87 tbird wont idle.

Topic: 87 tbird wont idle. (Read 2303 times) previous topic - next topic

87 tbird wont idle.

December 09, 2011, 04:50:30 PM

ok first off, it started dying when I would stop, at first it started right back up. I looked on here and decided to clean my iac. I cleaned my iac and drove for about a mile before it died suddenly. I have cleaned the iac, replaced the ths, new fuel filter and pump, new tfi. I checked iac and tps and their respective wires with a volt meter and they all checked out. Now the car is out front of my friends house and it will randomly start, and drive until i take my foot off the gas then it will die and wont start again for several minutes. I have no idea what to do now and I have no money to start buying parts hoping to stumble upon the solution. any ideas?

87 tbird wont idle.

Reply #1 – December 09, 2011, 05:25:21 PM

87 tbird wont idle.

Reply #2 – December 09, 2011, 09:01:20 PM

From the symptoms you mentioned, I'd bet BIG money you "profile ignition pickup" is bad. Ford guys call it the "PIP.". Non Ford guys call it the "pickup coil.". It's inside your distributor. To replace it, you have to remove the distributor gear and then take the distributor apart. If you DO have a bad PIP, I'd recommend going to AutoZone and buying a new distributor. You can buy a remanufactured distributor from them (with no module) for just $60. In most cases, it's not too much of a pain to replace your own PIP. If you're not mechanically inclined, it would probably be best not to try replacing it yourself.

87 tbird wont idle.

Reply #3 – December 09, 2011, 10:03:18 PM

I als

87 tbird wont idle.

Reply #4 – December 10, 2011, 01:27:16 PM

Haystack hooked me up with a new pip, though now we are thinking its computer related. Im going to yank out mine today to see if its got any bad connections.

87 tbird wont idle.

Reply #5 – December 10, 2011, 02:03:42 PM

87 tbird wont idle.

Reply #6 – December 10, 2011, 02:36:45 PM

Can you swap the IAC with a known good one...do a visual on your old one at least...sometimes they get the little hole gummed up and need cleaning...

What about the TFI (the flat thing that is screwed to the side of the distributor) You'll need a special tool to take the torx bolts out, but it too could be suspect. Again, test a known good one in it's place. Be sure to use heat sink compound on BOTH surfaces when you reinstall for good. They need all the help they can get to keep from getting hot...

And, since no one has asked...any codes?

87 tbird wont idle.

Reply #7 – December 10, 2011, 02:45:09 PM

I cleaned the hell out of my iac, the tfi was replaced three weeks ago. No we tried to pull codes but it doesnt work which is why we think its, the computer

87 tbird wont idle.

Reply #8 – December 10, 2011, 04:45:08 PM

Pulled the eec and opened it,up and it looks fine, no burns no,black marks or anything. Tested the wiring between the computer and ,y tps and it looks good so im out of ideas again.

87 tbird wont idle.

Reply #9 – December 10, 2011, 05:32:28 PM

To add to this. We were getting 12v at the tps on both orange and green wires, and no ground on the black wire. His map sensor also red 12v on the green or orange wire can't remember which.

We checked my crown vic at it was 5v and 1v and 5v on the map wire.

Right now I am guessing whatever regulates to power down to 5v is burned up. We need to look through some diagrams and figure out if the ground runs through the computer, and what pin it would go to, or where it grounds to make sure we don't have any broken wires. Right now I doubt it is a broken wire, because it would only effect one wire on the tps, not both. And especially less likely the map sensor.

I doubt it is the tfi. We swapped that a couple weeks ago. We were also getting 12 at the coil, injectors and tfi. One thing we have not done is loosen the dist and turn it to make sure we are firing injectors. I think 12v where we should be getting 5v, as supplied by the computer, needs fixed before we go too much further.

After pulling the ecu, we check continituity between pins and tps sensor. Couldn't get anything for ground on tps. Through any grounding pins to the ecu plug.

So I thin if we can figure out where the ground is, and if that's okay, it must be the computer. There is a fair bit of assumption there though.

87 tbird wont idle.

Reply #10 – December 10, 2011, 05:40:43 PM

Also, no codes. Check engine won't light up. The volt meter trick works, but my harbor fright cheapy volt meter display updates too slow to read the voltage change. If you hook up a test light, the voltage disappeared. I assumed it was bad wiring. If the ground for the test port runs through the ecm, it would make sense that if it was or is burnt up, it could respond that way.

87 tbird wont idle.

Reply #11 – December 11, 2011, 07:38:19 PM

Eec ground. Runs now.

87 tbird wont idle.

Reply #12 – December 11, 2011, 07:54:13 PM

87 tbird wont idle.

Reply #13 – December 12, 2011, 04:02:50 AM

usually the root cause of this whole 'blown sig return" is that someone at some time was trying to bypass the fuel pump relay in the trunk and injected 12v up the ass of the EEC (tan / light green wire).

like tom said just for FYI, if you ground the tan / light green wire and the car runs,, EEC is toast,,,
One side symptom of constantly grounding the tan wire is that your fuel pump will run continuous when you turn the key forward.
The fuel pump will take much longer to shut off when you turn the key off because its now waiting for the EEC relay to de-energize instead of the earlier de-energizing fuel pump relay.

The time delay on the EEC relay is a tad bit longer.

actually, i ran a 3.8L engine with this very problem for a long time with no noticeable adverse effects, kind a surprised me. .. it also would not give codes.

87 tbird wont idle.

Reply #14 – December 12, 2011, 04:09:55 AM

so you are ground sigrtn to the grounding pins(20,40,60) and checking connection between them? We did not actuall test the pins on the computer. To be honest, I pulled a brain fart and didn't realize the sigrtn was the ground for the tps sensor.

What we did today, broke into the car because we locked the keys in it. Threw in my mustang eec to check voltage on the tps wires. It was 12v when I checked it. I was sure it was a ground issue, when I realized that I was getting 12v on the sigrtn wire. Figured out the ecm ground ran to right behind the battery. On the grounding wire, SOMEONE cut out the connector between the harness and the ground location and it was not making a good connection. Re-twisted the wires and then had 5.1v at the tps and sigrtn had a good ground. Turned the key and it fired right up.

I think what was happening is the ground that was spliced in had a bad connection, and the test light pulled enough amps to overload the ground wire. Just a guess. If my buddy hasn't put the trim panels back in and re-mounted the computer, I will have him check connection between those pins in your picture.