Explosion, now no start.

[vikenabm]

A bit stumped, frustrated, would love help making a diagnostic task list to get my car started again. MKIII turbo swap into 1989 NA body, ran okay but was tracking down high pressure boost leaks with custom piping to the new intercooler. IN the process i carelessly set the timing wrong, or I think I did. It started with difficulty, ran horribly with a lot of fuel smell, wouldn't rev, and when i opened the throttle it exploded, loudly, and stopped abruptly. Restarted the same way, then did the same thing. Hasn't started since then. found CPS timing badly off but intake cam was still up when crank was at TDC. Turns over, but no sense of any ignition happening. pulling injector resistor connector doesn't affect the turn over sound at all.

Fuel: Fuel pressure is good, tried anywhere from 30psi to 45 with no luck.

Spark: Iridium plugs damp but not damaged, except number 6 plug was dry, also undamaged. cleaned them, checked resistances of plugs, wires, injectors, injector resistors. observed good sequential sparking in all 6 plugs mounted in a threaded metal holder. Engine grounds are all retapped and clean.

Compression: about 155psi in all cylinders.

Turbo impeller turns freely without play.

New RC injectors were working, but i put a new heat shrink on all of them. Don't know that I have any reference on what polarity they need, so if that matters please let me know. worried about injectors stuck open.

Questions:
is that explosion "detonation"? SOunded like the sound of a block on the bench being static pressure tested and having the valve popped open with a mallet to seat it. that type of loud pop but much louder resonating through the exhaust system.
What else should I test?

Thanks!

Mods:

K&N filter to Lexus AFM | 660cc RC | Holley 255 LPM FP | JE/Eagle internals | 2.5" hard pipes | Toyo high flow intercooler| S Sanchez ported head | 1.2mm beaded MHG | compression 9:1 w/0.5 overbore | modified ex mani | CXR 3" full exhaust | Slotted/drilled rotors |New WG spring @12psi w/ dual switching man boost | Colt Mild perf. Cams | Bosch BOV | XTD clutch | Tokico Illumina w/TEMS | ES bushings | 18" Pirelli P-zeros | Manual AFPR

[vikenabm]

Wow. Kind of quiet here. Is it always like this? Anyway, in case anyone reads this, yesterday I pulled the turbo - perfectly good rebuilt stock turbo with no sign of damage. Then while it was off I thought I'd do a leakdown test for boost leaks. Got pressurized to 60psi and found slow leakage from multiple places, greatest was from the gasket between the upper and lower intake manifolds, so I separated them slightly, painted some copper RTV from a spray can in there, and resealed with significant improvement. Then various other slow leaks showed up that didn't seem worth chasing, since it obviously was sealing sufficiently that even at 30psi it wouldn't leak enough to make a big difference.

checked cam timing, both set to stock TDC.

checked all the voltmeter tests you can do without the engine cranking or starting, all were ok, except EFI main relay was 1v below battery voltage, but still within specs with a charged battery. Will check connections and ground there and clean that up.

So that's it. For want of a better idea, I guess I'll put the turbo back on. and try starting it again.

I'm thinking maybe the problem is lack of fuel, for lack of a better idea. Spark and compression and timing all were checked and are pretty easy to observe, though I could stand to double check he igniter circuit to coil wiring. Would like a more direct test of the new RC 650 injectors to be sure they are opening and spraying correctly when installed in the engine, trying to think of how I can be absolutely sure they are operating ok.

I'd like to triple check everything possible before trying to start again. I'm beginning to consider swapping the ECU if I don't come up with a better idea soon. That will involve using an automatic trans ECU and making changes in wiring internally so it works with the manual trans, at least to start it. that's a bit of a PITA, so I was hoping to avoid it.

That's it: no real smoking gun found. Feeling like i'm missing something obvious here. Would love to hear from another real live supra owner out there.

[cre]

This isn't the busiest of Supra sites, no. I've been pretty busy and haven't had a chance to really read through it but I've been meaning to make some time to go through your post and see what I can come up with.

I'll look it all over tomorrow (it's very late here now) and let you know if I can think of anything that's missing. One issue that comes up from time to time it the CPS being clocked 180? off (refer to the FAQ thread on timing to make sure that one is right). And no, there is not proper polarity for the RC injectors, just a simple coil in there so nothing to worry about unless they're not wired in the proper order.

