Intermittent Power Loss when driving

[Hobo]

Background:
1982 Fiat Spider 2000 Fuel Injected

Issue:

While driving the car intermittently loses power. The lights stay on, radio continues to play U2 What a Beautiful day cassette of course. Surges as it feels like lack of fuel. Not familiar with trouble shooting AFM or oxygen sensor. Car starts ok.
Day starts with a smile and ends with a frown.

Started car today and struggled to keep it running unless working gas pedal on a continuous basis (field pump)?

Will answer any questions as best as possible to help you assist me in troubleshooting.....

Thank you for your expertise in advance.

Hobo Spider

[klweimer]

Hobo,

PM me your email and I'll send you a scan of the Fiat FI troubleshooting guide. It's the best reference out there for this kind of thing.

Kirk

[giuliot60]

We'll get this worked out Joe.

Come on peeps!

GT.

[courtenay]

I would look first at the intake 'hose' to the AFM. Loose clamp at the AFM or a crack somewhere along the thing. Any air getting into that hose is going to cause power loss.

[giuliot60]

I would look first at the intake 'hose' to the AFM. Loose clamp at the AFM or a crack somewhere along the thing. Any air getting into that hose is going to cause power loss.

You're not the first person to suggest that. We did remove it, but didn't notice anything suspect.

G.

[RRoller123]

Check for clogged charcoal canister and make up air lines back to the tank. The cap on top of the charcoal canister is sized to meter the proper air back through the canister. There is a 2-way valve back about the rear axle on driver's side in the air return line that is probably clogged on every car that has never had it changed. With a sealed gas cap, the lack of make up air could starve fuel to the pump. effectively the vacuum created in the gas tank fights the vacuum pull of the fuel pump.

[giuliot60]

Hmmm. Interesting. You think even on a 14K mile car RR? Wouldn't hurt to check it out. It is 35 yrs old.

Thanks!

GT

[RRoller123]

Stranger things have happened. Any whooshing or vacuum sounds when you take off the gas cap?

[narfire]

Think it is fuel problems? Or electrical?
Under the dist cap, check the wires. They get frayed over time and can cause stumbling before they break and fail completely. I also had a plug lead rub on the underside of the hood causing a miss and stumbling of sorts.
I had a loose connection to the little black thingy behind the coil that caused issues as well. Zapped strapped the connection and all is good now.

Bruce's idea of non metered air getting into the system is an easy thing to check. Some will use a plumbers propane bottle while the engine is idling to see if there is an increase in rpm as you move the bottle around the air intake components. Just be careful, propane sinks....if it finds a spark then you have another problem to deal with.
Water in the tank?
Injector(s) miss-firing?
Leaking injector hoses?

[joelittel]

Stranger things have happened. Any whooshing or vacuum sounds when you take off the gas cap?

From time to time I hear a wooshing or vacuum sound when I take off the gas cap.

Do I have an issue?

[Hobo]

Thank You. I will troubleshoot all of the items.
Did order a new Airflow Boot to arrive Monday. Will Post updates upon any changes.

...Sure wish someone could give me a gift of time. So hard to find time to spend on Fiat....

[RRoller123]

Stranger things have happened. Any whooshing or vacuum sounds when you take off the gas cap?

From time to time I hear a wooshing or vacuum sound when I take off the gas cap.

Do I have an issue?

Yes, the make up air system is likely clogged. With a sealed gas cap, the only way air gets back into the gas tank to replace the used fuel is through the charcoal cannister. Same with fill up, the only place for the air to go (other than leak past the fuel filler) is to be pushed through the line and back through the charcoal cannister and out to the atmosphere out the top, leaving some portion of the HCs along the way. During operation, the engine vacuum draws a small amount of air through the cannister and into the intake plenum and then burns the HC laden vapors.

Probably that little white 2-way valve above the rear axle on the driver's side, or a clogged charcoal cannister or a line to/from, or the cap at the top is clogged.

Pete

[joelittel]

Thanks RRoller!

This wasn't even on my radar until you mentioned it but as it turns out my lines were completely clogged.

[RRoller123]

I love it when a plan comes together!

Now explain to me why I have the damned "click of death" back again after taking care of C31 months ago!!! Arrggghhhh!!!!

[joelittel]

Oh no..... that's heartbreaking