Hey everyone, To start out I'm trying to help out a friend with a 88 Fiero he just bought. It has a 4.9 swap and is using an auto (assuming 4t60e but not 100% sure). The car had sat for who knows how long and the body was trashed but the swap looks cleanly done and does run and drive. I have zero experience with the 4.9 swap or the 4.9 at all really.
The harness in it does look well done, all the wire bundles are neatly heat shrinked and cleanly run. I'm not sure who did the harness or the swap, the gentleman he got it from took it in trade. We were told the engine/trans/PCM are from a 93 Deville but I'm not sure how to confirm this. It is a PFI fuel injected engine.
On to the problems.
-The main thing we noticed so far after sorting the brakes out is it doesn't seem to want to shift unless you let off the throttle. It will shift with very light throttle but other then that it will not shift until you let off. This includes wide open throttle as well. If you stab it, it will kick down and go to redline but then it will hit the rev limiter until you let off the gas, once you let off it will proceed to shift.
-Also under heavy throttle it seems to go lean, I have not had a wideband on it to confirm though but it does have that lean smell to it.
-There is a red 2 pin plug that is ziptied to the harness near the alternator, Im not sure if it is a plug that is unused or something we need to sort out. (I can get a picture of this later this afternoon if it helps)
-The last thing is we tried to run the codes (the check engine light is not hooked up so we don't know if there are any to begin with) and my scanner is unable to communicate. I did some reading and apparently this pcm is unable to be read due to how it was setup in the original car. (PCM number is 16132240) Is there any way to set it up to allow it to be read by a normal obd1 scanner?
Thanks for any help, I'm not sure where to begin with this and in all my searching a lot of posts lead to long dead links.
I don't know a lot about the auto transaxle with the 4.9 since I kept the Isuzu 5sp with my 4.9 swap. But you may want to start by getting a new ECM chip programmed by Stickpony (on PFF). That will rule out any programming issues that could be causing any or all of the issues mentioned.
4T60e has no throttle valve cable and a vacuum modulator protruding from the front of tranny below the multi-pin round connector for the wiring harness. The modulator is adjustable, remove the hose, there is an adjustment screw in the hose barb. Your description indicates that the modulator may be adjusted incorrectly. I would adjust it to shift at about 4300rpm at wot to take advantage of the torque. The 4.9 doesn't make much top end power but it makes a lot of bottom and midrange torque. Use it. Neils88 gives good advice, get a new chip or even maybe pcm; I have no problem communicating with mine with an obd1 scan tool. Is the aldl wired correctly?
[This message has been edited by olejoedad (edited 04-24-2017).]
Thank you both for your responses, To start I'll send Stickpony a PM to see if he would be able to program one for this.
On the Vacuum modulator, I believe this one is the original one. I checked this morning and this one does not have an adjustment screw. We are going to go ahead and replace it with an aftermarket one that is adjustable just in case that could be the issue.
With the aldl I honestly have no idea if its wired correctly, Looking at the plug there are only 3 wires going into it, black, tan, and white. Also in the plug there is a tan wire used as a jumper. Can you provide a schematic on how its supposed to be wired? I tried looking but couldn't find anything clear as to what went where.
This sounds like a Fiero Factory swap. (I own one.) The red 2-wire connector is unused. It was designed into the harness, and later on it was realized that it was un-needed.
Some people have had trouble getting a scanner to work with the 4.9. I have an AutoXRay scanner that works just fine. If you're trying to use WinALDL, it will NOT work.
Most all of the PCMs are 2240s, but there are over a half dozen programming "masks" that could have been used to set up the chip, due to all the possible configurations that were available. To correctly burn any kind of chip, the broadcast code off of the MEMCAL will likely be required. It should be stamped on a label on the PCM. It will be a 4 character alpha code. (BWYB, AKYN, or something like that.) The PCM should be in the stock location, under the console/glove box. You can also verify the broadcast code by removing the small cover from the PCM and looking through the little holes in the blue module (aka MEMCAL). The broadcast code should be stamped on a silver foil label, that is visible through one of the holes.
The odd shifting... Is possibly a loose connection. Shift timing is dependent upon the throttle position sensor reading. If the TPS is bad (or unplugged) it will cause the trans to shift at "funny" times. The vacuum modulator only controls shift firmness. Unless someone has changed the gearing in the transaxle (which is fairly uncommon with these swaps) a full throttle shift should take place at about 6K as indicated on the tach. (They typically did NOT recalibrate the tachs, when they did the swaps. That "6K indicated" is really only about 4500 RPM.)
