Need Ideas On Problem...

Need Help/Ideas On Problem...

1993 Ford Ranger, 2WD, 3.0 V6, Manual Trans.-

Sat for 2 years... I could no longer afford not to drive this (instead of my 1-ton) so I charged battery and started... It ran fine for 2 days, albeit smelling like paint thinner from exhaust. Stopped & filled fuel tank... Then, I had problems/ No power, would not rev... had to feather throttle to limp home. Then ran OK for a few miles, then same again.

After turning engine off and cooling overnight- Then would start fine, rev once (on own) then die. You could prolong the dieing if you lightly feathered the throttle. Thinking it might have been moisture in tank or the old fuel- I mixed in some SeaFoam fuel conditioner and some 104+ octane booster and changed the fuel filter/No change.

The fuel filter was not clogged, nor did it have any moisture , sediment nor contaminants. I checked the fuel pressure with the engine off- 40 pounds. I dumped the codes and the only codes were for a PIP circuit failure and HEGO lean on #1 and #2...

Ignition spark was good- firing and strong. Noid lights on injectors told me that all the injectors were getting a pulse signal. Both these tests indicated to me that the PIP circuit was functioning... I figure the loss of signal was because I was trying to gt running codes whil the engin was dieing... and left the ignition switch on after it died- to finish retrieving those codes.

There was no apparent vacuum leaks found... The MAF sensor has resistance between the terminals and has a good supply voltage. I couldn't check the running voltage between terminals C & D, as I couldn't keep it running by myself and still test. I cleaned the MAF with MAF Cleaner/no change.

In the process of testing, one of the times I started the engine, it fired up and ran fine!?! --> I had left the MAF sensor unplugged... I got a used MAF sensor from a 1994 Taurus and put it on mine, no change with it plugged in.

It runs and drives with the MAF unplugged: Consequently, it runs rich that way. I've driven that way for about 400 plus miles since. Tested Coolant temp sensor- OK. Throttle postion sensor- OK. Air bypass valve "seems" to work. I cannot find an Intake air temp sensor. I do not see any EGR valve nor an EGR solinoid on this motor, nor where on would mount. The HEGO sense voltage seems to fluctuate fine on both sensor circuits.

With the MAF sensor unplugged I get an internal PCM voltage failure code and HEGO #1 sensing rich code. Somehow, with it plugged in, I seem to be getting a signal to all the injectors, but must be a very narrow pulse/stopped down/not enough fuel. With it unplugged, you can smell it running rich.

Any ideas?

Could it be that there is still something wrong with the MAF sensor? Maybe the used MAF was also bad?

Could it be that I have an internal air leak or vacuum leak somewhere that is bypassing the PCM enrichment circuits? With the MAF unplugged and running- the vacuum seems at an OK level on a gauge... The idle air control valve seems to be adjusting the rpm for warmup and A/C operation, so I'm assuming that's OK(?).

The Fuel pressure regulator dropps the pressure from 40 pounds to 35 pounds with vacuum going to it. That's within specs.

I'm running out of things to test... I've been pretty much out-of-work for about 8 months, so I can't afford to just go out and buy parts to test.

Tried another MAF sensor from a '96 Taurus... Still no change. I guess that rules that out.

Now, I'm beating my head against a wall...

Well thats your problem... MAF sensors are designed for the specific engine its on... as in a 96 taurus MAF should only be used on a 96 taurus with the 3.0L. What you need is a 93 2wd ranger MAF sensor and you should be good.

Original_Ranger84 said:

Well thats your problem... MAF sensors are designed for the specific engine its on... as in a 96 taurus MAF only be used on a 96 taurus with the 3.0L. What you need is a 93 2wd ranger MAF sensor and you should be good.

Click to expand...

I was told that the MAF sensor was a little more generic than that. Interchange manuals have it as '91 thru '94 3.0 and 3.8 V6'es in Ranger, Escort, Explorer, Taurus, Thunderbird and Probe. Someone els told me early '90s Mustangs in 4.9l and 5.0l work also, but I can't confirm that. The '95 and '96es say they're the same internally and such- 'except' for the wiring connector which can be replaced with an updated connector. Lots of Ford sensors, injectors, other parts are interchangeable. The OEM part stores here sort of confirm that also, but they want over 4 times the amount for a new replacement. (Remember, I've been out of work for over 8 months.)

I think the Ford sensors that read the information and send that info to the PCM are somewhat generic. The PCM'es (0n the otherhand) and how they are configured software-wise (the options that are flashed) are not.

The MAF sensor I got from the '94 was the "same" part number as was my original. The '96 was the same p.n. except for the year code and the revision code.

Oh... well I'm used to no maf or new maf where its like really specific... i just figured it would be the same with older ones...

MAFoElffen said:

Could it be that I have an internal air leak or vacuum leak somewhere that is bypassing the PCM enrichment circuits

Click to expand...

Well, Vacuum is 18 inches at idle. WIth PVC hose plugged it's 19 inches... But dosn't amke a change with this problem.

