1993 3.0L Hard start / t-stat

austinrick · Feb 19, 2009

New member here. My '93 Ranger 3.0L with 300,000 mls is becoming hard to start (cold, especially). I've put new fuel filter on the list to replace, wondering if anyone has any other suggestions. This engine does not get much maintenance except oil & filter at 3K mls religiously, and the occasional air filter. Just changed plugs, cap & rotor last month. BTW, new Gold Top battery in December.

This engine has run rough at an idle since I bought it in '98 at 122K mls., but has never quit on me....ever. Will not run on 93 octane; I use mid-grade. It has never been a powerful engine (at least with this auto tranny and rear-end) but it runs very well at its age and I don't think there is anything wrong inside. I add 4 oz of Marvel Mystery Oil to 10 gl of gas; that really helps.

Besides a new fuel filter, any suggestions for getting a quick start?

While I'm at it: When changing the t-stat, how much concern should I have for breaking a housing bolt, and how difficult is that to extract? Do these Rangers all run with the temp gauge riding way to the left, around the white hash mark?

thanks for your input...... -Rick

rurouni20xx · Feb 19, 2009

mine stock ran between the n and the o on normal (93 guage) i changed the thermostat and she ran around n. its a 195 degree thermostat stock if im not mistaken, ive ran a 180 degree thermostat and they run close to the edge of the mark towards cold. i did notice however when i put the stock style back in the engine ran a lil better and smoother, i guess cuz the temperature at the heads was more nominal for complete combustion. my engine only overheated and just slightly (the r on the gage) when my water pump went out. she finally died at 280k due to oil pump failure, im going to rebuild it bigger. as far as the t/stat bolts breaking they are 3/8 bolts they can take a good amount of torque, id recommend a healthy coat of peanut butter blaster or knight penetrating oil first, oil of wintergreen works wonders too just to be on the safe side b4 i removed them. i know a lot of ppl prob havent heard of oil of wintergreen you can get it at like walgreens a few drops of it does great. when i went to change my exhaust flange gaskets the bolts were a pain (as always) my 1/2 inch impact wouldnt budge them at 380 lbs torque, a few drops of wintergreen and 5 mins later i removed the bolts w/ a hand ratchet. its that damn good.

austinrick · Feb 19, 2009

You're right about the t-stat - 195˚ is standard. I also ran the 180˚ for several years - ran really cool - but I think it burns the fuel more completely with th warmer t-stat.

Wintergreen oil......I'll remember that!

thx!

austinrick · Feb 19, 2009

Motorcraft Platinum - gap is set at the factory, and they were all in spec. I did not replace wires this time (maybe when the economy improves).

According to a local ace mechanic, there is no timing to set. Other components manage the firing timing. I dunno. But the thing is, in the 180K miles I've driven this truck, the rough idle has not gotten better or worse, except with premium fuel, or temporarily with new plugs. Same mechanic said that some 3.0L's just run rough no matter how much stuff you replace.

So, is a new fuel filter the ticket?

thx!

rurouni20xx · Feb 19, 2009

do you have a reusable air filter (k&n or something?) if so you may have an maf problem as well, id clean it just to make sure it isnt something along those lines. i got happy w/ the air filter oil on accident one time, i rough idled at 600rpm afterwards cuz of it. the only other thing i could think of is oxygen sensors, enuff carbon on those will def cause improper readings w/o throwing codes. as far as ignition timing being completely controlled on the newer models i think they still had a stock baseline timing mark that you could align w/ the computer. if you have the older distributor style id def check the timing w/ a light. glad we could help and welcome to trs btw!

austinrick · Feb 19, 2009

That's good to know, mtnrgr, thanks. No, I've never had the injectors truly cleaned. Used to run Seafoam through the gas tank, and it helped for a while, but now use Marv Myst Oil and don't want to mix them. No throttle body on this one (like my old TBI 3.8L); it's fully injected. I have a timing light. If I can recall how to use it, I'll check that timing myself.

