Any suggestions?

[ga.spyder]

Hey gang. My 82 has been laid up with a electrical mystery for a number of months now.I was so frustrated I went a month w/o even looking at it.I know you dont know the car but she has been the model of reliability.Track days ,rallies,car shows with barely a hiccup.Many trophies and awards,always been maintained. I found my problem was with the dizz,and also a bad mag p/u that was not working out of the box.Multiple issues and intermittent.Not a good combination!
I have consistent fire now,the car will start but I cant keep it running.It is definitely starting and running on the cold start injector.When I unplug it, the car will not start at all.I have changed to a known good fuel pump but it remains the same.I am curious as to how you would proceed from here? If you get a minute,any feedback or advice would be greatly appreciated! Thanks, Craig

[micbrody]

Start here:
Check the t-coolant temp probe. It sends signal to ECU which adjusts the length of time fuel injectors stay open.
Check the resistance at probe. I that is normal (from my memory, in the low hundreds of ohms when car is running at operating temperature; lower thousands when cold).
If that seems normal, check the resistance from temp connector to the connector to ECU. (I don't remember the ECU PIN numbers ; but it can be looked up.

[ga.spyder]

Thanks for that. I recently replaced that sensor,but my record with new parts hasn't been good lately! My mag p/u that was the source of all my ignition problems was brand new,and defective! I will look up the procedure and test that. It was also suggested to check my tach signal to the ecu

[spider2081]

Have you measured voltage on any of the fuel injector connectors?? The double relay needs voltage from fuse 2 (hot in start and run) positions of the ignition switch for the Injector portion of the dual relay to close and power the injectors.
The cold start valve and the fuel pump are powered through the in line fuse which is not in the fuse panel.

[ga.spyder]

Hey David. I have not checked that. Can that be checked with the key in the run position,or does the car need to be running? The fact that I have spark is encouraging,but I have never had any fuel system issues :roll.

[ga.spyder]

I reviewed your post and see that voltage should be there in run position

[ORFORD2004]

https://www.mirafiori.com/faq/fiatFI_may2002.pdf

[TimpanogosSlim]

This is why i loathe early injection systems - they are too primitive to talk to you about what their problems really are. The modern systems often tell you exactly what is going on. Some of them even give you the part number to order. The controller in my '07 VW once told me to re-torque the charging cable nut on the alternator because there was too much resistance on the connection. Right now it tells me that there is an intermittent vacuum leak.

The suggestion to read brad's l-jet guide is a good one.

L-Jet only knows what the coolant temperature at the tee is, what the position of the air meter is, and how many millivolts are coming from the o2 sensor. And it doesn't have any way to tell you about them.

You should be able to verify the ECT sensor with an ohm meter. It's just a thermistor - a resistor that changes it's value with the temperature.

7,000 to 12,000 OHMS at 14 degrees F
2,000 to 3,000 OHMS at 68 degrees F
250 to 400 OHMS at 176 degrees F

But my guess is that the air meter or it's wiring are suspect.

From brad's guide:

The air flow sensor flap should move freely and return quickly to the closed position. The sensor must be
clean. The air flow sensor is tested on the ECU connector. Unplug the ECU connector and connect an
ohmmeter between terminal 6 and terminal 8. Resistance should be no more than 600 OHMS. Connect
an ohmmeter between terminals 7 and 8. Resistance should be no more than 1200 OHMS. Connect an
ohmmeter between terminals 8 and 9. Resistance should be no more than 350 OHMS.

I'm surprised he doesn't have a procedure for bench testing the AFM? the factory manual for most cars with a barn door meter tell you how to do that. Connect probes to certain pins on the device and move the flap . . .

[TimpanogosSlim]

An additional L-Jet guide: http://www.njfiats.org/joomla/images/st ... BoschL.pdf

has specific troubleshooting steps for "starts won't run"

points to the double relay. fwiw i have two untested spares.

[klweimer]

Do you have the factory FI troubleshooting guide? It's really the best place to start when trying to track this stuff down. I had a similar problem and it was a broken wire somewhere in the harness between the temp sensor and the ECU. If you don't have it, shoot me a PM and I'll see if I can find a scanned version. While these systems may be primitive, they are also diagnosable with a few basic tools and skills.
Kirk

[Ramzi]

Do you have the factory FI troubleshooting guide?

Craig.

As Kirk suggested... use the diagnostic guide in the link from Mirafiori (previous post above). More often than not... the failure is not the coolant temp switch .. but rather the electrical connection / upstream wire. Simple enough to check w. ohm meter.

But run the diagnostic if in doubt.

[RRoller123]

L-Jet only knows what the coolant temperature at the tee is, what the position of the air meter is, and how many millivolts are coming from the o2 sensor. And it doesn't have any way to tell you about them.

Plus the temperature of the air passing through the AFM and the position of the throttle (when closed).

Does anyone know what the next generation of Bosch FI system is that came after the L-Jetronic

[TimpanogosSlim]

L-Jet only knows what the coolant temperature at the tee is, what the position of the air meter is, and how many millivolts are coming from the o2 sensor. And it doesn't have any way to tell you about them.

Plus the temperature of the air passing through the AFM and the position of the throttle (when closed).

Does anyone know what the next generation of Bosch FI system is that came after the L-Jetronic

Wikipedia indicates LE1 (cheaper jetronic), LU1 (cheaper jetronic with closed-loop lambda control), LH (digital jetronic with hot-wire MAF), and Mono-Jetronic which was more of a throttle body injection system, lacked any kind of air meter, but was digitally controlled.

It was gradually overtaken by Motronic, and there were several injection control systems that used bosch components with a non-bosch controller, like VW's Digifant and whatever the Toyota system in my land cruiser is (which uses a flapper box of obvious bosch design, with a Denso part number).

[ga.spyder]

Thank you everyone for the suggestions. This gives me some starting points to figure this out. I have talked directly to Brad, and I do have his diagnostic guide and a factory shop manual . Now that I have consistent spark, I am pretty confident I will get this resolved .

[ORFORD2004]

Check if you have signal at the injectors with test light