HatchEh2

long story short-



had a harvard blue Z6 boosted Eh2 (94 DX hatch) car accident (other at fault)
i get paid, bought a friends GSR swapped Eh3 (92 Si hatch).

wont run. picked thru the wires a bit and saw it was the TRUE MEANING of the word BUTCH. half OBD-1 half obd2 running on a chipped p72. gay 1990 model alarm w/ aftermarket gay locks.

swapping my alarm, my oem locks/windows/mirror conversion in so i chopped his all out. Decided to put my ENTIRE WIRE HARNESS in the car to cancel out any electrical problems.
tore out the dash, steering column (his was broke, using mine) heater core, blower, etc.
get to the tarp, tear it down, swap harnesses, make a few adjustments to compensate for the cruise control brake switch and such. throw it all back together with MY stuff.

FROM THE HEADLIGHTS TO THE ECU TO THE UNDER-DASH FUSE BOX IS ALL OUT OF MY OBD1 RUNNING CAR!

Pulled out the motor, cleaned it, checked TDC, new clutch and flywheel, fresh fluids, cleaned and painted the bay, installed my virgin OBD-1 engine harness on the motor, put in OBD-1 gsr injectors to plug correctly to my harness and made an adapter to run the OBD-2 dizzy.

everything together, turn the key, fuel pump primes, no codes, crank..... crank....crank.... kicks over.... dies...kicks over....dies.. ecu goes in smoke and burns out the Q31 resistor.


checked for spark: GREAT spark, new dizzy, nology wires.
compression: cyl-1: 220 cyl-2: 225 as is the rest, 225psi
check for TDC: DEAD ON
checked for fuel: NONE

pump primes... guage reads, rail fills, B&M regulator functional... but nothing in the cylinders.

put a noid on the injector plugs and crank the motor... NOTHING.

NO SIGNAL IS BEING SENT TO THE INJECTORS TO FIRE.

NO CEL

afraid to try other ecu's or itll fry that same resistor again...

now lets see H-T... if someone could somehow solve this, ill paypal you $25 if it runs.. no lie.

ill have pics up when i get the chance, cars at work.


Modified by HatchEh2 at 10:32 PM 5/29/2007

HatchEh2

bump

jackiechang

for free money if your an electrical person

Jagolas

for some crazy reason i want to say that there's a fuel injector relay or fuse under the hood or in the fuse box on the inside. check to see if it gets power.

punoy69

muffler bearings for sure paypal me $25 NOW!

FREE BUMP FOR YOU

elusive123

bump

delslo93

Did you have a resistor box wired up on your last setup when it was turboed??

HatchEh2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by delslo93 &raquo;</TD></TR><TR><TD CLASS="quote">Did you have a resistor box wired up on your last setup when it was turboed??</TD></TR></TABLE>
no resistor box. i ran saturated injectors. engine harness is a Virgin '94 DX. vtec was properly added aswell.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jagolas &raquo;</TD></TR><TR><TD CLASS="quote">for some crazy reason i want to say that there's a fuel injector relay or fuse under the hood or in the fuse box on the inside. check to see if it gets power.</TD></TR></TABLE> Every fuse and relay is still working just the way it did when i pulled it from my first hatch..


theres a Q31 resistor in the ECU at location R135 or 137 i believe.. thats the one that keeps burning out. im told this is caused by a faulty map sensor? dont know if i believe it, but its worth a shot. no map means the ecu has nothing to go off of to fire the injectors.. but ive seen cars 'start' before w/out the map hooked up...or with the map and TPS switched..

94Hatchd15b7

Glow pugs for sure!!!

HiProfile

It sounds like a main relay problem, but from what helms is saying, the relay supplies power to the ecu, injectors, and the 2nd relay inside the main relay, which is the pump-priming relay. If it was sorta-broke, it could still power the pump primer and the ecu, although the ecu may get secondary power. I know that the pump won't prime unless the far left connector of the ecu (looking at ecu's top/rear at pins). I'd check that the grounds for the injectors are good (yellow w/blk stripe), as they terminate with other grounds to the 'dead connector' on the driver's side. No ground will mean no circuit, giving no signal.

