4AGE help

[NVD-086]

Sorry for creating another "my 4AGE isn't working" thread guys but i'm having trouble on my install into my 86, The problem is from what we can gather the main injectors aren't firing the motor is starting, running for about 5 seconds but then dies out.. We unplugged the main injectors and it changed nothing.. (the motor fires first crank every time) The motor is a JDM big port out of another 86, the motor was running when i got it, but the guy we bought it off was only oh.. 17.. and well. he cut a few wires when taking it out.. so yeah, um any help would be appreciated.

(Yes, I've searched but found nothing of any real use)

Thanks Scotty

[abently]

From the vague detail you've provdied it sounds like the ECU may be having issues communicating with the Distributor / CAS ? To continue spark.

[The Real Roadrunner]

sounds like the fuel pump isnt keeping the rail full. injectors generally work or dont work, so i would check to see if the fuel pump open circuit relay is wired correctly and if not fix it.
you can check with a test light you should have power during cranking and it should hold it on whilst running.
if the engine dies the pump should still run for 3 secs afterwards.
hope that helps not confuses

cheers
linden

[roadsailing]

I would say its running off the cold start injector, unplug it and see if it makes any difference.

[Talasas]

Cold-start injector only runs during cranking, so I don't understand how it was running at all with the main injectors unplugged...

I'd be looking at making sure that the fuel pump is working and working well. Also, a good rough way to make sure your fuel pressure and volume is staying where it should be is if you go to start it a few minutes later and the pump has to pump fuel again to build up pressure again.

[roadsailing]

Cold-start injector only runs during cranking, so I don't understand how it was running at all with the main injectors unplugged...

wrong actually, it is controlled by its own thermostat, and turns off when the engine reaches a set temperature. it is turned on by the start signal, but turns off based on engine temp.

it might be the fuel pump relay you are thinking of, it is triggered by two signals, being "engine cranking" and "engine running"

it could only be running off the cranking signal, power your fuel pump manually and see if it makes a difference.

[NVD-086]

Hey guys, have some new info, we've been playing around with the ol girl tonight, we discoverd when we unplug the Vaccume sensor the engine runs on no worries, revs and what not, second the vaccume thingy is plugged in, the engine dies. any one heard of this?

[roadsailing]

havent heard of that, that is wierd.

post a pic of teh sensor you are talking about

[NVD-086]

Yep, here u go.. also have an audio clip of the motor runnin.. if it helps any one at all

[Talasas]

What an odd looking MAP sensor..... it doesn't look like the other 4AG(Z)E ones I've seen.

[Cuzzo]

Thats the bigport MAP sensor, hence the huge yellow plugs it uses. The part numbers on the smallport 4age and bigport 4age map sensors are different. Maybe its seeing the wrong value at the ecu because its the wrong map sensor for the engine. Have you got/tried another?

[NVD-086]

Nah, havnt got or tried another, I'll hunt one down in the morning before work, and see how i go,

[NVD-086]

ok, so the cars pretty much on the road now, my question is, do i need to run a Vacuum sensor? cause the engine is running OK with out it.. bit missey around 2 thousand rpm, but revs fine.. so yeah should i worry about using it?

[hemi twofifteen turbo]

You should find the problem as it might free rev fine but as soon as you put it under load it might be a different story. Basically without the map sensor the ecu doesn't know the difference between when your free revving or when your actually in gear and driving (under load). If while free revving there is no black smoke (rich) then at the same rpm's while driving where the load is much higher and the fuel demand much greater your going to be bouncing and popping down the street i'd assume. Also economy might be an issue too. Try and see if you can find the problem, borrow a map sensor off someone and see if that fixes it, Otherwise a map sensor off a late model toyota might work (I am using one but have yet to road test it)

[rxbenny]

what is the part number for your MAP sensor i will comp0are it to my bigport

the map sensor i required, and how much of a cut loom is it and why should the guys age be an issue? you bought it didnt you?