ECU problem?

pjnats · Post by **pjnats** » Sun Jul 08, 2007 10:45 pm

Has anyone replaced an ECU on their fuel injected Spider? If so, would you explain what occurred that led you or your mechanic to conclude that the ECU was the source of your problems. I know this may seem a backward way of diagnosing what's wrong with my Spider, but I thought I'd try this approach to see if your symtems were similar to mine. Thanks in advance for the help.

Pete Natalie
Erie, PA
'82 Spider

So Cal Mark · Post by **So Cal Mark** » Mon Jul 09, 2007 10:23 am

Fiat ecu's are pretty reliable generally. I've only seen a few that failed in the last 20 yrs, and two of those occured after the owner hooked the battery up backwards

pjnats · Post by **pjnats** » Mon Jul 09, 2007 1:07 pm

Thanks for the reply, Mark. I'm confident that if I lived in So. Cal. you'd get to the bottom of this for me. My Spider continues to run inconsistent at best. Sometimes it runs perfectly and then, as if a switch were turned on, it starts to choke and miss during the same drive. It leaves black carbon marks on my driveway, and the tail pipe is black on the opening. I'm sure that if I pull the plugs, they'll be coated in black as well. Does this sound like a faulty ECU, or is there a better explanation?

Pete Natalie
"82 FI Spider

brad131a4 · Post by **brad131a4** » Mon Jul 09, 2007 1:33 pm

if you haven't check already the sensor in the cooling system on the T seems to be about 90% of the problem with alot of the running problems with the injected models.

So Cal Mark · Post by **So Cal Mark** » Mon Jul 09, 2007 2:53 pm

not just the temp sensor, but the connector can cause lots of trouble. If it's broken or doesn't fit tight, replace the connector and pigtails.

pjnats · Post by **pjnats** » Mon Jul 09, 2007 4:50 pm

Thanks again, Mark. I actually purchased a new temp. sensor and installed it, with no resulting change. I will, however, take a very careful look at the wiring and connector. It has always been bent at a very tight angle; perhaps that accounts for the inconsistency in running. I'll let you know how I make out.

Pete

So Cal Mark · Post by **So Cal Mark** » Mon Jul 09, 2007 10:02 pm

the temp sensor is the most important aspect of mixture, you can also get a resistor that has a value within the warm engine range and use that in place of the sensor for testing. Also check the cold start injector for leakage inside the plenum and the pressure regulator for leakage into the vacuum hose

brad131a4 · Post by **brad131a4** » Sat Jul 14, 2007 2:46 am

Pete , if your'e still having problems and there isn't a fiat shop around go to a vw shop as they can diagnose the problem as the system is just about the same as what vw was running in there early fuel injected rabbits and scirrocos. They may give you a funny look at first but once you show them the system if they are any good they will know just what to do. Good luck.

So Cal Mark · Post by **So Cal Mark** » Sat Jul 14, 2007 10:19 am

early VWs used a CIS system that is not related in any way to the L-jet system Fiat used. Some euro cars did use the L-jet system but many more Japanese cars used a similar system than did euro imports. It's a very basic system and lots of repair info is available

pjnats · Post by **pjnats** » Sat Jul 14, 2007 9:03 pm

Just a quick update, the other day I tested the temp. sensor with of an ohm meter and got a reading of 355, which I believe is where it's supposed to be. The connection also seemed tight. I pulled the plugs, they were all carbon fouled as I suspected. I changed the plugs, and she ran great for the rest of the day and night. The next day I go to take her for a spin and she's sputtering and chocking as bad as ever. I'm still thinking it's the ECU and once again pulled my brother's (he just happens to also have an '82) to see what happens when I substitute his for mine. I'll let you know what happens when I do. Thanks again for all the input.

Pete

pjnats · Post by **pjnats** » Sat Jul 14, 2007 10:42 pm

Almost immediately after posting my last remarks I decided to just get off my duff and substitute ECUs. Guess what? She ran great! A mechanic who did some diagnostic work for me last year came to the conclusion that my ECU was bad. What happened after that is that I purchased a rebuilt ECU on Ebay toward the end of the season, and it didn't work in my car. That made me think that maybe something else was really wrong, and the mechanic was mistaken. I spent the next several months attempting to get my money back, and by the time I did, the season was over.

Since my brother's does work in my car, I have to conclude that my ECU is bad, and the one I bought on Ebay just wasn't compatible with my car. I still have a delima, however, as my brother needs his ECU back. What would you do at this point? Should I simply try to locate a used ECU, I know they're out there, or should I get mine rebuilt? I read about this company in Philly that totally recondidtions your ECU, but it is pricey. I'd be taking a gamble buying a used one, but as Mark has already said, he's seen very few bad ones over the years. (I guess you can add mine to that list, Mark.) Anyway, I'll appreciate any opinions offered.

Pete

So Cal Mark · Post by **So Cal Mark** » Sun Jul 15, 2007 1:26 am

what's odd is that the car runs okay for awhile. Usually a bad ecu will cause poor or no running all of the time. The only thing the ecu controls is the on time of the injectors, so rich running would be a situation where the injectors are on too long. You could check that with a volt/ohm meter that has a duty cycle function.
If you send me the serial/part number on your ecu I'll check to see if I have the right one for you.

pjnats · Post by **pjnats** » Mon Jul 16, 2007 1:33 pm

Just to be clear, Mark, I only ran my car for less than a day after I changed the plugs and adjusted the idle. By the next morning, all of the same symptoms appeared. As soon as I substituted ECU's, they went away. I'm certainly not saying that I understand what's going on, because I truly don't, and I gladly defer to your expertise. All I know is what happens when I use my brother's ECU. What does still concern me is what happened when I tried to use the rebuilt ECU that I bought on Ebay. That one did not work in my car, and it was supposed to be for my model year.

Anyway, the only number that I can find on my ECU is the Bosch part number, which is 0280000190. The number on my brother's ECU is a little different; it is Bosch 0280000207.

Pete

So Cal Mark · Post by **So Cal Mark** » Tue Jul 17, 2007 12:37 pm

I've got one with the same number. PM me if you're interested