I'd also try different injectors and a different ecu. An obd1 ecu should be able to start any other obd1 Honda, assuming the injectors are the same. It will obviously throw codes like vtec ecu on a non-vtec car, but it will still fire the injectors.

Bejita

Your injectors are crap or your fuel rail is crap....Are they hooked up correctly?

EE_Chris

Q31...is that what burns out when you plug the IAT connector into the EVAP solenoid and vice-versa?

HatchEh2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HiProfile &raquo;</TD></TR><TR><TD CLASS="quote">It sounds like a main relay problem, but from what helms is saying, the relay supplies power to the ecu, injectors, and the 2nd relay inside the main relay, which is the pump-priming relay. If it was sorta-broke, it could still power the pump primer and the ecu, although the ecu may get secondary power. I know that the pump won't prime unless the far left connector of the ecu (looking at ecu's top/rear at pins). I'd check that the grounds for the injectors are good (yellow w/blk stripe), as they terminate with other grounds to the 'dead connector' on the driver's side. No ground will mean no circuit, giving no signal.

I'd also try different injectors and a different ecu. An obd1 ecu should be able to start any other obd1 Honda, assuming the injectors are the same. It will obviously throw codes like vtec ecu on a non-vtec car, but it will still fire the injectors.</TD></TR></TABLE>

everything is outta my running hatch (wrecked one) every wire harness, plug, relay, etc.

update: injectors are now getting a pulse... and its no longer frying Q31 resistors. Swapped the map sensor for another and it started to pulse and stopped shorting out the ecus. then i swapped the old map again to make sure.. and for some reason it works now..

still wont stay running. and IF it starts.. its loppy and wont rev, just die.
cranking it on a good P06 and a virgin P28 since the rest (chipped p72 and chipped p28) need new Q31's now..

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bejita &raquo;</TD></TR><TR><TD CLASS="quote">Your injectors are crap or your fuel rail is crap....Are they hooked up correctly?</TD></TR></TABLE>
it had obd2 injectors in there before, when i converted the whole car back to OBD1 i bought a used set of obd1 gsr injectors. (in there now) ..and im startin to feel skeptical about them..
i pulled the wires and cranked the motor for a good amount of time. now what SHOULD happen is fuel should build up in the cyclinder... its dry, little or no fuel is being sprayed from the injectors.
gonna replace the filter and try my sohc injectors in there to see if thatll start it.

and yes. its hooked up right.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">Q31...is that what burns out when you plug the IAT connector into the EVAP solenoid and vice-versa?</TD></TR></TABLE>
to be honest, ive done both back in the day (iat swapped w/ EVAP and map swapped w/ TPS) and it never blew the ecu at all... would run like ****, but never blew the ecu... i dunno why my friend thought that.. he works at a dyno shop so i dont doubt his knowledge..to an extent.

abusedhusband

iTrader: (1)

bump for a good guy who needs help. this car is kicking our a$$e$.

HatchEh2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by abusedhusband &raquo;</TD></TR><TR><TD CLASS="quote">bump for a good guy who needs help. this car is kicking our a$$e$.</TD></TR></TABLE>

thanks bro, yo i was about ready to break into your hatch and try your injectors in mine when you left the shop haha

HatchEh2

bump before work... popin those sohc injectors in it today... ::crosses fingers::

elusive123

bump

b_serious

what ecu are u using now that the original blew? i had a problem like this.. but it was my harness was all hacked up wires in the map/tps sensors where switched sockets so it wouldnt start and if it did it lasted 2-3 seconds and when i stepped on the gas it would die or backfire then die

g23_ej1

i would say somewhere along the lines of changing out the harness you maybe cross plugged a plug and causing this to happen.. thats only half of the problem.. the other half does sound like a main relay problem.. take off the main relay, take it out of its shell and look at the solder points.. i can almost garuntee there will be a crack somewhere along the solder points from it getting so hot.. grab your solder gun and a little bit of solder and re-connect those points as well as any other you may see.. that'll fix your main.. ive done it plenty of times to crapped out relays..

