Timing way too advanced

[hardcore_al]

To get the engine to run ok I have to move the distributor way beyond it's adjustment range as you can see in the picture below. It runs quite well when I crank the dizzy that far over though



Things I have replace or ruled out:
-New fuel pump
-New fuel filter
-New FPR
-Cam timing is set correctly per TSRM
-Distributor is stabbed correctly per TSRM
-Vacuum leaks eliminated as best I can tell

My only idea now is the tps, adjusting it makes no difference nor does unplugging it all together. I haven't been able to find much info on adjusting or testing the older 3-wire square type TPS's though. They are just an on-off switch essentially though so I don't see how it could cause this.

I don't have a timing light, well I have two but they are both broken and I am sick of buying those stupid things; so I'm not sure what the actual timing is at, just that it is way way advanced.

I'll probably break down and buy another timing light tomorrow, but until then if anyone had any input I would be eternally grateful cause this is driving me nuts. Also If anyone has a working square TPS (83, manual) I will buy it off you.

[AJ]

Allen, your dignosis is probably correct...bad TPS...when the TPS in my '86 went bad my timing per the scope was 28 degress advanced?????

[hardcore_al]

It seems like everyone that has had TPS issues causing this have been 85+'s with the round style TPS, but I'm definitely gonna track down another tps and give it a shot. Thanks for the feedback AJ.

[AJ]

Copy Allen!!

[Donn29]

It can be quite tricky to install the dizzy at the right spot. Try pulling it out and putting it in a tooth off.

[hardcore_al]

I've had the dizzy in and out probably 10 or 15 times, and have checked the rotor and points against the TDC of the crank and cams; it's definitely in there right, although when I specifically try and put it in one tooth off it runs ok while still having a bolt installed.
How dangerous is running it with the timing this advanced/no tps? I assume the big risk here is detonation but will it be a ticking time bomb driving it around town like this?

[Donn29]

If it's that far off, the timing is wrong. Just keep redoing it until you have it right. You could have the cam pulley/belt not on right either. I've been there, and assumed the timing was good because I kept doing wrong, haha. 1 tooth off will do that exact thing you took a pic of. I know because I've done that probably 3 or 4 times!

Also,
TPS has little to do with how it runs. It only gives the ecu information on whether or not it should be in open or closed loop basically. For example: is the throttle open fully(switches to open loop), closed(should be idling and shuts the motor off if it is above ~2000rpm), or if the throttle is changing(google acceleration enrichment, if you want to learn about something unrelated to your problem).

[hardcore_al]

K, cams pulleys are coming off tonight and everything is getting done from scratch! Although I'll go ahead and grab another tps just for the sake of having a spare at least.
I was puzzling at how what is apparently an on-off switch indicating throttle position could have so much impact on ignition timing. I'm always looking to learn more as well (hence the years spent on this forum reading thousands of informative posts from you everyone else in the community) so I'll definitely do some reading on acceleration enrichment.

[Road Ripper]

I think the big thing here is checking that the woodruff key holding the crankshaft timing cog in place hasn't sheared. It can shear off and still hold the cog to the crank, but the cam timing will be retarded. I would guess advancing the distributor would bring the ignition timing back closer to where it should be, but the cams could still be off. I had this happen on my silver 85 shortly after I got it, and at first I thought the timing belt had slipped. Only way to know for sure is to remove the crank pulley, lower timing cover, etc. and have a look. Best of luck!

[StanS]

while you're learning see toy tech articles at www.autoshop101.com. Should keep you busy for a while.