So I have had a series of issues of why my 2.8 86 fiero gt won't run right. I have stumbled on something that I need explaining. If i crank the car, it cranks like it out of time and backfires and crackles out the exhaust, just runs like hell. If I pull both injector fuses it cranks over nicely and seems like the timing is correct.
I have removed the valve cover and made sure that the number one cylinder valves are closed at TDC. The rotor is advanced off number one on the cap slightly as the car is supposed to be advanced 10 degrees at TDC. When I did the timing, I did split the difference between number 1 and number 4 cylinder to get the 10 degrees required. I think number four was at 11 degrees and number one was at 9 degrees.
I am wondering if it is possible that the injectors are firing at the wrong time causing the backfiring and running like hell issue. Would this be controlled from inside the distributor? If so what should I do, just change the pick up and modulator?
Things I have changed along my path of trying to figure things out are:
ECM Injectors fuel regulator coil EGR plugs wires cap rotor
I had much the same symptoms during a engine rebuild. I took the distributor to the local parts store and they put itn the magic machine and determined the ICM failed 3 of 4 tests. Ignition Control Module .. Replaced that and the pick-up coil... and POW ran like a champ.
------------------ Mark ' 85 2m6 3.4PR In the Great Northwest!
Cranking better with no injectors is what you'd expect from a car with incorrect ignition timing - with nothing happening in the cylinders due to no fuel, the engine is just spinning around. Add fuel to the mix, and now you have incorrectly timed combustion fighting with engine rotation. Injectors are batch fired, all injectors are pulsed at the same time based on the tach signal. Be sure what you think is TDC is actually TDC, what you think is Cyl #1 is Cyl #1, and that the spark plug wires are in the right order (123456). Timing can be LOTS of degrees off and the engine will still start, so with the engine at TDC as indicated by the crank pulley set the distributor so that the rotor is pointing DIRECTLY at a tower. That is now #1. Then, 23456 going clockwise around the distributor. Remember even cylinders in back, odd cylinders in front running right to left (passenger side to driver's side).
When I did the timing, I made sure to have TDC on the passenger rear cylinder known as number one cylinder ( it was on compression stroke). As I stated the valves are both closed on number one cylinder when the timing mark is at TDC. I have double tripled checked the plug wires, I do have the hynes manual, I have followed it to the tee.
I did forget to mention that the car has 150 km and is all original except redoing the heads. Had low compression on the front head, apparently this is a common issue due to the heat generated on it. The pickup coil and ICM are original from 1986.
I like all the suggestion. keep tossing them at me. I will check everyone that i have not done already.
Ok so by the sounds of you guys, I going to rebuild the distributor. I'll order a new ICM and pickup tomorrow from NAPA and let you know how it turns out. I'll make sure to put the timing on TDC on compression before I pull the distributor and when I put it back I'll line it up directly with a post, then time the engine if it runs good!! let keep fingers crossed.
I have removed the valve cover and made sure that the number one cylinder valves are closed at TDC. The rotor is advanced off number one on the cap slightly as the car is supposed to be advanced 10 degrees at TDC. When I did the timing, I did split the difference between number 1 and number 4 cylinder to get the 10 degrees required. I think number four was at 11 degrees and number one was at 9 degrees.
And you had the jumper in place (ground and diagnostic terminals) when you did the timing?
When I did the timing, I made sure to have TDC on the passenger rear cylinder known as number one cylinder ( it was on compression stroke). As I stated the valves are both closed on number one cylinder when the timing mark is at TDC.
IMO, that alone still allows too much latitude for error in case the outer hub of the harmonic balancer has spun. It would be better to also make sure the valves are rocking on #4 when the timing mark is at TDC (and #1 is supposedly at the top of its compression stroke).
[This message has been edited by Patrick (edited 01-29-2016).]
Glad to see when its a honest group and its focus it to help out guys like me!!
I will try the distributor first and if that fails I will l go throught the efforts of pulling the front valve cover and check to see how # 4 looks ( not a easy job as you know)
...if that fails I will l go throught the efforts of pulling the front valve cover and check to see how # 4 looks ( not a easy job as you know)
For some reason I was picturing the valve cover(s) already off. The other option is to stick something through the spark plug hole to ensure that #1 piston is right up at the top of its travel when the timing mark indicates it's at TDC. If the outer hub of the balancer has spun, I believe the piston will already be on its way back down as the timing mark arrives at TDC.
