[AndyL]

Hi, My '81 Spider with 78K had been running like a top the past two years since its valve job, but a couple of months ago it started running rough when warm. It now stalls at idle. Starts and runs cold fine, and after about 20 minutes it runs fine, but it stalls when warm. Unfortunately my commute is about 10 minutes and stalling in intersections is getting embarrassing.

Fuel pressure is fine, injectors have been checked, thermostat is fine, fuel pump was removed from tank and inspected. Plug wires have just been replaced.

Any ideas? Thanks

 

[144]

Sounds like it could be a failing Thermostatic Actuator. The T/A enriches the mixture when the engine coolant is cold, then leans the mixture out to normal running as the engine coolant reaches running temp. A bad T/A will keep the mixture enriched and not lean it out, thus running very rich, fouling plugs, etc.

Look at the little arm on the rear of the injection pump when the engine is hot, engine off or only at idle (throttle closed). The gap between that arm and it's stop (reference screw) should be .019" or less. That very very little. With a failing T/A, that gap will be much larger indicating the mixture is not being leaned out to normal running.

 

[AndyL]

Thanks John, I'll take a look. Is the T/A a replaceable part?

 

[Qmulus]

Also check if it is too tight. My thermo actuator tests fine, in fact on the high side of the spec, and is at zero in this hot weather. I can't maintain an idle when it gets to that point and have to set the hand throttle to keep it at a running RPM.

Time for me to break out Wes Ingram's book.

FWIW, my car is an '80 back dated with individual throttles, no VVT, some performance cams and an Ingram 150hp pump.

 

[144]

Thanks John, I'll take a look. Is the T/A a replaceable part?

Yes. They cost $230 for a rebuilt actuator (no new ones anymore). Be careful with the old one because of the core charge of $100. Go to Ingram Enterprises, Inc. || Spica Pump Rebuilds and download the free guides there on the Fuel Supply System and Roadside Fault Diagnostics Guide. I wrote them both, so if you have any questions, you can PM me.

 

[AndyL]

Thanks Qmulus, I hadn't thought about using the hand throttle. It might get me through the intersections! How do you check to see if the T/A is too tight?

Thanks John, Your guides are great - very informative and really clear illustrations.

The weird thing is how predictable this problem is. The car starts fine cold and idles at about 1200. Almost exactly 10 blocks later the idle drops to 5-600 (or stalls) and it doesn't want to respond to the throttle. Then once it's hot it runs fine again.

 

[AndyL]

Well I haven't solved my problem, but I have learned alot - like my Spica FI has an oil filter! Who knew? And I've owned this car 28 years!

The CSS and FCS seem to be working. The gap between the little arm on the FI that connects to the throttle and the reference screw when hot is very small - and the car runs fine after warming up for 5-10 miles. The T/A measured 25 mm from the screw plate at the FI to the tip when cold, and has one washer ~1.5 mm under it. Should the screw in the FI the T/A contacts bounce back freely when you press on it?

I pulled out the BC and it seems fine. The spring is whole and in place. The oil looked like Capuccino. I sucked it out and replaced it.

John, In a post you said don't move the throttle when the BC is out. I'm not sure I did, but then I'm not sure I didn't. What would happen if you did?

Thanks

 

[144]

Haven't changed the Spica oil filter in 28 years. That has to be a record. Take a picture of what's left of it and post it.

Yes, the TA adjustement screw screws into a spring loaded mechanism.

If you moved the throttle with the BC out, the rack may have reset itself to full rich. Put the BC back, start the engine, run it up to 2000-3000 rpm and release the throttle. The rack should reset itself to the correct mixture setting based upon barometric/pressure altitude.

Andy, do you have an owner's manual? The oil filter is shown in there.

 

[michael speed]

Similiar Idle Troubles

Hi Guys,
I have a 1990 Spider and have been experiencing similar troubles on and off. Sometimes after a short drive, as I pull up to an intersection and press in the clutch, the car will just stall out. This happens inconsistantly. Sometime a problem, sometimes not. It runs up and down the highway fine, power feels good. Do you think the T/A is also the gremlin in this scenerio?
Thank you.
Michael

 

[144]

Hi Guys,
I have a 1990 Spider and have been experiencing similar troubles on and off. Sometimes after a short drive, as I pull up to an intersection and press in the clutch, the car will just stall out. This happens inconsistantly. Sometime a problem, sometimes not. It runs up and down the highway fine, power feels good. Do you think the T/A is also the gremlin in this scenerio?
Thank you.
Michael

No. Your car has an Bosch electronic fuel injection system and not the Spica mechanical fuel injection system. See if you're getting a rubbed wire (short) somewhere around the clutch pedal mechanism.

 

[Atomico]

It's the EGR system

Your problem, plaguing both a spica and Bosch fuel injected cars, is the egr valve failing. In the case of the original post, you are drowning the engine with exhaust air. Hence the lack to throttle response. On the 81 alfa I suggest checking all the vacuum lines make sure you don't have a leak, replacing the EGR valve, or changing your exhaust headers and intake since you may be emissions exempt.

This happened to my 81 spider.

 

[AndyL]

I finally fixed it after reading lots of posts here about idle problems. When the car was smogged they lengthened the link to the throttle butterfly to lower the idle and make it richer. I could tell from the clean threads. I put it back, readjusted the idle and the warm stall vanished.

I learned to adjust the T/A by removing or adding washers in a few minutes, built a dummy T/A, and changed my spica oil filter! The one I took out didn't look too bad.

After getting it running like a top again I decided to trade it in. It was (still is) a great car and I hope someone's enjoying it.