X died on the way home

countryguy53

countryguy53

Daily Driver
A while back my 86 fi x died near the house, it was acting like it was starving for fuel so i got it home changed filter which was over due, i added a pre pump filter and put in 4gal of non-ethanol gas and added two bottles of chev techron fi cleaner. it seemed to be running better but it occasionally would bog down and miss when i'd punch it.I drove it for about two months and it died again.So yesterday i checked the pressure going to the injectors at the port for the cold start injector. it was right on 36 and 28-30 when running, it would run for a while(3min)or so idling and reving a bit then die. seemed like it was starving for fuel again. when it would start it would miss and run rough for a while. Injectors seem to be clicking but i'm afraid that junk from the tank made it thru the old dirty filter and is clogging the injectors. since the fuel rail is above them..Anything that passed thru the nasty filter would drop to the injectors. I was thinking about using a bore scope and seeing if i could see a squirt into the cylinder thru the spark plug hole or do the injectors port into the intake manifold not the cylinder itself the rail is at 36lbs so if i energize the injector i was hoping to see a squirt to see if they were plugged or not. What voltage are the injectors? i used a meter but the voltage is so quick it couldn't get a voltage, just that it was going to the injector. i did check the timing and it was right on also i checked the belt to see if prehaps it has slipped but it was fine also....I'd appreciate any ideas if anyone has experienced anything like this....Was thinking about pulling injectors and having them rebuilt...who and where can i get the injectors worked on if necessary? thanks Gene
 
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This isn’t a direct injection system so the injectors squirt onto the back of the intake valve so you won’t “see” it. You should use a ‘noid’ light to test injector wiring.

Yes you could have had grundge get to the injectors but it is unlikely.

The variation you are seeing in the pressures is normal as there is a pressure regulator.

I would go through the injection system guide in the Wiki:

http://xwebforums.com/wiki/index.php/FuelInjectionTroubleshooting
 
thks will go thru wiki guide...was thinking that i could get fuel rail up to pressure and see if by only hooking up one injector and watching for pressure drop on the fuel rail to see if the injector activation would lower the pressure (showing the injector is opening) and do it to all the injectors one at a time and record the pressure drop if any.
when i changed the filter(when it died the first time) i think it did have nasty fuel coming out so i was afraid of this. hopefully i will get to it today i'll let ya know what i find...thanks gene
 
After holiday festivities i got back to the X...i have gone thru all the steps i You were right Kmead the injectors weren't plugged because the plugs were soaked... i verified spark to the plugs (new) checked timing several times(tire is off to access crank bolt and line up mark) (left guards off so easily accessed) all timing marks line up..on #4 (changed out distributor with spare)new cap and rotor. Still barely starts and stumbles won't rev much (even with turning the dist while running from dvr seat) running rich for sure black smoke coming from exaust will only run for a few minutes and dies ..before it died the o2 sensor light had been on quite a while so i changed it before it died i can't get the reset button under the console to reset it. button won't seem to push in to reset(is there a trick to get light out) haven't verified voltage out ofnew o2 sensor because it won't stal running long enough to get hot ....Could the reset button be telling the brain behind the pass seat to make it super rich and choke it out? Anyone have any ideas Was thinking about changing brain behind seat next.....
 
You might look at the cold start injector, it may be leaking and causing a too rich condition. You can block that injector off as it is off on its hose. And the car should still start, albeit with a bit more cranking and less confidence.

Clearly you should concentrate on what is making the car run so rich. Is the flap returning to its correct position? Have you opened the AFM and changed the spring preload or anything else in there?

Don’t worry about the O2 sensor, it doesn’t do a huge amount on this system and nothing at idle. I used a finishing nail to push the reset in, the button needs to travel a fair distance to reset, it will make a click when it gets there. The sensor light doesn’t affect nor change the operation of the main system, so no it wouldn’t cause the issue you are having.
 
I had a similar condition in an 84 for a while. It ended up being my Airflow meter....
 
Kmead,, i think i had the cold start injector unplugged when i was working on it last. ill check if its still unplugged i can crimp the hose feeding it, just in case...i was pissed so i just took a break from it... I did check it to see if its clean and moving but not much can be seen from either side(squirted it with some mass sensor cleaner but no change i do have a different AFM (i love parts cars) so i could try it haven't ever messed with it,its in a box from Midwest Bayless( loaned one to another X friend and he sent me a replacement for it) but did put it on my list of things to change if nothing else worked .. definately one of the benefits from having more than one X....will probably attack it tomorrow again
 
I was checking to see what i needed to remove the AFM, i noticed the top moved some so i grabbed it and pulled it up..it had been opened before (so much for thinking it hadn't been opened before) so i started the car and started playing with the arm as it moved with the air flow, if i held it back a bit it ran much smoother and had throttle response again. Its easily adjustable with a set screw i backed the arm adjustment back a bit ran much smoother...cleaned the contacts in the AFM on wiper and fuel pump...Since I had checked and tried everything i could think of i had to replace all the guards and clips i had removed during trouble shooting mode. So i will finish in the am...There are other adjustments they might have messed with... so maybe better to use the backup AFM (if it hasn't been opened also)... Guess ill see what happens
 
so once again i was once again i was wrong..the AFM, apparently wasn't the problem, when cold, it started harder still acted up after a few minutes, so to,tomorrow i'm changing out coil instead of checking then values cold... maybe when its hot it will fail...not sure what is left...going to list all the things i've done so far to see is i missed anything
 
I would try the other AFM before changing another thing.

You need to try and figure out which item is the offending part. This means isolating which one is the problem, so change only one thing at a time. By fiddling with the existing AFM you have changed a variety of variables, I would leave the rest of the system alone until you test by changing out the AFM and seeing what the effects are there.

Once you have verified that as not being the problem, then change the coil.
 
i put the other AFM on and it started harder, i changed the coil no change...and now that i've tried to get it started its probably flooded again since i can smell gas, i had the cold start injector unplugged so its not giving it extra gas...so i thought it might be lack of spark so i checked the coil output and it jumps like 1 1/2in so its working(so was the original coil) changed out resistor also...I am changing one thing at a time to isolate problem....
 
List of things i have done, new cap and rotor, new plugs,pre pump filter,have gauge on fuel rail (28 running and 36off and stays up), verified #4 timing,unclipped injector plugs (to be able to see which cylinder was missing),changed distribuitor, checked value of coil and resistor(cold) checked ok,changed out resistor and coil (since nothing else made a difference)and i had spares,changed AFM, changed oil and filter since i was afraid gas had gone into sump...i have ran out of ideas on what to check or change next i have done all of these things one at a time to check results... this car ran Great and all the sudden its gone to this...the only thing i have to change still is the ecu behind the pass seat....I,m about to sell the lot of them
 
I don't suppose you've checked to see if your exhaust is clear? Maybe a plugged cat will give a similar set of symptoms?
 
just because you unplugged the cold start injector does not mean it is not stuck open.

maybe take the injector out and plug the hole and see if that makes a difference (and to see if the injector is letting fuel past) (could do the same with the set of four unplugged and see if they are leaking)
 
i have cut out the cat so its a straight pipe now(so no blockage)...i have a pressure guage on fuel line and it doesn't bleed down I'm looking at the wiring diagram and there is a multiple relay they show on diagram does anyone know where its located? I'm looking at the fuel injection assy schematic from the book i downloaded for the 1500
 
The dual relay is located near the ECU. Have you checked the ECU connector? Water’s been known to travel down the harness and short out the ECU.
 
i was going to attack the ecu tomorrow, was thinking about changing it out, i have tried almost everything else.. tks for the location of the relay i'll check it also
 
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