4age not revving

[driftkid23]

Hy guys never thought I'd be one of those people that ask questions on a forum but I'm seriously out of ideas.


car - ke70

engine - jdm bigport 4age

problem- wont rev

ok so Ive just bought a 4age ke70 from a friend that just seems to not run right, it'll idle just fine but as soon as you blip the throttle it does and starts to stall like its sucking in too much air and not supplying the fuel for it.
but if you disconnect any injector and rev it, then it revs fine just on 3 cylinders. The moment you plug the injector back in it doesn't rev at all once again.
If you hold the throttle open the minimalist amount you can allow it to slowly pick up to 6000rpm but the moment you go any further throttle it just dies and goes back down

So far I've changed fuel pumps and upgraded the fuel lines to 8mm
different injectors
Fuel regulator
about 5 maf sensors
Igniter (changed to a camry one)
tps
Coil
cleaned all earths and added in some more
3 different ecus
changed timing numerous times (seems to slightly prefer to be at 25 degrees btdc) also was set properly with lining up the cams and crank.
looked everywhere for air leaks
re-sealed the iac (blocked off)
Also done test from the ecu to to most the wiring in the engine bay and can fault it.

I've looked everywhere on the forums and I couldn't find anything (with the actual end result at least)

also my friend said it was running fine in a defected shell then he put it into another shell and that's when it began

Plz someone halp

[Matt]

Joe had a similar problem not that long ago and it turned out to be the dizzy. If you arch out the spark plug lead on the rocker cover does it still do the same thing as disconnecting the injector?

some models have an injector resistor which can be determined by the colour of the injectors too

[Matt]

http://www.ae86drivingclub.com.au/forums/showthread.php/83129-4AGE-running-problem-Got-many-stumped-(AE82)-Electrical

that is his thread with videos

[tottacrolla]

Diagnostic ?
Is it the same if you disconnect the TPS ?
Cam timing correct ? (Don't trust the bottom pulley for the TDC mark as the rubber insulator in the pulley is known to break up and when this happens the outer part with the timing marks on can end up in any position relative to the crank.)

[Javal]

Check fuel flow.

[driftkid23]

Thanks guys for the replies!
mine basically runs like it does in those videos! It's just super weird when I rev it then it just dies flat which I didn't see in his video if he revved it at all.

fuel flow is good, 40 psi at the rail. Ill try getting another dizzy tomorrow if I can find one!

i was trying to get it to show up codes but for some reason I couldn't get it to work :(

i took the covers of to check the timing because I've been fooled before haha

tps does seem to make a difference when it's disconnected


i believe that it's got stock injectors (grey) and I'm pretty sure it's only the pink top ones that need the resistor pack (correct me if I am wrong)


ill check tomorrow if I disconnect the spark plug tomorrow! Hopefully that's it because its testing my patience hah

thank you so much everyone for helping!

[Matt]

Flow is different from pressure, you can have good fuel pressure but poor flow which will cause issues under any sort of load. If you have changed the fuel lines you are unlikely to have flow issues, but keep this in mind to check later on.

The grey injectors 100% don't need the pack I was referring to.

Have you got a check engine light connected? If you don't have one hooked up, it is worth doing it. Ignition power to one side of the globe and the earth side to the W pin on the ecu. That might shed some light on things. Just be careful you get a low wattage globe as the ecu doesn't like the high wattage ones.

I can never remember what plug it is on the bigports you have to connect a fuse into to get the car into diagnostic mode. But generally if you earth out TE1 to E1 it should cause the light to blink, you can splice this at the ecu plug if neccessary, but leave enough on it in case you cut straight through.

I've seen ecu's fail and cause misfiring and they wouldn't go into diag mode either. A couple were obvious with leaking capacitors, but a couple not so obvious.

Let us know when you find the cause, but my thoughts would be Dizzy or TPS related as you have done just about everything else.

[driftkid23]

Well that sucks, I wrote out a massive reply and my Internet went to shit and lost it.

yeah it's got brand new 8mm fuel lines though out and I have taken apart everything to ensure there is no obstructions within!


I don't have a a light connected but I used my test light as one through the pinouts, I've hooked up a switch between those pins so I can flick it and turn it into diagnostic mode


so far I'm trying to remain hopefully on the dizzy at this point because I've already tried tps and checked wiring from engine bay to ecu to ensure that's correct throughout and seems fine :(




If it isn't a dizzy I honestly think ill be all out of ideas!

[dove grey 64]

I've heard of similar issues and it came down to the dizzy not being wired up right, idles fine but wont rev. Normally two wires had been put on reversed

[driftkid23]

Just found this on youtube and its exactly what mine is doing but I can't seem to track down what he has done to fix it :( https://m.youtube.com/watch?list=UU5nC53iH1zpSjUisivprTAQ&v=ag0eAkbXdnw

[Big T]

Does it do it only when cold or hot as well?

[driftkid23]

All the time regardless of temp just found this to be the end result of that guys problem after some stalking but I can seem to figure out what he means, I don't know if I'm dumb or I'm super tired from 4 solid days on this bucket http://forums.club4ag.com/zerothread?id=70812&page=2

[tottacrolla]

Is 8mm fuel line an upgrade ?
Anyway try this easy test: restrict the fuel return line from the regulator, brake hose clamp or locking pliers are good for this.

[driftkid23]

Nah I just changed it seeing as the Carby lines are small and I wanted to make sure that I wasn't having any flow issues even though I know the Carby lines are plenty enough for a 4age. Tried that the other day and nothing :( this car is cursed or something

[Matt]

Do a compression test on it..

[driftkid23]

Comp test came up good,
Just had the timing gun on it whilst revving it (the very minimal amount of revs that I can get out of it)
even when I unplug an injector and I can rev it I noticed the timing still doesn't change. I checked all there wires to ecu for resistance and the dizzy is giving me pulses of resistance for spark and cas timing... Hmmmmmmmm