Raining and bored so I decided to do the TPS and Timing (It ran great before). I've done it several times over the past 19 years but now for some reason I'm having troubles. When I go to set the timing it runs fine for a little then idles and bounces around 300-200 Rpm and wants to die. Here's what I did and I have the FSM in front of me while doing (90 Vert):

Set TPS:
1) Warmed up car and did the bulbs. Two bulbs were on so I adjusted the screw until one lit and tightened the locknut.
2) Started it and cycled through various rpms and then turned off and re-verfified one LED was it. It was.

Timing:
1) Put a ground to the set coupler
2) attached timing light clamp to L1 lead, battery red post (+) and steering pump bracket (ground)
3) Started up and saw YELLOW mark was a little to the left and it would bounce past the timiming pin and back momentarily.
4) Loosened CAS and rotated so that the yellow mark on the pulley would align with the pin. As I go to do this I have to rush or the car would try to die. I set it and after I set it it would be too far ahead o the pin
5) Lastly, I went back to check the TPS and it showed 2 bulbs lit????.

?????

 

I think using a voltmeter is the best way to set the TPS and an ohmmeter is the best way to check if it is in spec or not.



With the car warm (you could even do it cold if you don't have the fast idle thermowax), see if your voltages are correct, and if not adjust to get them in spec. If you don't check voltage at the ECU (pain in the ***) you should be able to check it at the sensor itself. Note that these images came from a turbo FSM but it should be the same.

 

I did check the TPS with an ohm meter as well as light method. I forgot to say I doublechecked the TPS first to ensure it works properly before adjusting timing. I'm thinking I'm doing something stupid in the timing portion?

 

I'm guessing you dislodged the electrical plug from the BAC. Might be a quick fix. Check it out.

That's if it's not what else was mentioned above.

Or left the initial set coupler installed if you installed it prior to setting the timing.

 

Man I wish I didnt touch this car today. Ok, I adjusted the TPS again once after the car got to op temperature and got the single LED (pictures attached of all this). started car and let it run again just to make sure it was really hot, shut it down, diconnected TPS plug and took the ohms. Looks pretty good.

Oh, BAC connectorwas hooked up.

Problem: Is there anything with my timing hook ups in the picture?
1) Clamp on L1
2) Red clamp to (+) battery
3) Black (-) to strut tower blot as a ground
4) Intial set coupler to body ground (black wire w/ yellow terminals).

Here lies the problem. When I go to adjust the marks for timing it is rumbling to die. As I rotate the CAS it runs out of adjustment. If I back it off from the hard stop the YELLOW timing is WAY off.

If I take to initial set coupler off and put the CAS where it was before I started all this mess (I marked it before starting) it runs better but not good like before I started. The YELLOW mark has a tendancy to bounce around. You look and you think its ok and then bounces perodically to left or to right. RPMs start off fine when starting but drop and it tries to stay alive.

 

Tell you what. Undo the initial set coupler. That should allow the BAC to keep the rpms up around 750rpm.

As long as the rpms are under 1100-1200 rpm, the initial set coupler does not need to be installed. See what happens.

As for the timing light, just put the lights black clamp on the batterys neg terminal instead of the strut bolt. No gain but no loss doing it that way.

Light does not flicker??? Try the other Lead wire. Both fire at the same time so it makes no difference.

Timing light just flickers once and a while?? Turn the clamp on the sparkplug wire the opposite direction than what it is now/then.

Still not flashing all the time? PUt the clamp waaaay down near the sparkplug. Try the clamp both directions if it does not flash steady the first time you try it.

TPS should be set with the engine fully HOT.

 

Thanks HAILERS, I'll try it again w/o the inital set coupler tomorrow. Gonna put a full charge on the battery tonight just to be sure. Funny how I dont remember having the problem before. I thought (been a couple years) that the initial set coupler I had a wire looped to itself to the green plug, but I guess I always had it to the fender? Just cant remember.

I have better timing light I found in the closet. It has advancement **** that im not sure how to use it. I guess I'll set it at 0.

 

Been at it all morning and this is whats going on. I warm it up HOT and did the LED bulb thing and tried setting it again. I try to work quick because I know you have just a minute with that thermowax thingy. I set it to one bulb lit and run it again then check: 2 bulbs lit. So I repeat several times and same thing. Start out with one bulb, run the car and check: 2 bulbs.

So I try the Ohm meter. Set as close to 1 ohm then after running it is like 885 ohms. Once I get the car HOT I run to check the readings because you only have a minute to do so.

Timing: Starts up great and runs good with the YELLOW mark ~1/4 inch to the left or counterclockwise. Its hot but after running a few more minutes the YELLOW mark moves over and lines up somewhat with the timing mark but then it become crappy and not steady. It wants to bounce to the left or right with sound the car wants to die like its barely running. On the dash when its at its hottest thats when idle is struggling. I tried the different leads.

 

Its better to have the timing light clamp as close to the plug as possible like HAILERS suggest. Results much better as far as yellow mark bouncing. Right now yellow mark is on the timining mark (used 2 separate timing lights) and TPS at 0.90 Ohms. Still not good but will do. Had to stop from the exhaust fumes giving me a sore throat (eventhough garage door was open and fan going).

Will check when I get home tomorrow the timing mark and TPS. I sware they move on their own.

 

If you're having that many issues with maintaing even a remotely stable RPM you're likely in for a bit of trouble to begin with. Relying on the BAC to compensate for such a low mechanical idle (300rpm) is really overtaxing the poor thing. I'd strongly advise adjusting the screw ontop the TB with the BAC disconnected (initial set as well), and bump the idle up to at LEAST ~700 without the BAC. If the screw's all the way out and it still won't go any higher i'd start looking for some other culprits. As a last resort, slightly opening the throttle plates (after you close the idle bypass screw and open it up about a single turn) until the car mechanically idles at ~700 then reconnecting the BAC/fine tuning timing/TPS.