Sluggish power after changing brake rotors (Page 1/4)
danahart MAY 22, 09:15 PM
Hi all. Pretty new poster but have read a bunch on this forum. I just got a 1988 Formula a few weeks ago so am new to the Fiero world. Also pretty inexperienced mechanic skills but hoping to improve that now that I have a 30yr old car. Looking for advise on an issue I'm having.

Anyway, the car is a v6 manual and worked perfectly at time of purchase. I didn't drive it too much due to the very bad tires but enough to get an idea of how it felt. I finally got new wheels on it and went ahead and put new rotors on as well since the old ones were pretty rusty and the car came with a brand new extra set. I didn't change the brake pads as they looked fine. All good and I started driving it fairly regularly on short trips.

A few days later I noticed the car doesn't have as much power as I remembered. I don't think this happened at the same time as the brake/wheel work...I'm fairly sure it ran as normal for a few days before I noticed the lack of power. But it is somewhat subtle and if I'm not trying to quickly accelerate it can be easy to miss. I only mention the wheel/brake work as it is the only thing I've done to the car. Just to test to make sure there wasn't rubbing or locked up, while off I disengaged the ebrake and pushed the car back and forth on a flat driveway...it pushed very easily. I figured that if anything was rubbing I'd have heard or felt the resistance. Educate me if that is not a valid assumption.

Anyway, the car can get up to speed but it doesn't have the acceleration it used to. I almost have the accelerator touching the floor in first gear before I get moving enough to go to 2nd. Once moving it can maintain speed but again, just lacks power. I'll be in 4th on a slight hill going around 50 and have to have the pedal to the floor to maintain that speed in that gear. It is also struggling to get up my steep driveway in 1st a bit.

I haven't had a lot of time to investigate, the only thing I've done so far is to check the air filter to make sure there wasn't a blockage keeping air from getting in. All seemed ok there. I plan to pull the wheels and doublecheck the brakes again just to make sure I didn't mess something up...but again I figure that if I can freely spin the wheel then that should eliminate that possibility, right?

Any ideas on what the likely culprit is or the easiest things I could start to check first?

EDIT: No cat on the car.

UPDATE:
- 5/24: added the LinquiMolly fuel additive with a new tank of gas. Today I ran out for a short errand and the Service Engine Soon light came on. I checked and it is throwing code 44: Lean exhaust indicated (Left side on dual oxygen modules). I looked through the forum and it seemed there were a bunch of possible causes for this but maybe someone has a suggestion on this code combined with my loss of pep.

-Changed the air filter at some point I forget when.

- 6/1: Tested the fuel pressure. Primed it reads 40psi. When running it started at 35psi but went to 40 when driving. When stopped and turned off, pressure still read 36psi a half hour later. 12 hrs later it read 23psi. That all seems normal based on my internet reading so I assume I can rule out the fuel pump? I also changed the fuel filter. Changed pretty easily so I doubt it was the original one or super-old. Test drove and no change although the warning code 44 is no longer displaying...but I also didn't drive for more than 15min or so.

- 6/6: Found it was a injector fuse that was blown. I likely have a short someplace that I need to track down. But when using a new fuse, it works perfectly until the fuse blows again.

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

Jason88Notchie MAY 22, 10:09 PM
Sounds like your wheels are moving fine, so I wouldn't worry about that. The car probably sat for a bit in-between the sale of the car. And however long. The gas probably gummed up and is now reeking havoc through the system.

Easy stuff here. Change the air filter anyway. Their cheap. Dump a bottle of Liquid Molly gas treatment in on the next fill up. Run that through a fuel cycle. Then change the fuel filter. Fill it back up.

That's where you should start. Cheap easy solutions first.
Patrick MAY 22, 10:21 PM

quote
Originally posted by danahart:

Anyway, the car can get up to speed but it doesn't have the acceleration it used to. I almost have the accelerator touching the floor in first gear before I get moving enough to go to 2nd. Once moving it can maintain speed but again, just lacks power. I'll be in 4th on a slight hill going around 50 and have to have the pedal to the floor to maintain that speed in that gear. It is also struggling to get up my steep driveway in 1st a bit.