LinearTuning

I would look back to the splicing that you did. You may have crossed a couple wires or have one not ground properly. Check out Rywire.com. They could probably lead you in the right direction....if not..what setup are you running in the motor? Anything far off from stock that the original map won't let you start?

Good Luck...

Relic1

an ECU with a bad Q31 should still work fine. Q31 drives the EVAP purge solinoid and OBD1 ECUs do not set a CEL if it doesn't work.

The question is did you pop your IAT? VERY common to do if you have the plugs switched.
And will cause the car to think that it's -40* and run it really rich which will cause idle to be like you explained.

THC07

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 &raquo;</TD></TR><TR><TD CLASS="quote">an ECU with a bad Q31 should still work fine. Q31 drives the EVAP purge solinoid and OBD1 ECUs do not set a CEL if it doesn't work.
</TD></TR></TABLE>

yes will run just fine, and Q31 is for the IAT.

Is there an inertia switch for hondas?
when you get in a wreck that inertia switch turn off the fuel pump.

the only time ive ever had no signal for injectors was because of the ecu. and the immoblizer.

if you use other ecu to test, odds are you will burn Q31 in that ecu also.
try your ecu in another car first to rule it out.
good luck, that sucks

Relic1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by THC07 &raquo;</TD></TR><TR><TD CLASS="quote">Q31 is for the IAT. </TD></TR></TABLE>
umm no. Q31 is an output transistor that runs the EVAP purge solinoid through A20. It's commonly popped with swaps that have the engine harness removed or rewired.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Is there an inertia switch for hondas?
when you get in a wreck that inertia switch turn off the fuel pump.</TD></TR></TABLE>
built into the airbag control unit, but cycling power (removing the battery) will reset that.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">if you use other ecu to test, odds are you will burn Q31 in that ecu also.
try your ecu in another car first to rule it out.
</TD></TR></TABLE>
good advise


Also, if your IAT sensor is shorted it will pull the internal power of the ECU down and cause really funky things to happen.

THC07

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 &raquo;</TD></TR><TR><TD CLASS="quote">
umm no. Q31 is an output transistor that runs the EVAP purge solinoid through A20. .</TD></TR></TABLE>

lol, we might have to do Rock Paper Scissors on this topic.

why would q31 be on ecus that didn't even use EVAP purge solenoid's

Relic1

good question. I honestly don't know why almost all honda ECUs have Q31 populated even if they don't control anything. Maybe a simple cost of production run change. Maybe a late change to get rid of the EVAP purge system.
But very few of the ECUs I've seen have Q31 depop'd from the factory.
Switching the IAT and EVAP plugs (same plug, same aprox length, same area, so it's really easy to do) causes Q31 to pop and a good chance that the IAT sensor will be damaged.

reason - when the IAT and EVAP purge are switched... Q31 supplies power to the evap purge when the ignition furst turns on and when the car is cruiseing down the road, the IAT is a thermister, 12V accross it will draw a pretty good dose of power and pops Q31, it also damages the IAT because it's meant for low mA worth of power not multiple amps.
the IAT input to the ECU is an input, the EVAP purge just sits there and waits for 12V that will never come. The ECU sees a certain resistance to ground and thinking that it's the IAT thermister it thinks that it's cold out and pushes in more fuel.

Once switched back to normal, Q31 is gone and can not actuate the EVAP purge, but again no CEL so who cares. (unless you're a tree hugger) the IAT being damaged makes the ECU think that it's really cold outside and pushes in way more fuel than it needs. But doesn't set a CEL because the range of the IAT is still within tolerance.
If the IAT is completly shorted the load on the ECUs internal power supply causes very unpredictable operation.