1980 Fuel issues

[So Cal Mark]

a lean mixture won't damage the catalyst, but an overly rich mixture can cause it to overheat

[76was124]

I apologize, for jumping in having not read the entire post, but your comment about no resistance change on the AFM caught my attention.

I took it apart yesterday and the only question about it's free movement that I can see is the seemingly bizarre arc in my picture attached. Other than the arc it seems to move freely without any varied resistance. The first maybe 1/4 -1/2 inch of movement seems to have a little less resistance than the rest of the movement but I assume that is to ensure the fuel pump is properly powered to create enough airflow to push the opening more once engine starts and negative pressure is created.

Did you check for the correct ranges of resistance for the AFM on the terminal pairs at the ECU end of the wiring harness connector ? See Brad antiques' Fiat 124 Mod and Mainteneane manual and other publications at:http://www.artigue.com/fiat/

[RRoller123]

Good catch! If that is the case, you have likely hit upon the cause. Bad AFM.

Usually there are literally about 100 things that can cause the various symptoms that are frequently posted here. We respond with the combined universe of experience and suggestion. In the absence of that leading to a direct answer, the diagnostic manuals have to be turned to, and carefully followed, from start to resolution.

Pete

[micbrody]

"move freely without any varied resistance. The first maybe 1/4 -1/2 inch of movement seems "

I think he was referring to physical resistance (effort) to move the door which is attached to copper contact arm on resistor board( not electrical resistance).

Ideashappen, can clear this up for us?

[barticus]

Just looked at my afm flap the other day and your flap surely looks bent. Mine is straight. Just my two cents. Good luck with it. I'm having similar problems myself right now.

[ORFORD2004]

Arik live in Montreal and maybe he have injection.

[ideashappen]

Hey guys sorry for the delay in feedback. F*****g work....... I so appreciate your efforts.
Let me address micbrody first.

"move freely without any varied resistance. The first maybe 1/4 -1/2 inch of movement seems "

I think he was referring to physical resistance (effort) to move the door which is attached to copper contact arm on resistor board( not electrical resistance).

Ideashappen, can clear this up for us?

Yes I was referring to resistance in the physical movement of the flap itself.


Quick summary of past events posted first.....
Car started / Ran fine before and after winter storage
Next day car did not start at all except with direct fuel into air intake on top of the intake manifold. Dies as soon as forced fuel burns off.
Changed fuel filter and pump
Car starts but only for 2-5 seconds / can not rev engine or it dies. it will idle 2-5 seconds otherwise.
Checked 50000000 thousand things suggested. No real difference.
Unplug the AFM from ECU to see what happens.... car starts but runs crazy rich.
Decided to open my AFM to look at the circuits etc in there.
Replug AFM in.
If I manually play with the flap I can keep it running. If I got the timing right I could open the flap manually and was able to rev the engine.
I marked original spot where the flap tension adjuster was and slacked the springs tension...... considerably . Almost a whole half turn.
BOOM car starts without any manipulation on my part.
With a little tweaking of both idle speed and spring tension I could drive the car for about 5-10 minutes. Or until car hits +- 190C.
That is where we pretty much left off...........

I decided at that point it has to be the AFM.
I found one in Montreal . Paid 250 canadian. (For you guys in the states.... that's about 22$ Now lol.... seriously around 195$) He also gave me the plastic intake hose as mine was cracked all over.
I installed it and guess what........ it did the exact same f*****g thing. 2-5 seconds idle then dead. BUT...... BIG BUT here....
I decided to do the exact same thing with the idle speed and spring tension and when the car is 'cold' it starts almost right away. I drive any distance I like. (If the car is hot (190-ish) It is very hard to start if it will start at all. after an hour it will start and drive again. On Saturday I drove 90kms (54M) Highway. When I arrived I stopped the car. Tried to start it and it laughed at me. After a few hours I returned back to the car and it started, I drove home by smaller roads at a distance of 110 kms (66m). When I arrived I stopped the car, tried to start it again, and it started.

NOW....... I say it runs.... Let me be clear. It is 'drivable' but far from where it should be. It balks at about 2500-2800 rpm.
I can not accelerate fast (not that I ever do) without it 'balking' but at certain Rpms it has power like before.
When I come to a stop the idle is rough to the point sometimes I ride the pedal abit to bring rpms to 1200+- to ensure I don't die there.
The Air/fuel mixture is way to rich (Which would probably explain why it will start easier cold than hot)

That is where I am..........

Any ideas?

[ideashappen]

Arik live in Montreal and maybe he have injection.

Ok thanks orford, but could you tell me who Arik is?

