toyocrf

i have a 1993 toyota pickup just rebuilt it with a torker cam,a pace setter header, and k and n intake im pretty sure i got the timing almost right i got a timing light let the motor warm up jump the terminals and check the crank with the light. with the motor idiling at bout 750 850 rpms it sits at tdc instead of 5 btdc the check engine light blinking constant (that means nothing wrong) if i accelerate to bout 1500 rpms the timing mark is at 5 btdc when i unplug the jumper wire i do not see any change in idle or timing marks i have no check engine light showing still idling at round 750 850 but i have no power can barely pick up speed in first and second when i went to third it really bogged and began to pop and backfire i heard that the throttle positioning sensor may need to be adjusted to get the ecu to set ignition timing correctly once you unplug the jumper wire i took the thermostat housing off to get to the screws on the tps but the hanes manual isnt much help i still havent got the bottom screw out, will work on it more tomorrow but any info on adjusting the tps or any other ideas would be very helpful

yayfortrees

The timing is not set right. It should be 5 degrees BTDC at idle, not 1500.

PismoJoe

x2

and there should be exact RPM when setting timing, it should be 750 RPM @idle manual trans, 800 RPM @idle automatic trans.

toyocrf

i kno it is supposed to be at 5 but ive heard that the tps not set correctly can affect timing im afraid if i move the distributor another tooth it wont run at all id like to kno more about adjusting the tps

4Crawler

iTrader: (3)

How to set the TPS:
- http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

thook

If you look at the link 4crawler provided, you'll notice the suggestion to swap the stock phillips head TPS fasteners for allan heads. If it's convenient enough for you to do, I'd suggest it as well. You should be able to get them at an O'Reilly. They should have a bolt chart that you can match the thread size up. It makes it easier when trying to get the TPS adjust. correct without having to pull the throttle body or the thermo housing off. You can reach the set screws with an angled allan wrench.

This makes it possible to set the TPS in another way, as well. Instead of using feeler guages and a DDM, while the engine is running, pivot the TPS clockwise and CCW slowly until you find the point at which the RPM changes. This is the idle position and where the TPS needs to be to get the timing set. The TPS should be set at the low RPM side of the change point. Of course, by setting the TPS by the book w/feeler guages you're able to make sure the TPS is functional on all other circuits besides the idle, but for your purposes getting the idle setting correct is all you need. Now, if you have running problems after setting the TPS at idle, you may need to go back with the meter and guages to check.