Misfire or knock after ignition tune up

[sleeprtsi]

Try to make this concise and precise.
Car is a 5spd 90 LX hatch with a v1, systemax heads, intake and (I believe) cam, long tubes with stock gears. There's some sort of canned tuner on it with a knob to select tune. This is my 2nd summer with the car, before now only changed fluids and plugs and thought about how to fix the wiring mess,

Began starting hard when warm about a month ago and then died on me while driving: no tach and no spark, also found the battery was about to go.

Tracked it down to a bad TFI using the guide, so I replaced coil, cap, rotor, plugs (gapped to .043) and wir.es (wish I had just change the dist too)
Had a real hard time setting the timing (had to rotate the dist 70* to remove the TFI). SO cleaned the balancer and put a big yellow mark on 0. Set my timing light to 12 degrees advanced and tried to have the car stay ~900RPM, it idles poorly and very rich. I noticed the plug that advanced timing removed from the dist. and there was a block off plate on the dist where it should go (pic attached). work around for bad tuning?

Any rate, starts pretty easy but misfires or knocks hard, especially when you first dip into the throttle. I've tried going back a few degrees and foward a few and it seems to run poorly either way. before I take out the plugs and reccheck the cap, what else shuld I look at?

 

[General karthief]

I'd check TDC with 0* on the balancer first, I've never used a dial back timing light (is that what they are called?). I do believe you have a timing issue.

 

[keel]

I noticed the plug that advanced timing removed from the dist. and there was a block off plate on the dist where it should go (pic attached). work around for bad tuning?

As far as I know there is no plug for advancing timing on the distributor, the timing advance is all performed by the ECU via the TFI module.

However, the other plug shown in the picture, the one hanging out on top of the timing cover, contains the spout connector which will lock the timing when removed. It is important to do this when setting the timing. Otherwise you cannot accurately set base timing because the computer will move it around on you. Maybe that is why you had a hard time adjusting timing?

 

[Noobz347]

Run through the surging idle checklist and do the base idle reset procedure.

Cranks OK, but No Start Checklist for Fuel Injected Mustangs

Cranks OK, but No Start Checklist for Fuel Injected 5.0 Mustangs model years 1986-1995 A word about this checklist before you start: it is arranged in a specific order to put the most likely failure items first. That will save you time, energy and money. Start at the top of the list and work...

stangnet.com

 

[limp]

You might want to make sure your balancer has not slipped....

 

[General karthief]

My answer is based on the idle and knocking mentioned after moving the distributor, the distributor appears to me to be off like a tooth or two

 

[sleeprtsi]

Been busy with work so haven't been able to reply..

@Noobz347 , the link in the no start checklist didn't work, took a little searching but I'll go over that this weekend when I have some free time
@General karthief , I didn't pull the distributor, but maybe clocking it to get the TFI out did something? I'll take yours and @limp advice and check to see where the rotor is at when I verify TDC with the balancer.

Once I get this sorted out I think it's time to look into tuning, intercooling and cleaning up the wiring..

 

[manicmechanic007]

If you did not pull the distributor out
Try just lining up the factory chisel marks
Then when you do check the timing, you will find it right on 10 degrees with the spout out

 

[CAMTWO1070]

So you changed just the TFI module and didnt do a test on the Halls effect trigger?

What was the brand and the color of the TFI module you replaced the bad one with?

On my engine that had a similar issue it turned out that the Halls Effect Sensor was faulty but wouldnt throw a CEL.....

Depending on the mileage on the engine the thrustplate could be worn enough to start camwalk which takes its toll on the lower bushing in the distributor housing and starts issues with clearances up top in the halls effect trigger area..


This problem started when the actual plastic started shrinking and malforming from heat and age................




From what youve explained about mods and from what I can see with the pink injectors the chip with the canned tune is allowing those injectors and mods to jive with the setup better..


Never rule out the fact that your ECU may need to be gone over and new capacitors put inside because Electrolytic capacitors are some evil lil doo-dads when they start to leak electrolyte all over the pc board in 3 spots that can cause other issues ....

 

[sleeprtsi]

I've got a lot of other things I want to address and I could barely carve out the time today to get as far as I did.

Long and short, the advance on the timing light is off. I've had the timing light for IDK how long, but I set the base to ~8* visual with the light set to 0 and it ran pretty good. Idle still hunts, and it seems to take too long for water temps to cool after boost and i want to replace the distributor......

I've got a new timing light ordered and I'll set it to 10* and se how she runs. After that, I think my next thing is to have the ecu tested (someone do that?) and look at getting a way for me to tune it and look at values myself.

 

[General karthief]

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