i keep having to adjust timing. wtf?

Hi all,
95 gt, H/C/I, original stock distributor, original stock coil, new MSD dist cap, old vortech/msd ingition control box (or whatever it's called), new spark plugs, 20+ year old plug wires (motorosport 9mm). 1 month old thing that is mounted on the passenger fender that controls the spark i think. damn I can't recall its name. it's the thing that would overheat and stop the car from running. the car also has something called a PIH (performance Improvement Harness) and a 93 computer. I think the only purpose of the PIH is to allow the 93 computer to be connected, AND, the 93 computer may have come with the PIH as a kit. not sure.
there is no CEL on, but I haven't checked for codes as of yet. maybe tomorrow.

the new plugs were installed recently right before the following sequence or during it (can't recall which):
I recently got the car up and running from its 17 year slumber (the engine was fired up a few times over the years, but no real driving that could have I any timing issues) and had to adjust the timing. I adjusted the timing to about 12 BTDC and it ran great (let's call this adjustment 1). a day or two later, it wasn't running great, and I had to adjust timing to about 10 BTDC (adjustment 2) and it was great again. next day it wasn't great and had to adjust it a tiny bit more to about 9.8 BTDC (adjustment 3). The next day (yesterday), not running great again. I plan to adjust the timing again, expecting to have to move it more toward 9 BTDC.

by 'not running great', I mean if I got on the gas, at best it would be revving a lot but not accelerating as quickly as it should and at worst it would bog a little and back fire and such. by 'great' i mean I was happy as hell.

The only thing that changed over these days were the weather temperature (30s-40s), gas refill (after adjustment 2) and maybe the new plugs (maybe before adjustment 1 but maybe after 1 and before 2, can't recall).

the idle has a horrible lope once it gets warmed up a little (after about 1 or 2 minutes) and will stall if I don't give it some gas. it will idle at about 1100 and then drop a little and surge to about 1500, then drop closer to 500 and surge back to 1500+, then nearly stall and surge, then stall. not always 4 cycles, but that's the general idea. this is something I will be working on next (in a new thread after I check/replace as vacuum lines), but mention it here in case it is a symptom of something that might help figure out the timing thing.

any thoughts on this?

thanks

General karthief said:

The thought here is to start 2 or 3 threads about a car having problems that are likely related so members can ask the same questions over again and give you conflicting advice.
Sitting for 17 years
Not sure but was the heads,cam,intake swapped 17 years ago along with the 93 computer and related PIH (??).
Did you buy it this way or you did this to it?

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no, my thought was to keep issues separate, but i dont have much knowledge, so i did the best i could. if you think it would be better to have one big thread about my car and its many issues, im all for it. let me know. it would save me the hassle of having to type the history over and over. it seems though that that way the info would get muddled worse?

unless youre talking about the idle surge and timing and implying they are likely directly related, then i wont make another thread for the idle (if the hose replacement didnt fix it) and we can talk about both here. whatever you like.

I bought the car new in 95. lots modifications happened before 97 including C/H/I, including supercharger (why I have the vortech/msd box, 30lb injectors, and mass air calibrated for 30lb). I did not install the parts. That was done by what I believe was somebody who knew what they were doing.

the car became un-driveable around 2003 due to that part on the fender that controls the spark or something. it heats up and cuts off spark and then I had to let it cool for 20 minutes or so before it would run again. this was long before the current state of the internet or I would have fixed that then. I bought a corolla and the mustang sat. No mods on the car since 95-97 other than the mention cam swap and i bypassed the smog pump.

around 3-4 years ago, can't recall exactly, I took the heads off the car and swapped out the cam that was in there for something milder because the charger was gone. I had the heads maintenanced, new springs, seals, etc. the time frames arent precise, but enough to give an idea of history. i cleaned the piston heads and the lower intake, and upper intake best i could. when i put the engine back together, it fired right up, but I still couldnt drive it because of that part that heats up and fails. i replaced that a month or two ago, and here we are.

