no start after rebuild
 

ok I have been on this forum for months now. I just finally registered because this is an issue I have not found a suitable solution to. the car was givin to me by my good friend of 20 years. its a 91 turbo. the car lost a bearing and was parked 2 years before I started on it. I pulled the motor and got a low mileage long block, tore it down and completely rebuilt it with good stuff, added a header and garrett t04e turbo and hks downpipe, hks evc pro, hks 2mm hg, arp head bolts, arp rod bolts, high performance piston rings, custom made wastegate and matching bov, and greddy turbo timer. power steering, ac, and clutch fan deleted. everything is installed correctly. I used vacuum diagrams from this forum and also the tsrm.

the car will not start. triple checked timing, rewired cas, and checked for fuel pressure. cranks but will not start. also tried resetting the security system by opening all doors, hood, liftgate, and lock/unlocking all doors. no dice. check voltage at coil pack, igniter, and found them good. has new plugs in it as well. have gone threw every check that I could find on this site and others without success. there is also no spark which obviously why it wont start (im guessing). so there is where I need to start. but how?

Well, let's start simple. Does the car turn over at all when you turn the key? Any diagnostic codes stored? Have you checked to ensure the CPS isn't installed 180? off? Have you tested for power that the ECU (Batt, B+ and B1+)?

yes double and triple checked the cps. showing 12v at b1 and no + voltages on bat and b2. the plug is removed from ecu while checking

oh ya and yes, cranks but does not turn over. thanks

anyone else have any clues??

Uh, yeah:

Unless I misread or you mistyped the ECU isn't getting power at two essential inputs.

yes obviously, was hoping for a place toi start on this

Ah, my apologies. As +B and +B1 are both sourced from the Main EFI relay and the Circuit opening relay I would check the harness in between. I am quite surprised that you have power to one and not the other.

Batt gets its power from the 15A EFI relay. If you are getting power to one of the +B lines though this fuse is unlikely to be the cause of the problem and again, you are most likely looking as a wiring problem.

All three should have power whether the harness is plugged in or not, so long as the ignition switch is in the "ON" position. Have you perhaps tested the ignition switch?

Have you inspected your wire harness since reinstalling the engine?

Here is the wiring diagram for the ECU:
http://www.cygnusx1.net/Supra/Librar...px?S=Main&P=46

i did a visual check of the harness before installing. I didnt unwrap the the wire loom tho to check inside. I will check the ignition switch as well as try to get power to the ecu. I am also suprised that only b1 is getting power and not the other two. your right, sounds like a wiring problem. when I hoocked up my multi meter to those other 2 the voltage actually showed a negative of about 1.5v on both. not sure what that means...thanks much cre for your input.

ok, I removed all engine grounds and made new ones. now I'm showing a voltage at b2 and batt but its only between 4v and 5v.... still no start tho

Do you know how to test for voltage drop across a line? You place one test lead at each end of the wire (the wire needs to be connected so there is voltage to read), place the negative lead on the side closest to the + terminal in the circuit then place the negative on the other end. The voltage you see reported will be the total drop across the wire. More than a couple hundred mV and the wire should be replaced.

When testing across a larger circuit it is sometimes easier to test the whole thing and then slowly close in until you've found the individual point of failure. So in this case you'd place the negative probe on the battery's + terminal. Then you'd place the positive probe at the harness' +B connector resulting in a reading of a drop of about 10v. Now you move back along the circuit to the next junction and test. If the voltage drop is still present you move along to the the next junction closer to the battery. If it isn't then you test the voltage drop across the wire at the ECU harness and that first junction.

now the car is back firing thru the intake and exhaust pipes are getting warm...I havent check any voltages yet, but the back firing thing has been the most activity since it was installed? good thing?

The back firing means the mechanical timing is a mile off. Realign everything to 0? then look into the voltage issues.

ok, will do, and i'll get back. thanks much for your help

oh ya and to get the timing right i'll need to know which wire go where on the cas. I had to get a new connector because the wire on mine were deteriorated and came out of the connector. I can only guess where the go. I had a guy bring over another harness so I could tell but he will not answer my calls now. the wires before the connector on the stock haarness are a different color then the ones after so I cant match the colors? anyone have a picture of theirs? thanks!

What? The CPS harness perhaps? The wires on the side of the CPS are not matched to the harness.... at least I've yet to see one that matches. I can get the colors from my '88, but they may be different getting the info from someone with an '89 or newer would probably be best.

If you're not talking about the CPS harness (has 4 wires) then post a pic.

I got them right now, looked at a friends harness. got new coil packs now and have a good strong spark. still just backfires into the intake. all voltages check out. ignition switch is good. refueled gas tank, timing is perfect, no dice. still occasionally backfires into the intake.

Backfiring into the intake indicates that the intake valves are opening too soon after ignition.... I know of no other way for this to happen than the mechanical timing being off; I am not talking about the spark advance if that is what you are referring to.

what should I do to fix?

Bill UK covered it well in pictoral form here: http://www.toyota-supra.info/forums/...on-sensor.html Those three items set the mechanical timing, then you tighten the timing belt tensioner pulley (do NOT over torque it!!!), then you set the ignition timing with the timing light.

oh ya gotcha, I did that already at least 15 times lol

Well, I don't know what to tell you then... did you get all the shims back in the right places? Get the cam gear dowels in the center hole on both cam and gear? Perhaps someone else will have a suggestion, but I can't think of anything.

ok finally got it started. doesnt run long as i expected due to vaccuum bugs. I am tho pretty sure oil should not shoot out the exhaust side of the turbo, am I right?

Ummm.... oil + exhaust.... not unless turbo technology has gotten VERY strange in recent years. ;)

haha ya I know. turbo is blown apparently so off it goes and back to the drawing board. thanks for all your help cre!!