Which compression tester gauge?

[mukumu kurubushi]

Hi guys,

My car has developed a poor starting idle :( I'm having a dig around on the internet and doing some experimenting...

Im going to do a compression test first just to rule out the possibility of the engine being on its way out. Halfrauds sell a gauge, does anyone know if its any good?

http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_19 9553_langId_-1_categoryId_165557


Thanks

[Prof]

You can do a compression test with these gauges, but it's hard to get the peak reading. You need to hold the pin in while you crank the engine - so will need 2 people for the test. Watch the gauge - it should give 3 evenish peak readings.

Like I say - it's not ideal, but will give an indication.

Poor idling can be down to quite a lot of things, does it get better as the engine warms up ?

What are the symptoms ?

[mukumu kurubushi]

Hi Prof

It does idle better after the engine's warmed up. A bit on the low side (~600rpm) but its stable and has always been low since i bought it.

I'd been starting the car in neutral and (as far as i know), this is the only time its had this problem.

I read about the cold start assist and i don't fully understand how it operates, but it could be a likely cause since I started the engine this morning in gear and clutch pedal in (bypassing it??) and it started perfectly (revved up to 2k, then dropped down and held a solid 1200rpm idle).

I'm trying out a few different startup scenarios to try and pinpoint when it happens.

The compression test is also for my own peace of mind since i never got one done when i bought the car :spank

[Prof]

Starting it in 1st gear (well with clutch down), will disable the AWS (Automatic Warmup System) on a Euro/UK car with stock ECU. But your's is an import and I don't know if it has the same setup.

I vaguely remember seeing a commander in your car - is it running PowerFC ECU ?

One thing that might affect initial startup is the fuel pump relay.

Depending on whether it's a warm or cold start, the pump resistor/relay is set to deliver full 12v to the fuel pump on startup, and this switches off after a minute or so, dropping the voltage to approx 9V. If you short out the yellow 2 pin connector near the drivers shock tower, it forces the pump to 12v all the time - if there is an issue with the resistor circuit not working correctly, you can short this 2 pin plug, and then check pump voltage at the back - connector for the pump is under the metal plate (left hand side as you look into the boot) - you should see 12V on the thicker 2 wires.

Another cause of idle/startup silliness is poor TPS adjustment - worth a search on how to set this up correctly.

Finally, check that you've no error codes if you are on a stock ECU - if you are on a PFC - it probably tells you if any sensors are down - I think it also tells you if TPS is ok

[grinder]

was this the orange beasty at rotorstock ??

[mukumu kurubushi]

I didn't think I had AWS. It never did the 3k startup ceremony thing, but starting with clutch in seemed to help somehow.

I'm running a stock ECU, haven't fitted the PFC yet but i remember i was testing out the holder for the commander and forgot to take it out!! haha :o

I did wonder if it was fueling-related, possibly injectors?. My car has a little white smoke on startup which goes away when its warmed up (heard this is normal). But it does backfire a lot and smells quite funky. Also stinks quite heavily above 3500prm with the window down. Seems odd for a stock-ish engine?


was this the orange beasty at rotorstock ??

Yep that's the one. Or yellow, or mustard depending on the light!

[ashc]

you could stick the pfc in (takes a few min), turn ignition on but not engine, and see if any sensors are shot using the commander (settings/etc/sensor check). initialize the map with the commander (if it isn't meant for your car) then do the idle learn routine (start engine, wiat for idle to settle, few minutes later turn on rear heater, wait for idle to settle, few minutes later turn on lights, wait for idle to settle, job done)
see if that sorts it?

[Prof]

If you've got the stock ECU and it's affected by whether the clutch is down that could suggest the TPS is in need of setting. Once it's warmed up, if you increase rev's gradually from idle, does it hit a point where it 'bounces' up and down ?

If that does happen, then TPS needs adjusting, or you've a dead spot on the TPS variable resistor.

[TiddlesRX7]

My car has a little white smoke on startup which goes away when its warmed up (heard this is normal). But it does backfire a lot and smells quite funky. Also stinks quite heavily above 3500prm with the window down. Seems odd for a stock-ish engine?