General karthief said:

Ok, I went back and looked at your previous posts and you seem to have several issues you are trying to resolve. My advice is this, and keep in mind that I'm not there hands on so I have limited visual insite, this car used to have a blower on it, and you didn't do the install, it has a bunch of stuff related to the blower still installed, so (and this is what I would do) take inventory of non stock parts and remove the things that are related to the blower, repair/replace with stock computer, wiring and anything else that is not supposed to be there.
Not knowing what h/c/i that's on it so it would be hard to say if it is part of the problem. I doubt they are.
Keep to this thread as it seems to have the most info relating to your set up.

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thanks
thats an option that i have thought of and i think was suggested previously for some other issue, but there is a chance i will be getting the charge fixed and put back on (which was another suggestion).
i will check all the vacuum hoses first and see what happens and go from there. im not against removing the currently unneeded items though.

in general, this is some crazy situation, right?

jozsefsz said:

A couple of things to maybe try. If it sat a really long time the fuel filter should be changed, and it's unfortunately possible that the fuel degraded and varnished up the filter-sock in the tank. The bog you describe might be not getting enough fuel. A fuel-pressure gauge could help determine if it's anything related to that. Adding new fuel won't fix that unfortunately, changing the pump will.

The other thing on the timing - it's possible that as the computer is learning (updating its long-term fuel-trims) that it's leaning things out (so your car runs better with less timing advance). Go back to 10 degrees (stock), and reset the computer (disconnect battery for 30 minutes or so). Drive it until it starts to run poorly again. Then, instead of adjusting timing, try resetting the computer again and see if it runs good again. That'll help determine if it's the learning messing things up for you (the root cause being that you might have a fueling problem that needs to be addressed).

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hi,
so, while I'm debating removing all blower related pieces or putting the blower back on, I plan to check/fix obv things like checking and replacing vacuum lines for example.

regarding the fuel delivery, I did replace the gas tank, pump/screen, and filter around the time I did the engine, I think it was after the engine actually, so probably less than 3-4 years ago, but not much less. I have a fuel pressure gauge on the fuel rail. if anything I probably have too much fuel with the probably oversized pump (can't recall the flow though) and 30lb injectors. I have a regulator, but I cant adjust it below like 35psi it seems. after that, the adjustment screw just comes out of the regulator. the pump was really rusty.

96pushrod said:

Personally I believe the PIH to be a complete waste of money. The 94/95 eec is completely tune-able.

When you set timing, did you do it with the spout out?

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you may be right about PIH, but that's what I have for now unless I get a 95 computer.

yes, spout out after warming up the car.

dcm0123 said:

Used 95 V8 computers should be cheap and easy to come by
.
You took out one part (supercharger) of a system which required a modified computer, MAF sensor, ejector and cam to run properly.
To get it to run right again without the blower you may need to change everything back to OEM (possible exception of the milder cam) or reprogram the computer, have the MAF re calibrated and install smaller injectors.

Your idle speed is controlled by the computer. If it is varying, the computer is compensating for something. The hunting issue could be related to the throttle position sensor voltage calibration or computer settings.

Timing is also controlled by the computer except when you have the spout out. With an OEM computer it should not vary if the spout is out. Not sure how your computer is set up. Also not sure how the MSD box could affect timing. The component on the fender which can effect timing and spark is the ignition control module. If this caused your initial problems replace it with a Motorcraft part only.

We have a supercharged 351W with similar modifications to yours except controlled by Tweecer with a 94 computer and no PIH.

PS- After writing this I did some research on the PIH since I never heard of it. May not be that easy to revert back to a 95 computer because they had to modify the existing harness for the PIH and 93 computer to work. It also indicates you now have a BAP sensor as opposed to the MAF sensor so you maybe better keeping the harness, computer and BAP sensor.

