electronic fuel injection system

[BuDavid]

is your flow meter ok? if it is old maybe the potentiometer is shorted at certain points, I had this problem, it gave me a big hedache until I discovered it after opening the flow meter!

or it might be as simple as if someone screwe up your spark plugs wires??

go for the basics if you want my advice. somethings that dont cost and fast to deal with.

good luck

[gator]

My advise .. take out the crappy FI in this car and put a good header and a nice new set of SU's. I did this to my 77 and have NO regrets. The car pulls harder, gets better mpg, runs better over all and I have no more problem diagnosing a problem. If you have sprk and fuel, you car runs good (in simple terms) And I think that by the time would have spent all the money fixing the old FI system, I am better off going the way I went.

Sorry .. I know this is not an answer to your question .. I am just pitting my opinion forward for those who are interested.

Cheers ! Ü Bruce

[sblake01]

That's why I posed the questions in my previous post. To get up to speed on exactly what's been done both testing wise and in parts replacement. I guess he chose not to respond. What's been said so far only leads to speculation which may or may not solve the problem. Before I could offer suggestions, I'd need to know the present status in a descripiton less vague than what's been posted so far. Because, so far, there is a laundry list of things that could be causing what's described in post #6 and #9. Post #1 really doesn't say anything. And my fuel injection works fine on both of my cars. My mileage is good and removing the system is not really the answer. You can either troubleshoot carbs or you can troubleshoot EFI. If you know how.

[DatsunZsRule]

I agree Stephen. Like I said in post #2 "We need info man"

Now about FI being "Crappy" is False. The few who say that there EFI Z gets poor gas mileage and is sluggish clearly know nothing about how to work on them. The truth is they are very reliable and require little to no adjusting and get excellent gas mileage when they are working properly.

Thats my opinion. Don't give up Ron, you'll figure it out

[FirstGenZ]

Don't count out a bad ECU. It's very rare but does happen. I'm surprised that no one has mentioned the cold start valve or the temp sender or the thermotime switch. All can create problems. Always remember that a lot of the parts and pieces are very old. Everything can and will fail at some time. Check everything. Good luck.

[KDMatt]

Another thing I would check is the AFM. If it, say, couldn't open past a certain position, I would imagine that could, or would certainly make it difficult to rev too high, and would easily cause a fouling condition seeing as it would be limiting the amount of air that could flow.

Also, the thermotime/cold-start circuit is only energized while the starter is cranking (at least, that's how it's supposed to go), I can't imagine that would cause any difficulties with the car already running.

... My opinion. :beard:

[sblake01]

Also, the thermotime/cold-start circuit is only energized while the starter is cranking (at least, that's how it's supposed to go), I can't imagine that would cause any difficulties with the car already running.

... My opinion. :beard:

Unless, of course, the cold start valve leaks.

[thefastestz]

actually there is so much that could be wrong in the FI system. Vacuum problems were always plauging me...everything else was good...so i guess i was lucky.

[KDMatt]

Unless, of course, the cold start valve leaks.

Of course :stupid:

[ron32966]

is your flow meter ok? if it is old maybe the potentiometer is shorted at certain points, I had this problem, it gave me a big hedache until I discovered it after opening the flow meter!

or it might be as simple as if someone screwe up your spark plugs wires??

go for the basics if you want my advice. somethings that dont cost and fast to deal with.

good luck

The flow meter is new. I'm going to check the flow meter with the ECU harness. Also, I've double checked the spark plug wires. They're ok. I'll keep at it. Thanks for your suggestions. Ron

[ron32966]

Don't count out a bad ECU. It's very rare but does happen. I'm surprised that no one has mentioned the cold start valve or the temp sender or the thermotime switch. All can create problems. Always remember that a lot of the parts and pieces are very old. Everything can and will fail at some time. Check everything. Good luck.

I've replaced about 90% of all the FI parts and ignition. I plan on doing a total restoration and will put all new parts that are available. I will double check everything eventually. Thanks. Ron

[ron32966]

Another thing I would check is the AFM. If it, say, couldn't open past a certain position, I would imagine that could, or would certainly make it difficult to rev too high, and would easily cause a fouling condition seeing as it would be limiting the amount of air that could flow.

Also, the thermotime/cold-start circuit is only energized while the starter is cranking (at least, that's how it's supposed to go), I can't imagine that would cause any difficulties with the car already running.

... My opinion. :beard:

I have replace the AFM. The fuel line to the cold-start injector is plugged off. Ron