when ever i hook my battery up and turn the key to the on position and the primary injectors kick on? any ideas? 86 bone stock 6port.

 

Remove the BAC's electrical plug and MAGICALLY the injectors will not kick on. In other words, aint' the injectors your hearing.

 

uh ya IT IS! BAC is not plugged in i took the UIM off and unplugged the injectors and boom no more!

 

Fuel injectors have 12v going to them any time the key is to ON or better. That act does not make them open/pulse. The ECU makes them pulse by ...pulsing a ground signal to them. That pulse only happens when the CAS is turning and sending a signal to the ECU.

IF the wire b/t the injector and the ECU touches ground, the injector will open, but not pulse. So if the injectors wire was shorted to ground, then the injector would click/stay wide open. No fuel would be injected unless the fuel rail was pressurized. The fuel rail won't be pressurized unless the key had been HELD to Start or the engine had been running recently.

 

If the fuel rail is pressurized will the pump continue to operate and cycle fuel back
to the return line?

 

HAILERS i will check for it grounding. also when i have the battery charger on (dead battery) the tach reads a constant 3k. i thought maybe it was because it was on the battery charger. any possible way the cas is sending a constant tach sig? when i jump the fuel pump u can hear it spray thru the injectors.

Marv yeah the pump is on as long as the engine is on/cranking or the jumper is jumped.

 

The fuel pump puts out about eighty psi. The FPR regulates the rail pressure to approx 39 psi, and anything above that goes back to the fuel tank. Constant flow if the engine is running OR the fuel pump check connector is jumpered with the key to ON. Fuel pump does not work by alone putting the key to ON. That's for MARV.

Odd the tach at three grand. That's been mentioned at least one time on this forum, but I don't remember the fix/reason....right now.

IF the battery is charged up, does the tach read three grand with key to ON?????

Yeah. The injectors (which one?) is shorted to gnd on the wire going from the injector to the ECU. Try this, pull the SMALL plug from the ECU. Then key to On and see if the injector still sprays...or not. If it stops spraying then it's a ECU problem most likely. But I don't think it's going to be the ECU.

Which injector? One of the primarys I take it since you removed the upper manifold to see the injector. Front or rear injector?

The injector wires in the small ECU plug are : light green, light green/black, light green/white, light green/red.

You know, when the pump is running, and fuel is constantly passing thru the fuel rails, there will be a hissing sound of the fuel passing thru the FPR, and maybe clicking of the Pulsation Damper (honorable mention of that in the FSM). How about repeating what you did above, but this time remove the primary fuel injectors elect plugs and listen then. If the injectors spray without the engine running, pretty soon fuel will pour out the exhaust flanges/tail pipe. Depends on HOW LONG.

The CAS has to be turning for it to send a signal to the ECU which in turn causes the injectors to pulse. It HAS to turn for sure. Easy to prove. Pull the small white plug off the CAS.

 

both injectors come on. i dont know what it reads with a good battery. i have to get one this week. i will try uplugging the cas the unplugging the connector on the ECU. when the pump is on and the injectors r unplugged you dont hear them spraying. plug them in and boom its there and they hum or somthin. give me a min and i will tell you what happens with the ECU plug and cas plug.

 

it appears a resistor on the ecu is toast. will post a pic in a min

 

 

It does look a little messed up. So? When you disconnect the small plug on the ECU the injectors stop opening?

 

bingo

 

well i just unplugged it period and it stoped

 

Makes one worry a bit why or what caused it to have a meltdown. Shorted wires etc.

Did this car/engine ever work with that ECU. I mean, with you there, not some story from the previous owner. Is this car supposed to be stock? No harness changes?

 

I have not had it runing. could a bad injector cause this? all stock harness. no mods. i will check the harness to see what i find.

 

An injector MIGHT if it was shorted internally. I'm not sure what caused all that damage in the ECU. A shorted wire b/t the injector plug and the ECU small plug MIGHT cause that.

Then again, I'm clueless about the parts that are burnt up inside the ECU.

 

i can only assume thats whats causing them to stay open. again i will check for shorts. also i will replace the injectors with one of my spare sets. my next thing is does anyone know the ohm value for that resistor? i cant read the bands on it.

 

the trace leads to a pin that according to the FSM goes to the Port Air Solenoid Valve. which if i remember right didnt look like it had the factory wiring on it....well anyway that has been disconnected from the engine. Should the injectors have stoped if i unplugged the big plug?

 

Well, the engine won't run with the large plug off because of several things like the coil inputs/outputs going thur it and CAS input/outputs.

I mentioned the small plug because it has the wires for the four injectors in it. Remove that and no fuel injection.

Shorting of the PORT Air and Split Air solenoids is a little common on this forum. Usually causes a EGI fuse to blow and melt a wire plus ECU damage. Shorting is probably caused by unscrewing of those solenoids and letting the two wires twist up and fray. Usually that does not make the ECU go bad in other areas from what I remember reading on this forum.

I'd disconnect all four injector plugs and the small plug on the ECU. Then ohm out all four injector wires to see if they are shorted to gnd or not. You might take a look at the fuel injectors solenoid resistor package to see if someone has been *messing* with it.

The FSM has a section called CONTROL UNIT and it has three pages that show the funtion of each plug on the ECU. I've non idea why your ECU was putting a gnd on the injector(s) or which injector. I've never heard of that happening before on this site and it's never happened to me.

 

ok well after i got my volt meter i can confirm 100% that the pin is for that solenoid. but i did find out that pulling the small plugs stops the injectors. i also swapped with some good injectors and it made no diff. so its my ecu but where and why?

 

ok after further looking at the board i noticed a new part damaged. a transistor D1309. there are about 5 of them all the same. you can see in the pic above to the right almost top of the pic right under the green part. with my multi meter i traced one of the leads to pin 3A on the plug

 

3A is a gnd. Maybe someone put the batt in backwards. No way to Know. Pinouts are in the FSM. Fuel and Emissions.

 

ok thx. im not sure if i can find a replacement for it or not. i found a S5 engine for 450, intake, sensors, wiring harness, ecu, and it has good compression. the only issue is the electric OMP. I know you can buy a chip upgrade for it but i dont wanna pay 100 bucks for somthin i might be able to build myself. any details on what the upgrade is?

 

Digital Tuning. Go to their site and they have a workaround.

Series four wire harness won't mate with a series five ECU though. The harness on the engine is the EM harness. The series five EM harness will not mate with the series four Front harness. The plugs and wire pinouts are extremly differnt. Not compatable. You need the front harness to mate with the EM harness, because the coil and CAS wires pass b/t the two.

 

the work around you are talking about is 100 bucks? right? if i buy that s5 engine it includes the full harness. like i said is there any other way to work around the OMP?