Hope that helps a bit.
Edit - I program my own chips, but do not do chips for other people. I don't want the responsibility, if something goes wrong. (I have, however, never screwed up anything I couldn't fix. ) If I were going to pay someone to do a chip for me, it would probably be Stickpony.
------------------ Raydar 88 Formula IMSA Fastback. 4.9, NVG T550 Praise the Lowered!
[This message has been edited by Raydar (edited 04-25-2017).]
I really should have copied all those pics. I relied heavily on your thread for my build, but I think I only pasted in links to it. I may still have some helpful stuff in mine... https://www.fiero.nl/forum/Forum2/HTML/129733.html
Thank you both for your responses, To start I'll send Stickpony a PM to see if he would be able to program one for this.
On the Vacuum modulator, I believe this one is the original one. I checked this morning and this one does not have an adjustment screw. We are going to go ahead and replace it with an aftermarket one that is adjustable just in case that could be the issue.
With the aldl I honestly have no idea if its wired correctly, Looking at the plug there are only 3 wires going into it, black, tan, and white. Also in the plug there is a tan wire used as a jumper. Can you provide a schematic on how its supposed to be wired? I tried looking but couldn't find anything clear as to what went where.
Thanks again
the vacuum modulator has no adjustment, shifting is controlled by the PCM
the vacuum modulator has no adjustment, shifting is controlled by the PCM
The replacement vacuum modulators are adjustable. I have one. I believe that they just control the shift firmness.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
The replacement vacuum modulators are adjustable. I have one. I believe that they just control the shift firmness.
Well... At least they "sort of" do. I cranked and cranked on the adjustment screw in my replacement modulator. It may have increased the shift firmness, slightly. Affected the shift points not at all.
Thanks everyone, Raydar I believe you may be right on this being a Fiero Factory swap, The tach on this one is not calibrated. I went and checked the broadcast code on it and I have 2 different ones. The one on the sticker for the PCM and a different one on the chip in it. The sticker on the PCM is AZXF where as the chip says BWYH.
I checked the TPS with a multimeter earlier (and if the guide I followed was correct) it checked out good. I also looked around for any loose connections and didn't see anything in the engine bay that looked unplugged or any broken wires.
All of the engine/trans wiring look untouched and are all still neatly shrink wrapped with the exception of 1 wire at the PCM. Its a purple wire at C4 that had been cut had a 4 inch piece of red wire poorly soldered in and a green wire also soldered to it at one of the connections for the red "extension" wire. The green wire goes to nothing. If the schematic I was looking at is correct that wire is for the brake switch. I can't understand why someone did that but Ill clean it up and resolder it tomorrow to make sure that isn't causing any problems.
Just an update on the trans shifting issues, We got it all fixed and shifting properly now. The small rubber connection from the throttle body to the hard line for the vacuum modulator had internally collapsed cutting all vacuum supply to the modulator. We replaced that and its shifting great now
Just an update on the trans shifting issues, We got it all fixed and shifting properly now. The small rubber connection from the throttle body to the hard line for the vacuum modulator had internally collapsed cutting all vacuum supply to the modulator. We replaced that and its shifting great now
Just an update on the trans shifting issues, We got it all fixed and shifting properly now. The small rubber connection from the throttle body to the hard line for the vacuum modulator had internally collapsed cutting all vacuum supply to the modulator. We replaced that and its shifting great now
its great when its a simple fix!
you should still get my chip though, so you can dial in the speedo correctly, as well as the speed seen by the ECM, get all the extraneous codes removed, and get the improved performance , get the top speed limiter removed, get the VATS programmed out( fiero factory used a cheap circuit trick, which often times fails after a few years, leaving you stranded on the side of the road). more than 50% of my chips over the years have been to correct Fiero Factory installs , sicne they don't correct for any variables of your particular car.
[This message has been edited by stickpony (edited 04-30-2017).]
interesting. i wonder why the adjustment was added...
They figured that backyard mechanics aren't happy unless they have little adjustment screws they can turn and play with so they feel like they are actually doing something. It's like having a Fisher-Price Activity Center under the hood...
) 
I relied heavily on your thread for my build, but I think I only pasted in links to it. I may still have some helpful stuff in mine... 
It's like having a Fisher-Price Activity Center under the hood...
