Ok guys , here the timing issues i'm having with my car ! It's a 89 lx mustang and it is a factory 5.0 car and AOD trans , I went to set the timing on the car after i did a twin turbo setup and began by pulling the spout out to set the base timing at 5 degrees btdc and with the timing light i verified that it was at 5 degrees ideling and then i revved the motor to 3000 rpms , the timing started retarding it self to 0 degrees .. I said , WTF , i didn't know that the base timing was suppose to move with the spout out ?? I left the base timing at 5 degrees and installed the spout back in and the timing went up to 26 degrees and then i revered the motor to 3000 rpms again and the timing started to retard again and the higher you revved it the more the timing retards it self to nearly 0 degrees ....!! So , first thing i did was , i pulled the distributor out and replaced it with another dist and new module and refired the motor and went to set the base at 5 degrees and it did the same thing and went to retarding the timing when you revved the motor up !! So i thougth that maybe the ecm was bad , so i had a spare and swaped it out and went back to check the timing and it did the same thing with the retarding the timing when revved up . By this time i'm getting fustrated with the whole ordeal and went home . That night i pulled up a schematic of the wiring from the TFI plug in narness to the 60 pin plug to the ecm and made some notes on what to pin out and check the next day and i thought that i found the problem with the "PIP" circuit and refired the motor to check the timing and it was holding the timing while it was cold and then when it went to operational temps , it started retarding timing again !! I then thought it was temperture related and retried a new ACT and ECT sensor and it did the same thing and started retarding timing again !!! I'm about to get fed up with this project and how i'm looking for "ideers" (LOL) from you guys out there that may have a solution to my problems on my timing issues .......?? LMK Thanks Rob.R

PS! May be it time for a mega sguirt system and be done with it .......

 

Damn ! 14 views , and nobody knows or has ever had this problem with there stock ecm ....??

 

Ok might sound stupid but the balancer might be spinning???Or maybe the gear on the cam has problems!!! Or the dist is spinning after tighten down!!! The PCM should have no control over the timeing with the spout out!!! Again that might sound very stupid aka easy things but just trying to give you some ideas!!! Keep us updated!!!


Thanks

John

 

I don't know if this will help... I am always one of preventative maintenance... I always replace the intake air temp sensor, coolant temp sensor and coolant temp sending unit... two different things... one goes to gauge and the other is for long term and short term fuel trim adjustments... along with the o2 sensors... you said it acts fine until it goes into closed loop... reads from sensors instead of prom settings anyways... I would check to make sure the balancer hasn't slipped... too! Best way to check is put cylinder one at tdc... and make sure that the timing indicator points...to zero. I wouldn't think it's the balancer because it doesn't do it cold... I would recommend you check the spout connector because you may have a short in the wiring causing it to pull the timing parameters back into loop. I have seen a number of stupid things... as far as wiring goes... I am also one to put a couple of secondary ground straps on because I have seen too many weird electrical problems.. and check near your starter solenoid where your fusible links are and make sure everything is good there ... no exposed wires or signs of melting...these are all typical problem areas I have run into... hope it can help.
brandon

 

Thanks guys for your response to my post ! But most of the parameters that you guys have posted have been check , from verifying tdc mark on the balancer , to even cutting the spout housing off and wiring in a toggle switch inline to open and close the loop for checking the timing... As stated , if will retard timing with minor heating of the motor and it even does it before it goes into close loop ... I'm going to make a new stand alone TFI harness from the distributor to the 60 pin connector at the ecm and give that a try to see if i can get the timing to stablize .. Anyways , thanks for your time and info and i will keep ya'll posted on what i fine on my mystical timing issues ............. Later Rob.R

 

Ok guys , last night i ended up building a new stand alone harness from the distributor to the ECM and wiring in new pin connectors ... Whaalaa , the timing acted perfect and took her for a cruise and she behaved like it was suppose to .... Drove her back to the shop and checked the timing again and it was dead on !! The only other explaination i can figure out to it working right with a new narness, is that the heat was breaking the return signals in the old wiring harness due to high resistance when the motor warmed up ... Anyways , the twin set up feels real strong with a mild 10# boost tune and the street tires aren't liking it ....... Later Rob.R