Looking at a '95 Grand Prix (Page 1/2)
Twilight Fenrir SEP 29, 02:16 PM
Hello there,

My Fiero is becoming incredibly unreliable, and I can't figure it out right now, so I'm looking at a cheap car to get me through the winter.

I've found a '95 Pontiac Grand Prix SE for $300. The engine runs great, doesn't seem to burn any oil, doesn't seem to leak any fluids externally either. Awesome. But, for $300, there is of course a catch. The trailing arm mounts are completely gone.

Weirdly, this is the only area with rust on the car. But it is severe rust. There's nothing left at all of the unibody frame within about a foot of the mounts. I'm a blacksmith, so fabbing the metal to get it drivable probably won't be a big issue. But I do have a couple questions...

Firstly, if I buy the car, I have to get it home. I'm wondering if running a pair of ratchet straps to the front of each trailing arm, and up to the front of the car would let me get about 20 miles on fairly smooth roads. I know that's sketchy as hell, but I need to get it to my shop, and towing isn't an option at the moment.

Second, he mentioned the transmission, when just put into Drive, wouldn't do anything. But if you put it into low, second, etc manually, that it worked fine. Is this a major catastrophe? I would assume if it can be done manually, it's whatever regulates the shifting that is at fault. That the transmission itself is probably fine. Is this the case? What regulates the shifting on this? Is it vacuum modulated, or electronic? I can live with having to shift this way, I wanted a manual transmission anyway :P But if this will stop working in the next 5 months, then I'm in trouble. He says he's been driving it this way since he bought the car 5 years ago, and I get the impression he is mechanically competent and on the level with me, but he IS trying to sell something :P

Third... If for some reason I can't get the metal back together.... I've read the 3.1 will drop right into a Fiero, but was confused about some posts saying it will bolt right in, while others talk about using parts from the stock 2.8. Would the 3.1 bolt up to my Isuzu 5spd in place of my 2.5L? I understand I have to install the Prix's ECM and such, but I should be able to do so. Would I need to get the 2.8L throttle cable?

Thanks.

[This message has been edited by Twilight Fenrir (edited 09-29-2015).]

carnut122 SEP 29, 03:08 PM
I can only solve your first issue. Have the guy deliver the car to your house. That transmission issue sounds like a valve body issue of some sort. Others have dropped in 3.1 into Fieros but I can assure you it will take some work. Maybe you should search 3.1 threads in the tech section?
Twilight Fenrir SEP 30, 10:30 AM
Well, I think I found most of my answers through research...

I'm reasonably confident in my band-aid being able to get me home from looking at the structures and engineering of what WAS there. I also have a good idea what I'm going to dk to repair it.

The transmission in 94+ transmissions in the GPs are known for having a faulty solenoid inside of them, that takes out the ability for the transmission to shift itself. Making 1st gear, and 4th gear impossible to shift into. The car will take off from 2nd, and it will cruise in third alright. But it can't be put into overdrive. The part CAN be changed without pulling the transmission, just have to remove the side cover, which still requires a good deal of work, but it's something I can manage if I feel the need. It's not going to fail any worse, and the trans is likely mechanically sound.

I didn't get solid information on the Fiero swap... I have a better idea what has to go into it, but not 100%. That's not a priority right now, though. More a thought of what I can do in the future. Not something I'm looking to do now.
thesameguy SEP 30, 03:09 PM
No time to fix Fiero, but time to reconstruct body structure and repair a transmission on a 20 year old Grand Prix? Seems like you're just trading projects, not really saving time or money. ?
carnut122 SEP 30, 07:14 PM

quote
Originally posted by Twilight Fenrir:
The transmission in 94+ transmissions in the GPs are known for having a faulty solenoid inside of them, that takes out the ability for the transmission to shift itself. Making 1st gear, and 4th gear impossible to shift into. The car will take off from 2nd, and it will cruise in third alright. But it can't be put into overdrive. The part CAN be changed without pulling the transmission, just have to remove the side cover, which still requires a good deal of work, but it's something I can manage if I feel the need. It's not going to fail any worse, and the trans is likely mechanically sound.

.



I'm not sure what "limp home mode" is on these trannys, but when my daughter's transmission went out on her Sebring, it stayed in second gear the entire time. Are you sure it's shifting at all?
Twilight Fenrir OCT 01, 08:22 AM

quote
Originally posted by carnut122:


I'm not sure what "limp home mode" is on these trannys, but when my daughter's transmission went out on her Sebring, it stayed in second gear the entire time. Are you sure it's shifting at all?



No, but I'm going to take it for a test drive today. And either buy it, or not right after. The owner says it can be manually shifted, and has been driven that way since he got it 5 years ago.

My research says that if power is cut to the solenoids (which the failure of the TPCS can cause by shorting and blowing the fuse that feeds all of them) the transmission, when in drive, will default to 3rd gear. Putting it into low, or 2nd should result in the transmission going into 2nd gear. So in theory, it functionally only has 2 gears unless I replace that solenoid. But I'll be able to verify after my drive today.

quote
Originally posted by thesameguy:

No time to fix Fiero, but time to reconstruct body structure and repair a transmission on a 20 year old Grand Prix? Seems like you're just trading projects, not really saving time or money. ?


You've definitely got a point, and I recognize that... But I've thrown a lot of time and money at what's currently wrong with my Fiero, with zero improvement. I just can't do it anymore right now.

Reconstructing the suspension mounts won't take that long. I've got all the steel I need. And being a blacksmith, I have plenty of tools to do it overkill. I don't plan to fiddle with the transmission right now. If it's something that needs immediate attention, I'm probably going to pass on the car.

Either way it's a gamble. Getting and working on a new car is just plain more fun :P It also doubles my odds of having one running car through the whole winter. Plus, this car could be the solution to my Fiero's problems :P Replacing the engine and ECM is a 100% certain way to eliminate my engine problems :P

Just need to get through until next year... Then I'm going to buy an Elio when they go i to production n.n

[This message has been edited by Twilight Fenrir (edited 10-01-2015).]

Twilight Fenrir OCT 01, 09:44 PM
Yep, transmission shifts great. It even goes into overdrive fine n.n Putting it in "D" from a standstill the car does default to 3rd gear, and doesn't exactly get going very quickly. But manually putting it in 1st or 2nd and it goes nice. It needs a new water pump ($15, and it's right on top of the engine, easiest water pump to change I've ever seen) but otherwise there doesn't seem to be anything wrong with the engine.

The ratchet straps worked great for getting the car home. Couldn't feel any looseness in the rear end, handled great all the way home. This is going to be a magnificent car <3

The turn signals are wonky, but they are behaving just like my Fiero's did when the flasher went bad. Looks like it's a standard unit, so I'll just yank one out of my other cars and cram it in there. Worst case scenario, I can manually make it blink like I did on the way home :P

Not bad for $300

[This message has been edited by Twilight Fenrir (edited 10-01-2015).]

thesameguy OCT 02, 10:23 AM
Good deal, glad you got it sorted!
Patrick OCT 02, 09:14 PM

quote
Originally posted by Twilight Fenrir:

But, for $300, there is of course a catch. The trailing arm mounts are completely gone.

Weirdly, this is the only area with rust on the car.



Ummm... what's that rust-colored stuff along the bottom of the side of the car?

RWDPLZ OCT 05, 01:44 AM

quote
Originally posted by Patrick:

Ummm... what's that rust-colored stuff along the bottom of the side of the car?



Butter. AND NOTHING MORE.