Have you confirmed ignition timing with a strobe lamp? Retarded timing (such as because of a broken EST wire) would cause overheating.

I would say on my car that the Y-pipe and turbine housing become a visible cherry red after perhaps cruising 20 minutes on the autoroute. This is only visible at night. In the day, the glow is not visible. From what I have seen on turbo car forums (VW 1.8T), this is normal.

There is a myth that lean AFRs result in high temperatures. This is untrue, stoich AFR results in the hottest gas.

Imagine that you have a stoich situation with a certain amount of air/fuel... if you add more nitrogen/oxygen to the cylinder, this extra mass (which cannot participate in a chemical reaction) absorbs heat.

Hello Rafe!!
Maybe you can download TurnerproRT and tune it yourself or record some logs and send them to Sinister Performance (Darthfiero here in the forumI believe) and he can help you.
I haven't done anyting with him but everything I've hear of him has been very positive!

Rei

Thanks to both of you for the replies.
Yes I will be checking the timing and yes I have Tunerpro on one of my portable computers.
It's just I'm such a numpty (dork) in getting the computer to sync with the bluetooth ALDL connector that I've never managed to take data logs!

I contacted Ryan as well. But you're right, without data logs he won't be able to see what's going on....

I will however look again at my knock sensors today as I've had problems in the past. They do throw codes and retard the timing!

Regards,
Rafe

------------------
"Turbo Slug" - '87 Fiero GT. 3800 turbo. Sticky tyres. Driven hard!
https://www.youtube.com/cha...1wZvWQlkYxTjivW_0XNg

Ryan (GM Tuners - Darthfiero) got back to me with some of his legendary expertise. Thanks Ryan!

He confirmed that it's a probably a wiring problem between the ECM and the PCM, or that the ECM or PCM are at fault.
I hope not for the ECMs/PCMs, because getting these in Europe is going to be expensive!

The engine is running with retarded timing which in turn increases the exhaust gas temperature. It's probably not going into sequentiel injection either, which only makes things worse!
Whatever, the fault codes must be treated before anything else.

The wiring is more likely as the little black cam signal wire (between ECM and PCM) is a known culprit in the 3800 world.
The grounds/earths are to check as well.
Since I did some of my harness with reused cables and plugs, there is a high probability that something is now broken and/or a bad contact.
I'll have to open the rest of the harness (not my manufacture) up just to make sure as well.

Regards,
Rafe

PS: So my memcal (that Ryan tuned many years ago) in the PCM only needs 1 knock sensor. I must remember that as well when I put it all back together!

------------------
"Turbo Slug" - '87 Fiero GT. 3800 turbo. Sticky tyres. Driven hard!
https://www.youtube.com/cha...1wZvWQlkYxTjivW_0XNg

So I pulled out the engine wiring harness, plus the PCM et the ICM for testing:





I've been through every wire and double checked every circuit and earth, following the pinouts:



Nothing in the wiring seems to be at fault, except that the IAC wires were reversed according to the pinout.
I don't know if this is the cause of my hot idle stalling sometimes?



Stalling at idle isn't really the big problem, so probably the ICM and/or the PCM are at fault for the retarded running and cherry red exhaust manifolds !

I'm going to put it all back together and see if by a miracle the faults codes are gone and the thing runs better....?!

Probably not!

------------------
"Turbo Slug" - '87 Fiero GT. 3800 turbo. Sticky tyres. Driven hard!
https://www.youtube.com/cha...1wZvWQlkYxTjivW_0XNg

Looks like someone is a MCM fan (chopped!)

Best of luck on the repairs.

quote Originally posted by Blacktree: Looks like someone is a MCM fan (chopped!) Best of luck on the repairs.

Yeah, I'm probably the only Mighty Car Mods fan in France!

And yes, I'll need luck (and money) with this whole PCM/ICM thing! The wiring doesn't seem at fault...

------------------
"Turbo Slug" - '87 Fiero GT. 3800 turbo. Sticky tyres. Driven hard!
https://www.youtube.com/cha...1wZvWQlkYxTjivW_0XNg

OK, a bit of progress this weekend with the engine harness back in.
I took the time (more than I did in 2014/2015 !) to put plastic conduit over much of the wiring to aleviate any potential rubbing through of the wires.
The wiring is routed slightly better so not be "crushed" between the pulley tensioner/water outlet bracket and cylinder head this time.


