1980 F.I. Spider runs good until it warms up

[kirkle]

I have a 1980 Fiat Spider 2000 fuel injected that I just bought. It ran great during my test drive of it before purchasing it. Now that I own it, It seems to be having some issues. When the engine is cold it will run fine but as the engine warms up it acts up. It will idle fine but as you try to accelerate it seems to be starving for fuel. I have changed the fuel filter and fuel pump with no success. I have also checked all the fuel lines for any damage or loose connections and they all seem to be in good shape. Any ideas of what else could be causing this would be greatly appreciated.

[meangreenspider]

I had issues with my 82 FI and a gentleman was kind enough to send me this link. I was back on the road in a few hours.

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



I would begin with the throttle position switch and adjusting the screw beside the switch. Good luck

[zachmac]

It could be your Auxiliary Air Valve (AAV) is stuck open. It is the componet mounted on the front of the engine on the drivers side on top with a hose from the intake air nozzle over to the intake plenum and a two wire connector. it's function is to allow more air to feed the plenum WITHOUT it passing through the throttle plate so that on a cold start you idle higher until you warm up. it is suppossed to close based on engine heat and that wire connector powering a little heating element inside. If it sticks open you will be fetting to much air once warm versus the fuel the TPS is saying you need. Try pinching / clamping the hose to or form it once you warm up the car and see if the driveability improves. If yes than you need to clean or replace the AAV. If no then the problem is elsewhere. The document link above is a good read for any FI car owner.

[So Cal Mark]

if the aar is not closing, the idle should be high. I'd check the coolant temp sensor resistance throughout the range for a proper reading

[zachmac]

[quote="So Cal Mark"]if the aar is not closing, the idle should be high.

Unless a PO has adjusted it to compensate by closing down the throttle plate and air bypass although Mark is probably right as I don't think you can get it to idle very low when warm with a full open AAR no matter how far you close down the idle stop and air bleed. What is you idle RPm at startup cold and when warmed up?

[kirkle]

I've checked the AAR and it appears to be functioning normal. Tested the throttle position switch, AFM and replaced the coolant temp. sensor and am still having issues. It idles around 1200 rpm and drives normal until put under a load above 2000 rpm. It seems like it is starving for fuel when the demand is increased. The fuel pump and filter are new and I checked that it was getting 35 psi at the fuel lone off the cold start valve.

Does anyone have any more suggestions?

[kristoj]

Call me crazy, but could it be an ignition issue rather than related to the FI system?

[mkassing]

It sounds like you and I have the same issue; any luck?