82 short at battery... no start... dead ECU?

[micbrody]

"You're probably right but I'm trying to figure out why I have no spark. After blowing 4 fuses during the event, I still think it's a either a hidden wiring problem in the dash somewhere or the ECU. I'm trying to exhaust all possibilities that are cheap since an ECU is $$$$!"

I think a "no spark" issue would be independent of any ECU problem. First just confirm whether distributor is outputing a spark when cranking

[spider2081]

Have you made any progress with starting your car??? Are you sure you have no spark? If your cars ignition wiring has not been modified, the blown fuses have nothing to do with no spark. All of the wires associated with the ignition are unfused from the battery through the ignition switch to the coil. Most of the fuses in the fuse panel are for accessories like the cars lights ,radio fans, etc. The fuel pump fuse is an inline factory installed fuse holder. Fuse B supplies voltage to the double relays internal control relay and eventually powers the injectors and powers energises the fuel pump relay in the double relay. There is a good chance the blown fuses are not related to the engine running.

[thewired1]

OK... update on my testing.

I DO have spark at the plugs. Apparently I didn't have it seated properly (it's a new tool and first time I'm using this one). Before I knew that I swapped out the ignition coil with an MSD Blaster 2 just to test. No change to start, so I put my Merrelli back in.

I've been going through the "Bosch Jetronic troubleshooting manual". Here's what I've tested so far:
• Spark at plugs!!!
• Fuel pressure at rail. Drained fuel and it filled up again with fuel. So pump appears to work. Haven't checked pressure in PSI, my guage leaks gas, but I'm assuming nothing changed there since before it was running.
• Tested some of the points on the dual relay (it's hard to see in there with the AC system blocking the way). All worked so far. Check further?
• Unable to remove the fuel injector wiring clip to see if it lights up. It's on soo tight I'm afraid to crack it.
• Tested all of the points on the ECU harness cable. Everything has resistance within spec'd range or lights up as indicated with probe.

OK... with about 75% of the jetronic troubleshooting manual checking out OK.... do we think it's the ECU? Or should I go back and check the item's I missed.

[ORFORD2004]

You should try spray carburetor cleaner using the straw in the intake by removing one vaccum line. After that try to start the car. If it try to start, then you know that it is a gas problem.

[thewired1]

I reconnected the ECU, battery, etc and...

Nothing

I sprayed some carb cleaner just passed the AFM as well and nothing still.

** BTW I used about 1 squirt each time. Not too much Carb Cleaner was used.

[spider2081]

I don't see where you have checked the static engine timing. With the crank timing mark at TDC are the cam timing marks correct?? There are rubber plugs in the metal timing belt guards. Remove those plugs and sight through the hole. There is a hole in the timing gear that should be aligned with the cast line or ridge in the cam box. Both cams should be checked for alignment the the distributors rotor should be pointing to #4 cylinder in the distributor cap. If everything is not aligned rotate the engine another 360 degrees and recheck.

[thewired1]

Correct. It was running beautifully before the electrical short so I was avoiding mechanical adjustments. I'll check it out though

[klweimer]

thewired1,

I would slug through the balance of the FI troubleshooting manual. Or, take a break from that and start on the electrical system troubleshooting manual I sent you. I agree that the mechanical stuff like cam timing should not have changed. Have you checked the cold start valve? If you have spark and assuming the ignition timing hasn't changed, then fuel delivery is the main suspect. The cold start valve runs off a simple thermo time switch that is relatively independent of the rest of the the FI system. If it's working you should get at least a few coughs when you turn the the engine over.

Kirk

[micbrody]

If you have spark,there should be some "ignition coughing/combustion" from at least the cold start injector........ unless fuel pump not energized.

You said you tested fuel pump. Have you checked if fuel pump energized during start? Try this: remove air filter;
Put key ignition to "on".
Manually open flap with hand; or lodge screw driver. Listen to see if fuel pump turns on. If it doesn't , then there is a circuit problem with fuel pump .
Could be ignition switch; inline fuse; bad switch contact in AFM;
(Still all could be explained by backwards connection of double relay)

[thewired1]

micbrody... I've done exactly that. With the AFM exposed I was able to move the flap and hear the fuel pump motor. I also released pressure on the fuel rail and with the key "on" fill it again. I didn't check the pressure in PSI with a guage but it's getting more fuel.

I think I'm missing something... Fuel, spark, air.... it should fire. Even with Carb Clean in the intake, it should fire or sputter. There was a short on the battery and fuses were blown and it shut down. Something must happened at that moment.

I am going to revisit some items and see if I'm missing something.

[spider2081]

When you spray the car cleaner in to the intake I usually remove the large hose from the intake plenum then open the throttle plate and give a good 10 second spray into the plenum past the throttle plate. Then replace the large hose.

The cold start valve runs off a simple thermo time switch that is relatively independent of the rest of the the FI system.

The cold start valve is powered through the dual relay. It is not controlled by the dual relay but the power passes through the relay. theoretically as long as the relay is connected the cold start valve should have voltage applied to it. The thermal timer supplies the ground for the cold start valve to operate.

[micbrody]

did you try starting car with screw driver in AFM? If it starts that way, then you have a big unmetered air leak. Sources of this could be: big plastic air intake; brake booster; AAV,.........
Again, doesn't explain why this would be after battery "short"......
As for spark test, how did you check it? If you had a bad output wire from coil, that could explain it.......again, doesn't make sense after battery short.......just trying to think outside the box......

If ECU bad, then that means cold start injector could also be bad (unrelated to ECU problem) also not squirting gas to at least cause some coughing......
You said you just got car. Do you know if csi works?

[klweimer]

thewired1,

Which 4 fuses did you blow? Maybe you said and I missed it...

Kirk

[klweimer]

Random thought. You might check the voltage to the ECU during cranking.
Kirk

[thewired1]

Heads up... I took yesterday off from working on the Fiat for a family members birthday. I'm going to put together a list of things to test and answer today. Thanks for everyone's input!

I'm starting to feel this issue is a real crash course in fiat ownership. Once I get it running I'll be considerably more comfortable with how everything works.... I'm a glass-half-full kind a guy!