I unplugged the IAC after warmup and plugged the MAF back in- No change. I tested the signal voltage for the IAC... Within spec's cold thru warmed up. Had anothr IAC pluged in whil testing this and it is functionoing fine. Plugged the ports by using a blank gasket to clos off the ports- no change.

I'm not sure this motor has an Intake Air Temperature sensor. Can't find any in the air cleanr housing nor the rubber intake snorkel.

There is no EGR valve nor EGR solinoid.

I guess maybe I have 2 options... (1) Save the money to have someone look at it that can read the flashed PCM options. (2) Reinvestigate the MAF option with testing a new one, Which will alos take saving up the money.

The IAC I assume would be the cylindrical object above the TB, it is on my truck and its the same with the old 2.9L too.

It could also be an O2 sensor too... if the o2 doesn't work it would tell the engine its running lean possibly.

Original_Ranger84 said:

The IAC I assume would be the cylindrical object above the TB, it is on my truck and its the same with the old 2.9L too.

It could also be an O2 sensor too... if the o2 doesn't work it would tell the engine its running lean possibly.

Click to expand...

Yes... That's the IAC valve. Had another thread started on testing that and bypassing that circuit (blocking off after warmup) that seems to have ruled that out...

As FYI, someone had PM'ed me about the IAT and HEGO (thanks Earl) and here's what happened:
--- My reply to Earl ---
"I found the IAT sensor on the airbox. Tested and it intially - seemed as an open circuit. Went to Pick-A-Part and picked an IAT and 2 HEGO's ($6 a piece). Found out the IAT I had was still good... LOL. I didn't have my VOM on a low enough range to test it. Set to the 20k range and presto. Was same as the one I got. Put other one on anyway/No change.

I checked my HEGO fuse... #18 in the interior fuse box. Was good and had power going through it. Mine doesn't have upstream 02 sensors, just 2 HEGO's. I noticed one of them had a few dents on the exterior, so I replaced both. Still no change.

Today, I looked at enough 3.0 V-6'es in the wrecking yard to figure out that mine doesn't have an EGR valve nor EGR solinoid. Their is a blank "Ford" plate where it would mount on the intake manifold and the exhauast manifold is cast for the land, but is not drilled and tapped for the tubing.

I'm still sort of at a loss."

YES--- I still need help with this problem.

So I assume you looked at similar year rangers with the 3.0L?

Well right now the only thing that comes to mind is a possible vacuum leak... and when the MAF thinks it is getting said amount of air it adjusts the fuel to fit but its getting more air from a leak or hole somewhere. What about this EGR plate? It could have a leak around it?

I'll check the EGR Plate this afternoon while I'm on break from work...

It's the older OHC V6'es that were infamous for intake leaks right? (Not the OHV 3.0...) Strange that this problem occured all of a sudden... And that on the way home the first day of this problem, that it was there/dgot better and drove fine for about 3 miles (on windy mountain roads) then was there again- and ever since.

I'm not sure which ones had which problems... but if you heard somewhere that the intakes leak on them then that could very well be your problem.

The ones that had "that" problem had dual ports in the intake... Don't think I hav that problem or I would have a problem running whether th MAF sensor was plugged or unplugged.

EGR plate wasn't leaking. Argh!!! Guess the next step is to get some vacuum caps and plug off "ALL" the vacuum sources. I'll see if this makes a difference. My friend memtioned maybe it's the cannister purge circuit stuck open...

ANyone notice if I missed anything in the way of sensors to check? How do I test the PCM?

okay your truck does not make any sense at all. when your maf is unplugged it should not run period as the engine is not sensing any airflow into the engine. another thing there was never a 3.8 in a ranger, and the mafs are different. the 3.0/2.3 mafs will interchange, you can also get one out of a 2.0 contour (remove the air filter and pop the inner plate out its sitting there.) cant remember on the 4.0 if it will fit, but it has the same airbox from 2.3/3.0/4.0 ranger. when i made my cai my maf fell off (still plugged in) and the truck died, reconnected and ran fine. what it sounds like to me is your truck is running in idle/throttle closed postion, and when you apply throttle it leans out. id look into your throttle position sensor (sensor on the throttle shaft opposite of the throttle cable). what could be happening is your engine is pulling more air when the throttle is opening, tps says 0 degrees (closed) and your maf is sensing the air, so its closing your iacv and leans out killing your truck.

I commented on your other thread too. I have a '93. it has no egr, and no egr solenoid also. many parts do transfer, as long as the part numbers match. I have put iacv from '93 tauruses on my ranger. and they have the same #'s.

where was the air temp sensor found? mine is not where it is said to be. its supposed to be between the air box, and throttle body. but there is nothing there except the air intake tunnel.

mine hast turned into a choke type issue. it acts like its not getting air. where if I hold the throttle open to get air,
so i am thinking at this point its the air intake sensor. the ais, and the ects, all need to work telling the ecm, how much to open and close the iac. which is controlled by vacuume too.