1980 FI SPIDER Problems under throttle load

[pparana25]

Ok so the 1980 spider is having a few problems, here is the list from least worrysome to most, take your pick and thanks for the help:

1. Temp gauge pegs itself from 180 on in an instant it will go all the way hot

2. Car will die when fan comes on

3. Car is hunting alot, cant seem to get it to run under 1000-1200

4. Car will die if you "floor it, slow on the throttle and it seems to move up ok, under load same problem but worse, like it is being starved of fuel

List of items replaced

1. mass airflow sensor
2. cold air bypass
3. throttle switch
4. cooling temp (inline) thermo time switch, 02 sensor
5. plugs wires, rotor ext.
6. all fuel injector seals
7 alternator
8 starter
9 misc other stuff.

I am thinking this may have to do with some ground, or possibly with the vacuum advance on the distributor, any help would be great

[wengr]

Hi, I have experienced #1 - temp gauge shoots up to maximum while the car ran fine other than a slightly high idle sometimes. I don't know what causes it for sure but I believe it has nothing to do with the FI. got to be electrical or an air bubble. I vote for air bubble because in my case actual overheating was soon to follow. sorry can't help with FI issue but plenty of others will.

[So Cal Mark]

1. replace the temp sender for the top half of the gauge
2. If you hold the rpm higher does it still die? Put a voltmeter on the battery and see what the running voltage is
3. check idle switch adjustment, check for air leaks on the intake system
4. have you checked the basics? Battery voltage, clean tight battery terminals, ignition timing, air flow meter flap movement?
Were the replacement parts new, rebuilt or used? Did you clean all of the electrical connections to those parts? The vacuum advance won't affect any of the issues you're having

[rlux4]

If you haven't done so yet, I'd suggest you download Brad Artigue's Fiat 124 Engine Maintenance and Modification. Chapter 5 has a good explanation of the basics of our Bosch FI system. It also has a FI tuning procedures section.
When you say the engine dies "when fan comes on", I assume you're talking about the radiator fan. If this is the case, I'd look for wiring modification done to the circuits (temp sensor and fan power) involved. Neither circuit is FI related, so they shouldn't cut out power to anything in that system. Disclaimer: Our cars have two temp. sensors, the one for the FI system is in the cooling "T", the one to signal the radiator fan to come on is at the bottom of the radiator, driver's side.
Ron

[wengr]

1. replace the temp sender for the top half of the gauge

is this the forward or the rearward one?

[So Cal Mark]

it should be the black one, disconnect the wire with the key on. It shouldn't affect the gauge reading. Then ground the wire and the gauge should peg to the red zone.

[pparana25]

1. replace the temp sender for the top half of the gauge
2. If you hold the rpm higher does it still die? Put a voltmeter on the battery and see what the running voltage is
3. check idle switch adjustment, check for air leaks on the intake system
4. have you checked the basics? Battery voltage, clean tight battery terminals, ignition timing, air flow meter flap movement?
Were the replacement parts new, rebuilt or used? Did you clean all of the electrical connections to those parts? The vacuum advance won't affect any of the issues you're having

1. temp sender? on the top of the engine by the spark plugs?

2. no it does not die at the top, it will stay running,

3. idle switch is set properly, no air leaks

4. i will review the battery stuff, I am leaning towards this one, timing is 10 deg before top dead, airflow meter flap is fine, parts were a combo of new and rebuilt. Would the battery draw cause these many problems, also why under load and throttle would you get this type of issue, I think the battery may be part of it, however I am thinking there has to be one other issue here.

[So Cal Mark]

a cracked intake boot usually shows up under load, but have you check fuel pressure and volume?

[pparana25]

a cracked intake boot usually shows up under load, but have you check fuel pressure and volume?

intake boot is new, as is the fuel pump and regulator, also the pump runs all the time, not sure why. I replaced the ground for the battery and some other grounds to no luck, car running getting about 14.5 to the battery. I am gonna double check the mass airflow sensor, it was a rebuild maybe a defective one or so. Also there is a yellow wire all by itself up in the drivers side front about a foot back looks like someone cut it, I am going to take the multimeter to it and see what she says, I think I might take a photo. Also keep in mind a slow walk up seems to not be an issue, a full out gunning does it, this is not under load.


Thanks,

Phil

[rlux4]

A minor point, but it's not a mass air sensor, it is not that sophisticated, it only measures air flow, not density. Mark makes a good point about the volume of fuel. Is your fuel pump correct for our cars? It sounds like the volume isn't keeping up with demand on sudden increase.
Ron

[pparana25]

yeah it is a direct rebuild, however today I ordered a bunch of new stuff, will have to try it out, I ended up pulling the tank out today, lots of rust and stuff in there ( I had drained it once but the car had been sitting for 15 years) So I am gonna try to clean that up and see if it makes a difference, Any ideas on how to clean that tank up would be great.

[rlux4]

Pope posted a good method a while back, you might try this:
http://www.fiatspider.com/f08/viewtopic ... ank#p30521
You may need to back wash or replace your fuel filter. The pump has a back flow preventer in it so you can't back wash it.
Good luck, I think once you get the rust out of the system you'll have a better flow of fuel.
Ron

[So Cal Mark]

if the cars been sitting 15 years, I'll bet the injectors aren't flowing much fuel

[pparana25]

i Will pull them and check flow ,Any idea why the pump would be running all the time, I thought it only came on when the car was cranked over, just wondering if I have some more miswiring. I should have just bought a new car. Will give an update once I have replaced a few more items, this car has been my Nemesis for 2 years, mocking me in my extra garage bay. Got to get it running before I move. Any ideas would be great


Thanks,

Phil

[So Cal Mark]

it's not uncommon to find pumps that have been rewired when an owner can't figure out how to fix the system. There is a switch inside the air flow meter that activates the pump. The flap in the afm has to move for the pump to operate. It's very easy to adjust that switch to make the pump run constantly. Try unplugging the afm, and see if the pump still runs when the key is on. If it does, someone has rewired the pump. If the pump doesn't run, then the afm switch is misadjusted