kd460

Started fishing the TPS wires out of the main harness last night. I agree with kandgo, it gives your fingers (and patience) a work out.

Well, I've managed to get the wire out all the way to the firewall. I started at the tps and worked my way back. The curved dental pic is a great tool for this (thanks for the suggestion Rick). All I have left is separating from the loom along the firewall to the computor. I'll manage that this eve. Have a few questions:

My first problem encountered is the ground wire. I believe it's the ground wire, it is black with a blue stripe). Following along the loom, at about the back of the inj. pump (near the master cylinder area), the black/blue wire joins another black wire. This black wire is thicker and appears to have heavier insulation. I can not separate this black wire from the harness. So I continued to separate just the orange/green and the purple/white wires. I did put the black/blue wire into the new loom untill I ran into this split/splice.

Should I separate this splice and add a ground wire all the way so the ground is in the separate loom with the other two tps wires? I remember kandgo stating that his ground wire ran to the front of the black and terminated up there?

It would be easy to just reroute and terminate the ground wire up front on the block somewhere, or just snip the ground wire at the splice and run new untill I get to the computor and reconnect. Am I wasting my time with trying to separate the ground wire from the rest of the harness? I could just route the other two wires into the separate loom and leave the ground the way it is (in the min loom).

Also, I just have the new loom running along the side of the old main loom. Is this OK? Is it separated enough to cut down on interference routing it this way?

I have yet to drive it since separating about 2/3 rds of the distance of wire. That will happen in about an hour. So I don't know if I have any improvements yet. Or I might not se any untill it is all done.

One other quick question, has anybody tried this TPS mod?

TPS Filter Construction - Bring a dead TPS back to life

Steve Clayton Gemcuttr1@cs.com sent this simple technique for filtering the output of a noisy TPS.

I did some experimenting and found that an electrolytic capacitor (440 microFarads, 35 Vdc) with the negative side connected to the SIG RETURN wire and the positive side hooked to the TPS SIG wire gave me absolutely *troublefree* operation! Even though my TPS is basically trashed, the capacitor filters out almost all of the electrical noise, and my auto tranny once again shifts like factory-new!

I dug into the wire bundle coming out of the PCM and soldered the capacitor as close to the plug as I could manage - thinking some "TPS problems" may actually be wiring/connector problems in disguise.

Results with other values were:

220 mF, 35 Vdc - too little filtering. Tranny a little flaky.
1000 mF, 35 Vdc - far too much filtering, and a 1.5 second delay in transmission shift response crept in.
BTW, I might add that since I added the capacitor, my cruise control hasn't dropped out even once in 15K miles - usually a twice-per-week occurence (I drive 1500 miles a week). What I believe is that the dropout problem is caused by an electrical noise spike from the TPS - which is *exactly* what the capacitor filters out.

Please consider this tip a free gift for oilburner fans! The capacitor costs just 40 cents, and I hope it will save TDR members and others lots of money! After all, you can by a lot of #2 diesel for $200! :-)

Just curious if anybody tried it and what was the results. Thanks, Kevin

kandgo

I left the ground wire alone with no problems,ranthe wires in a small wire loom protector from wally world and zip tied it back to the main harness. The next day after seperating the TPS wires, I took off on a 2000 mile round trip with no TConv. problems at all, while I was close to the pcm I went ahead and wired two switches for a TConv. one hidden under the dash that kills the one on the dash so as if I let anyone use my truck IE: the wife or the girls they cannot use the TC switch and mess something up. I also soaked the TPS with dielectric contact cleaner if you remember and then some dielectric grease on the shaft and it has now been close to 3000 miles with no problems at all, either TC or cruise. Glad to hear your problems went away also. Goodluck,,,Rick

kd460

Thanks Rick, thats pretty much what I did. I left the ground in the main harness and worked with the other wires only. Same thing for the wire loom. It follows the main harness.

I took it out for a test run the other day (the complete re-routing is done) and the first thing I noticed is overdrive kicks in about 5 mphs later than before. It was only about a 5 mile test run so the jury is still out. I did reset my computor (diconnected batteries) last night. I'll go out for a ride today to see what it's like.

I want to recheck my voltages on the tps to see if anything has changed from just doing the rerouting. Thanks, Kevin

Swamp_Donkey

Very interesting with the capacitor's. I wish I wasn't such a meathead when it comes to anything electrical. It is the ONLY thing that always gives me greif on my truck. When I get back out of the bushes in 3 weeks, I am going to see if I can fine tune my TPS, kickdown, shift points etc.

