Stalls but Starts Back up (When Warm) (Page 1/2)
Jeffdylanproctor JUN 28, 10:44 PM
Thanks everyone for helping me solve the High Idle issue (Coolant Temp Sensor fixed it). But herein lies a different issue: stalling while driving.

27 miles into my backroad commute the car stalled while driving. I pushed in the clutch, coasted for ten seconds, and hit the key. It started back up fine.
The same thing happened again at mile 36. Then again around mile 40 as I pulled into my destination. It will cut out while driving, sputtering as if its not getting fuel or spark, but then you can start it back up after a few seconds and it will run fine for a while longer. Once the problem begins it seems to escalate.

The car had all day to cool off. I installed a new Ignition Control Module and then headed home. The same problem manifested again, at almost the exact same mileage.

No codes. Fuel Mileage is around 25mpg. The temp gauge reads in the 170 range, and my infrared thermometer shows that to be fairly accurate. Still, the problem seems to be temperature related.

It's like when the car gets to a up to a certain tempterature it has an electronic component fail, cutting out either fuel or spark (probably not air but maybe the electronics on the throttle body?)

This is a very specific problem. Never had a car do anything like this. Usually if they break down they break down, and not just need to be turned off and on again.

I did a search and this seems to be a known problem for 2.8 Fieros, but I couldn't find any definitive answers to what is causing it. It's so specific that I wouldn't expect there to be a massive list of different problems that could cause this unique quirk.

Does the vast knowledge on here know what could be causing this?

[This message has been edited by Jeffdylanproctor (edited 06-28-2023).]

Patrick JUN 28, 11:56 PM

quote
Originally posted by Jeffdylanproctor:

The temp gauge reads in the 170 range, and my infrared thermometer shows that to be fairly accurate. Still, the problem seems to be temperature related.



I don't think this is related to your stalling problem, but 170° is pretty cool for a warmed up engine. Is there not a thermostat installed? The factory 'stat is 195°.


quote
Originally posted by Jeffdylanproctor:

I installed a new Ignition Control Module and then headed home. The same problem manifested again, at almost the exact same mileage.



Sounds like it's the ICM, but may not necessarily be the ICM. Read what I posted earlier today Here.

Out of curiosity, what brand ICM did you install?

[This message has been edited by Patrick (edited 06-28-2023).]

jelly2m8 JUN 29, 03:46 AM
Very nice description of the problem. You mentioned sputtering. Sputtering is very likely a fueling issue, Ignition / ICM is usually an instant shut down, like turning the ignition key to off.

Are you able to source a fuel pressure gauge and monitor that while the issue arises?
Jeffdylanproctor JUN 29, 09:01 AM

quote
Originally posted by Patrick:
Out of curiosity, what brand ICM did you install?




The brand was Standard ($59), as that was the only choice the local parts store had in stock.

It had a thermostat when I bought it, and not knowing its conditon, I replaced it with a new 195 thermostat. But yes, the car runs very cool, the only time it gets up to 200 or more is if its waiting in traffic on these summer days. The cooling fan will kick on with the A/C on, but its never got hot enough to turn itself on. It cools down quickly when moving.

[This message has been edited by Jeffdylanproctor (edited 06-29-2023).]

Jeffdylanproctor JUN 29, 09:19 AM

quote
Originally posted by jelly2m8:

Very nice description of the problem. You mentioned sputtering. Sputtering is very likely a fueling issue, Ignition / ICM is usually an instant shut down, like turning the ignition key to off.



I was thinking it felt like a fuel issue, and I had reasoned out that since the car will start back up so easily, that its something must be getting caught in the fuel pump or filter (or maybe somewhere else) and once the pressure was relieved the thing would be released and the flow restored.

I've driven the car to work twice now, and the problem happens on the way in and again back home. The sputtering issue doesn't develop when I drive localy around the house in short 10-15 minute trips, but only after about 30 minutes, and then it gets more and more frequent.


quote
Are you able to source a fuel pressure gauge and monitor that while the issue arises?



I may end up ordering one.

[This message has been edited by Jeffdylanproctor (edited 06-29-2023).]

Jeffdylanproctor JUN 29, 11:20 AM
Anyone know what this is?



The wires going into the white plug look very non-factory
Jeffdylanproctor JUN 29, 11:23 AM
Also, does anyone know if the stalling/sputtering issue could have something to do with the Cold Start Injector?

Or the Fuel Pressure Regulator that sits on the fuel rail?
Fie Ro JUN 29, 06:06 PM
I would do a fuelpressure test first, maybe the fuelpump is going out. Also check for consistent power and ground to the fuelpump.


quote
Originally posted by Jeffdylanproctor:

Also, does anyone know if the stalling/sputtering issue could have something to do with the Cold Start Injector?

Or the Fuel Pressure Regulator that sits on the fuel rail?



Sparkplugs can tell if you are running too rich or too lean.
Patrick JUN 29, 07:04 PM

quote
Originally posted by Jeffdylanproctor:

The temp gauge reads in the 170 range, and my infrared thermometer shows that to be fairly accurate.




quote
Originally posted by Jeffdylanproctor:

It had a thermostat when I bought it, and not knowing its conditon, I replaced it with a new 195 thermostat. But yes, the car runs very cool, the only time it gets up to 200 or more is if its waiting in traffic on these summer days. The cooling fan will kick on with the A/C on, but its never got hot enough to turn itself on. It cools down quickly when moving.



Sounds to me then that this thermostat is stuck open.

In regards to the fuel pressure (or lack thereof) perhaps being the culprit, yes, it's certainly a possibility. Checking the fuel pressure on the Fiero's 2.8 engine is very easy. If you don't have access to a pressure tester, one thing you could try is starting fluid. When the engine starts to "sputter", spray starting fluid into the intake (I guess you'd have to loosen the rubber snorkel for access). If the engine comes to life, it's probably a fueling issue. If the engine continues to sputter, we're back to the ignition.

[This message has been edited by Patrick (edited 06-29-2023).]

Patrick JUN 29, 07:26 PM

quote
Originally posted by Jeffdylanproctor:

Anyone know what this is?

CLICK FOR FULL SIZE



Some sort of replacement for the tach filter?

Failing tach filters can affect engine performance. Disconnect this device and see what happens.

[EDIT] Found it.

[This message has been edited by Patrick (edited 06-29-2023).]