1985 pininfarina still driving me crazy SOS

[rieg1]

My car is still siting on jack stands and still will only run for 3 to 10 minutes. I have bypassed the carbon filter but the symptoms continue. After the engine quits I can restart it after 5 minutes and it will sit and run without problems until I shut it off. I thought If I loosened the fuel cap it would avoid the quitting but that is not the case, same result. Can anyone think of something I should try maybe a sensor when it reaches a certain temp? It quits between 120 and 150 degrees according to the gauge before the fan comes on. This problem is like clock work happens every time. Just to kill time I took the starter off and had it rebuilt at the shop where I take my tractor starters and such wow what a difference spins so much faster. Maybe computer is causing this?? It is getting plenty of fuel and air so what could it be, also I replaced the pick up coil and had the module checked. Haven't had the coil checked, not sure how to do that. I am sending out an SOS thanks for any help you can send.

[ekstrandt]

test the fuel pressure regulator or just replace it as its probably old.

[micbrody]

It can be many components; but with some more clarifications and details, I think I can help.

1) car runs for 3-10 minutes and then quits. Can you tell me what initial rpms when it just turns over; and then every minute until it dies?

2) you mentioned you can start it 5 minutes later. Does that mean it won’t start before 5 minutes? Also: if you wait more time, does situation repeat itself? And like the first question: Can you record rpms every minute from just after start to 5 minutes out?
Also: what does initial temp gauge read on 2nd successful start? And to confirm: after 2nd successful start, there are no problems and car runs indefinitely

[rieg1]

Thanks, when the car first starts it is at normal idle 800 rpm the temp is 0 I can rev the engine during the first starting as much as I want it runs normal. The temp reaches maybe 130 to 150 it spits a few times and just quits. If I try to start it after it quits it will not start. I let it sit for a few minutes 3 to 5 and it starts right up runs great, I can drive it the rest of the day and it will be fine. I can drive to where ever I want shut it off come back and it starts right up I guess as long as it doesn't completely cool down it is fine. It is when it cools down over night that it problem starts all over again. The fan kicks on at about 190 or 200 after starting the second time. Engine does not reach normal temp the first time it starts it quits before reaching that temp. I'll try just about anything to get this thing running or maybe I should put it back in storage for another 12 years. thanks for any help you can give, rieg swoh

[ORFORD2004]

Coolant sensor in your T or the connector?

[micbrody]

The first thing I would try is to remove and clean auxiliary air valve. When car is cold, the valve allows air to bypass throttle plate so the extra air can match the extra fuel from cold start injector. As car heats up, a bimetalic spring engages the shutter and shuts off the valve. Both the ambient heat from engine and an active 12 volt (I think 12 volts) heated internal bimetalic strip speeds the process up.
The way to clean it is fill with carb cleaner; cover holes with fingers and shake. Repeat a few times. Then rinse the same way with dilute soapy water and let it dry. You can check the passive function of it by placing in freezer. After 5-10 minutes , look through it and shutter should have big opening. Then take a hair dryer (or carefully with heat gun) heat it and shutter should shut. As for electrical function: I haven’t done it but probably some voltage (but not sure about volts or amps).
My theory is that when super cold start (morning), the shutter is gunked up and just doesn’t shut fast enough when heated. After car sits for 5 minutes, the hotter ambient temp of engine gets shutter open enough.

[toplessexpat]

I’d get the FI diagnostic guide - it’s available on forum.mirafiori.com and work through it methodically. It does sound like one of the FI components though, possibly the coolant temp sensor, or it might be a malfunctioning cold start injector that isn’t quite closing.

Good luck

A

[rieg1]

Ok guys I will check those things, not sure where the coolant sensor is unless it is the one on the bottom or the radiator. I have noticed that the bottom of the radiator takes forever to get any heat to it. My car will actually get hot if I don't turn on my fan with a switch that I put on the dash. After the initial heat up and the engine has got to operating temp the fan will kick on by itself. The car will overheat if I don't intervene on the first heat up after that the fan will kick on and off on its own. I have changed the switch at the bottom of the radiator and have replaced the external thermostat. It does seem to take way to long for the thermostat to open, top hoses will be very hot but the bottom hoses are still cold same with the thermostat top hot bottom not so much.
I don't know where the auxiliary air valve is unless it is on the air flow meter but I will find it! I will also check the fuel pressure regulator not sure how but I will find out. Thanks so much for the ideas. Looks like I have some work to do. I'll check the FI system as well, when I got it out of storage the car would only run for a few seconds on the cold start valve, start run a few seconds and quit I finally got the injectors unstuck and now it will at least start and run for a few minutes. Strange thing is I drove this car for years with no problems until I quit driving it for 12 years. Shame on me. Life just got too busy. A terrible excuse I know. Thanks for listening.

[micbrody]

Sounds like you need to flush radiator and fill again. You have a vapor lock. There are many ways to fill coolant system ; but easiest is to add a coolant addition piece to heating tube (one of the highest parts of coolant system (mine is made by Prestone).
As for temp probe: the main one is at coolant tee just in front of timing belt. The “probe” at bottom of radiator is a thermostat that just measures coolant temperature and turns on radiator fan when temp gets to 200-210f. But if there is a big vapor lock, no fluid travels by the probe

[micbrody]

Auxiliary air valve is a circular 3-4 in diameter , that is mounted to middle of engine at very front/top; just behind the timing belt. There is a hose that goes from big rubber/plastic intake to it; and on other side the a hose goes from device to intake plenum (near cold start injector ). It also has a black electrical connector to it

[ORFORD2004]

not sure where the coolant sensor is unless it is the one on the bottom or the radiator.

In the front of the engine top center. Top radiator hose plug there.

[lanciahf]

Coolant sensor in your T or the connector?

Just had this happen to a fellow spider owner at the Philly show. We bypassed the sensor with a paper clip and he was able to continue.

Shop manuals are a wonderful thing.

[micbrody]

Getting back to temp sender at coolant T. If there is air trapped there, then that probably could also explain (or contribute ) to issue. It tells
ECU temp which then has ECU decide on how long for ejectors to fire . So if no coolant fluid going past probe , the engine air/fuel mixture will be screwed up

[RRoller123]

+1, this is why I always jack the front end up as high as the jack will allow, to get that sensor opening higher than the rest of the cooling system components, then fill it to the brim. Massage the hoses, and if you still have the throttle plate heater, disconnect and fill that separately.

[rieg1]

Thanks guys for all the info, can't check any of those things for several days as we are out of town with the family for a week or so. I will get back with you all when I get a chance to work on it. I do have a complete shop manual for it or at least I did have. I let my brother use it and I think only half of it came back. I knew about the air lock problem with the cooling system and I thought I had that taken care of but after 12 years in the bank barn who knows. thanks again!! My brother sold his 85 two years ago as he was building a new house and needed the cash. Maybe the other half of my shop manual went with his car. I think my extra leather seat back went with it as well.