220 mF, 35 Vdc ........... don't even know what that means! I got alot to learn. Might as well give it a try one day. Whats the worst that can happen? I will chop up some more of the factory wiring and make things worse. Story of my life.

kandgo

Hey KD460!! If you do not like the later shift on the overdrive, You can adjust it out somewhat with the tps voltage via the linkage, as you know. You can go to far and have the down shift problems, but there is some room for it. I prefer the later Over drive kicking in as it lets me up the rpms and line pressure on the trans. Even with the reflash I had done from the dealer on the Over drive, I adjusted mine further up to around 50 mph wich suits me better. As you have found out it sure works getting them wires out of there. SwampDonkey I have been away and just yesterday read about your nightmare!! Glad to hear you are making headway on it!! I know it is a pain to mess the factory wire harness as in taking out the originals all the way to the pcm but it really dosen't take that long, Your problem as you have found out is when you cut the wires. Goodluck, Rick

Swamp_Donkey

Well....... even after re-wiring the tps, it is still jumping in and out of lock-up. I took it for a longer test drive. Also it took about 3-4 seconds and almost 60 mph to go into OD. I might as well throw in the "new" TPS.

Kandgo.... where is the info on the shift linkage adjustment. It will be another 2 days before I can get my FSM back! It is light years ahead of where I was a week ago, but still needs help. I thought I was done with it.

kd460

Swamp_Donkey, as far as the capacitor, they look lile a tiny household flashlight battery. I'm sure you have seen them before, you just don't know what they are called. Radio shack has them for a buck or two at the most.

I picked one up but never installed. The value was a little diffrerent, 470mF (mF microfarads I think), 35 vDC (volts dc current). But that value does not matter cause in electrinics there is always a perentage allowed to be off in this case plus or minus 10%. Resistors are this way as well.

You won't have to cut any more wiring. The capacitor is like a little can (beer can that is ). With two stiff bare wires coming out of the bottom. You can put the wires into the connector the same way you put a safety pin or a paper clip in to hook up your meter. Just tape it to the wires to hold the can and give it a try. If it works, then you can solder on some pigtail wire, protect the capacitor, and install it permanantly. I'll be interested to hear how it worked out.

It was also mentioned (Infidel I think) to check your trans temp sensor. I would consider this if not check already. The next thing would be continuity in the tps wires that you have been working on. You never know. I agree, since you have it, change out to the new TPS.

BTW, a condensor used to be used in old cars and motorcycles back in the days of points ignition systems. Although I don't have any experience with them, cause that was waaaaaay before my time... (ha ha)

Sorry for your frustrations. Keep pluggin away at it. You'll figure it out. Good luck. Kevin

Swamp_Donkey

What is happening now is it is like the tranny is comepletely slipping out of gear. Almost like it is supposed to be locked up, but nothing is connected. Driving along and the tach will zing up to 3000 rps with no connection to rear wheels. Pop it into N and baby it for awhile and then "something" is happy and the tranny feels just as strong as usual.

Please tell me I can hook up my mystery switch and all these problems will be gone! I am hesitant to do this, because I have eaten up 2 pcm's already. Still got one of my old eaten up pcm's. Both VB have done this flaring thing, so chances are that it is not inn the VB but with my lovely electrical system.


All this is still happening even after the "new" tps. this temp sensor is it the same one as the gov press sensor? Or is it the one by the shifting linkage?

Good golly I am in a world of hurt.

Swamp_Donkey

Just doing a little more thinking. Should I have spliced into the orange/blue wire as well. I also just chopped that one. Could that be part of my problem?

kd460

If your saying to re-install the orange/blue wire back to it's non-bypassed state, then do it. I don't think there is a splice in that wire but it can't hurt.

What about the ground (black/blue) wire. Did you bypass that one? Cause that definetely has splices in it. If that has been rewired, then hook it back up to it's original.

Also what about a good old fashoined ground on the tranny or pcm itself. Are they in good shape? How about any fuses or relays. Did you check them? Sorry, I'm not a pro when it comes to this but just trying to help. To me it sounds like electrical (like your thinking) and the most obvious would be a bad ground.

So check continuity of the TPS wires, then check for a good ground, then check electrical components on the tranny.

The mystery switch may help till you figure out what the problem is, but you still have the problem. If used the wrong way, the mystery switch can kill the tranny. The problem you are experiencing will still need to be addressed. Hook everything back up to original and go from there. Good luck, Kevin

infidel

Swampy, try the 1k resistor trick on the temp sensor like I suggested. The wire goes into the trans on the drivers side and is seperate from the one to the gov press sensor.