MAFS testing

[Xeek]

- tps measured 1.07V closed, smoothly rised to 4.54V at WOT. i turned the idle screw down until closed throttle reached 0.97V. now its 0.97-4.54V nice and smooth.
- new IAC read 0.98 ohms on the sensor itself.

from easyautodiagnostics: The TP Sensor’s connector is BAD, usually the locking tab is broken and the connector has worked itself loose, causing an intermittent false connection.

tps connector has 2 locking clips, one is broken off. other then that, the maf clip is broken, coil pack clip is broken, all 6 injector clips are broken.
ive played with the idle voltage and giggled the clip so maybe itll fix itself now. no idea.

 

[FIND]

Check your connection on your ECT too where you spiced in for your fan controller.

 

[Xeek]

i tried to take the plug off to check the sensor but i couldnt grab it to well so i left it for now. ill do it tomorrow then. ill get the ohm reading of the sensor. and for voltage: ignition 'on', lead on signal wire and other wire on neg post on battery? thats what i did for the tps anyway

 

[Xeek]

turning it down to .97 via the idle screw made it so i had to hold the gas until the temp gauge got to the first notch in the normal range until itd stay on by itself, at 500rpm. that makes me think the idle is way to low, but it should be perfect once my problems are fixed.
after driving, 850 rpm. in park 1300rpm

but no CEL at all...... strange.

i wont get the ect reading until after work. slight chance during work.

 

[FIND]

No, I meant to test your signal from your ECT after where you spliced the wire for your fan controller. Be sure that you have a good connection and that the circuit for the fan controller isn't changing the resistance to too great a degree. You may have the fan controller working fine on that circuit, but in a parallel circuit, resistance drops.

In parallel circuits, the resistance of the circuit is equal to the reciprocal of the sum of the reciprocals resistances of the circuits. In other words, if you had 2 100 ohm resistors in parallel, your total resistance is equal to 50 ohms.

1/R = 1/R1 + 1/R2, so 1/100 + 1/100 = 2/100 = 1/50, so 50 ohms.

Of course, I am not sure how your fan controller works precisely, so it may be that its circuit offers significant resistance, in which case it wouldn't effect the circuit greatly. But there is still the chance you have a bad connection where you spliced. First thing I learned when I was a diesel mechanic, where there are splices in wires, that is where the wiring has failed.


Also, like I said about the CEL, doesn't surprise me at all. Some sensors like the ECT and IAT can be almost completely shot and they won't throw a code. Actually, it takes an awful lot to make a first gen throw a code now that I think about it. Check engine lights are pretty serious on a first gen.... not like later models where it comes on for every little thing, like a slightly loose gas cap or other such nonsense.

 

[jd4242]

turning it down to .97 via the idle screw made it so i had to hold the gas until the temp gauge got to the first notch in the normal range until itd stay on by itself, at 500rpm. that makes me think the idle is way to low, but it should be perfect once my problems are fixed.
after driving, 850 rpm. in park 1300rpm

but no CEL at all...... strange.

i wont get the ect reading until after work. slight chance during work.

Thays not how you set it.you need to unplug the tps,start and set idle to where you want it by the screw then plug it back in.you adjust the voltage by loosing the two screw on the tps and moving it back and forth till you get the voltage you need.

 

[Dono]

I say cut the temperature sensor wire to the fan, and just wire the fan so its on all the time (Just for a morning) and see if your issue goes away.

I can see the resistance (Less resistance, actually) of something else on the same temperature sensor causing issues.

 

[Xeek]

No, I meant to test your signal from your ECT after where you spliced the wire for your fan controller. Be sure that you have a good connection and that the circuit for the fan controller isn't changing the resistance to too great a degree. You may have the fan controller working fine on that circuit, but in a parallel circuit, resistance drops.

Of course, I am not sure how your fan controller works precisely, so it may be that its circuit offers significant resistance, in which case it wouldn't effect the circuit greatly.

i was gonna test the sensor itself AND while plugged in at the plug. my splice is done with a quick tap thing and wrapped with elec tape about 5" after the plug. and covered with conduit.

my controller specifically says in the manual to splice the signal wire on your ect. and for older cars without one, buy that companys sensor to use, which is a ect that threads in. so i doubt it would be stealing power and creating a lower signal to confuse my computer. unless its wires are wrong.
but.. before i had the controller, i had a flip switch behind my headlight for the fan connected to the battery, and i still had a cel for #41, lean back then.

Thays not how you set it.you need to unplug the tps,start and set idle to where you want it by the screw then plug it back in.you adjust the voltage by loosing the two screw on the tps and moving it back and forth till you get the voltage you need.

i had done that a long time ago. but then i started messing with the screw in the summer to get more 'lope'. now i had to raise it due to stalling in the cold. so if the sensor didnt get loose and shift, all i had to do to fix it is reset to screw til i got the right voltage.

but just to rule out anything, i will try what you said. what am i looking for fully warm and in park with the tps unplugged? 600?



the reason i ever messed with the screw, just to mimic this(idle), which it did sound like this morning:
http://www.youtube.com/watch?v=5WT-MsjenzY

 

[Xeek]

I say cut the temperature sensor wire to the fan, and just wire the fan so its on all the time (Just for a morning) and see if your issue goes away.

I can see the resistance (Less resistance, actually) of something else on the same temperature sensor causing issues.

i just posted about that then saw this.

i had the fan directly wired to the battery with a switch mounted behind my headlight and fused for a month or so waiting for my controller to come back. i still had the lean cel back then, but being it was during summer, it didnt try to stall like it does now in winter.

