Two odd problems

[Coasting2aStall]

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.

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.

 

[Coasting2aStall]

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 ***** 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.

 

[2stroke]

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.

 

[Roadrunner777]

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!

 

[Coasting2aStall]

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.

 

[Coasting2aStall]

Ok, with IAC blocked set it for 1000rpm. With IAC unblocked, that went to 1200rpm idle. That seems to done it, power is back. I just took it down county road, didnt take it out on hiway to see if CEL came on. It stayed off during test. Perhaps the automatic transmission codes alone dont trigger the CEL. See how it does cold start. If that hesitation and roughness is gone then thats my answer. And try a gasket with restricted hole to see if I can get idle down at least closer to 1000rpm.