Hi all 94 reg cab 4.ol 13ok.. my wife just got it, been doing some small things like replaced dome light, replaced cargo/third brake light, truck starts and seems to run ok. but i get a headache in it which i believe is carbon monoxide, has a leak or something? i text previous owner, he said he replaced 02 sensors, but didnt say if they were bosch or a good brand.. also trucks has a oil pressure and coolant temp gauge fitted on by the gear shift as the dash gauges for those functions are out. does this mean the CTS may not be working and affecting fuel/air I do not know these trucks i only just found out what this strange silver looking thing was it is the IAC, I Believe, then there is this black plastic vacuum type cylinder by the passenger side firewall, what is that? and right against the drivers side fire wall is a small reservoir type thingy, is this something to do with ABS? i do have an ABS light on, was hoping it was the bulb out on the third brake light or something quirky like that no such luck its still on after starting engine. but i am concerned about this running rich/strong smell as we really cant take it far as is it, its dangerous, may have to get a smoke test? any ideas appreciated, thanks for reading. long winded sorry , but just got the truck, trying to get caught up..

 

most Ford's have a single wire temp sender for the gauge & a 2 wire CTS for the PCM/computer. The temp gauge will be wired to the single wire sender. I wouldn't worry about the under dash gauge.

Always start with the REALLY easy stuff first.

1. if the check engine light is on, pull the trouble codes. You might get a 338 "coolant temp sensor voltage out of range."

2> Check fuel pressure. If the gauge bleeds down quickly with the engine turned off theres a leak somewhere & that's why it's running rich.

3. Test with a vacuum gauge. Do the test for a clogged exhaust.

You can also remove the 2 wire CTS connector & see if it still runs rich

 

thanks for the reply, i dont have a lot of tools in my arsenal, but i can disconnect the 2 wire cts down by the thermostat to see if that makes any difference. where would i connect a fuel gauge to check for pressure? i dont have one but i know they are reasonable at like harbor freight. what pressure should i look for with the engine off ?

i can fiddle around with the hoses to make sure they are al tight, but i dont know how to do a vacuum check.

I have never pulled codes on a vehicle of obd 1 age, i do on my 97 Towncar with my obd 2 scanner, so how does it work on obd 1? p.s no CEL on at the moment.


lots of questions, its the wifes truck , she just got it, but i am the one who has to get up to speed on it, thanks again, i need as much info as you can provide,,lol. have a good one.

 

Look on top of the engine for the schraeder valve which looks like a tire valve. The last fuel pressure gauge that I bought was from Harbor Freight about 20 bucks. You want the on for fuel injection. It will come with the adapters for your Ford. Screw the gauge on & start it up. IIRC on your 94 should be around 40 PSI. Turn the engine off & watch the gauge for 10 minutes it should stay steady.

OBD 1 scanners are dirt cheap, see if you can find one at Harbor freight that pulls stores & displays the codes. Or you might be able to adapt your current scanner to obd-1. Or do a google search for how to pull codes using the check engine light. With it running so rich i'm surprised the CEL isn't on.

Have a muffler shop check it for exhaust leaks.

 

thanks for info.. i was just outside tinkering after reading your reply
i took off the connector on the 2 wire cts and the cel came on, so i assume that is working, i also disconnected a sensor on the intake manifold towards the back of the engine above and just infront of the pcv and the cel came on, what is that some kind of MAP sensor? i wiggled around some of the vacuum lines, around that black plastic thing by the passenger side firewall, what is that some kind of vacuum storage? as you can see this engine is alien to me, i found a tube off on top of a black box about 10 inches square just below the radiator cap on the drivers side the and it has a black cap on it, and a sensor about 6 inches back, tried to trace them but they disappear around all the power steering pipes/tubes.. what is that? i was thinking about a smoke test for leaks do most muffler shops do that? it gives me a headache prob CO Leaking somewhere, previous owner said he changed 02 sensor but didnt say if they were a good brand as i know that can screw up the computer,, thanks for reading i really appreciate it, as i do offer help sometimes on the lincoln sight, as i know those cars soooo much better, this truck is like a steam engine to me..lol boop boop !!!

 

A 94 has a MAF instead of a MAP. There is an idle air control valve bolted to the side of the throttle body. It routes air around the closed throttle plate. Might be one of the ones you mentioned. Not sure what the other items you mentioned are.

You can thank me for this suggestion later. Go to helminc.com & order the 1994 Ranger " Vacuum & electrical troubleshooting manual". It will give you the location of every sensor/fuse/electrical connector/splice etc etc on the truck. It's so much easier to fix electrical problems when you have this manual. About 20 bucks

 

I checked it out they only have the basic manual for glove box, but i found one on amazon. I did clean the MAF, Its right next to the air filter box, has two torx screws on it, have to work next couple of days 12 hr shifts , so it will be on hold. thanks all for your input thus far

 

I was going to try to bleed the clutch on my wifes 94 4.ol , but need some assistance, but while i was out there i replaced the VSS on the rear diff , as it has a permanent ABS light on after start up, now it is off, so i didnt get the clutch done but no lights up on the dash !! i did contort myself under the dash by the pedals and you can tell someone has been there before as the clip around the bottom of the interlock switch is all mangled and the rod where the piston attaches to the pedal, there is nothing holding it on , if you hold the switch and depress the clutch it the pedal slides right off. what should be there a split pin or circlip? thanks for reading

 

an update on the 94 4.o l, i tried the old carb cleaner to see if idle changes trick, didnt seem to do anything, i have looked around and checked vacuum connections they seem to be ok. i couldnt get the throttle sensor off to clean that, so maybe a possibility? i checked the fuel pressure it is 30 at idle and seems to hold for abut 10 mins then goes down to 25 but i think that is the actual gauge leaking even though i put thread tape on both ends..
so any suggestions greatly appreciated otherwise come payday next i am going to have to go to a muffler shop for a smoke test.thanks for reading
p.s will have to check fuel pressure while under load what should i expect?