V70-98 strange problem.

anonim2007 · Post by **anonim2007** » 13 Sep 2007, 15:13

ok ppl, I really need your help; I'll try to explain this as clear I can, english is not my first language.

car info: V70 - 98 gas, non turbo, automatic, 222.000km (canada)

I start in the morning, cold engine, start at half key, idle OK, absolutely no problem.
Drive 4, 5 minutes engine warm up to normal temperature the problem appear: variable idle 800-1100rpm, when in driving loose of power, acceleration poor, very rough running, not able to goes up to 2000rmp. With car stopped, with drive stick in run (stop at traffic light for example) the same thing, with drive stick in parking engine looks OK, idle constant, rpm responding fast , acceleration looks good. Sometimes the check engine light goes on, sometimes no. Most of the times came on.
All this problems during 10-15 min, if I run more than that all came back to normal.
After I stop the car, if engine still hot, all runing OK, if the engine back cold the same problem.

Only one code P0204 Injector Circuit Malfunction Cylinder 4

What I changed or verified:

distributor cap, distributions rotor, spark plugs and wires kits - changed new
RPM sensor checked - ok
camshaft sensor checked - ok
injector no 4 checked - ok
ignition coil checked - ok

all this I actually replaced them with used parts, absolutely the same problems.

Pls, any ideas?
could be related with some transmission problems? gear box malfunction?

Post by **MadeInJapan** » 13 Sep 2007, 15:18

Hmmmm, 4th injector circuit malfunction....could be intermittent. Check the relay on the fan shroud...on the passenger side (front of the car)...it's the one that sends the signal to the injector. Could be bad solder....cold there's contact, as it warms, solder expands and causes a break, but as it gets even hotter, the expansion completes the circuit again. This is just a guess.
Maybe others will chime in with some other across-the-web diagnostics.

anonim2007 · Post by **anonim2007** » 13 Sep 2007, 15:39

it is quite strange,
where are this relay located?
cause I looked at wiring diagram and didn't figure an injector relay.
all the injectors have two wires:

one give them 12V from a junction point right after the fuel system main relay passing the 11B fuse

the other one came directly from computer, one wire for each injector.

edit: I remember to have one of this relay on 850, but on V70 didn't find it.

anonim2007 · Post by **anonim2007** » 14 Sep 2007, 09:31

no ideas? no one?

chuckcintron · Post by **chuckcintron** » 14 Sep 2007, 11:01

'Loping', or cycling up and down within an rpm range (800-1100rpm) can sometimes be caused by a vacuum problem, or a problem at the throttle body. I'd check the idle control motor.

Also, there's a chance that the mass air flow meter could be defective, sending the incorrect flow data to the ECU, and causing the computer to modulate the throttle incorrectly.

-Chuck

anonim2007 · Post by **anonim2007** » 19 Sep 2007, 18:14

did someone know where to buy a ECU (the main computer) for the above car?
preferably used, not new.

Klausc · Post by **Klausc** » 20 Sep 2007, 16:33

anonim2007 wrote:did someone know where to buy a ECU (the main computer) for the above car?
preferably used, not new.

Do not buy an ECU, that is not your problem. Go back to the #4 injector. Check the wires very closely, they may be shorting out where they go into the cap. Also clean the electrical plug while you are at it.
It gets very hot, so do this while the engine is cold.

Klaus