[EDIT] I knew there was a reason why I thought the valve cover was already removed.
quote
Originally posted by medicman:
I have removed the valve cover and made sure that the number one cylinder valves are closed at TDC.
[This message has been edited by Patrick (edited 02-01-2016).]
I ordered the ICM and pickup this morning and NAPA delivered them to me. The ICM they sent me is used! I called them and they don't have anymore in stock till Monday. As if I'm going to installed a used part! I like the idea of making the TDC indicator out of a spark plug. I'm going to fashion one up later today. Seems so simple but I would of never of thought of that.
Anyways I'll strip down my distributor and find TDC while I wait for the new I on Monday.
You may want to try that used one......if it is a tested Delco. New off-brand ICMs are not necessarily good, and often fail in short order. Make sure you get the proper white heat-sink paste, and not clear di-electric grease.
It's a NAPA part not a Delco part. I took some pictures on my phone but do not know how to upload them onto the site. The pickup came off in pieces. It's really soft and feels like a cheese cake lol.
Take a picture of the rotor before and after pulling the distributor up. The rotor turns as the distributor moves up and down and you need to get it back where it was.
You might also want to mark the position of the gear relative to the shaft before removing the pin.
Make sure you don't trap or crush the pickup coil wires under the cap.
Before you start, if you know how to post pictures on the forum, could you show us your distributor with the cap and wires as they are now? Often when people report these problems it turns out the distributor is installed in a curious orientation.
I don't know how to post pics. I can say that I made sure the engine is at TDC on number one cylinder prior to taking out the distributor.
To give a idea where my number one was on the cap, if you were standing at the back bumper looking at the cap, my number one was at the 5 o'clock position. The two electrical plugs were facing 9 o'clock.
I'm going to clean up all the parts and wait for NAPA to deliver my new ICM on Monday. I plan on retiming the engine after I have the distributor set back in. I'm just going to make sure the rotor is pointing directly any a post before I do anything.
I'm really hoping that this solves my issues or I'll be picking the brains of everyone here!
To post pictures click on the red white and blue PIP icon at the bottom of the page. You download the PIP and use it to upload photos to the forum. You may need to resize your photos if they are too large or high-resolution.
You might try Google or something to find Fiero distributor images. See if yours looks lined up right. It does sound about right and it's difficult to get it very far out of whack without modification due to the length and position of those wires that connect to the module, coil, etc. However if it's in some other configuration that's likely a clue that a PO had problems and jury-rigged it to run.
I don't understand how it can run without the injectors. Could it be they're stuck open?
Gall, I hear you on the frt. My Echlin was part of a bigger order of about $60 shipped from the same supplier for about $16. Look for the little truck symbol in the Rock catalog indicating one source. It helps. I don''t remember the OEM price of the ICM, but must have been over $ 20 last time I replaced in LA. The heat killed 'em there., Here no problem with heat.
I have read and reread your original post and am wondering, Why didn't you just mark where your distributer and rotor button and block all were before you took your distributer out ? As long as you didn't move anything after taking the distributer out, crank the engine, that you have already done. nothing would have changed so you could just replace everything back in the exact same place and driven away.
Or did I miss something or forget something I read?
I have pulled dozens of distributers and reinstalled/replaced everything then without making sure it was at number 1.
Now in your case with this problem you have made more work for yourself than anything else. But to fix this now you have to remove the valve cover and follow the rotation of the rotor and timing mark as well as the valves in number 1. remember it turns all that at the same time so everything should be the same, as long as you have them on the compression stroke. and you can tell that by what valve on number 1 is just beginning to open on the up stroke, before hitting TDC. Oh and to make sure you are on the up stroke just put a long bladed screwdriver into number one, it will push the screwdriver up and down while a helper is turning the crankshaft by hand with a long bar with the harmonic balancer bolt, always turn in the direction of rotation.
