81 spider issues

[Doug81spyder]

Hello from a new member in Stratford Ontario Canada.
I am just completing a restoration of a 81 spider 2000. It has seen the road over the last couple of weeks but engine issues have cropped up. The car starts and idles perfectly, holds 900-1000 rpm no problem. The longer the car ran the better the performance became. Then all of a sudden nothing, the car quits. I can re start and it idles fine, however when I put it under load (in gear) it sputters and lurches and will not hold the revs. I can leave it sit and return latter and it starts and drives fine for a couple of miles then the same thing again. I am looking for diagnostic help and experiences of the same. My thoughts are that the mass air flow sensor is in need of replacement as a first step. Or do I look at the O2 sensor or RPM sensor or all. Any thoughts on this would be greatly appreciated.

[rlux4]

First off, a semantics issue. Our cars don't have a mass air flow sensor, we have an air flow meter. The flow of incoming air moves a flap that is attached to an arm that moves over a potentieometer. This is read by the ECU as amount of air coming in. The flap has very tight tolerance in the chamber, so any build up of gunk will inhibit free movement of it. You can check the flap movement without taking the AFM apart, just disconnect the air boot, reach in and move the flap through it's whole range of motion. It should move easily and freely. The other component on our system that is critical is the temp sensor in the coolant T. If it's bad it causes all kinds of problems.
Keep us updated.
Ron

[Doug81spyder]

Thanks Ron:
Everything is moving freely and the inner flap forms a tight seal. After driving for a extended period of time the temperature hits 190 and stays there, fans works - no issue there.
I have own the car since 1984, but it has not seen the road for the last 8/9 years or so.
We all no how time works it way into things, but the car had been running top shelf for the first couple of days.

new fuel pump
fuel filter
clean gas
tight/clean connections
new air filter
my thoughts are of the signal from the flow meter

[pooldoctorstl]

The temp sensor that sends signal to the gauge is not the one that the ECU uses for fuel management. It may be 190 on the gauge but the ECU may think something different. The first step to diagnosing problems with our FI systems is to download and get familiar with Brad Artigue's FI manual and also get his wiring diagrams for your car. You can get them here: http://artigue.com/?page_id=3.

Check all of the basics first because it could be a fuel or an ignition issue. Good luck and keep us posted on your progress.

Jeff

[2ndwind]

Jeff,
That's what I thought too based on Brad's wiring diagram and my following the wires for my non-functioning gauge. Where is the temp sensor for the ecu, please?

[Foster48x]

I had a similar issue not to long ago and it ended up being a vacuum leak in the main intake hose coming off the afm. I would check the basic stuff like that before you start digging too deep.

The temp sensor is on the coolant tee.

Rick

[pooldoctorstl]

Yep, as Foster said, ECU sensor is in the coolant TEE and the gauge sensor is in the head between the spark plugs. If the gauge doesn't work, also check all of your grounds and wire connections.

Lastly, you should post problems like this in the "Engines & Tuning" section. You will get more responses there for specific engine issues like this. This introductions section is just to introduce yourself, say hi and tell us a little about your car.

Jeff

[Doug81spyder]

Thanks to all for the suggestions and info. Turns out I was over thinking a little. I started with the basics and came to realize I had rust in the gas tank from sitting for too many years. Cleaned out the tank, new lines and filters and (too steal another companies tag line) zoom, zoom. Car is running great. Once again, thanks for being a sounding board to bounce issue off of.