 

[Xeek]

Also, like I said about the CEL, doesn't surprise me at all. Some sensors like the ECT and IAT can be almost completely shot and they won't throw a code. Actually, it takes an awful lot to make a first gen throw a code now that I think about it.

its a little more then that, this is only the 2nd time since april where ive driven and NOT gotten a cel for being lean. so it surprised me








i havent mentioned yet that i hate electrical gremlins. so..
i hate electrical gremlins. all gremlins actually. except the ones from the movie

 

[FIND]

they are fine as long as you don't feed them after midnight.

 

[Xeek]

ohm tested the ect itself. 4.01 and kept rising to 4.30 before i took it off. it had been cooling off for an hour according to the chart on the site below, it would be ~165F. seems right. http://www.oldfuelinjection.com/?p=28

for the wire harness, you you want me to test on the sensor side or the ecm side of where my splice is? this is difficult as i dont have the special tool to do this. i just have one with sharp probes that arent 'brand new' sharp anymore




just cause you asked jd, i wanted to make sure and rule it out. i unplugged the tps and started it. it idled at 600-650rpm. after revving it a few times it settled to 650-700rpm. cel of course. i did not touch the idle screw, so that means the tps should be aligned correctly at .97v still.

i do need to take a pic of my tps harness. it might very well be the problem, one of the two clips is broken off completely. i can visually see it angled slightly due to one side not being locked down.

 

[FIND]

A visual inspection of the splice will probably work. You just want to be sure that there is no corrosion and that the primary wire hasn't broken. If the controller advises you to put it on the ECT, the circuit it uses probably has significant resistance and won't affect your ECU, so I guess there is no reason to test after the splice. While you have it off though, it is a good time to strip some of that insulation off and solder it all together instead of using one of those junk clip on splices.

For your TPS, try applying some SMALL dabs of dielectric grease to the pins, then put the harness on. Once you have it in place, go around the plug with a nylon zip tie so that it is tight, then it shouldn't move around so much. You can wrap a little electrical tape to hold it to the TPS too if you are feeling frisky.

Also, reach between your UIM with a long screwdriver and push on each plug for the injectors to be sure they are 100% seated, since you said the clips were broken on a couple. Also, what kinda shape is your PCV in?

Last thing I would recommend testing..... The harness coming off the MAF, hold the wires straight so they don't bend using some type of splint like a Popsicle. Then start your truck and see if that solves your problem. I just saw a Taurus today with a bad idle, I was going to stick my probes in the plug on the MAF and check it, but once I grabbed the wires the idle evened out. I cut the wires an inch back from the plug, repinned the plug and it fixed it. One of the wires were broken inside the insulation. Food for thought.

 

[Xeek]

yea i dont like quick plastic splices either. but i dont have a gun or know howto use it so i stick with those.

good tip on the clips. ill zip tie the hell out of it. i have some of that grease also to use.

i was gonna test the ohms on the injectors but couldnt get in there, but ill see if i cant make the clips go down at all.
pcv was brand new in march. but i had it hooked up to an oil remover:

i removed it a month ago due to it always pulled the pcv halfway out of the valve cover from the weight. and the filter was tapping on my booster while driving and it got annoying.


maf wires, i wouldnt be able to see it, its all hidden under the insulation right? i know when i pulled the rubber guard back off the plug my wires looked like an "S"

 

[FIND]

No, you probably wouldn't see it. Those kinds of things tend to be tiny breaks under the insulation, and the gaps are sometimes small enough that current passes through, but the minuscule gap increases resistance in the wire. Once the wires warm up, the copper expands, and therefore the gap shrinks lowering resistance. If it is small enough, it wouldn't cause you to throw a code.

Turn your MAF 90 degrees, you use a cone filter anyways, so you should have room to do it. That should make the wires straight enough that if there was a break under the insulation, it would be joined.

I like the oil separator idea by the way! Next time you are gonna have to mount that to the firewall.... Though, it probably doesn't do much, but I bet your UIM stayed cleaner than mine while it was there.

As for zipties, you just need one going around the plug end of the harness, the circumference of it, just to make it tighter when you push it on the sensor.

 

[Xeek]

turning 90* doesnt work. its not in the stock position anymore ive turned it some. easy way, what should the plug face?

for the filter, i need a way smaller one. it was jsut to large. i have no idea if it got clogged and bypassed everything, or if it jsut didnt work for me. cause my upper intake has a lot of gas/oil in it. unless something else was throwing it in there..

ill have to figure out something for the zipties. i was like 'awesome idea!' then went outside and looked and was like 'what the hell??' lol i tried to make an "X" but it kept slipping and squeezing the wires. i did put dielectric grease in there tho

 

[Xeek]

i unwrapped my ect splice. without undoing the splice and looking in there everything was still tight and wasnt exposed. so i wrapped it back up.

and how do you suggest positioning this?

 

[FIND]

rotate it so the plug points down

 

[jd4242]

rotate it so the plug points down

Huh??i think thats the right way there.thats the direction they come stock

 

[Xeek]

i know what he means. he said to keep the wires straight. having it pointed down hangs the wires straight down. i figured that out shortly after posting the pic.

although it was warmer today. normally i start it at 5.30am in 30* or at 4.30 and its only 50-ish.
today it felt like 60 something, i threw my jacket off.
anyway, with that temp difference, i rotated the mafs, and ziptied the tps. it still wanted to stall, but it got better before it reached the C on the gauge. which cant be but 100*? normally itd have to reach the N in normal.


i really want to say, start from scratch with a junkyard harness and possibly ecu?
im deff gonna strip it and test all the wires and put fresh conduit and tape on it. problem is theres only one 1st gen at the junkyard and its a 93(o2s, egr, all that crap). no idea whats going on, normally they have atleast 5 at a time :/



edit: i forgot to shove the injector plugs tighter. ill try that tomorrow