Overall, I think I did a slightly better job this time:


I'm also making provision for updating the PCM if needed. Here we see an extra green/white wire for the separate front bank knock sensor.


I will be doing the wiring for the MAP sensor as well. (Not photographed as yet.)

Talking about PCMs, I have a friend who has offered to look for an OBD2 compatible PCM in the USA for me.
I think that the best one for my application is a PCM from a '97 or later 3800 car. I think the part number is 16236757 ?
Would any of you 3800 turbo experts chip in and give some advice?
Ease of tunability etc...


In the list of "jobs to do" is welding up the crack that formed below my wastegate. Again, probably due to the overheating exhaust gas temperatures:



And finally for now, the replacement of the fuel lines with ethanol resistant hoses. (Yes I know, one doesn't use rubber braded hoses for fuel lines! And yes, the garage smelled of petrol (gasoline) fumes every time. But these hoses were left over from my previous project and I was in a hurry to get the car finished in 2015.)



Regards,
Rafe
------------------
"Turbo Slug" - '87 Fiero GT. 3800 turbo. Sticky tyres. Driven hard!
https://www.youtube.com/cha...1wZvWQlkYxTjivW_0XNg

[This message has been edited by Frenchrafe (edited 01-25-2021).]

One of my high school teachers used to say "If you can't find the time to do it right the first time, how will you find time to do it again?" That's good advice. Sometimes I follow it.

So I did a little bit of work in the garage this weekend.
Welded the crack in the exhaust :


The new fuel lines with "stealthy" black fittings:


I also dismantled the selector mechanism on the gearbox. There is a bit too much play when changing gear. The spindle pin will need replacing along with a little weld to rebuild up the toggle/pin on the lever:



The engine is running again with no apparent codes being thrown? However, I will be upgrading my PCM over the next few weeks (months?) with a later OBD2 unit as I have no faith anymore with this '94-'95 PCM.
Just got to wait for the thing to be shipped!

Regards,
Rafe

------------------
"Turbo Slug" - '87 Fiero GT. 3800 turbo. Sticky tyres. Driven hard!
https://www.youtube.com/cha...1wZvWQlkYxTjivW_0XNg

[This message has been edited by Frenchrafe (edited 01-31-2021).]

The OBD-II ECU should be a nice upgrade. It'll have more computing power (i.e. quicker response to changing conditions), and more tuning options.

quote Originally posted by Blacktree: The OBD-II ECU should be a nice upgrade. It'll have more computing power (i.e. quicker response to changing conditions), and more tuning options.

👍😉

------------------
"Turbo Slug" - '87 Fiero GT. 3800 turbo. Sticky tyres. Driven hard!
https://www.youtube.com/cha...1wZvWQlkYxTjivW_0XNg

I made a new gearbox shifter mechanism pin from fresh 8mm hard steel bar. The old pin had worn 0.1 to 0.2mm - not much I know, but noticable when moved.
I also welded/built up ("rechargement" in French) the small pin on the lever.



Now it's back together but to be honest I can't tell the difference with the gear selection while the car is static in the garage?
We'll see the next time on the track if I miss my 2nd/3rd or 3rd/2nd gear changes!


The rest of the car is pretty much assembled now and just waiting on the new (for me) PCM...

Regards,
Rafe

------------------
"Turbo Slug" - '87 Fiero GT. 3800 turbo. Sticky tyres. Driven hard!
https://www.youtube.com/cha...1wZvWQlkYxTjivW_0XNg

Here is the latest "Turbo Slug" video which gives the retrospective of this build:

https://youtu.be/zFp07WovKXk



Since I can't acces my original pages on this thread with the "Englishrafe" pseudo, I haven't managed to repost the missing photos.
After this one last post, I'll probably let this thread go to the archives now.

Bonne continuation / best regards,
Rafe

------------------
"Turbo Slug" - '87 Fiero GT. 3800 turbo. Sticky tyres. Driven hard!
https://www.youtube.com/cha...1wZvWQlkYxTjivW_0XNg

[This message has been edited by Frenchrafe (edited 03-19-2021).]