[vikenabm]

Originally Posted by cre

This isn't the busiest of Supra sites, no. I've been pretty busy and haven't had a chance to really read through it but I've been meaning to make some time to go through your post and see what I can come up with.

I'll look it all over tomorrow (it's very late here now) and let you know if I can think of anything that's missing. One issue that comes up from time to time it the CPS being clocked 180? off (refer to the FAQ thread on timing to make sure that one is right). And no, there is not proper polarity for the RC injectors, just a simple coil in there so nothing to worry about unless they're not wired in the proper order.

Thanks for your kind and generous attention. I do appreciate it. I dont know that timing was off by any specific amount. I know it was way off, and I think I must have forgotten to set the crank to tdc. I know the cam timing was correct and still is.

[cre]

The cam's timing is entirely dependant on the crank's position. Timing is not set in any way if all of the components are not set at a matching degree. The distributor, cams and crank ALL must be at zero or your efforts are wasted. First go and ensure that the mechanical timing is properly set, then set the ignition advance (as detailed in the TSRM). Report back with any additional findings.

EDIT:
Ok, I re-read your post and am a little confused I suppose. Go over the thread linked to below and make sure everything is 100% correctly aligned. If you've removed the cam gears at any point make sure the dowels were installed in the center hole on each cam and likewise on the gears. If you're running adjustable cams dial them to 0? initially.

http://www.toyota-supra.info/forums/...-e-timing.html

[vikenabm]

Originally Posted by cre

... Ok, I re-read your post and am a little confused I suppose. Go over the thread linked to below and make sure everything is 100% correctly aligned. If you've removed the cam gears at any point make sure the dowels were installed in the center hole on each cam and likewise on the gears. If you're running adjustable cams dial them to 0? initially.

Got this but apparently my response was swallowed by the Verizon network.

Rechecked timing this week. it was set according to the exact procedure you linked to, and cam matchmarks and crank mark are still aligned correctly. The pictures are very nice and clear, and I've set the timing many times before. Unfortunately, the timing advance can't be set without the engine running, but I can approximate it with the engine cranking using a timing gun. I think that type of electrical test for timing would be a good reality check anyway and I hope that will be sufficient proof without pulling the CPS again. The CPS was the last thing I had pulled and reset - and done carefully - before posting the problem on here. The timing gears were removed when rebuilding, They are the stock gears, so position is set by the fit of the gear on the cams.

I will
1) verify that the cam lobes are aligned as expected with the match marks, just to be extra certain, on Saturday.
2)Will check each cylinder for spark with inductive timing gun to verify correct sequence as wiring from igniter to coils was extended and soldered due to fraying and breakage.
3) remove CPS cover and verify armature alignment with crank and cam timing marks at TDC.

I'll let you know when this is completed.

Thanks.

[vikenabm]

Good instincts on looking at timing. the timing was all set correctly: cams, crank, CPS installation, but I found two wires reversed on the connector to the CPS.

My understanding from the TEWD is that the engine harness connector is supposed to look like:

Blue Red
pin1 pin 2

Black Yellow
pin 3 pin 4

I had black and yellow reversed when I fixed the worn connector. How i had any spark at all I still don't understand.

Now the coil packs are still confusing. In the tewd it doesn't clearly say which wire from the igniter goes to which coil, but labels the wires
IG1 to coil pack connector pin 1,
IG2 to coil pack connector pin 2
and then the third wire to pin 3 isn't labeled with a moniker
coil pack pin 4 is B+ common.



Fixing and putting engine back together. will report back.

[cre]

The coil pack wiring is a common upset but, oddly enough, it's not something which has made its way into my repository of Supra tech info. It has been posted here in the MKIII forum a couple times though. If you find a good thread with solid info on it let me know and I'll copy it into the FAQ section... I'd look for something but I've got company and had to sneak away to get on here for this long.... The wife's just real funny about me not paying her family enough attention.

