1986 2M4 Hi guys, I put an new EGR valve on the car last week as it was missing when I bought it, put a new set of wires on it and it stopped the missing while driving(what a difference in the car). Here is the problem that I am having. Ever since I got the car I can hear this in the exhaust.(thump, thump), it's a random sound, like a small miss. I replaced the wires this week, distributor cap and rotor button about a month ago, I replaced all the plugs with AC Delco's last fall they have about 3000 klm's on it. Right now when the car is cold it will do it's high idle and fall back down fairly quick, never done that with the old wires. But when I go to take off and let the clutch out it like it wants to die, push the clutch back in and rev her some more and I can manage to take off. So when I change from 1st to 2nd she hesitates when I give her the gas, but once I get on the high way and the car warms up it doesn't happen after, only when it's cold. I check the readings on the CTS and they are spot on!! Not sure what the problem is there. I decided to check the timing on it since I have the new wires and she seems to be working better, its the timing light that clips onto the outside of the wire. I checked on the cylinder closest to the battery and it has a steady blink, but when I check the cylinder closest to the gearbox it's missing and sometimes not steady. I checked all the other cylinders and they have a steady blink. What would cause this and would this be related to the miss in the exhaust that I hear? If I am not mistaken this is the cylinder that is down on compression compared to the rest, I believe it's around 138 and the rest is 145 or 150. Anyone got a pic of the timing marks down by the crank?
Any thoughts Also the timing light was doing this the summer when I was trying to time it. The timing is rock steady on the crank on the cylinder closest to the battery but the one next to the crank is all over the place. not sure 100% how the timing light picks up the spark, is it getting it from the wire or from the plug?
[This message has been edited by newfiejeff (edited 12-14-2014).]
What I found with the lights I've used is they trigger from the high voltage pulse through the wire. If your plug isn't firing you won't get that pulse. I would try swapping out the plug first.
I was researching and found a response that said that a bad cap can cause a wire to fire intermittently, even if it's a new cap, it could still be bad/cheap. I would assume the timing light gets its signal from the wire and the plug only fires if it gets a pulse so I wouldn't bother replacing the plug myself. I went through a lot of replacing sensors and adjustments on my engine and double checking my timing only to find out it was at 6 degrees before TDC instead of 10 even though I had timed it a few weeks earlier, and the hold down bolt was tight. I am curious why or how it got off but it removed most of the stumble I've been having..
Update. Since the new wires, the car was working great compared to the old wires, no more missing while driving. I posted about the intermittent timing light, checked it tonight and it must have been a loose connection with the light as it is flashing steady now. I checked the timing and it was almost TDC, I adjusted it to 8 degrees and the car is like a new car now. Not sure what it is like when the car is cold, will have to check it tomorrow and see. Will keep you updated.
The issues that I was having when the car was cold was due to timing being off. The car now is so smooth and finally working, now if I never had to put it away for the winter!!!
I want to do a timing test but i don't know wich bolt need to be loosed and which part to turn, the cap or the distributor. None of them turn even after loosing the obvious bolt.
Before asking i'll go thru the video of Buddy Graigg but didn't help when you are a newy in mecanic.
Are you sure you have the bolt loosen enough? The cap is screwed to the distributor base and you turn the whole distributor, so in turn the cap turns as well. I am sure someone will chime in here, but if I had that issue and in your shoes I would loosen the bolt enough remove the cap and then give the distributor base a tap with a rubber mallet to see if it would loosen. If you get it to move then put the cap on and tighten the bolt and start over the procedure for timing your car.
you know how to time the vehicle?
Did you see if your fiero is off her timing? You loosened the bolt right next to the distributor?
[This message has been edited by newfiejeff (edited 12-21-2014).]
Hey Patrick, I am thinking on my duke, which the bolt is right in front of you, you must have a 2.8. Yes the bolt holds down the triangle plate, I am not saying tap that piece but the distributor as sometimes they stick to turn and just a tap will loosen it.
Because i just start doing mecanic it taking twice and third of yhe time doing everything so after xmas i ´ll played with it. I enjoyed the day i'll be good and confident with mecanic.
I should probably do some kind of tuturial with pics after christmas on how to time the Iron Duke. I assume that it was a simple process for most people but with someone who has limited mechanic work or just getting into it and the fiero is a great place to start it's not always straight forward.
Believe me I have asked many stupid questions here on simple things, so we are all green to certain things, so take no offence anyone.
There should almost be a seperate section or something on the Iron Duke and people including myself should do some or more tuturial's on just about everything that can be done on the fiero or people is after doing. Yanny keep us informed on the timing issue!!