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thanks
regarding the BAP vs MAP, a month or two ago i was checking the computer to see if there was a chip installed (there didnt appear to be). the computer is under the passenger seat, and with the computer was some device/part which i wasn't sure what it was. i checked the part number and if i recall correctly, it showed up as a MAF which is weird because I think I looked up the PIH info as well and it should be a BAP.

when the car was in its glory days, i recall no issues other than the bad ignition control module, so this sounds like another vote for checking the basics and reinstalling the charger which, i mean, isnt all that bad an option.

thanks again

96pushrod said:

If you want, I have a spare 94/95 engine harness you can have. I don’t know if you intend on keeping the eec you have now.

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hey, didn't see this until just now.
thanks for the offer. not sure what I'm going to do, but I appreciate the offer.
i am going to take care of all the little things like making sure theres no vacuum leaks before i move on to bigger changes like that
thanks again

NXcoupe said:

what makes you think retarding the timing will fix whatever it is you feel is wrong? Set the timing to 13 deg before tdc and don't touch it. Third, that box on the fender may be a boost retard box, not sure without a part number off of it.

By not running good, what do you mean? Misfire, breaking up, surging, lack of power, etc? I'd like to help but need to know the problem first

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regarding the timing adjustment, i have no idea, but i like to tinker and I took a shot.
i admittedly dont know much about what im doing.
where did you come up with 13 deg from, just curious. i think everything i saw said 10 or 12 iirc.

by 'not running great', I mean if I got on the gas, at best it would be revving a lot but not accelerating as quickly as it should and at worst it would bog a little and back fire and such. by 'great' i mean I was happy as hell. bog a little isnt a strong enough term, it would bog more than a little.

next time i get under the hood i will check the part number and see what i come up with. it's not the box that came with the supercharger, but it is similar. i *think* it is more than just for boost. i think this partly because when i was getting things back together i tried to run the car with it removed and the car didnt like being revved high at all, and reconnecting it things were fine (or at least better than with it disconnected). EDIT: forgot to add, the PIH literature says an ignition box has to be used with the harness, i didnt realize that until after i had removed the box and reconnected it, but after i read that, i thought huh, ok so the car running better with the box connected makes sense.

thanks

NXcoupe said:

I installed many PIH harnesses back in the day and never ran an ignition box. I don't know where you read that. Retarding timing kills power and can make the engine pop out the intake. 13 deg advanced makes for a total at wot of 28 deg or so. If your pcm has a chip in it, it's designed to be set at 10 deg.

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the car definitely ran better with the box connected, and it wasnt a placebo effect because i was removing it to try and simplify things. if i thought it was better with it off i would have left it disconnected.

i checked for a chip a while back, there doesnt seem to be one. i looked in the port on the side of the computer.

jozsefsz said:

A couple of things to maybe try. If it sat a really long time the fuel filter should be changed, and it's unfortunately possible that the fuel degraded and varnished up the filter-sock in the tank. The bog you describe might be not getting enough fuel. A fuel-pressure gauge could help determine if it's anything related to that. Adding new fuel won't fix that unfortunately, changing the pump will.

The other thing on the timing - it's possible that as the computer is learning (updating its long-term fuel-trims) that it's leaning things out (so your car runs better with less timing advance). Go back to 10 degrees (stock), and reset the computer (disconnect battery for 30 minutes or so). Drive it until it starts to run poorly again. Then, instead of adjusting timing, try resetting the computer again and see if it runs good again. That'll help determine if it's the learning messing things up for you (the root cause being that you might have a fueling problem that needs to be addressed).

Click to expand...

so while checking and fixing vacuum leaks, i discovered that the fuel pressure regulator was leaking, badly. fuel was flowing out of it into the vacuum lines as if there wasnt a diaphragm in it at all. just pouring out. i have since replaced the regulator and because i charged the battery, i had the battery disconnected overnight. will see how it goes after some more driving.

does fuel being dumped in the vacuum lines (and getting sucked into the intake) sound like something that could screw around with the timing?