 2 min accessory off, then 2 min everything on.

Wouldn't be a bad idle to run the codes after a few start/stop cycles.

 

[Slobin3d]

New development....

Went to test my fuel pressure, fired the car up after hooking up the gauge, no leaks, and it ran for about 30 seconds, then died. Restarted, and ran long enough to get around to look at the pressure gauge, then died. Did that 2 more times then no fire. Gauge read 40 pounds, and even after if wouldn't fire it would run up to 40. As soon as I shut it off it would drop to 10 psi


Pump sounds quite compared to normal, and I picked up a 255lph to swap into it anyway.

I can't seem to find my inline spark plugs tester, but that's next on my list of tests

 

[Slobin3d]

A positive update!

The pickup was bad in the distributor, cause the car to die. I picked up a new one, and after chasing down a bad "new" tfi that came on the dizzy, she runs again.


Not only that, but my high rpm dead spot seems to almost be gone. Instead of it quitting violently at 2800~3000 rpm it kind of falls off at 4800, 2nd gear is more abrupt then first.

It's an improvement. I reset the timing to 14°, back to where it was. Should I drop it back to 12 or 10, and see if it helps, or would that not cause my cutting out issue anyway.

I'm not hearing any ping as it sits

 

[General karthief]

You could try backing off the timing but honestly I don't think it's the problem, I would check the tps sweep but I figure you've already done that.

 

[Slobin3d]

You could try backing off the timing but honestly I don't think it's the problem, I would check the tps sweep but I figure you've already done that.

Ok, I have checked it in the past, but I rechecked my base tps voltage and it was at 1.01v, so I backed it back down. But last I checked it was still below 1v, so unless it moved on me, it's maybe not holding a consistent voltage?

 

[General karthief]

Check the sweep voltage, hook your meter up and see if the voltage rise is smooth all the way to wot. I had a bucking problem at 1500-1800 rpm I chased forever, my tps was at .98 but as I moved the linkage simulating acceleration and it was bouncing the meter to 0 at what would be about 1500 to 1800 and then was smooth after that, like a flat spot, smooth above and below.
The static voltage is not that important as long as it's close to 1 volt

 

[Slobin3d]

Check the sweep voltage, hook your meter up and see if the voltage rise is smooth all the way to wot. I had a bucking problem at 1500-1800 rpm I chased forever, my tps was at .98 but as I moved the linkage simulating acceleration and it was bouncing the meter to 0 at what would be about 1500 to 1800 and then was smooth after that, like a flat spot, smooth above and below.
The static voltage is not that important as long as it's close to 1 volt

I reset base idle from 1000 to.around 700, and 8 rechecked the idle voltage, it had jumped back up to 1.1 . I flipped the tps 180° where it allowed a bit more sweep, and seems to be holding at .98, but I can't go any lower.

I did a sweep test, and it's solid, no dead spots. I did however find that the throttle feels a bit gritty. Not enough to hold it open or stick closed, but it feels like maybe there's a bushing or bearing that's out, maybe the butterfly is rubbing in the housing. No vacuum leak though.

 

[Slobin3d]

So I replaced my fuel pump with a 255lph and the fuel filter, good thing too, it was zip tied to the sending unit, there were all kinds of trash in the tank, a old pickup sock, and chunks of plastic, the fuel filter was held on with more zip ties, and the locking clips were broken and ziptied to the hardlines.

Drives much better with the new pump, but by accident I did a run with the idle air unplugged, and it runs great without it, no.mid throttle hesitation. Idles like crap, and sometimes dies, but off idle it's perfect.
I didn't think the IAC, did anything off idle?

 

[5.0Droptop]

So I replaced my fuel pump with a 255lph and the fuel filter, good thing too, it was zip tied to the sending unit, there were all kinds of trash in the tank, a old pickup sock, and chunks of plastic, the fuel filter was held on with more zip ties, and the locking clips were broken and ziptied to the hardlines.

Drives much better with the new pump, but by accident I did a run with the idle air unplugged, and it runs great without it, no.mid throttle hesitation. Idles like crap, and sometimes dies, but off idle it's perfect.
I didn't think the IAC, did anything off idle?

Maybe its shorting out giving the ecu bad info.

 

[stpete]

I haven't read all the responses, but your car seems to be in the condition that mine was. The checklist mentioned by Noobz a couple pages back took me quite a while to get through, but eventually got my engine running/idling smooth.

Also, be careful not to run your AC without the fan running. The AC will be blowing it's top before you even see your engine temperature start to climb. My recommendation is to go back to mechanical. I still owe the guy that hid the fan switch under the dash in my old car a kick in the nether region.

 

[Slobin3d]

Went to fix the inop speedo, found that the cable at the trans had been cut, and the VSS removed, and plugged. I replaced that with a new one and red gear to match the 3.73 gears. That help a bit with getting the idle to settle down. And now I know how fast I'm going.

 

[Noobz347]

Went to fix the inop speedo, found that the cable at the trans had been cut, and the VSS removed, and plugged. I replaced that with a new one and red gear to match the 3.73 gears. That help a bit with getting the idle to settle down. And now I know how fast I'm going.

I'm not sure why but the server put your post into moderation. Let me know if that keeps happening.

 

[General karthief]

He may need a little moderation now that he knows how fast he's going