khoyer

Ok folks so I'm going to attempt to keep this short.

I just picked up an Evo 9 RS and it smokes at idle as well as deceleration. I naturally started by doing a compression test. all numbers were within 10-15. I know that the rings are getting lose and will need to be build soon(ish) but that isn't my problem. I then performed a leak down all cylinders were 7-10%.

when I picked up the car it was on E85 so I immediately drained all that and filled up with 93 and retuned it to run on pump gas. I also performed an oil change and now have the fuel trims really close which is a large step in the right direction.

so now I started looking into the valve stem seals. and those all look perfectly fine. so I figured F**k it ill just run this thing smoking until she goes and then ill build a new motor. however before I put everything back together I ran another compression test. This time I ran it with all the plugs removed and after cranking a few times I noticed it started to reek of fuel.

with a flashlight looking at the pistons cylinder 1, 2, and 4 were completely bone dry. but cylinder 3 was pooling up with some fluid. couldn't determine weather it was oil or fuel.

These are the steps I took to verify the problem.
waited until the piston dried up again and unplugged injector #3. cranked the car numerous times and then checked the pistons theyre all completely dry. so then I plug injector 3 back in. and crank again. now it reeks of fuel again and cylinder 3 is pooling up with fuel.

then I removed injector 2 and 3 and hooked them up to a 9v battery to make sure they were opening/closing appropriately. then reinstalled. cranked the car again. more fuel in cylinder 3.

Final test I performed was plugging the injector 3 electrical plug into the #4 injector and cranked the car again. this time cylinder 4 filled up with fuel.

so I have narrowed it down to being a problem with my injector #3 wiring. But have NO clue where to go from here. what tests can I perform and what should I do next??
any help is much appreciated!!

khoyer

also I just tested the voltage on all the injector clips. one pin on each of them tests at 11.6. the other pin has no voltage and doesn't seem to be grounded either. idk what the other pin does. Also does it matter which pin gets the power? because #2 clip is opposite of all the rest.

4b11slayer

I think the second wire is ecu ground controlled.

They should all have power on same side.

roni4g63

iTrader: (1)

like 4b11slayer said, its likely the ecu grounds the other pin, therefore its a ground PWM injector, Hmm, seems like a resistance issue, for some odd reason #3 may not be getting enough resistance (this is just a guess) there should be a resistor plug on the firewall, check that an make sure the wiring is not chamfered. Again, this is just a guess. Goodluck man

4b11slayer

If it was an injector issue, youd likely have driveability issues such as a misfire.

khoyer

The resistor plug has the injector bypass on it. The silver piece on the firewall is unplugged and has the spoolnup plug on the other end.

This morning i checked both the grounds for the CAS and those are good. I then tried checking ground for the injector plugs. I tried on #3 and #4 and couldn't get a signal on ground for either pin on either of them. Of/on/cranking.

I can't stand tracking down wiring issues 😑

khoyer

ok update. I pulled ALL of the shielding and tape off of the wiring from injector 1-4 and to the CAS back to where everything meets. the ground that mounts on the head next to the CAS was completely exposed. like 100% of the wire was exposed with no shielding. it had all melted and started melting and fusing to other random wires. and while all of the injector wires were untouched I am replacing that wire tonight and re wrapping all the exposed ones and testing again.

khoyer

Update again. Cut out the old melted wire and ran a new one and fixed all wiring. Then cut the injector #3 ground wire and cut the wire on the ecu side as well, then ran a new wire to verify that the wire wasnt getting grounded out somewhere else. still had the same problem.

At this point I'm completely out of ideas. We even removed the ecu and opened it up to inspect the circuit board. Looked clean nothing burned out.

Car also has a TPS voltage CEL. I'm thinking I have a few wiring harness problems but don't know how to verify without buying a whole new harness

barneyb

Is there a ground in this bundle? The engine needs all the grounds connected. Otherwise, the wires overheat.

The ground I would check first is in the starter harness.

khoyer

I bought a new engine wiring harness. This one's been tampered with to much and don't want to unshielded the whole thing. Will update when I get the new harness installed

khoyer

Bumping for more advice here guys.

barneyb

What do you want to know?

khoyer

it would be super helpful if someone else could pull all spark plugs. unplug cas. and crank for like 15 seconds and then take a light to the cylinders and see if ANY of them are wet. When the cars running I think its firing ok. just don't know why it would open an injector while cranking with CAS unplugged.

Biggiesacks

Sounds like an ECU problem. Could be a roasted FET on the board if you have already eliminated the posibility of a short in the harness. Correct me if this sounds wrong, but when the ECU turns on the fuel pump (crank signal) and energizes the high side of the injector circuit the # 3 injector just starts dumping fuel? The ECU controls the opening of the injectors on the low side and if its sending constant ground to the injector that would indicate to me a fault with the electronics. Dunno if you have done a test like this, but put a test light (or meter in voltage testing mode) on the battery + and touch it to the negative (to ecu) side of the Injector harness plugs. Turn the ignition on are you seeing a light or voltage? That would indicate a short(maybe in the ecu). If nothing comes on (light voltage) try cranking, you should see pulses of light /voltage.

4b11slayer

Op is there any issues with car? Does it start and run with out misfire?