Need 4.9 Expert (Page 1/11)
fierofool JUN 13, 06:33 PM
Looking for a 4.9 expert within reasonable distance of Atlanta, Ga. I already know about The Fiero Factory. That's where the original installation was done. Not knocking them, but original owner says it's never been right. Now, it's worse than ever.
J Gunsett JUN 14, 10:07 AM
Tell us what is wrong and the problems you are having. Has it had any mods done to the engine? Stick or auto?

Jack
Dennis LaGrua JUN 14, 11:47 AM

quote
Originally posted by fierofool:

Looking for a 4.9 expert within reasonable distance of Atlanta, Ga. I already know about The Fiero Factory. That's where the original installation was done. Not knocking them, but original owner says it's never been right. Now, it's worse than ever.



I've done this swap and am familiar with them. While not near Atlanta, I will be at Carlisle and would be glad to chat about solutions. While I wear a name badge, if you wish to track me down, I will PM my cell number to you. Feel free to give me a buzz. Don't claim to be an expert but have done computer controlled engine work for many years. If you can do an ECM scan beforehand that would help.


------------------
" 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, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, 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 "

[This message has been edited by Dennis LaGrua (edited 06-14-2021).]

fierofool JUN 14, 05:26 PM
I'll be at Carlisle, too. I wanted to meet you but missed you 2 years ago. If I can't find you, I'll have the "C8 Prototype" and should be close by.

The car is a Formula with manual trans and belongs to a club member who, after 2 years, has become so disgusted that he's given up. I'll have to get a listing of everything done and see if I can get a scan copy.

Jack, the car has had every sensor on it replaced. The distributor has been replaced with a new one. The ECM was replaced. No change, so the original was put back in. The injectors were replaced because the car had been running extremely rich. That problem has been mostly resolved.

The engine runs well when the ECM is jumpered. Set the base timing and remove the jumper and it runs lousy.

Prior to the member acquiring the car, the original owner had been driving it. I believe for a number of years. It began randomly running on 4 cylinders, then 8. No common happening to make it begin missing on 4, then back to 8. We found a fuse block mounted on the right strut tower had a bad contact and one of the injector fuses was losing contact from time to time. That fuse block has been replaced and a shield installed over it to keep out water. Now, it runs on all 8.

Another problem is that it continually throws the belt. The battery has to be removed to replace it. It was found that the idler/tensioner was bad and was replaced. That didn't fix the problem.

Dennis, would you be open to chatting with the owner? I'm just trying to find a solution for him.
fierofool JUN 14, 05:53 PM
Here's the list. Can't get a scan at this time.

ECM changed 3 times.
New Distributor
New injectors
New Plugs
New TPS
Continuity checked between all sensors and ECM
Grounds checked
ICM and Hall Effect sensors swapped around
Mechanical timing verified to be correct
New fuel pressure regulator
New EGR valve
No ECM has thrown any codes
New O-2 sensor
No check engine light when shorting A&B
Firing order verified to be correct
Set timing to 10-12 BTC with A&B shorted, runs good
Pull jumper and it begins missing, coughing, sputtering
Runs a little rich, but not choking anyone out of the shop like it was a year ago.

He's seriously about to confirm the saying "They all catch fire".

[This message has been edited by fierofool (edited 06-14-2021).]

Dennis LaGrua JUN 14, 08:09 PM
Judging by what you have indicated. Check to make sure that pin C9 of the ECM is connected to 12V ignition. It should be the Lt.blue/orange lead. If you do not read 12V on C9 (ignition on) the ECM will not go into closed loop and operate correctly. I recommend taking out the VOM meter to measure the voltage there.

------------------
" 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, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, 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 "

fierofool JUN 14, 08:53 PM
I'll see if I can get hi to try once more. As said, he's ready to burn it. I suggested something earlier and he said he's done. I'm just trying to decide if it's easily fixable before I consider buying it. Like the problem with it running on just 4 cylinders. Caused by a loose fuse holder. I would have to stretch finances, but I'm willing to tow it up to you if the price is right and I buy the car.
Dennis LaGrua JUN 15, 04:20 AM
[/b]
quote
Originally posted by fierofool:

I'll see if I can get hi to try once more. As said, he's ready to burn it. I suggested something earlier and he said he's done. I'm just trying to decide if it's easily fixable before I consider buying it. Like the problem with it running on just 4 cylinders. Caused by a loose fuse holder. I would have to stretch finances, but I'm willing to tow it up to you if the price is right and I buy the car.



Still say that the problem is most likely electronic. Probably a good scan of the ECM and a check of the wiring at pin C9 as in my post above may pinpoint the problem. Anything is fixable. It just takes time to diagnose and fix. The 4.9L is an excellent engine, strong light and reliable. IMO, the best Cadillac engine ever made.

------------------
" 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, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, 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 "

[This message has been edited by Dennis LaGrua (edited 06-15-2021).]

fierofool JUN 15, 08:47 AM
I forwarded your advice on the C9. Let's give it the day to see if he tries it.

[This message has been edited by fierofool (edited 06-15-2021).]

fierofool JUN 15, 04:16 PM
Dennis, I'm sending you a pic of the ECM connector in your email. C9 is pink. You can see the full color pinout in the photo.

[This message has been edited by fierofool (edited 06-15-2021).]