[SOLVED!] 2JZ-GTE Swap into MA70 - Misfiring issues - Will PAY for a correct answer..

[richardjeffries]

I'm getting so desperate. I will literally pay whoever solves this problem $100 USD via PayPal. This does not mean to give me 20 suggestions and hope one is right but if someone knows the answer for sure and says "it's _____", I swear on everything holy I will pay you for solving this problem.

Please, I need intelligent responses.

The car is a 1991 Supra Turbo with an Aristo 2JZ-GTE swap with a small single turbo (10psi) and stock everything else. Running a Denso TT fuel pump @ 12v.

1) Car was running perfectly in November of last year (Nov. 2011)
2) Car developed an oil leak at the pump
3) Pulled the motor, replaced the oil pump and all nearby parts (seals, gaskets, belts, etc)
4) Now running really odd, no codes, just strange
5) Time to move and car HAD to be driven about 100 miles, drove it slow (50-55mph) (Feb. 2012)
6) Checked codes again and found Code 12, found it to be a wiring problem
7) Pulled the harness, made my own new harness from scratch with all new wirings, pins, seals, plugs, etc
8) Installed the harness (last month, May 2012), and did the "12v mod" (fuel pump gets 12v all the time now w/relay)
9) Car now starts and runs fine but has intermittent, constant, but random, misfire


Few questions:
Do you think it's at all possible that using too small of a gauge wiring for the CPS's could cause this? I used 20-22ga
The car is perfect and smooth until it warms up, and the misfire is consistent with the RPM drop of warming up.


My diagnostics, engine at operating temperature, and voltages tested at ECU:
Ambient Temp Outside: 85F
MAP (PIM) - 1.5v (Gauge reads ~ -20inhg)
IAT (THA) - .69v - .71v
Coolant Temp (THW) - 1.43v
O2 Sensor (OX) - 0.08v -0.92v
Fuel pressure at rail - 38-40psi

I do not hear a clicking sound coming from the IAC when I turn the car off, however it seems to be operating fine because the car idles very well, it just misfires.


Stuff I've done that hasn't helped:
-Brand new spark plugs gapped at .030" (NGK 4644)
-Using a different set of coil packs (known working)
-Using a brand new Denso o2 sensor (OEM)
-Using a very low mileage IAC, just replaced
-Just cleaned all of my injectors and rail (and manually pulsed them into a jar to see pattern and none were obviously bad/leaky/stuck)
-Tested continuity and voltage everywhere with good results (ISC, Injectors, Coils, MAP, TPS, etc)


I thought the fuel flowing through the rail sounded .. odd .. not consistent but pulsing .. anyone have this? Opinions?



Idling, revving, no difference as to misfire..



Again, but open DP ..

[midnight_purple_GA70]

its not so much the gauge of the wire its more the amps the wiring can handle...

cant do videos at work will have a listen later...

check fuel pressure at the rail as well

[richardjeffries]

Thanks. Fuel pressure at the rail is 38-40psi. Adding to original post.

Wire is mil spec. I'm sure even the small gauge can handle a decent amount of amperage.

Thanks, looking forward to more responses

[b3n_rix]

double check your filters, if already done, check the on pump filter in the car, might be blocked causing a surge

[wilbo666]

The CAS does not require significant current so I can't see the gauge being an issue.

Have you tried your engine ECU on another engine?
Tried your igniter on another engine?
Have you had any luck trying to isolate the cylinder that is missing?


To be honest it would seem likely that the the issue is in your new loom given that is pretty well all that has changed! Earthing is good in the new loom and as per factory wiring? i.e. MAP, TPS, etc have their own signal earth to the engine ECU?

Cheers
Wilbo

[richardjeffries]

The CAS does not require significant current so I can't see the gauge being an issue.

Have you tried your engine ECU on another engine?
Tried your igniter on another engine?
Have you had any luck trying to isolate the cylinder that is missing?


To be honest it would seem likely that the the issue is in your new loom given that is pretty well all that has changed! Earthing is good in the new loom and as per factory wiring? i.e. MAP, TPS, etc have their own signal earth to the engine ECU?

Cheers
Wilbo

I will be trying known working igniter and ECU very soon.

Haven't been able to isolate which cyl yet. All spark plugs look great and all identical. Any other recommendations for isolating which cyl?

I know it seems likely that it's the loom but I replicated the stock loom exactly. All grounds are the same, power is the same, splices are in the same location, etc.

I hooked up the 5v ref wires identical to stock as well.

What else can I do? What I also realized is that I had this problem a year ago with the old loom too.. Could it be ECU caps? I'll link the old thread when I find it again.

Thanks

[richardjeffries]

http://www.supraforums.com/forum/sho...500&highlight=

That was very similar. Had that problem in September.

[richardjeffries]

Ugh .. $150 ..

[BlackSupra]

I will be trying known working igniter and ECU very soon.

Haven't been able to isolate which cyl yet. All spark plugs look great and all identical. Any other recommendations for isolating which cyl?

I know it seems likely that it's the loom but I replicated the stock loom exactly. All grounds are the same, power is the same, splices are in the same location, etc.

I hooked up the 5v ref wires identical to stock as well.

What else can I do? What I also realized is that I had this problem a year ago with the old loom too.. Could it be ECU caps? I'll link the old thread when I find it again.

Thanks

Have you shielded the CPS wires right up to the plug?

[richardjeffries]

Have you shielded the CPS wires right up to the plug?

Yes I did.

This is the harness I made:







Found this tonight ..

[4th surf]

I'd replace all of the caps and have the tracks on the motherboard freshened. I have had similar problems with 1UZ V8s and also EFi Turbo diesel Surfs boil down to the same thing. There is also an incorrect feed somewhere on your new loom which may be down to just one pin that can cause the same thing or even a pin not contacting correctly on the ECU side. I tell you now that this is going to be something small and stupid that takes ages to find

[combatantsomeone]

I would suggest getting another ecu as it is possible to mess up replacing the caps.. I know I did lol

[George]

richardjeffries which Aristo? VVTI or not?
does your loom have diagnostic connector?

[richardjeffries]

I'd replace all of the caps and have the tracks on the motherboard freshened. I have had similar problems with 1UZ V8s and also EFi Turbo diesel Surfs boil down to the same thing. There is also an incorrect feed somewhere on your new loom which may be down to just one pin that can cause the same thing or even a pin not contacting correctly on the ECU side. I tell you now that this is going to be something small and stupid that takes ages to find

What makes you suspect something is wrong with my new loom? The old one had many many wiring issues which is why I suspect it caused this problem. The new loom has never worked quite right so I think the ECU issue was there to begin with.

I would suggest getting another ecu as it is possible to mess up replacing the caps.. I know I did lol

I used to modify Xbox motherboards and solder on mod chips and stuff. Had to cut and repair traces and solder onto areas that were small as a needle. I think I can handle it (but we will see) ..

richardjeffries which Aristo? VVTI or not?
does your loom have diagnostic connector?

Non-VVTI. No diag connector at the moment. I've run TE1 to a switch in the glove box which I can flip to activate the code display. Why, what were you thinking?

[George]

pre-obd2 toyotas are connected to a laptop via very simple 2-transistor adapter. There's some free software on the web to run diagnostics for them

Always nice to know what ECU actually "sees". These values may differ from the ones you test with your multimeter