1986 Fiero SE Stall in Gear (Page 1/3)
AstroChemist MAY 06, 04:22 PM
Hello everyone. I have an 86 Fiero SE. I recently changed plugs, cables, distributor, cap, flushed coolant, changed oil, new filters. The car has been sitting essentially since the late 90s. Now, I finally got it to run (yay!) but only in idle, and the idle is high. (2000-2500 [3000 if pretty cold]) The issue I'm having now though, is despite the clean (albeit high idle) when I shift into gear, I get a very rough transition at around 500-1k rpm and then the car sputters and dies as soon as even a drop of gas is given. This happens in drive gears and in reverse. But I can idle indefinitely and even apply throttle while idle without any noticeable issues.

Current engine code is a 15 so I'm planning on replacing the temp sensor and thermostat here in a couple days, but I don't think that would cause this issue because the temp sensor has a fallback, doesn't it?
Looking for any help,
AstroChemist


P.S. my timing is several degrees ccw because otherwise the car will slowly die in idle. Going based off the harmonic balancer, I have an idle of 1.5k rpm for 30 or so seconds before it slowly dies off. There's also pretty bad throttle lag if I stay at the timing from the harmonic balancer. Even though it has the best idle rpm.
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Vroom, Vroom.
-My 86 Fiero

[This message has been edited by AstroChemist (edited 05-06-2024).]

olejoedad MAY 07, 06:54 AM
It sounds like a large vacuum leak.
First place 8 would check would be the #GR tube that runs from the underside of the upper plenum to the EGR valve.
They are known to be a failure point.
fierofool MAY 07, 02:06 PM
It may also be that the torque control solenoid is about to totally fail. Look on the front of the transmission for a sensor and harness wire pointing at the driver's butt. Unplug the harness and see if that will stop the stalling. It won't stop the idle problem, though.
AstroChemist MAY 07, 04:30 PM

quote
Originally posted by fierofool:

It may also be that the torque control solenoid is about to totally fail. Look on the front of the transmission for a sensor and harness wire pointing at the driver's butt. Unplug the harness and see if that will stop the stalling. It won't stop the idle problem, though.



So I took a look today, (I'm still getting used to the mess the old owner made) and here's what I found:

The egr tube is missing (I knew that) but I have it blocked off with a plate, and the vac line is blocked too. Theres probably an exhaust leak bc of that but surely not a vac leak right?

The connector for the TCC is just gone. So its already unplugged I guess.

The fluid levels are all good. There's no thermostat in (I ordered one already)

I think that's about all I found so far. Despite cranking up all day yesterday with no issues, I can't seem to get it to really run. To be fair, I don't have a working gas gauge so I can't tell when it's out or not. But I put a gallon in yesterday and haven't been driving it so I doubt it's out? It idles rough at just under 1k for a few secs then dies.
Patrick MAY 07, 04:46 PM

quote
Originally posted by AstroChemist:

The egr tube is missing (I knew that) but I have it blocked off with a plate, and the vac line is blocked too. Theres probably an exhaust leak bc of that but surely not a vac leak right?



Wrong. The missing EGR tube was originally connected to the underside of the top intake plenum. If that's not blocked off/sealed properly, then it's a definite source for a (huge) vacuum leak.

Just so you know, this (as well as your previous threads) belong in Technical Discussion & Questions. No, you're not able to move them now. Only Cliff Pennock can move or delete threads.

[This message has been edited by Patrick (edited 05-07-2024).]

AstroChemist MAY 07, 08:44 PM

quote
Originally posted by Patrick:

Wrong. The missing EGR tube was originally connected to the underside of the top intake plenum. If that's not blocked off/sealed properly, then it's a definite source for a (huge) vacuum leak.

Just so you know, this (as well as your previous threads) belong in Technical Discussion & Questions. No, you're not able to move them now. Only Cliff Pennock can move or delete threads.





I see, I'll go ahead and check that asap then. Apologies for the wrong location, I'm still new here. I'll be sure to post in the correct spot next time.
Patrick MAY 07, 11:01 PM
I'm just curious... when you blocked off the opening in the EGR valve (or the exhaust crossover pipe if the valve itself is also missing), where did you think the other end of the missing EGR tube might've gone to?

[This message has been edited by Patrick (edited 05-07-2024).]

AstroChemist MAY 08, 01:45 AM

quote
Originally posted by Patrick:

I'm just curious... when you blocked off the opening in the EGR valve (or the exhaust crossover pipe if the valve itself is also missing), where did you think the other end of the missing EGR tube might've gone to?




... To Narnia I suppose. I see what you mean. I thought the egr system operated backwards to how it actually does.

I went back in and checked all vacuum lines, and made sure the egr port on the underside of the plenum was blocked off. It already had a plate there, I just didn't notice it before. That makes me think it's not a vacuum leak, I can't seem to find any source of one.

[This message has been edited by AstroChemist (edited 05-08-2024).]

Patrick MAY 08, 01:41 PM

Cover the end of the throttle body with the palm of your hand while the engine's running. It should immediately stall. If the engine continues to run, there's a vacuum leak.
AstroChemist MAY 08, 07:49 PM

quote
Originally posted by Patrick:


Cover the end of the throttle body with the palm of your hand while the engine's running. It should immediately stall. If the engine continues to run, there's a vacuum leak.



It immediately stalls.

I fixed the issue, still have a hard shift but that's fine. Cars running smoothly

[This message has been edited by AstroChemist (edited 05-08-2024).]