SPFI Throttle Sensor Test

[tweety]

Ok, got a few issues including the engine not starting now but more on that later.

 

Short update- have ordered another 2 MAF's from the states to Oz.  It appears though that it could be operating ok.

The SPFI TPS test has been completed. I'll try to simplify this as best I can. There is a problem.

According to the detailed test this was done as per proceedure.

Step1/  Checking continuity between terminals A and B

action-  checked and ok.



Step2/  Check for continuity after inserting a thickness gauge between the stopper screw and stopper.     Using an ohmmeter, check that continuity exists between terminals A and B, when the throttle is fully closed, and that no continuity exists when the throttle is fully opened.

action- checked and ok

Step3/      Insert a feeler gauge (thickness gauge) of 0.0122 in. (0.31mm) between the stopper screw on the throttle chamber and the stopper (this corresponds to the throttle opening of 1.0 degree). Ensure that continuity exists between terminals A and B.
     
    Insert a feeler gauge (thickness gauge) of 0.0311 in. (0.79mm) between the stopper screw on the throttle chamber and the stopper (this corresponds to a throttle opening of 2.5 degrees). Ensure that continuity exists between terminals A and B.

result- .31mm feeler ok, .79 feeler not.  Adjustment requiredas per instructions which are

     
   " If above specifications are not as specified, loosen the throttle sensor attaching screws, then turn the throttle sensor body until the correct adjustment is obtained."

Step4/  "Throttle Opening Signal"

Check continuity between terminals B and D, then terminals B and C

    Using an ohmmeter, measure resistance between terminals B and D, then between B and C (changes with the opening of the throttle valve).
     
    The ohmmeter should read 3.5-6.5 kilo-ohms between terminals B and D.

Result- B and D is 4.7 ohms- ok.

Result- B and C is 0.5 ohms throttle closed- ok (less than 1.0).  Throttle fully opened - 4.9-5.1 ohms....far in excess of 2.4 ohms.



Now interesting enough the reading of 2.4 ohms (its suppose to vary with increase and decrease of throttle) occurs at half throttle right where the dead spot begins.

I assume this sensor is RS!

The battery has been on trickle charge.  Took it for a test run. The engine certainly started well and idle was nice and not as high when first started as it was previously- good.  Got it home and revved it and it misses beyond half throttle!!! bogs down, loses revs.

Then the starter motor strained to turn the engine over. Connect the charger to the battery and it indicates fully charged.  Turn ignition on and eCU connectors and find ECU code is 3 long flashes   in addition to the 5 quick flashes it normally has for model designation.  Check the trouble shooting manual and cant find 30 in the codes but 31 is throttle sensor.

So has adjusting it to achieve the second feeler guage setting upset the sensor for higher revving?  Gee....I'm at a loss.  opinions?

[naru]

There should be NO continuity w/the .79mm feeler.

 

You seem to have dropped a decimal point in the second part.

B&D should be 4.7k or 4700 ohms

B&C should be under 1000 ohms,throttle closed

B&C should be OVER 2400,throttle open full(about 80% of B&D,about 3700 in your case)

 

B&C should change continously thru the full range of throttle movement.

If not,TPS is fubared.

 

I would make sure B is well grounded and D has 5 volts.

Don`t see how any minor adjustment of the idle switch would greatly affect the throttle opening signal.

 

Code 31 is only for open or shorted TPSs.An out of range one won`t set the code.(wiring problem might)

Code 35 maybe?

[tweety]

There should be NO continuity w/the .79mm feeler.

 

You seem to have dropped a decimal point in the second part.

B&D should be 4.7k or 4700 ohms

B&C should be under 1000 ohms,throttle closed

B&C should be OVER 2400,throttle open full(about 80% of B&D,about 3700 in your case)

 

B&C should change continously thru the full range of throttle movement.

If not,TPS is fubared.

 

I would make sure B is well grounded and D has 5 volts.

Don`t see how any minor adjustment of the idle switch would greatly affect the throttle opening signal.

 

Code 31 is only for open or shorted TPSs.An out of range one won`t set the code.(wiring problem might)

Code 35 maybe?

 

 

Ok NARU.  you ar e great help.

 

I noticed that when the TPS is adjusted I can get the 5000 ohms down to 3700 what it should be on open full throttle.  Then when I checked B and C it was 300 ohms. So all good there.

 

B and C changes continuously as you said up throttle and own.

 

D has 5 volts- all good there.

 

B is not grounded.  I used the multi meter on the manifold and on B and it has no resistance?????

Also, the ECU now has codes 31 and 35.

 

Would the codes come about because the TPS has now been tampered with??  Why wouldnt B be grounded? Could it be that B not being grounded could be a wiring issue and hence the codes? I see code 35 is canister purge- I dont have any anti pollution equipment at all on my EA81. Being a trike I dont need it her ein my state in Oz.

[jono]

so, you may need to see if you or Scott wired anything into canister purge pin on ecu - may need to put a resistance between pin and ground or even just a pollution solenoid hooked up, just not switching anything.

[naru]

No resistance (0 ohms) is good here.Infinite resistance is bad.

If infinite,I would pull the ECU plug and check continuity between the relevant pin and B.

 

I recently had a problem w/poor connections at the ECU myself.

[tweety]

mmm, I recall there was one resistor added near the bottom of the throttle body.  Will check that cause I think there were two wires that were left free.

 

Ok Jono- you have given me some checking to do. will be a while before I get around to it and report back.

 

me think Naru, some crc in all the connections is the way.

Edited September 18, 2013 by tweety

[l75eya]

Tweety, as you are the grand Master wizard of all things spfi from your trials with the trike, is there a way you can please refresh the pictures in this thread? I'm scouring the boards learning about the spfi system trying to diagnose a throttle stumble. Your threads are invaluable.

[Crazyeights]

SPFI hard to find throttle stumble (especially if it's better when cold) sure could be a flaky TPS. I chased one of these on my car for quite a while.  It's a night and day difference once it's running properly. Good Luck!

[maozebong]

a big tip to spfi troubleshooting, test all these values at the ecu, and wiggle the harness section/connectors by the battery. i find at least 2-3 harness problems on spfi's a year that come in my shop. alternatively, backprobe at the engine harness connector. 

the engine harness is frequently unsecured and flexes when the engine moves. causes alot of intermittent engine lights and issues. 

[l75eya]

Thanks for those two tips guys. I will be scoring further to find which pins to check and so on and so forth. Gotta find my factory manual somewheres.