Engine problems

[Jr. Sparky]

We run our car on a Honda CBR 600RR engine with a race dynamics ECU. The engine has been acting up lately and refuses to start. Whenever we crank the engine it stalls mid-way in the process the ECU and other electronic equipment stop getting power. We did a number of tests.We used a oscillatory scope to check the crank position sensor, no abnormalities were found over there. The compression test gave us 152 148 142 and 150 psi in the first, second, third and fourth cylinder respectively which I agree is less but enough to start the engine. The injector spray test was done and they are working fine. We did a spark test and the spark plugs are sparking brilliantly outside. Thinking of it being a grounding problem I attached a ground cable from the engine block to the ground pin but to no avail. I noticed that whenever the engine stalled the ECU rebooted itself , to prevent that we gave the ECU power from another battery altogether but the problem persisted. The weird thing is that when all the injectors were disconnected the engine stalled once or twice but then it cranked continuously and the same goes for the ignition coils. I suspected that the starter motor wasn’t getting enough power due to a fault with wires so I made a new starter motor circuit and had another battery give power exclusively to the starter motor. Hence we had one battery supplying power to the starter motor, one to the ECU and one to the rest of the car and the engine still stalled and refused to start. Help will be really appreciated.

[Jr. Sparky]

We run our car on a Honda CBR 600RR engine with a race dynamics ECU. The engine has been acting up lately and refuses to start. Whenever we crank the engine it stalls mid-way in the process the ECU and other electronic equipment stop getting power. We did a number of tests.We used a oscillatory scope to check the crank position sensor, no abnormalities were found over there. The compression test gave us 152 148 142 and 150 psi in the first, second, third and fourth cylinder respectively which I agree is less but enough to start the engine. The injector spray test was done and they are working fine. We did a spark test and the spark plugs are sparking brilliantly outside. Thinking of it being a grounding problem I attached a ground cable from the engine block to the ground pin but to no avail. I noticed that whenever the engine stalled the ECU rebooted itself , to prevent that we gave the ECU power from another battery altogether but the problem persisted. The weird thing is that when all the injectors were disconnected the engine stalled once or twice but then it cranked continuously and the same goes for the ignition coils. I suspected that the starter motor wasn’t getting enough power due to a fault with wires so I made a new starter motor circuit and had another battery give power exclusively to the starter motor. Hence we had one battery supplying power to the starter motor, one to the ECU and one to the rest of the car and the engine still stalled and refused to start. Help will be really appreciated.

[Gaanja]

Did you try talking to Karthik? He would be the best person to tell you whats wrong.

Sent you a PM with my number. Call if need help

[Jr. Sparky]

I am in Bangalore ,talked to kartik. We ran a few tests and decided to change the starter motor. Gonna fire up the car tomorrow, lets see what happens

[Fulcrum]

Does the engine fire ? As in does the process of combustion start and then the engine dies or it just doesnt start. Does the engine crank freely when you remove the plugs ?

-
Inder Sehra
Orion Racing India.

[Jr. Sparky]

No the engine doesn't fire, it just stalls while cranking and yes it cranks freely when i disconnect the spark plugs

[Fulcrum]

If it is as you say , then it must be a starter system problem , the ECU's got nothing to do with it . Check the wiring ,replace the starter motor with a spare if you have one .

-
Inder Sehra
Orion Racing India.

[Jr. Sparky]

We put the spare starter motor, checked the wiring and still no improvement

[TMichaels]

Sounds to me like a timing setup problem. We once destroyed our starter gears with very early ignition angles during cranking which lead to a backward turning engine during cranking!
Given the fact that the engine cranks fine whenever you are "avoiding" a combustion in the cylinders by either disconnecting injectors or ignition this seems to be likely.

Regards,

Tobias

[DcooL]

Check your ground side wiring on the coils. Seems like you may be shorting something only when the coils are plugged into the cylinders, and the ECU coil drivers do not seem to like this. The ECU rebooting led me to believe so, the starter not cranking points to an intermittent short. Make sure your plugs are clean tipped

You may also just not have enough juice to be able to crank against the compression, since you say the engine cranks without compression. Else it may also be the issue Tobias mentions - though its a long shot.

[Gaanja]

Hey Dhruv,

If you guys are still in Bangalore and have no tyet sorted out your problem, give me a call and let me know where you are. I'll try and drop in tomorrow after work and help you guys out.

[Jr. Sparky]

I've already checked the grounding and nothing shorts when both the injectors and the spark plugs are connected simultaneously. So, i'm gonna go with Tobias and fiddle with the spark advance. Will post the results tomorrow.

[Jr. Sparky]

Its working now. There was an issue with the spark advance :-) thanks a lot people

[TMichaels]

You are welcome http://fsae.com/groupee_common/emoticons/icon_smile.gif

Regards,

Tobias

[AKAY]

How many degrees you advanced?