motor stumbles after it warms up

[fixkick]

old sammi, are one of the best cars off road. many love them, nimble wins, in the end. (high cg and weight are killers)

I inherited this Sammi for $$.
We drove it for a couple days and noticed an occasional engine stumble and infrequent backfire (to tail pipe or air cleaner) when off throttle.
We also noticed a prevalent fuel smell and what seemed to be excessive fuel consumption (but haven't driven it enough to calculate).
so its running rich, and if too rich and air leaks near,, the exhuast on all cars explode called muffler explosion, and clear name.
My wife was driving it and it stalled at a stop. (my guess would be the poor spark plugs just fouled out. (
She restarted and said it was missing and generally running very poorly.
She tried to limp it, but it stalled out again and she had to get it towed home.
its a non stock car, and as such diagnosis can be horrid. lacking all facts of the changes.

Recap: 1988 1/2 Samurai, 1.3 with 90 TBI conversion, ECU = 89 Tracker, coil/distribute is vintage 88? what?, EGR valve & associated parts removed, NAG switch removed.
I guess you mean the donor car was a 1.6L G16a ,1990 TBI. but the means, ECU , harnesses, sensors, TBI intake and all parts from G16,
did the Check engine light get deleted, some how? that is first. always. if the ECU is upset, it be wise to ask it , after all it can go to limphome or worse BACKUP mode, the ECU is a 56B30 on 5speed. is that it?


I've been trying to troubleshoot the problem:
It starts and idles (a little rough) when cold, stalls once it starts to warm up. Plugs are black and exhaust is smoky (reeks of fuel). TBI looks wet inside (fuel seen streaming on throttle plate).
- No codes (not sure if the ECU to harness wiring is correct, its not); CEL comes on steady prior to start and goes out while running. Diagnostic fuse in fuse box doesn't do anything (NAG removed). The nag has nothing to do with CEL, when you pull then NAG switch from the cluster, the CEL now owns the circuit for ever.
first off the

TBI wiring harness has a Diagnostic Switch Terminal behind the battery.
Jumper does not produce any flash codes (no code 12). IT MUST, or is wired wrong or is now STUCK in backup mode.
code 12 are MANDATORY, this is A number 1, always, 89 to 95 years.
it just a lamp and 2 wire, one wire is power,12vdc from cluster power buss, the 2nd wire goes to ECU CEL pin, a supper simple circuit,
the schematic is clear here.
sspence said he never tried to check codes.
the 19
- Fuel pressure seems good (40 psi at filter port and 50 psi deadhead after FPR while cranking), FPR leakdown and vacuum checks (smoothly decreasing fuel pressure) seem OK, but TBI is flooding.
- Haven't done any other sensor/actuator checks yet. Not sure whether I should replace the ECU first or not.
- Not sure if all the vacuum lines are routed correctly for this configuration (with EGR valve removed). Searching for a diagram or photo.

Next step?

to use any TBI system, or conversion
you MUST wire up the CEL correctly and a DIAG pin jumper port
Must or spend forever trying to guess why the ECU is unhappy. hopeless this is...

we are talking here, 4 wires.
2 for the lamp
2 for diag. one is ground.
that must work.
if the lamp is present, and power on one side, and ecu CEL pin other and the lamp is good ,. (14v @100ma or less 50mA is spec)
and if the lamp does not come on ever, the ECU is toasted.
i see yours glows, if wired right that is a good sign.
but the diag pins are not present. its just 2 wires. ground and diag.
if you jump that pin to ground and it wont flash a code, the ECU is bad. 12s or any code, even code 53. 53 can mean wrong EGR.

if flashes 12s, we can work out why it failing,
keep in mind 12s does not mean all is well , it means no shorted or open sensors and spark present, and CMP firing.
The ECU can also short out 1 of the 2 injectors lines, and it will go rich for ever. and the ECU is blind to this error.
This ecu also goes rich if the 02 fails, it can go super rich, (cured in 1996)
Id also test the map fully on using my MAP page.

keep in mind the your car has old mech, distributor, so we check timing at idle and then scream the throttle to be sure those sticky advance weights work,
see 30deg. of advance or more, gunning the throttle , if not it will waste fuel big time.
if spark is ok, then fueling is wrong and that is 100% ECU and its sensors.

hope that helps,. cheers.