L67 Swapped 85gt haivng issues (Page 1/1)
jhobbins JUN 11, 03:50 PM
Hi Guys, I am in my first summer of owning this car, and I did not do the swap. I'm trying to iron out some issues I'm having. The two primary issues are #1 it does not like to stay running when warmed up. Yesterday it was 90+ degrees outside and I literally could not keep it running. Today its in the 70s, and I was able to drive it around no problem but after I shut it off it would not start again. I'm sure it will once it cools off a bit, but I am definitely having a heat related issue. Issue #2 is at about 2500 rpms it breaks up and does not want to rev any higher.
So far I have replaced coils, plugs, wires, I have tested fuel pressure at idle and up to 2500 rpms, and everything is in spec. I am getting no codes for misfire, and hptuners is not picking up any knock or misfires, although it is pulling timing back as I get above 2000 rpms. I can email both the tune and catalogs to anyone who thinks it will help.
One strange thing I noticed is that hptuners is reading the throttle position as 0 the entire time I drive, but the torque pro app reads my throttle position so I am not sure why that is.
Thanks in advance
OntarioKev JUN 11, 04:55 PM
How familiar are you with HPTuners? If the throttle is showing as 0 but torque reads it you must be monitoring the incorrect PID.

You say it is pulling back timing but not knocking. There are only a few tables that will cause timing to retard, like ECT, IAT or knock. Perhaps you aren't monitoring the correct knock sensor PID?

Does the car have the 4t65e-hd, or a manual transmission?
dear1700 JUN 11, 11:08 PM
Sounds like a bad crank sensor to me. It’s fairly cheap, pull crank pulley and replace.
jhobbins JUN 12, 11:16 AM

quote
Originally posted by OntarioKev:

How familiar are you with HPTuners? If the throttle is showing as 0 but torque reads it you must be monitoring the incorrect PID.

You say it is pulling back timing but not knocking. There are only a few tables that will cause timing to retard, like ECT, IAT or knock. Perhaps you aren't monitoring the correct knock sensor PID?

Does the car have the 4t65e-hd, or a manual transmission?



New to hptuners, not to tuning though. I used tunercats a ton on my old firebird.

I cehcked and I believe I was monitoring the wrong tps pid. Torque pro also showed no knock and very few misfires.

It has the 4t65e-hd transmission.

I would think either the ICM or the crank sensor would throw a code, right?

[This message has been edited by jhobbins (edited 06-12-2020).]

Frenchrafe JUN 16, 11:31 AM
I've recently had similar problems with my 3800:

http://www.fiero.nl/forum/Forum2/HTML/143866.html

Check your heater hose routing to make sure that the coolant is circulating properly through the block?
I had localised overheating that caused all sorts of heatsoak errors to occur, with hot starting problems, bad running etc...
Routing just the heater feed from the 3800 outlet and returning via the original Fiero piping seems to fix bad coolant circulation.
You must block off the heater return on the 3800 - at least that's what I've found out.

Just my 2 euros worth of experience!

Regards,
Rafe

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

Dennis LaGrua JUN 19, 10:33 AM
I know that many Fiero home mechanics don't enjoy hearing this, but if you are serious about repairing an OBD2 controlled engine, I cannot over emphasize the importance of owning a quality scan tool. IMO HP Tuners scanning suite is excellent as you can graph performance over a wide range of RPM, MAP and MAF readings, in addition to the code read. While its not a panacea it really helps. If you are on a budget some of the ELM 327 plug in module/ smart phone scanners can do a good job as well.

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" 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 "