Two odd problems

[Coasting2aStall]

This is 1994 RAnger with manual transmisson and 4.0L

First, my exhaust gets loud enough to annoy me when engine is warm. Probably wouldnt get me a ticket unless I really stomped on pedal in front of a cop. Its quiet at idle but any acceleration and it sounds like a bad muffler. Quiets when at speed. Doesnt do this when cold. I replaced the muffler and it helped a little bit, but still lot noisier than I like. Used piece heater hose as stethescope and noise is out tailpipe, not from any joint/connection.

Second I am now getting check engine light. Its OBD1 and only get code 70, ECM failure??? Thing runs fine, idles fine, enough power. Trying to see what the heck it means, google keeps bringing up something about bad data connection with dash??? Gauges all work, so???

 

[TDG]

Its OBD1 and only get code 70

How did you get that code?

Asking because it's not listed on the code list I have access to (93 Explorer, should be similar EEC) nor are there any codes that end in 0 which sort of makes sense if one is using a paperclip and counting the light flashes - how do you count a "0" light flash?

 

[Coasting2aStall]

I have a code reader you plug in under the hood. Only code it showed was "code 70, ECM failure". Thats the exact display shown on the code reader screen. No idea if this is good code for this particular Ranger, but the code does exist in OBD1 Ford codes.

Its not big deal as truck runs fine and I dont have emission inspection in my state. So nobody other than me gives a rats behind if my check engine light is on. I just rather have check engine light off if possible, so I know if something new has triggered a code.

 

[Coasting2aStall]

hmm, ok list of codes found at Ranger station. 70 is described as:

(M) 3.8L AXOD - Data link to instrument cluster fault. Service any other EEC codes, erase memory and retest

And yea see point a zero would prevent you using paper clip method.

So is it my code reader?

 

[Coasting2aStall]

You ever feel stupid, I sure do.

I just reread the english part of users manual for the code scanner. I was doing it wrong. Warmed up truck and redid it. No more code 70. This time got code saying MAF sensor out of range and a code for evaporative canister not functioning. The MAF code is odd, I tested MAF with voltmeter and its well within specs.

And had idea to put that old muffler I replaced with new one, onto end of tailpipe just to see if it made a difference. It did, lot quieter even with it just sticking into tailpipe, not clamped or welded tight. But needing two mufflers..... really? I weld so will splice it ahead of current muffler underneath truck. Just cost me bit of time. I imagine a second new shiney muffler might be even quieter, but this one works well enough. I just want it quiet enough not to get on my nerves and so Ranger doesnt sound like some old rattletrap truck owned by a high school kid running straight pipes or something.

 

[arco777]

MAF sensors can work partially. When they fail they rarely fail altogether, usually exhibiting odd symptoms instead. Try a known good MAF or a new one. Keep in mind that MAFs from other Fords may look the same but are calibrated differently and won't run right. Also check the heated element wires of the MAF and make sure they are not cruddy/sooty. You can clean them with spray type electronics cleaner.

Evap canister is a simple system. If it isn't functioning, usually the issue is the vacuum elbows at the canister (they crack over time) or the purge solenoid quit working. The purge solenoid is located under the intake but can be wiggled out; it has a two wire connector and a cylindrical body with the fuel vapor line coming from the canister, to the solenoid, to the fitting under the throttle body.

 

[Coasting2aStall]

Thanks, thanks, thanks, no idea Ford made MAF that are interchangable physically with different calibrations.

Ok, previous owner of this truck was a fan of pick a part yards, and he wasnt too picky, whatever physically fits kinda philosophy. I sorta understand that, lot times there isnt an exact duplicate of your vehicle available and you dont have money for parts store. So although this MAF is bright and shiney and tests fine with voltmeter, guessing its not exact spec for this truck. On other hand with 190k on odometer I am guessing this is a lower mile engine, not original. The strong engine plus no rust is why I bought the thing. Yea if this isnt proper MAF, then that could explain the low mpg, seriously I have had carb V8s and automatic with no overdrive, that got much better mpg.

 

[arco777]

What is the part number visible on your MAF?

As for mileage, I haven't yet had a first gen Explorer that got over 17mpg.

 

[Coasting2aStall]

Try 11mpg. Remember this is with a manual transmission! 17mpg sounds like a pipe dream. It does run well as is! Anyway cold day, it warms up some, go out and look for a number. And of course suppose it could be wiring or ECM. Nothing is ever simple as it seems.

Main thing make sure MAF and ECM match. I suppose MAF being very important part, that its not one to cheap out on. Seems the original from factory was made by Hitachi? That nice new shiney looking one could been some Chinese clone part....

From googling seems the 2.3L and 3.0L MAF were similar, and the 4.0L and some of the non high performance 5.0L MAF were similar? So many OEM numbers and then huge number of aftermarket MAF suppliers with their own numbers..... Trying to figure what is actually compatible???

 

[Coasting2aStall]

MAF=F07F-12B579-A1C
ECM=F27F12A650CB

The MAF seems like it could be correct. But the ECM isnt and maybe not completely compatible. Though might be faulty MAF. Like say it runs well, with enough power for a six in a 4200 pound vehicle, just 11mpg. Bugs me, but seriously I am old retired guy that doesnt put that many miles on a vehicle so maybe doesnt matter.

