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Two odd problems

Discussion in 'Stock 1991 - 1994 Explorers' started by Coasting2aStall, February 3, 2018.

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    1. Coasting2aStall

      Coasting2aStall New Member

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      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???
       
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    3. TDG

      TDG Elite Explorer

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      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?
       
    4. Coasting2aStall

      Coasting2aStall New Member

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      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.
       
    5. Coasting2aStall

      Coasting2aStall New Member

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

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

      So is it my code reader?
       
    6. Coasting2aStall

      Coasting2aStall New Member

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      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.
       
    7. arco777

      arco777 Elite Explorer

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      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.
       
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    8. Coasting2aStall

      Coasting2aStall New Member

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      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.
       
    9. arco777

      arco777 Elite Explorer

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      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.
       
    10. Coasting2aStall

      Coasting2aStall New Member

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      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???
       
    11. Coasting2aStall

      Coasting2aStall New Member

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      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.
       
    12. Coasting2aStall

      Coasting2aStall New Member

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      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.
       
    13. arco777

      arco777 Elite Explorer

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      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.
       
    14. arco777

      arco777 Elite Explorer

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      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.
       
    15. Coasting2aStall

      Coasting2aStall New Member

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      In big font right above the bar code, its A2L1
       
    16. Coasting2aStall

      Coasting2aStall New Member

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      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.
       
    17. arco777

      arco777 Elite Explorer

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      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.
       
    18. Coasting2aStall

      Coasting2aStall New Member

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      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.
       
    19. 2stroke

      2stroke Elite Explorer

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      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.
       
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    20. Coasting2aStall

      Coasting2aStall New Member

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      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.
       
      Last edited: February 7, 2018
    21. 2stroke

      2stroke Elite Explorer

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      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.
       
    22. Coasting2aStall

      Coasting2aStall New Member

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      Do you have California emissions? 1994 California Rangers had sequential injection and EGR. I hadnt heard of any 1994 Federal Rangers having such. But hey its a Ford, so they could went to sequential injection sometime during 1994 model year when they ran out of older parts.

      Mine however has NO EGR. Thank goodness.

      Too late on wasting my money. Its on its way, supposed to be here Friday. $30 so not too big of a gamble. I fully expect that it will throw same code for MAF out of range. But there is no way to know if that code is because of the the current 3.0L ECM and some MAF incompatibility. Or just a failing MAF. ECM was $30 and new MAF is $80. Try the cheapest guess first.

      Like say it runs fine as is, just 11mpg which is crazy low but not unheard of on these. A failing or incompatible MAF would explain things.

      Oh I was looking and those silly purge valves are like $40. The electrical connector is directly on end of the valve. There is a older Ford purge valve with two wires coming out of the valve and connector at end of the wires. Its $12.

      What heck is difference, they obviously do same thing, but would ECM detect it being functional with the cheaper and probably older version spliced in? How does the ECM decide if purge valve is functional?

      Frankly not sure which bodily orifice they pull some of these prices out of. They obviously have little to do with actual production costs.
       
    23. Coasting2aStall

      Coasting2aStall New Member

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      Ok, update. I just got the ECM in mail. Says 93 Explorer on it but the number wasnt the one I bought. Its an ECM for an automatic transmission 93 Explorer. Ok, first thought is a string of naughty words.

      But what the heck, popped it in and started Ranger up. High idle and and seemed wee bit rough though that smoothed out. BUT the check engine light goes out and stays out!!!!! Which is weird cause it should be complaining about both the missing automatic transmission and about the purge valve (its rusted solid). Ok, take it for a drive. Its both quieter during acceleration, and has more pep. It also lets engine rev higher without forcing it. I am guessing Ranger would get better mpg with this ECM. Probably get my wished for 15mpg though thats nothing to brag about in a compact pickup. One thing that is annoying, its slow to come down to idle and as I say it wants to idle at 900rpm. I assume because its set up for automatic so it wont stall.

      I guess I should put scanner on it and test for codes that maybe didnt trip the CEL. But do I bitch that its not the one I bought or not? The one I bought was for manual transmission. But it wasnt guaranteed, it if worked fine but otherwise in auction they said they are selling it as a paper weight, so if it doesnt work, tough tulips.

      This one obviously works.
       
    24. 2stroke

      2stroke Elite Explorer

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      It does take a while for the ECM to learn the parameters. Drive it in a normal manner for a couple days, and see if the idle comes down. I would hope you can get better than 15 MPG. Mine is just about to pass 300,000 miles, has known problems, and still gets 19-20 MPG on the highway. It's closer to 15-16 for regular driving. As you said, who knows with Ford. Mine is a 94 B4000, 4x4 with manual transmission. As far as I know, it has never been out of Minnesota, and I highly doubt it's the California emissions model.
       
    25. Roadrunner777

      Roadrunner777 Well-Known Member

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      Yeah, that slow drop to idle is surely for the A/T... although I have seen this happen with a bad MAF and the ECM goes to safe-mode.Sounds like you have a winner!
       
    26. Coasting2aStall

      Coasting2aStall New Member

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      Ok, it WAS showing all kinds better power. Not anymore. Now when cold no CEL, but it hesitates and surges and just not very nice. When it warms up its about same power as it was with the 3.0L ECM, though its a lot quieter on acceleration, I wont need a second muffler. And after few miles down hiway, the CEL comes on.

      Throws codes: 522,629,566, and 172.
      The first three are the ECM complaining about the missing signals from an automatic transmission. On EEC-IV, dont think this matters other than possibly CEL light lit. The last is O2 lean code.

      Well I can see it is running lot like a too lean carb would run back in the good ole days. Not sure if its because of the missing signals from automatic or something else. I assume something else since CEL doesnt come on until it warms up going down hiway.

      I will mention I adjusted throttle stop. With engine warmed up and IAC blocked, I set throttle stop so it idles at 750rpm. Then unblocked IAC. This may be the cause of my problems. Before I adjusted it, it was idling at 1200. That was annoying. But as I found out in another thread, the throttle stop also changes the TPS. I might be better off putting it back to 1200rpm and doing a trick I read about on a Mustang forum. They said restrict size of hole behind the IAC with homemade gasket. This would lower idle speed without changing TPS setting. Seems more than one model Ford had this high idle problem. Perhaps partly intentional to get emissions down???

      Oh I topped off tank to get better notion of fuel mileage with this ECM. I was bragging before saying 11mpg, actually got 8.76mpg. That is just silly, I have gotten better with an old Chevy one ton with carb 454-V8 and automatic. It would get flat 10mpg loaded, unloaded, whatever I did to it. But that was expected with big engine in a heavy pickup.
       

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