My Haynes book seems to recommend de-pressurizing the fuel system prior to removing the fuel filter. As in, removing the gas cap AND unplugging the inertia switch and turning the engine over for 15-20 seconds. Pop the gas cap, yes, but is the rest necessary?

thx

rurouni20xx · Feb 19, 2009

same for me on the fuel filter, just be prepared to change your shirt...lol. i was talking about cleaning the mass air flow sensor, the part in between your airbox to the tube that goes in the inlet of the intake (your throttle plate, hence thats called the throttlebody, its part of the upper intake plenum mine is the same way.) between the marvel myst oil and the midgrade your injectors should be fine, the oxygen sensors on your exhaust may be a lil fouled up from running over time, and the internal heating elements in the sensors may have burned out as well.

betomonroy · Feb 19, 2009

This all sound good. But the fact of the matter is very basic.
1.- Your truck is hard to start.
2.- Recquieres it's stock t-stat to keep a higher temp on the heads so that it can burn fuel more efficiently.
3.0- Recquires Marvel Mistery Oil in the gas to help.
This all indicates the possibility of running a very tired engine.
Start thinking Overhauling or Swap. After all... She has been very loyal for over 300K miles.

austinrick · Feb 20, 2009

Thanks to everyone for the hints and wisdom.

Those t-stat bolts can also erode and cavitate down to nothing; that's why I'm afraid of breaking one or both. I do not have a budget for getting a shop or pro mechanic involved to save my butt If soaking with penetrating oil or wintergreen is good, cheap insurance, I'll plan to try it, and come back with new bolts regardless.

I had considered the oxygen sensor as something I could replace myself. I have a simple multi-meter and Haynes book; 'spose I could check that part in the driveway.

Thanks for your thoughts, betomonroy. This engine will have to go indefinitely. The compression was good in recent years, mileage is so-so, burns 1-1.25 qt of oil in 3,000 mls. Texas summers without functioning a/c are brutal, but I'm getting used to them. I went through lots of them in the '65 Dodge van with that slant 6 sitting right next to me. I can handle this.

If anything, I need to replace the radiator which is leaking on cold mornings.

rurouni20xx · Feb 20, 2009

damn mine started burning a 1qt every 1000 miles since 220k, i guess yours went thru less stressful miles than mine. one thing that bugged me is when my dad got the trk originally every time you put it in 4wd it would use a qt, ford dealer said dont worry about it. the 4wd was rarely used because of this, then when i rear ended a car it quit working so i just kept driving it. any thoughts on why a brand new engine would do that?

fastpakr · Feb 20, 2009

I must be misunderstanding the question. You're saying that your engine burned a quart of oil when you engaged the transfer case?

rurouni20xx · Feb 20, 2009

when you pushed the 4wd button, and put it in 4wd, you could drive a short distance (we usually used it as a just in case when crossing a ditch or something) and disengaged it, did the backup thing to unlock the autolockers, about 1/2 mile down the road the check oil light came on. check the oil, it was exactly 1 qt low. did this since it was brand new and the dealer down here (the trk was bought in ny but lived in la most of its life) said dont worry about it its normal.

betomonroy · Feb 20, 2009

Oh Rick... I'm not from Texas (thouigh I live in San Antonio). I am from the lower California Desert. So Summer here is incredible cool to me. It's awsome... its refreshing... is wtf... NOT HOT LIKE 127 F.
But anyhow... I admire your intention to go as far as possible. So I hope I can pitch in some help.
Try going lower octane and lower the mixture of Marvel to 3 oz.
Change tha spark plugs to a one level hoter than stock.
Than do a very therall cleaning of the throttle body and IAC sensor.
Make sure you clean these units off the vehicule and on a well ventilated area.
Than make sure You also clean all the related components of your EGR valve. Including the connector and tubing that comes out of your intake.
Since You have been driving on Marvel Mistery Oil I can assure You that this engine components must have a ton of Sludge.
I am sure that this is going to help a lot. I know is a long task... but it will pay for itself. Trust me... it is not expensive and you can Do it yourself. :icon_thumby:

Craftymongoose · Jul 7, 2016

I understand this is a 1993 ranger 3.0l.
If this is correct the ignition time is VERY adjustable.
And since so many people think it isn't, this I an excellent place to begin to address your run/performance issues.
Locate your 'spout connector' and grab a timing light.
You'll need a 10mm socket, wiggler, and about a 1' extension to reach it comfortably from the passenger side.
The base timing is 10* btdc and the distributor sounds way-over-retarded to get bad performance from 89-93 octane.
Mine has been advanced to 13* on regular and 16* running premium as a base adjustment.
Though you can also get a 'premium rod' from the dealer to allow the distributor to compensate for premium gas's spark-curve and then re-time to match it.

Craftymongoose · Jul 7, 2016

And as for using a quart of oil to cross a ditch in 4x4, assuming you checked your oil before crossing and were sure of the loss in just the crossing from level ground to level ground...
-check vacuum routing..?
-valve-stem-seals + tilt?
-checked for pan/block crack that only opens under high loads?

1993 3.0L Hard start / t-stat

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