I haven't got a manual handy but I am sure someone will be able to tell you what valve is the intake valve, that will get you dam close, then if you can't adjust the timing to make it run right you might be off a tooth or so one way or the other. Easiest fix would have been to just rotate the distributer 180 degrease before ever doing anything else.
Pick up a service manual, factory service manual is best, but Chilton, Motors, Haynes even will give you lots of helpful info and you won't have to wait for someone here to post an answer. The info you need is all right in one of those books, you know those things made out of paper that you turn the pages, they even have pictures, best 15 to 50 bucks you will ever spend.
Old school Rules !
And oh ya did you have any of those things you replaced tested before replacing them? Because just throwing parts at a problem can get dammed expensive. also are you sure all the plug wirers are right?
Steve
------------------ Technology is great when it works, and one big pain in the ass when it doesn't
Detroit iron rules all the rest are just toys.
[This message has been edited by 84fiero123 (edited 02-01-2016).]
I am positive it's on number one, I had the valve cover off and made sure that both valves were closed and the rotor was pointing at number one.
The car was running fine before all this out of timing symptoms started. I know I had it timed correctly in the past.
I was advised to find TDC and don't worry about marking the distributor, just set the timing again afterwards.
I have no way of testing the pickup coIl or ICM but being 30 years old and the condition they came off, I'm guessing they needed to be changed. The connector off the pickup was rotted off, just bare connectors left, plugged into the ICM.
Since I've changed everything else possible, this is about the last thing to change. I have checked to see if the chain jumped a tooth but that's not happened. If the cam was worn down badly, it could backfire and spit but that would be a gradual thing not a instant thing.
I have put all the parts of the distributor in my glass beader and blasted them sparkling new again. I've installed the pickup coil and now just waiting for a new ICM to be delivered. I'm hoping to get the distributor installed today and try the car. I've got fingers crossed.
...But to fix this now you have to remove the valve cover and follow the rotation of the rotor and timing mark as well as the valves in number 1. remember it turns all that at the same time so everything should be the same, as long as you have them on the compression stroke. and you can tell that by what valve on number 1 is just beginning to open on the up stroke, before hitting TDC. Oh and to make sure you are on the up stroke just put a long bladed screwdriver into number one, it will push the screwdriver up and down while a helper is turning the crankshaft by hand with a long bar with the harmonic balancer bolt, always turn in the direction of rotation.
It's unnecessary to do that much work.
Stick your finger in the #1 spark plug hole. You'll feel/hear air when you are on the compression stroke. Then it's a matter of determining TDC with a screwdriver or tool as you keep turning engine. If you overshoot, you can turn the engine backward 180 degrees and try it again. You can also verify if the timing mark is correct or whether the balancer ring has shifted.
So here is a update, I changed the ICM and pickup and the car started right up, ran rough due to not being timed but I just turned the distributor about 1/8 of a inch clockwise and the idle picked up and it smoothed out. I'm going to do a official timing Thursday. Seems like I'm on the right path. No backfiring at all, nice cranking, the things you would expect from any car.
I'm guessing that my base idle will be around 1100 in park/neutral and 700 in drive when its all set up.
I do know that the throttle plate was adjusted by a person who thought it was a problem in the throttle body. I know there is information somewhere to check that its set up right if I have any further issues.
I'm going to do a official timing Thursday. Seems like I'm on the right path. No backfiring at all, nice cranking, the things you would expect from any car.
Just be aware that the outer ring of the harmonic balancer could still have spun, which when it occurs, makes timing quite a challenge (until the balancer is replaced).
I made sure before I pulled the distributor that the balancer was on zero and number one cylinder was at TDC with a depth gauge. So I'm guessing it hasnt spun.
At the very beginning you say if you remove the injector fuses it "cranks over nicely." Are you saying it starts? Does this car run? Does it drive? Or are you just trying to get it started?
As a update, I have the car running great. I set the timing at 10 degrees, made sure the plugs are a nice brown and let it idle for a good 30 min to get to operating temp. It revs out nicely without hesitation.
SO I want to thank everyone who has taken the time to post a suggestion to how to heal my little fiero. If i can return the favor one day, I will be more than willing.
nothing would have changed so you could just replace everything back in the exact same place and driven away. 
also are you sure all the plug wirers are right?