[vikenabm]

7MGTE ignition system wiring specs


WARNING: post edited - had error in my wiring which I hope I corrected. this is my best understanding of how it is supposed to look.

adapted from another forum, TEWD, and also my TCCS manual from the Allen Instutute training manual from 1990


Coil pack order is: (left to right from front of motor)

Coil pack____________To cyls__wire colors

Coil A Passenger coil____1&6____Black, Tan

Coil B Middle coil_______3&4____Green, Tan

Coil C Driver side coil____5&2____White, Tan

To Engine harness per TEWD:
(Here's where it gets messy! The TSRM appears to have the WRONG pin numbers in their diagram on page IG-15 for the ignitor test procedure, where pin 3 and 4 appear to be labeled in reverse. The test procedure should not work as diagramed because the IGDA and IGDB signals do not appear to be correct. More on this below. Also, the functions from the CPU don't wire to the same function at the ignitor. The functions labeled at the ignitor in the diagram don't make sense and my TCCS manual from the Allen Institute says they are WRONG. The functions from the CPU make perfect sense so I included these in my table below. They mean "IGT = ignition trigger, IGDA = ignition determinant A, IGDB = ignition determinant B, and IGF - Ignition Fail)

CP wiring___CP connector _Engine harness wire color __Ignitor 6 way con._____Function __|_ CPU Activating Function__Ignitor 4 way con. pins to activate
Black__________Pin 1 __light blue/red stripe__________Pin 2______________"IG1" __|___IGT and IGDB__________ 2&3 in TEWD (and TCCS manual)
Green_________Pin 3 ___yellow___________________Pin 4 _____________ "IG2" _|___IGT and IGDA __________2&4 in TEWD
White_________Pin 2 ___light blue/yellow stripe_______Pin 1______________"IG3" ___|___IGT alone _________ 2 Alone in TEWD
Tan___________Pin 4 ___Black/orange stripe_________Pin 3______________"B+" -goes to ignition switch and EFI resistor pin 2


coil firing order: Note coil packs fire vehicle right to vehicle left, ie passenger side to driver's side. . that is how most sources number the coils 1-3 or A-C:

Coil A, plug 1 (and 6 wasted) ie "IG1" , IGDA=0, IGDB=1
Coil B, Plug 3 (and 4 wasted) ie "IG2" , IGDA=1, IGDB=0
Coil C, Plug 5(and 2 wasted) ie "IG3, IGDA=0, IGDB=0

Coi. A, Plug 6 (and 1 wasted) IG1 again
Coil B, Plug 4 (and 3 wasted) IG2 again
Coil C, Plug 2 (and 5 wasted) IG3 again

SO to test the ignitor, it should be the following procedure:

Apply a constant +3v where indicated in first column then touch pin 2 with a +3v pins on the ignitor 4 pin connector:

constant 3V transient 3v read resistance
none ignitor Pin 2 coil C connector (center coil) white wire pin 2
ignitor Pin 3 ignitor Pin 2 coil A connector (passenger side coil) black wire pin 2
ignitor Pin 4 ignitorPin 2 coil B connector (driver side coil) green wire pin 2

Note: my digital voltmeter, which is a high end model, does not respond quickly enough to reliably see the drop in resistance in the coil connector wires. I made a bracket for my plugs to watch them fire and confirmed that they work as expected when wired and tested this way.

[vikenabm]

Well it took a while, because I fried a few links and fuses jumpering the car too late at night and not paying attention. Now I can say the car is back to where it was before the explosion, when it just wasn't quite starting and was misfiring. It catches slightly and sputters just barely for a second. It seems to barely combust, and disconnecting the fuel injector resistor to cut fuel leads to a stronger sputter on the first try. It's like it is flooding before starting. then checking timing while cranking, I get almost no gun flashes, like it's not picking up a spark current. Pulling plug one and trying with plug exposed shows it sparking erratically and weakly and fouled but not wet plug.

So I think I have a problem with spark. I have tested coil and wire resistance, all fine, but I put in new irridium plugs after I tested compression, and i went with a colder plug due to my increased compression ration and plan to boost to 20 or 25psi eventually. I will try again with plain old copper plugs, retest coils and wires, check ignitor transistor, and report back here for posterity.

Questions: when people run colder plugs for high boost do they generally also have aftermarket ignition? WOuld there be any benefit to keeping my plugs and increasing spark power via different ignitor or coils? What are the best upgrades to the ignition, if any?