H6 is pissing around again

[Guest keltik]

Same problem as last time. Hesitation getting on the throttle and an annoying "super sensitive" throttle at low rpm.

Hard to describe the problem, so heres my best shot: Changing gear, instead of getting a nice smooth brrrrrrrom when back on the gas, it f***s around and lurches a bit then settles down into smooth acceleration.

Also when cruising out of town at 50kph the other day in 5th, it was as if the smallest touch of the go pedal resulted in me breaking the speed limit. Had to keep going on and off the gas or just change down to 4th.

Idle also started playing up. The idle speed would quickly hunt between about 700rpm and 850rpm...instead of the nice smooth 650 i used to get.

Unplugged the TPS - car ran perfect. Was like a bloody miracle had taken place. It was 1000% nicer to drive.

Tested TPS and got a nice smooth curve from about 20ohm down to 5ohm. Out of ideas.

[Joker]

cruising at 50 in 5th - yes i have seen this in action!

4th if I am lucky - blimin torque hog

[NotAWhiteGTB]

 JoKer said:

cruising at 50 in 5th - yes i have seen this in action!

4th if I am lucky - blimin torque hog

Your just jealous ;D

See if you can find another TPS to try out to see if your problem continues just for 100% peace of mind that is isnt that.

Also does it do this when its cold or all the time? If its running like poo's when its cold i would suggest that it is running to lean in warm up, which you could reset your ecu to see if that solves the issue. Although, when you say it ran better after unpluging the TPS i doubt it would be that.

[Guest]

not a vacuum leak at all? could be a random hose off somewhere?

[Guest keltik]

Does it hot and cold buddy

Seems to be worse when cold tho. f***ing thing. Guess i should solder my SSM wire back together and talk palmfeilds into letting me borrow their scanner for an hour.

ps. dont you just love how much s*** our engines will run without? No TPS, IACS, MAP sensor, IAT sensor, O2 sensor and the car still starts, idles and drives.

Will check for vac leaks but its only got 2 or 3 vac lines so that wont take me long.

Edit: Wait a minute....I reused my intake manifold gaskets when i did my gearbox conversion....now im wondering if one of them could be leaking.

[Guest boostcut]

spray some brakeclean on them and find out?

[wrx_lou]

Is there anything brakeclean cant do?

[Guest boostcut]

clean brakes! its actually shit for cleaning dust out. you are better off using hot soapy water for that.

[Guest]

Iv had a few bad tps on h6's recently. You cant pick it up on a scan tool or a multimeter but with a scope you can see that it fluctuates enough to cause a problem. It will also cause strange auto shifting when cruising.

[Guest]

sounds like a vacuum leak spec with the hunting cant remember what we used to spray but if sprayed on the suspect gaskets and the revs rise theres ya culprit

[Guest keltik]

Will throw it on a scope and see what comes up.

[Guest keltik]

Stuck TPS on a scope. It gave a nice clean sweep with no significant noise. Intake gaskets are sweet, Pulling a good vac at idle.

Car only seems to have this problem intermittently. I dont think im going to be able to track it down without a significant cash investment so have resorted to plan "el-cheapo".

When the problem rears its ugly arse - unplug the TPS and drive happy.

[nzkaosnz]

hmmm.

try replacing TPS

If its intermittant, then it may behave perfectly for a scope.

I did that on mine, then took to the old one with dremel, cutting top off. Turned out the copper track had corroded off the PCB.

Also, do you have an AFM?

[Guest]

Scope TPS input at ECU

sensor itself may be fine but wiring to ecu could be an issue

Also check Mv between engine block and battery -ve, max you want is 100Mv

Let me know how ya get on

[Guest keltik]

Havnt had chance to get the scope in the car. Checked resistance between engine block and battery - its around 10ohm with engine running. On the 200mv scale i get a reading of around 8.5 to 12.0

Car behaved rather well for most of the last week but turned into a real prick on saturday when we had heavy rain. Dont see why as none of the engine bay gets wet in the rain.

[Guest boostcut]

heavy rain means moisture everywhere... i would have to think something up with the ecu , you can send it away and have it checked for free, at anything electrical nelson

[Guest]

I have a good H6 TPS here if you want to throw it in and see if it make a differance. You pay postage and you can borrow it for a couple of months.

[ODB]

have you tried resetting the ECU?

I might have missed it but......

[Guest keltik]

 ODB said:

have you tried resetting the ECU?

I might have missed it but......

Yeah tried resetting the ECU a couple times. I can tell its been reset as the fuel trims are all over the show for the first couple drives afterwards.

I'll hold off on trying a new TPS until ive checked the TPS wiring.

Had the ECU out on sunday to put my speed cut controller back in and it was all nice n dry. No signs of water spots on the case or around the area.

[ODB]

any exposed wiring around the tps at all?

Water might not be gettiing in the ecu but could be moist on wiring for the tps i suppose

[Guest]

 keltik']

[quote name='ODB said:

have you tried resetting the ECU?

I might have missed it but......

/quote]

Yeah tried resetting the ECU a couple times. I can tell its been reset as the fuel trims are all over the show for the first couple drives afterwards.

I'll hold off on trying a new TPS until ive checked the TPS wiring.

Had the ECU out on sunday to put my speed cut controller back in and it was all nice n dry. No signs of water spots on the case or around the area.

Fuel trims will be zero upon full reset, soi if car is driving weird. Then there is an issue that the trims are trying to compensate for

[Guest keltik]

Well by fuel trims, i mean throttle response feels different and the idle takes about 30 seconds to get back to 600.

Any ideas what these problems could be? Does the SSM have the ability to display fuel trims and ignition advance in real time?

[Guest]

ssm will display short and long term fuel trims in real time ( cause that what it's doing )

Long term is the learnt data and takes time to adjust (compensates for wearing components ie injector flow rates)

Short term is instant trim as AFR is incorrect

To explain real basically its the short term trim over a period of time that creates the long term trim

[Guest keltik]

Ok, time to re-solder the SSM line and go see palmfields.