Topic: rich problem, the smell of defeat

[82expghost]

OK for starters, i have a 77 pinto with a 2.3 turbo motor and harness from a XR4TI
upgrades include
equal length turbo manifold
front mount intercooler
walbro 255 with aem fuel pressure regulator
knife edged intake
LA3 ecu

sensors that i have thrown at the problem
tps
idle air solenoid
new brown top injectors/ remember LA3 ecu
new tfi harness/ pigtail (old one turned to dust) (wires soldered on, no butt connectors)

there may be more i am leaving out, ask and i will answer

for the problem now, i have been driving my pinto for a month now without issues, was super fun to drive, couldn't keep the rear wheels still, after driving for a whole day straight (4 hours of driving) was running fine, turned off car, about 2 hours later i came out to start it and all it would do is pop and blow flames out its butt, so i had to push it around the block to my garage. tested the system and found my fuel injectors were to blame at first, pressure the system to 41 psi and turn pump off (key never on, aux switch for pump) and noticed it would drop to zero in about 5 second flat.
ordered new injectors, they hold pressure for the whole day, maybe drop 1 psi after 10 hours.
feeling better, started the car, couldn't hold idle, finally after adjusting the tps and idle screw i got the car to idle smoother, alittle rich smelling.
went to take for test drive and have absolutely no power, i can idle from a dead stop to about 15 and then starts to pop and buck like i have 60 degrees advanced. but car can sit in one spot and rev freely
pulled back in the garage and checked timing over, all points line up right, checked timing 10 degrees btdc with pip unplugged, in right spot
checked voltages of all the sensors and everything is in range

I'm defeated, any suggestions?
and today my new motorcraft Copper plugs and motorcraft plug wires will be going on since stinger and svo forums said the duralast plug wires can cause the same issue
any body got ideas in case the wires and plugs are not to blame?

[82expghost]

for everyones silent questions
i changed the plugs and wires, still have a huge dead spot and has no power under load

so now my next question
anybody with a 88 thunderbird ecu and motor, I do not have a obd1 test port, so i need a detailed description of what color wires are where on the plug, or a good picture with the wire colors showing, I'm at the point I'm going to check ecu codes and possibly meter all the pins to find discrepancies

[oldkayaker]

With you using a XR4TI harness just checking that you repined the computer connector for the LA3.

Since it was running good one moment and bad the next, I would assume something stopped working properly, i.e. a component died, one of many grounds came loose, a crank or cam key sheared, or.  The orange ground wire on the turbo compressor housing seems to be important.  Since you got into the TFI harness, make sure the cable shield is still there.  With wiring "turned to dust" could indicate other areas of the harness may be in bad condition too which could make finding the problem hard and time consuming.  Running the computer codes should help.

See links on wiring and running codes.
http://www.turboford.org/faq/88_ford_t-bird_complete.pdf      see figure 2 about 2/3 of the way down
http://www.rothfam.com/svo/reference/88Thunderbird.pdf
http://www.tomco-inc.com/Tech_Tips/ttt6.pdf

Based on the above, install the meter/light between the battery positive and the yellow-black wire going to computer pin 17 (STO), jumper between black-white wire going to computer pin 46 (SIG RTN) and the white-red wire going to computer pin 48 (STI).  Having not done this, please check links for correct interpretation .

[82expghost]

I have checked multiple times with the harness, its pinned right, for hours it ran with this set up, it would be probably around a week or about 200 hours of driving, I pulled the dizzy and didn't find a hurt teeth on the aux shaft or on the dizzy gear. I will check the cam and crank key, that's going to be a pain, so im going to run codes first. I checked the vam and it has all the correct voltages. the baro electrical was correct also, the tps was the only culprit I have found, and fixed it, its only problem was it would not max out at wot.

next question is, the ect (engine cool temp) what should its votage be and or resistance?

[oldkayaker]

I agree it is more likely to be a electrical problem than a mechanical one.  Running the codes should give a idea of what is going on.  From reading, EFI's are very susceptible to grounds that are not perfect (loose connection).  A unlikely but possible problem with these old computers is the electrolytic capacitors going bad, see link.
http://sbftech.com/index.php/topic,15654.0.html

These links show the ECT characteristic s along with that of other sensors.
http://www.rothfam.com/svo/reference/sensors.pdf
http://web.archive.org/web/20131229172303/http://oldfuelinjection.com/?p=10

[82expghost]

both of the sets of attachments are great, the scanner comes in today, and im going to wire some jumpers in the harness to the scanner and try that out

the tfi plug was crispy from old age, i havnt found a tfi plug from the 80s that wasnt

i cant wait to check some of the sensors, i have a feeling im going to be removing the harness, i might know the grounds that are wrong, the ecu has two grounds that i have noticed, ecu body ground and sensor ground, the merkur electrical book just stated ecu body ground and the sensor ground had the symbol of the dot with three lines indecating grounded out, i now know that is wrong and it should be not hooked to chassis and sensor ground should have a uninterupted path from sensor to ecu on its "ground"

i feel like im finally getting somewhere!
Thanks oldkayaker!

