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Getting an 86GT roadworthy by ounmongk
Started on: 06-24-2014 07:02 PM
Replies: 1 (51 views)
Last post by: Neils88 on 06-24-2014 07:32 PM
Posts: 90
From: Denver, CO, USA
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Report this Post06-24-2014 07:02 PM Click Here to See the Profile for ounmongkClick Here to Email ounmongkSend a Private Message to ounmongkEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hi all,

First time posting here in several years!

Some background info: Bought an 86 GT for $1,600 knowing it was going to take a lot of work to get it to pass inspections. This was fine for me since I wanted to learn more about engines and automobiles in general. Up until buying this GT, I only knew about changing the oil and coolant.

Fast forward to 2011 when I bought the car and it didn't pass emissions. Also had a high idle due to several vacuum leaks.

Thanks to the Mile High Fiero Club (and MrFiero for actual hands on the car and teaching me what things do what), the car was brought up as close to original/stock as possible. There were a few mods that one of the previous owners did that just really wrecked the wiring among other things

I think the car is fairly close to being comfortably drivable, where it wouldn't die in the middle of Denver's busy streets.

List of actions so far:
1) Replaced spark plugs
2) Replaced plastic vacuum lines with rodney dickman steel lines
3) Fixed EGR tube vacuum leak
4) Replaced fuel filter
5) Replaced ignition module
6) Replaced MAP sensor
7) Replaced O2 sensor
8) Fixed a bad solder joint where previous owner installed a Lean/Rich gauge. (Also got rid of the gauge)
9) Replaced fuel pump

Still to do:
1) Replace nasty coolant and flush
2) Replace 10+ year old tires

Here's my current issue:

- Idle (According to the Fiero Store ECM scan tool) settles to 1000 (+- 50) rpm when engine is warm.
- INTegrator value is well under 128. Only gets up to 128 when over 3000rpm. Typical values from 10-50 at idle.
- BLM very slowly decreases a point at a time. Took about 10 minutes of idling warm for BLM to drop to 120, which I believe is the bottom limit it will go?
- No error codes stored
- Haven't driven the car around since replacing the fuel pump, only up and down my driveway.

1) With a seemingly steady idle around 1000, is it safe to assume that vacuum leaks are not present?
2) Assuming there are no vacuum leaks present, what other things would cause the INT value to be so abnormal and BLM to drop so slowly?

I've found many posts here where the BLM is low and the INT is right around 128, but not any for my case. I have the datalog available if needed.

Thanks in advance!
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Report this Post06-24-2014 07:32 PM Click Here to See the Profile for Neils88Click Here to Email Neils88Send a Private Message to Neils88Edit/Delete MessageReply w/QuoteDirect Link to This Post
I'm guessing you unplugged the battery when changing the fuel pump (or some other components). If so, you will need to allow the ECM to reset itself. Allow the car to idle for about 3 minutes, then drive at a constant highway speed for 20 minutes, followed by 20 minutes in stop and go city driving. This allows the ECM to reset it's parameters. Once you've done this, take your measurements again and see if there are any changes.

[This message has been edited by Neils88 (edited 06-24-2014).]

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