inconsistent spark Options

[Gtguy22]

ok, so i changed my distributer, cap, rotor, and plugs. Trying to get this car back on the road, but my spark is inconsistent, literally some times i have it, sometimes i dont. What the hell is going on here?

[Davinci]

A correction. the CEMF does not hit the ECU directly via E12. in fact there is no e12 on the ECU there is how ever E21 and E2. both of these are specifically "Sensor grounds" so when you feel like setting the car on fire look there for some of your problems. The CEMF would be most directly provided a path to your ECM via the Igniter from either the IGF or IGT wires. (these connections are very sensitive by design in so instantaneous voltage spikes are very troublesome at these terminals)

But I am an optimist so lets assume that all of the proceeding text is hyperbole and does not apply to your situation. what now!?!

the BGB give you the process for troubleshooting everything so i recommend that you follow the processes outlined there. After completing the 130 page diagnostic procedures and they all pass you have found yourself standing next to me on a ledge ready to jump off.

A good ECU, Every signal wire passes continuity, and there are no shorts to ground. Power is present and at the right voltage everywhere the book says it should be. the only thing you cant get is the engine to realize that there is absolutely no reason for it to not run.

This is the point that most ELECTRICAL shops would give up ( your local mechanic has just cost you 500 dollars in parts swapping and 20 hours in labor and you are still required to tow it to my shop)

Here is what is keeping your car stalled.

the NE coil in your after market "OE" distributor is not as efficient as the Toyota factory pickup. it will pass any and all bench test time and time again but not start your car.

lets compound the situation. the signal is borderline at best and the wire harness is capable of killing the signal depending on the temperature; this happens because a wires internal resistance is temperature sensitive. in most metals the resistance increases according to temperature increases.

let me wrap this up because i am far too tired to go on about this car.

If you are suffering from the WTF no spark situation after you have checked your condenser go looking at your wire harness. if you notice small nicks at the base of the connector seals on the wire insulation you need to rethink the Parts swapping strategy. Clean the grease off and look further at that nick you will see the copper is either Green (oxidizing), Brown (oxidation causing heat), or Black ( cooked from heat caused by the resistance to the flow of current) or completely broken, but not shinny like copper should be.

Do not waste a minute trying to repair that harness, go to the scrappers and buy one, or call me and i will find you one but do not let the thought of being able to save it cost you dearly. If you see any of the conductors looking like the description above you will be hard pressed to find shinny copper anywhere in the wire. any repairs would be a waste because the problem will remain hidden in the wire and come back to bite you again.

DO this instead.

go out to your car and remove each body to battery to chassis grounds and replace it with 8 gauge wire. You own a Toyota so follow their guidelines and do not solder any of the ring terminals to the wire. just provide a good solid crimp from a decent ratcheting crimp tool designed for automotive electrical connectors. take a file and clean off the paint surrounding the bolt hole that the ground is connecting to and then spray the surface with electronic connection cleaner. a good product from CRC is the QD electronic connection cleaner and its available at walmart for 5 dollars. the best around right now is Deoxit for about 20 dollars. don't spend anytime cleaning the threads in the bolt hole, this operation will not help you because now that the paint is not in the way the electrons are going to flow into the body through the larger terminal pad area and not through the bolt. this is a good thing because bolts were never designed to be direct conductors. It will help you to add a couple of extra grounds from the engine to the body to the transmission, and even to the exhaust. once completed put Vaseline on it or battery terminal protection spray.

follow toyotas BGB instructions for removing the wiring harness and do not jump a single step, follow it exactly. clean all the connector junctions that join the engine harness to the body harness with the spray.

install the new harness in the car and then move forward on reverifying your sensors are working properly based on the steps in the BGB.


Lastly, it is important that you take this piece of advice from me.... From the day you are born and until 3 days after you die do not buy a part from an after market supplier like pep boys, o'Riley's, Advanced, Auto zone, and the list continues on for all memoriam. If you are anything like me you are too poor to buy cheap parts so if the part you need moves, has a wire on it, holds a fluid, or is important to the successful operation of your vehicle go buy it from the dealer. it will cost you less money the following week when you get to factor up all the money you did not spend on labor and buying additional parts hunting for a solution.

Alright, im going to bed so i hope this helps but if not i apologize for taking so much of your valuable time.

Have a better day,

Craig Campbell
Davinci Auto Electric
757-655-1008

This post has been edited by Davinci: Dec 17, 2009 - 2:14 AM