I recently purchased a 86gt 4spd car that isn't running right. I am trying to set the timing but when in diagnostic mode I can't see the timing mark. I can see it if I hook up the timing light when it is running normally. Appearently the previous owner set the timing without going into diagnostic mode first. The car also wants to die whenever I ground the 2 diagnostic ports together so it is practically impossible to put a light on it in diagnostic mode.
What can I do to get the timing right and get the car running again????
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06:20 PM
PFF
System Bot
AutoTech Member
Posts: 2385 From: St. Charles, Illinois Registered: Aug 2004
Ok, so I got the #1 cylinder at or near TDC. I then pulled the dist. cap and noticed the rotor is pointed toward the #4 point. I know that numbers 1 and 4 are opposite each other on both the dist. cap and the timing chain alignment. Do I just need to turn the dist. around 180 degrees so the rotor is pointed at number 1?
You cannot turn the distributor around that far due to the ignition module hitting the plenum. You will need to lift it up and reposition it where you need it. Be careful that you are not at TDC for #4 and the distributor is actually in the correct spot....
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10:11 PM
Rhino88gt Member
Posts: 718 From: Maumelle, AR Registered: Jun 2003
The easiest would be to remove the #1 spark plug then have someone turn the engine clockwise by hand while you place your finger over the spark plug hole. As #1 comes up on the compression stroke you will feel and hear air escaping by your finger. Now look at the harmonic balancer for the wide cut mark. There are 2 skinny and 1 wide cuts on the HB. (Each mark represents TDC for each cylinder in turn) Now carefully move the wide mark until it lines up with 0 on the timing scale. You should not have to move the HB very far in order to line up the wide mark. The outer ring on the HB has been known to shift causing major headaches. This is TDC for #1 cylinder.
Now look at the timing scale. It runs from left to right as 12 - 8 - 4 - 0 . The perfect mark is 10* Before Top Dead Center (BTDC).
The distributor rotor rotates clockwise. To advance the timing (go from 0 to 12 on the timing scale) move the dist counter-clockwise. To retard timing then go clockwise to move the timing mark from 12 to 0. Where is your wide mark at right now?
[This message has been edited by Hudini (edited 03-24-2008).]
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08:49 AM
Rhino88gt Member
Posts: 718 From: Maumelle, AR Registered: Jun 2003
well, if I hook the light up when the car is idling it is on the 10* mark, but it doesn't run long enough for me to see where it's at in diagnostic mode.
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11:58 AM
pswayne Member
Posts: 1282 From: Lawrenceville, GA USA Registered: Sep 2006
Before you do any lifting of the distributor or any other disassembly, why not try a little "seat of the pants" timing adjustment. Paint some marks on the distributor and mounting for reference, then loosen it and twist it clockwise a few degrees, and tighten it back down. Now try to start the car. If that doesn't work try counter clockwise a few degrees from your reference marks. Once you get it running reasonably well, then you can short the A-B terminals and try the timing light.
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12:48 PM
Mar 25th, 2008
Rhino88gt Member
Posts: 718 From: Maumelle, AR Registered: Jun 2003
well, I got the timing issue fixed. the car started idling much better. NOW there is a nice loud KNOCK coming from the front bank somewhere!! I did a compression test, all cylinders were between 118 and 125. I pulled the front rocker cover off and a couple rocker arms have a "little wiggle" in them buth they're not broke. So Im guessing it's time to drop the motor and find a replacement.
The previous owner said about 6 months although I have no idea how accurate or truthful that statement is. Im guessing it is a rod bearing unless y'all have some better insight.
With the engine running at idle and warm, pull one spark plug wire at a time (at the distributor cap is ok, watch out for being zapped), and listen. If the knock goes away on one particular cylinder then that's the one. Generally rod knocks are louder under load and go mostly away under coast. Low oil pressure is a dead give-away.
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01:54 PM
Robert 2 Member
Posts: 2401 From: St Hubert Quebec Canada Registered: Jan 2006
How can you guys get a Fiero 2.8 running while the valve covers are out ? Think you have to remove the whole plenum and middle intake and lower ,to have acces to remove the cover . Thus meaning all the wires are disconnected and all the vacuum line too . And it take a while to undo those things
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02:10 PM
Rhino88gt Member
Posts: 718 From: Maumelle, AR Registered: Jun 2003
well, yes, the upper and middle intakes have to come off but the lower doesn't. It took me about 45 minutes to get it that far. If a rod is knocking, I dont really care which cylinder it is, as Im not going to pay to rebuild a 2.8. Since there are no exact replacements available around here, it's engine swap time.
I asked about how long it was sitting in case you had a lifter not pumped up and just ticking a bit loud. I once had a solid lift cam motor bend a pushrod that sounded like a knock.
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09:29 PM
Mar 27th, 2008
Rhino88gt Member
Posts: 718 From: Maumelle, AR Registered: Jun 2003