MFI Gurus - Electrical Help

[GDSOB]

In trying to cure my cold blooded starting problems I discovered the Start Enrichment Solenoid is not getting power. The solenoid works when I jumper it and it starts great with a fuel trickle. So the problem appears to be the auxillary starting relay. I unplugged the relay and the car acts like its normal cold blooded self...

Is there a good way to test this relay?

The relay also controls the Temperature Time Switch- do I need this? What does it do?

Is it advisable to eliminate the relay and use a momentary push button for the start enrichment solenoid? If so, where is a good source to power it?

[GDSOB]

Did a search- should have done in the first place. Looks like I need to test the thermo time switch.

[Oldporsche]

For the most part these motors like rich starts when they are cold.

This is probably because they have so much valve port area for the size of the motor. (This is not my observation, I'm just paraphrasing Dan Gurney)

David Duffield

[304065]

Here's a good thread on the subject:

More MFI

[ErVikingo]

Thanks for the link John. My car (69 S) is a dog when cold. It takes at least 30 seconds to start in South Florida (and thats in summer). Once warm, it starts up immediately.

Any links to easy to follow checks to see whats wrong? Oh yeah, once warm, my idle is too fast (1300-1500).

I have another problem now, I did not use the car for approx a year. It started as usual and worked OK for 60 or so miles. After that, it works OK if not pushed hard. If I push it, it bogs badly.

I guess I gummed up the pump or the injectors and fouled the plugs.

Ideas? Is it too late to put a bottle of Stabil? I burned at least 1/2 tank and filled it up with fresh premium but that had no effect.

Really looking forward to suggestions

[304065]

Juan,

Re: Starting, it sounds like your cold-start mechanism isn't working right. On the '69, there's an enrichment solenoid on the pump itself that pushes the rack full-rich. You might jump the solenoid with a wire from the hot fuse in the triple block to see if it's clicking.

To check if the rack is sticking, remove the rubber cap on the forward end of the MFI pump (engine OFF, please, it's hard to run a 10-key adding machine with only three fingers!) and stick something in there to push the rack back, then release it. . . the rack should snap back into place.

Now, once the thermostat is at operating temperature, the engine idles too high. This tells you, too much fuel, too much air.

The best way to fix the idle is to run through the entire Check-Measure-Adjust routine. High idle can be fixed by adjusting the air bleed screws in the individual throttle stacks (that takes care of the air) and the idle mixture screw (that takes care of the fuel). Be SURE that the engine is at operating temperature (at least 180F) when you do this, because as it heats up things move around, and you must be certain that the thermostat operating rod is as long (lean) as it's gonna get.

[ErVikingo]

That check-measure-adjust routine sounds like fun (not!)

I'll be careful with my fingers. Its hard enough using it with a bad case of tenosivytis (sp)........

Cheers/thanks, Juan