[82expghost]

so the first thing i did was remove the harness and check all its wires before running tests, and right off the bat i found where ford had multiple constant 12v wires heat smashed together has fallen apart and was rubbing the sensor ground wires which were also falling apart, so hopefully today i will be done soldering all the points and heat shrink wrapping them, and adding a obd1 plug in under my dash. then to test run the engine again and check for codes

[65ShelbyClone]

Yeah, I disassembled the '86 Thunderbird harness that is in my car and it was a wild ride to say the least. I should have just bought a MegaSquirt harness and next time I will, but my budget was down to pocket change in a tin can at the time.

It's beaucoup bucks, but aftermarket stock 2.3T harnesses are still available if things get so bad yours has to be replaced.

Confucius say man who smell defeat should change socks.

[Wittsend]

First, my sympathies. When I did my swap my car would idle with a miss but at wide open throttle ran well. Worse yet, at about 2,500 RPM it had a noticeable miss. You could see it in the tach too. I did EVERYTHING and nothing seemed to change the problem.  I dealt with this for nearly three years.  Then on my 101st attempt (figure of speech, not actual number) to find the problem I in frustration hooked the 12V + directly to the coil and the problem pretty much went away.

 Rather than trace the problem through the harness (and anyway the harness HAD the correct voltage at the coil) I just put a relay between the battery and the coil, activated by the ignition switch. 3+ years and I'm still doing well.  BTW, I used the ill advised 88 T/C harness, sorted wires for what seemed like a week and still had about 15-20 "not sure of" wires.  My effort to use everything Turbo Coupe (relay box, alternator, etc.) did NOT workout to the advantage I thought it would.

So, yes there is obvious discouragement, but don't let it be defeat.

[82expghost]

Update on my issue,....... FIXED!

I was ohm ing everything like a mad man and found that most of the time the sensor return for the tps and vane and baro kept hitting 5.8 volts even though nothing was wrong with the tps or vane or baro, i fixed all the old nasty wires ford messed up with their smash style what ever you call it conections, they are all soldered, but theat didnt fix the froblem, and thats when i used the pages for ohming every thing that oldkayaker posted. i finally found the issue was that negative signal return ohm was 4.7,... its suposed to be .1 So i kept checking the harness till i got to the ecu, checked ecu pin for neg signal return against negative battery pin on ecu and still had 4.7 ohms

Next step was take ecu apart and look at it for anything noticable that would cause issues, took me 10 minutes tracing lines when i saw a bubble in the gelcoat of the board, poked and prodded it and found that signal return was broken on the board. Not burnt in any way, allittle amazed, so my next step was to solder a wire from one point to another and see if that fixes the proble, note to anybody attempting this, use alot of resin, its old and hard to get to act like solder, but i got a 3/4 long wire soldered to it and put it in the car and tested it to see if i still had problems

FULL RANGE OF THROTTLE! woo fixed it!
 i would post pics but this site doesnt alow my pic types

[Wittsend]

Congratulation on the fix. And, yes, Jerry (Old Kayker) has come to my rescue with great information too. Me, I've got the original LA-3 in the car - and two spares LA-3's in my desk drawer. :-)

[oldkayaker]

Congratulation s on finding the finding the problem, amazing tenacity.  I do not recall ever reading about a circuit board trace separating like yours did.  Spare components including computers come in very handy when trouble shooting.  Having refurbished the wiring harness, you have headed off some future problems.  In addition to having a running car, you now have a more intimate knowledge of your car's inner workings (maybe more than desired).

It finally occurred to me what "smashed" connection meant.  The normal term is "crimped" connection.  When done right with quality lugs and crimper, the crimped connection is great.  There have been some on line discussions on the merits of crimp versus solder for signal level connections (usually no conclusion reached).

[65ShelbyClone]

What Ford did is or something like resistance welding. Here is an example, although Ford's production-level welds really do look ugly and smashed, especially after 30 years in a harness collecting dirt and tape goop.

http://www.assemblymag.com/articles/91832-the-splice-is-right

Update on my issue,....... FIXED!

Next step was take ecu apart and look at it for anything noticable that would cause issues, took me 10 minutes tracing lines when i saw a bubble in the gelcoat of the board, poked and prodded it and found that signal return was broken on the board. Not burnt in any way, allittle amazed, so my next step was to solder a wire from one point to another and see if that fixes the proble, note to anybody attempting this, use alot of resin, its old and hard to get to act like solder, but i got a 3/4 long wire soldered to it and put it in the car and tested it to see if i still had problems

FULL RANGE OF THROTTLE! woo fixed it!

Bravo! Most people would have stopped at the ECU plug and just gone searching for another computer.

I opened up an '85 PF2 Merkur computer I have and it looks like an old desk phone inside. The only thing it's missing is curvy traces from hand-laid masks. I think they started using surface-mount components on a single board in '86 or '87.

[oldkayaker]

Thanks 65ShelbyClone for the article.  I have not kept up with the times and never seen/noticed that type of splice.  It looks like a more efficient production method and you do not have to worry about using a quality lug. 

[65ShelbyClone]

The only reason I even know what "resistance welding" is is because they do some where I work. Most of it involves welding mission-critical electrical contacts together.