Forum > It's all about the Turbo...

rich problem, the smell of defeat

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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
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?

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

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.      see figure 2 about 2/3 of the way down

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 .

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?

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.,15654.0.html

These links show the ECT characteristic s along with that of other sensors.


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