poor running FI Spider

[sjwcougs]

Car starts right up, but idles and runs very poor under load. I was driving it back in September and as we were driving poor seemed to surge and then die. It kind of sounds like when the temp sensor gets disconnected, but that is not it. That was also replaced very recently. I did notice a screw on the distributor backing out when i noticed similar symptoms another time, but that isn't it. All of this seemed to happen pretty suddenly. There is a lot of exhaust at idle during these poor running conditions. Sorry my description is poor. Any ideas on where to start would be great. I'm pretty new to Fiat mechanical work, but have the shop manual and have some ability to do repairs. Timing?

[narfire]

Timing could be an issue and easy to check. Look behind the cam wheels, you should see the cam wheels have a hole in them. These will line up with a raised metal line on the front of the cam towers. At the same time take a look at the alt. pully on the crank. There will be a small indent on the edge of the rim,this should line up with the longest tip of the 3 "prong?" pointer mounted onto the block,pass side. When all three are lined up you'll be at TDC. If the holes or crank are out then I'd suspect the belt has slipped. I was one tooth out on the cam and the car ran but did not feel like it had the same power as when it was all lined up correctly. I trust you have spark on all 4 cyls, and the cap/rotor is in good shape. When at TDC the rotor is set to hit #4 wire.. Are the lobes on the dist shaft whacking the mag. pickup?
If the electrical is lined up and you have spark,I goto fuel next...

[So Cal Mark]

your symptoms are really vague; I'd like a much better description. For instance, after it dies is it hard to start? Running poorly under load; does it misfire? slow down with more load?
Has the car had any maintenance? Fuel filter ever replaced? air filter replaced? Air intake boot inspected for cracks? Fuel pressure checked?

[sjwcougs]

Thanks for the feedback. The car doesn't really misfire after it starts and I can actually drive it a bit, but with no power. It fires right up no problem and runds "failry" smooth at idle. This leads me to believe there is something wrong with the FI since it happened so suddenly. I wouldn't drive it any further than down the street and back right now. I have had the fuel filter, air filter, and air intake hose all replaced.

[sjwcougs]

I have not had the fuel pressure checked. A few years ago I had the timing belt and distributor cap replaced.

[sjwcougs]

I adjusted the TPS yesterday evening and today I installed the new battery. Running light years better. When I disconnected the old battery the connection at the postive post seemed very loose. Could the poor connection cause all of thee poor running conditions? I really don't think the TPS adjustment did anything to make the difference.

[So Cal Mark]

without a good connection, all of the voltages in the system could be way off causing a myriad of odd problems

[sjwcougs]

after getting excited about the potential loose battery connection fixing all my woes I am back at square one. Car ran lousy today just when I took her out of the garage. When idling I cannot hold consistent RPMs. Missing a little, but more of a inconsistent power. It sounds bogged down and exhaust smells of fuel. I also noticed today the fuel pump didn't seem to shut off at one point when I had the key in the on position. Fuel pump issue or fuel pressure regulator?

[So Cal Mark]

the pump running with the key on could indicate a problem with the switch in the afm or the dual relay. A leaking pressure regulator will cause the engine to run extremely rich. To check it, just remove the vacuum hose to it. If there are traces of fuel in the vacuum hose, the regulator is leaking.
Without a few tools though, diagnosing the fi system is darn near impossible. You need at minimum a volt meter and noid light

[sjwcougs]

I have a most tools I have a multimeter, but no noid light. I will head out to check fuel in vacuum hose. How do I check the problems with the AFM switch and or double relay? I have been fortunate that in the three years I have owned this car I haven't really had any poor running conditions. Time to get into it! The thing that catches me as strange is the surging power feel. Almost like somebody driving a stick for the first time.

[rlux4]

Here's a step by step for checking the dual relay, it'll also tell you if the AFM is sending the signal to it.
http://www.wcmotors.com/personal/Fiat%2 ... agnostics/
Ron

[So Cal Mark]

surging is usually a lean condition; how's the fuel pressure? fuel filter not plugged? Air leaks on the intake? Catalyst condition?