[AriK]

It's me but unfortunately i'm not the FI guy you're looking for. I'm in Laval, if there's anything else i can assist you with let me know. You will get through this and when you do we can plan a cruise.
Cheers.

[aj81spider]

It's a shot in the dark, but I would check the wires between the AFM and the ECU for partial shorts. What leads me to suggest that is:

> You unplug the AFM and it runs (albeit rich)
> You change the spring tension and it runs

Changing the spring tension means the flap opens further for a given amount of vacuum and sends a bigger signal to the ECU.

It may be you have a frayed wire that has a partial short or changed resistance. It's worth a look.

[micbrody]

Ok;

So probably not the AFM . I did not think that was problem. Reset the spring tension in the AFM to original. (also, though I would not chase this down now, fuel pump should not operate with AFM disconnected)

Since car is consistently running rich: Need to check two parts of ignition sequence:

1) coolant temperature sensor at coolant tee. This checks temperature of coolant (engine) and enriches fuel mixture by having ECU lengthen time the fuel injectors stay open. I believe (by memory), the resistance measured across probe should be in the thousands when engine is cold; and in the low hundreds when engine up to temperature. If the wire/connector is broken to/on probe and not making any connections, the car won't start (or extreme difficulty); or internals of probe bad.

2) cold start injector (CSI): This is the 5th injector located going into engine at air intake side of engine (located pointing towards driver on front, top left of engine. This is energized for a brief second or two during a cold start. It's electrical activation is in series with temperature sensor (thermo timing switch (TTS); VERY hard to see....located near bottom of engine where cyclonic oil/air separator goes). When engine cold, the temperature sensor activates the CSI. The combination of engine temperature and electrical heating causes a bimetalic strip to eventually disconnect the electricity to CSI.. If TTS is stuck to energized and/or CSI valve is mechanically stuck open, then the engine will be overly rich continuously. Two easy ways to rule this out: Find the fuel hose that feeds the CSI. It's a vertical fuel hose that comes from the fuel rail. IF the hose looks pliable (won't crack), take a vise clamp and clamp hose. See if car starts. It might take some cranking since no CSI injection; but eventually it will start (you can hit gas pedal; might help). But one it starts, see if engine behaves normally. If it does, then you know which system needs to be fixed. (could be bad TTS; or stuck open CSI). If tubing too brittle to clamp, then using allen wrench (I needed to cut short the allen wrench to fit), remove the CSI; (cover hole with tape..... not going to run engine that long) have CSI point into container (glass so you can see), and start engine. If engine cold, the injector should shoot fuel; but only for a second or two. The longest it should stay on is 7.5 seconds at -20 deg C). If it stays open continuously, then that's a big problem

I knew very little about cars until I bought my car in end of 2014. I have had many minor issues. In trying to fix the issues, I have found it quite rewarding to actually learn about these systems. The board is such a great resource! Trying to pay it forward.

Below are two links to help diagnose your problems.









http://www.cardiagnostics.be/-now/.../B ... Manual.pdf

http://www.hiperformancestore.com/ljetronic.htm

[76was124]

Regarding CSI:

Is there any reason not to just remove the electrical connector on the CSI?

I cringe every time I have to remove the fuel line off that old brittle plastic fuel line fitting on the CSI.

My thought is with the electrical connector disconnected, you have two potential observations that could point you in the right direction if currently it starts easy, but runs bad shortly after because you are running rich.

With a dead cold engine, remove the electrical connector.
1. If the engine starts easy, but runs bad as it warms up...the CSI is probably leaking, or stuck open.

2. If the engine is hard to start cold, but runs well when warm, the the CSI isn't turning off when you have the connector plugged in.

One other question for you....in your post about swapping AFMs, you mentioned you got an extra boot because your old one had major cracks!! Air leaks is one of the first things that need to be eliminated. Is your current air intake boot leak free? How about all the other air/vacuum lines? AAV housing leak free, Brake booster line etc.?

[Ellie]

Hi there, this has been a great thread to follow, mainly coz I have a similar issue with my '82 and was intermittent for a couple of weeks but now wont start at all. After turning over numerous times she'll just occasionally start up but then putter out after 5 secs. I have a slightly off topic question though, in the picture earlier on showing the two grounding connections on the plenum. There is that stud just to the left of that ground right in the middle of the plenum. What is it? and there is a hose that comes out from the bottom of it, where does that go to?

[RRoller123]

It is a vacuum port and the hose there goes to the top of the charcoal canister. There is another one further to the left that goes to the top of the fuel pressure regulator on the fuel rail just below the plenum.

Pete

[Ellie]

Thanks Pete, I was checking all the hoses for the FI and found that one just hanging loose. I don't suppose if that wasn't connected it could be causing the, don't start, stall after 3 sec's issue?