1988 LFX Build Lessons Learned/How to (Page 10/11)
RandomTask JUN 29, 02:36 PM
It's been a long time since I bumped this thread. Car runs and drives. Had the exhaust fabbed and put on. Still goes ape crap after it goes into closed loop. Tuner looked at it and realized it was pulling ~60* of timing. . .

I have a strong suspicion of what it is; been concentrating on building my dream garage so this has been on the back burner.

So right now it just sits waiting for me to work on it

[This message has been edited by RandomTask (edited 06-29-2023).]

Trinten JUN 30, 10:24 AM
Cool that the problem was found. Sucks that it was an issue the tuner did, thankfully he caught it and it didn't damage the engine.

Where are the pics you mentioned wanting to put up almost 4 months ago?
rglasco101 JUN 30, 03:16 PM
did you have to make any mods to your cradle? I could not really tell from the pictures and honestly may have missed it
RandomTask AUG 30, 12:14 AM

quote
Originally posted by Trinten:

Cool that the problem was found. Sucks that it was an issue the tuner did, thankfully he caught it and it didn't damage the engine.

Where are the pics you mentioned wanting to put up almost 4 months ago?



To be clear, it wasn't the tuner. My suspicion is the following:


1.) The LFX ECU -must- get a PWM signal from the driveline else it thinks the engine is working but not moving the car. To do this, I had to install a voltage up resistor on my hal effect sensor. I either got the wires crossed or I put the wrong resistance on it.
RandomTask AUG 30, 12:16 AM

quote
Originally posted by rglasco101:

did you have to make any mods to your cradle? I could not really tell from the pictures and honestly may have missed it



I did nothing to the cradle short of weld the two engine mounts onto it. I purchased the trans mounts from someone who fabricated them for the F40.

The only crap thing about this is that the purchased F40 mounts prevent the use of the rear sway bar. Pickhard performance (sp) has been working w/ Paul to replicate what his fiero uses; I will be picking one of these up once they come for sale.
fredtoast AUG 30, 08:12 AM
Currently driving a '13 Impala. Love this engine. Pulls hard, revs high, and gets 26 MPG in a car that weighs 3800 lbs. And even though I love the rumble of a V8 I want to keep my Fiero a little more "stealth".

I can't use my current car as a doner because it is too nice. But definitely planning on using the LFX.
NGJohnsonIII JUN 07, 07:42 AM
With the permission of RandomTask I'm picking this thread back up. My father and I have been Fiero people since about 1998 but it's been a while since either of us had one on the road. We ended up picking up RandomTask's 88 LFX swapped Formula and are trying to finish the project. First off, I'd like to thank RandomTask for all of this help and for selling us his baby. I promised to bring it to Summit Point for an HPDE event so he can drive it after we get it going, and I intend to keep that promise!

The car sat for a few years and after figuring out it wouldn't start due to the ECM not being powered, we fixed that issue, installed a fresh battery, and she fired right up but still dies after warming up and makes some timing chain noise before stalling, which makes me think the VVT is acting up. We're getting DTCs for an O2 sensor, accelerator pedal, oil pressure sending unit, and clutch pedal position. We replaced the accelerator pedal, which cleared that code, and we're replacing the bad O2 sensor, which should clear that code. The ECM isn't receiving an oil pressure signal, as the oil filter relocation kit removed the oil pressure sending unit. We ordered a new sending unit and will tie it into the filter relocation kit, but we're having a hard time finding the sending unit connector in the wiring harness. I'm hoping this might solve the issue with the car pulling too much timing when it warms up. I purchased HP Tuners and plan to remove the clutch pedal position sensor function as I'm told it's not needed, is that accurate?

Does anyone have any additional information on how to get the VSS signal to the ECM on the F40 when it's not equipped with a factory VSS?

Thanks!
Trinten JUN 07, 08:20 PM
Hey NG!

Welcome to the boards, glad to see you picked up a project and are already making progress!

As I am terrible with PFF's native search, I'd say use google, preface your search with site:fiero.nl and search for F40 VSS. There's more than a few guys here that have swapped in F40s (FieroGuru is one that springs to mind for me, and his threads are always full of great technical info). So you'll likely be able to chase down that answer there.

Good luck!!
rbell2915 JUN 08, 07:50 PM
Good luck on wrapping this up!
Will JUN 09, 08:25 AM

quote
Originally posted by NGJohnsonIII:

With the permission of RandomTask I'm picking this thread back up. My father and I have been Fiero people since about 1998 but it's been a while since either of us had one on the road. We ended up picking up RandomTask's 88 LFX swapped Formula and are trying to finish the project. First off, I'd like to thank RandomTask for all of this help and for selling us his baby. I promised to bring it to Summit Point for an HPDE event so he can drive it after we get it going, and I intend to keep that promise!

The car sat for a few years and after figuring out it wouldn't start due to the ECM not being powered, we fixed that issue, installed a fresh battery, and she fired right up but still dies after warming up and makes some timing chain noise before stalling, which makes me think the VVT is acting up. We're getting DTCs for an O2 sensor, accelerator pedal, oil pressure sending unit, and clutch pedal position. We replaced the accelerator pedal, which cleared that code, and we're replacing the bad O2 sensor, which should clear that code. The ECM isn't receiving an oil pressure signal, as the oil filter relocation kit removed the oil pressure sending unit. We ordered a new sending unit and will tie it into the filter relocation kit, but we're having a hard time finding the sending unit connector in the wiring harness. I'm hoping this might solve the issue with the car pulling too much timing when it warms up. I purchased HP Tuners and plan to remove the clutch pedal position sensor function as I'm told it's not needed, is that accurate?

Does anyone have any additional information on how to get the VSS signal to the ECM on the F40 when it's not equipped with a factory VSS?

Thanks!



Cool! Congrats on the new acquisition!

I'm in Springfield, VA and I'd like to see the car at some point.