Spluttering/ Misfiring, Loss of Power, Cutout at Idle

engines
alfaromeo

#1

My 1988 Alfa Romeo 75 3.0 V6 hasn’t been running for around 5 years and we’re struggling to get it working.

It starts first time and runs. However, it sometimes runs rough at idle (more often when cold) and cuts out, with a simultanous rattle from around the back of the car as the revs are dropping below 600RPM. It can usually be saved by applying throttle

When you apply full throttle, there is a pop from the engine and a sudden lack of power, throwing you forward in your seat.

WORK DONE:
New fuel pump (old one was making a loud winning noise) - this didn’t solve the issue
New fuel filter
New spark plugs
Distributor cap & rotor cleaned (scrapped off carbon)

Oil changed
New radiator
Brakes & clutch bled
Most of fuel drained, filled with fresh fuel


#2

A vehicle sitting that long can mess up the fuel injectors.

Try dumping a bottle of Seafoam in the gas tank and cross your fingers.

http://seafoamsales.com/auto/

Tester


#3

Good idea above on the fuel injectors, assuming your car uses fuel injection. You may have a good deal more work to do to get a clean fuel supply and working injectors, so be prepared for possibly having to replace the tank and all the injectors. Measuring the fuel rail pressure at this point makes sense too. Besides the fuel system, suggest to replace the dist cap and rotor w/new ones, and install new spark plug wires too. 1988, the ECM is pre-obd II, but it still may post diagnostic codes you can read out by a blinking light. If so, blink them out and tell us what they say. Make sure the battery voltage is between 13 -15.5 volts and holding steady with the engine running, and at least 12 volts with the engine off. Use a timing light to check the ignition base timing, and that it advances to spec. The weird behavior on accel might be related to that. A couple more things to try in your spare time. Hold a dollar bill over the exhaust pipe at idle. Does the dollar ever move rapidly toward the car, like it wants to get sucked into the pipe? It shouldn’t. That would imply a miss or similar problem. And an intake manifold vacuum reading at idle can be helpful for problems like this, might diagnose a vacuum system leak. Best of luck w/your Alfa. The only actual experience I have with Alfas was reading the children’s book “The little red roadster”, which I highly recommend even if you don’t own an Alfa or not a kid.


#4

This is a duplicate post of “Car RPM drops on full throttle, no power”


#5

This car has an L-Jetronic Bosch fuel injection system.

Take a read of this site HERE;

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

It hasn’t been updated since 2003 but then this IS a 30 year old car and these are exactly the kinds of problems you’ve been discussing.