 

[Coasting2aStall]

Pricing MAF and any experience with ISUMO brand? Sounds Japanese and about cheap as the no name Chinese clones.

Also found reasonable priced used federal emissions ECM for a 1993 Explorer with manual transmission. Pretty sure thats close enough for government work.

 

[arco777]

Check catch code (4 digit, like UMP1 for example) labeled on the PCM near the connector. I can research whether that is correct for your model. I'll look up your MAF number once I get home.

 

[arco777]

I'm not familiar with "isumo" but it sounds Chinese. Sumo is a common word used in many Chinese "brand" names. A quick trademark search shows they are owned by Swift Auto Parts.

I personally trust Motorcraft parts, and have had good luck with Denso parts (Japanese company). Delphi makes a decent MAF as well. Have not had good luck with Bosch or BWD parts lately.

 

[Coasting2aStall]

Check catch code (4 digit, like UMP1 for example) labeled on the PCM near the connector. I can research whether that is correct for your model. I'll look up your MAF number once I get home.

In big font right above the bar code, its A2L1

 

[Coasting2aStall]

I'm not familiar with "isumo" but it sounds Chinese. Sumo is a common word used in many Chinese "brand" names. A quick trademark search shows they are owned by Swift Auto Parts.

I personally trust Motorcraft parts, and have had good luck with Denso parts (Japanese company). Delphi makes a decent MAF as well. Have not had good luck with Bosch or BWD parts lately.

RockAuto.com is showing Hitachi as OEM manufacturer of the Motorcraft MAF.

Ok, will forget the Isumo stuff. I learned my lesson not to buy Chinese in experience with a TPS. Replaced it with genuine Motorcraft, solved that problem, just not always Motorcraft parts available for older stuff or in this case they want a core charge on a rebuilt unit. No new Motorcraft MAF. But Japanese brands tend to be pretty good quality if they are the manufacturer. Course that doesnt mean its made in Japan. They outsource like all other big companies. Just hopefully hold high standard.

Hmm, ok on your suggestion/experience, looking at RockAuto.com, Delphi probably the bargain namebrand MAF.

 

[arco777]

MAF=F07F-12B579-A1C
ECM=F27F12A650CB

1. From some quick research it looks like that MAF is correct (my 94 uses the same one but with a A2B revision code).

2. The PCM does not seem correct; I can't find that catch code anywhere, and the part number comes back to a 93-94 Aerostar equipped with a 3.0 liter V6. The Aerostar was available with a 4.0, but the 3.0 is a completely different engine family.

If it is indeed an Aerostar 3.0 PCM, my next question would be whether there were pinout changes required. Many Ford PCMs used the same style of connector but pins were in different locations and different ones did different things. I would hope that the previous owner of your truck didn't re-pin the connector.

I would sell you one of my spare PCMs really cheap, but mine are for automatic transmission models.

 

[Coasting2aStall]

I thank you again for your help. Yea, tough call, the truck runs ok. Now whether its got a bad MAF or whether this MAF is incompatible with the 3.0L ECM.... I dont know the guy I bought the truck from, but from some of the other ham handed stuff I have corrected, I am doubting he did anything like repin the connector. I mean instead of replacing a bad FPR, he just removed the vacuum line and plugged it. Diaphram was ruptured. Plugging the line kept gas from being sucked into the manifold.

I found a cheap ECM for a 93 Explorer with manual transmission on ebay. Think I will try that first. 4.0L, manual transmission, batch injection, federal emissions... should work fine. Supposedly from junkyard clearing out old stock. They arent warrantying it so buyer beware. But worth a shot. If it works but throws same codes, I will know its the MAF or suppose the wiring/connector. Knowing I always make wrong choice on first attempt, no doubt it probably is a faulty MAF....

Looking at MAF on Amazon. Their Ranger Delphi MAF got some bad reviews. Their Ranger Hitachi MAF didnt have any reviews, but other Hitachi MAFs got nearly 100% positive reviews. I take it Hitachi makes good MAFs. $80, but cheaper than buying something else that doesnt work and still have to pay for quality one that does.

 

[2stroke]

I'd take another look at that ECM. As you stated, the 93 is a batch fire, but your 94 is a sequential. I'd have to look at the wire diagram to be sure, but yours may not run with that ECM.

 

[Coasting2aStall]

I'd take another look at that ECM. As you stated, the 93 is a batch fire, but your 94 is a sequential. I'd have to look at the wire diagram to be sure, but yours may not run with that ECM.

From way I understand, the 1994 Explorer was sequential injection. The 1994 Ranger and Aerostar with 4.0L were still batch injection. Thus the 94 Ranger 4.0L has more in common with the 1993 Explorer 4.0L. Pretty much the same, at least for Federal versions.

I have a 94 Ranger.

 

[2stroke]

I'm not saying it is, but my 1994 Mazda B4000 is basically a ranger clone, and it has sequential injection and EGR. You may be right, I just don't want you to waste your money.