Does it have a cat? If so, the innards have potentially let go and are now plugging the exit of the cat. If you can safely get under the car and bash the bottom of the cat with the palm of your hand, does it rattle?

My experience with a plugged cat documented Here.
"One reason I’m suspicious is that I don’t feel the engine has a whole lot of mid-range to top end power."
danahart MAY 22, 10:24 PM
No. I should have stated that originally - no CAT.


quote
Originally posted by Patrick:

Does it have a cat? If so, the innards have potentially let go and are now plugging the exit of the cat. If you can safely get under the car and bash the bottom of the cat with the palm of your hand, does it rattle?

My experience with a plugged cat documented Here.
"One reason I’m suspicious is that I don’t feel the engine has a whole lot of mid-range to top end power."
danahart MAY 22, 10:30 PM
Thanks for the suggestions. I'll do that and see if I see any results.


quote
Originally posted by Jason88Notchie:

Sounds like your wheels are moving fine, so I wouldn't worry about that. The car probably sat for a bit in-between the sale of the car. And however long. The gas probably gummed up and is now reeking havoc through the system.

Easy stuff here. Change the air filter anyway. Their cheap. Dump a bottle of Liquid Molly gas treatment in on the next fill up. Run that through a fuel cycle. Then change the fuel filter. Fill it back up.

That's where you should start. Cheap easy solutions first.
Jason88Notchie MAY 22, 10:34 PM

quote
Originally posted by Patrick:

Does it have a cat? If so, the innards have potentially let go and are now plugging the exit of the cat. If you can safely get under the car and bash the bottom of the cat with the palm of your hand, does it rattle?

My experience with a plugged cat documented Here.
"One reason I’m suspicious is that I don’t feel the engine has a whole lot of mid-range to top end power."



Good one.

EDIT

If you had a CAT. Lol.

[This message has been edited by Jason88Notchie (edited 05-22-2024).]

Patrick MAY 22, 10:34 PM

quote
Originally posted by danahart:

No. I should have stated that originally - no CAT.



There could possibly still be an issue with the innards of a past cat plugging the muffler's exit. I'm grasping here, but if the engine runs smooth and just doesn't seem to have any power, it's sometimes a blockage of the exhaust.

Have you checked your ignition timing... with the ALDL jumper in place? It wouldn't be the first time a distributor has loosened enough to rotate and retard the ignition timing.

[This message has been edited by Patrick (edited 05-22-2024).]

Jason88Notchie MAY 22, 11:05 PM

quote
Originally posted by Patrick:

There could possibly still be an issue with the innards of a past cat plugging the muffler's exit. I'm grasping here, but if the engine runs smooth and just doesn't seem to have any power, it's sometimes a blockage of the exhaust.

Have you checked your ignition timing... with the ALDL jumper in place? It wouldn't be the first time a distributor has loosened enough to rotate and retard the ignition timing.




Could be issue with the exhaust but how do you know if he has a muffler? Lol...kidding.

I'm "leaning" more toward the fuel side. Car can run ok with clogged filter. But once fuel velocity reaches the max output of the filter the engine will starve. Mid to high range RPM.
Jason88Notchie MAY 22, 11:08 PM
Also I wouldn't mess with the timing yet..that would be down the road if the other solutions don't work.
Patrick MAY 23, 12:05 AM

quote
Originally posted by Jason88Notchie:

Also I wouldn't mess with the timing yet..that would be down the road if the other solutions don't work.



Jason, I've got to totally disagree with you there. IMO, ignition timing is one of the most, if not the most basic thing to check when an engine (with a distributor) isn't running properly. So many new (younger) Fiero owners have never even seen a timing light, let alone used one. Odds are, the OP has never checked the ignition timing since he acquired the car. Who's to say the previous owner ever timed the ignition properly? I don't trust anyone. It needs to be done.