You sure your not talking about my car! Its sounds very familiar.

you could stick the pfc in (takes a few min), turn ignition on but not engine, and see if any sensors are shot using the commander (settings/etc/sensor check). initialize the map with the commander (if it isn't meant for your car) then do the idle learn routine (start engine, wiat for idle to settle, few minutes later turn on rear heater, wait for idle to settle, few minutes later turn on lights, wait for idle to settle, job done)
see if that sorts it?
I might try this with mine just to see what happens.

[mukumu kurubushi]

Im not sure if im getting the "bouncing" you describe Prof. Tried it tonight and all I get it a lot of popping and spluttering.

I'd love to plug in my pfc just to see what it would do but i don't know enough about tuning to be confident to do it by myself!

[pdtaylor18]

Might be one of the Primary injectors faulty chucking in too much fuel.
Is the PFC a FC3S specific? If it is let me know as I have one I have yet to install and wondered what sensors you have with it.

[mukumu kurubushi]

Hi Pete,

It is FC3S specific. The AP Engineering one. Although mine only came with a wiring loom harness, no sensors.

From what i've read on the US forums... it's just an FD powerfc that fires the trailing coil differently (don't know why it needs to :3Confused). So i've still to find a 3 bar map sensor and an FD intake air temp sensor. And also some resistors soldered into the harness if you run low impedence injectors.

I've had a read up on adjusting the TPS... looks like a busy weekend for me!

[L18M]

was this the orange beasty at rotorstock ??

not sure how many mustard/ yellow/ orange bomex kitted fc's there were (actually only one :Giggle) but think if u just say the one with the HUGE gear knob then EVERYONE will know which fc it is :Giggle

[L18M]

I'd love to plug in my pfc just to see what it would do but i don't know enough about tuning to be confident to do it by myself!

not that simple as if u just plug in ur pfc, you have 2 options:
1, run the map installed already (which might not be best as not sure what it was mapped for)
2, reset / run base map which will be really rich AND you have to 'set' the idle (ie leave engine runninf for 10 min, then switch on fax to max and run for 10 min then air con for 10 min etc)

so dont think will help much :xconfused

[mukumu kurubushi]

not sure how many mustard/ yellow/ orange bomex kitted fc's there were (actually only one :Giggle) but think if u just say the one with the HUGE gear knob then EVERYONE will know which fc it is :Giggle

Haha.. yea i didnt have any problems finding my car among the hordes of FDs :p

Well, after starting with the clutch in for a while, and my car seeming fairly happy, I tried for the past couple of days starting in neutral. And this time it was idling better! :confused::reallymad:2Confused of course it would!!

Until this evening, when it started and instantly died. Tried starting it again, and it was idling under 1krpm. Gave it a blip of the pedal and idle moved up to 1500rpm. For about 30 seconds then dive bombed back down to 500.

A fair bit of white stuff coming from the rear end... Mostly condensation and water sitting in the exhaust (raining) but a little bit of smoke mixed in, which smelled to me kind of oily, though im no expert. It goes away after driving for a bit and the engines warm.

Think as Prof says the TPS need properly adjusting, which i'll have a go at this weekend.

Slightly concerned/paranoid about the white smoke (maybe a hint of blue) as it's my first rotary and the results from my internet searches seem to suggest its either A) completely normal or B) time for a rebuild :2Confused :rollin

What do you guys think?

[TiddlesRX7]

The smoke sounds normal to me. they all seem to do it at first. As long as its not doing it all the time I wouldn't worry too much about it. The idle though could be one of many things. Vac leak, TPS, Thremo wax thingy etc etc.

[Prof]

Small amount of blue and even white is normal on startup - blue=oil and white is probably fuel - but if it smells sweet then it could be coolant - but it's most likely fuel - they are gassy when they start.

[mukumu kurubushi]

Did a compression test today which i think went ok, got 3 strong needle bounces on each rotor. Rear was reaching around 100psi, front a little lower, but still well into the 90s. I took some videos so you can see.
http://www.youtube.com/watch?v=wmS2YzD1cB0

http://www.youtube.com/watch?v=YnnlPqMSrAM

TPS adjustment made a slight difference, but I've yet to try a proper cold start. Still idles quite low (500rpm).

Now, when i drop the clutch pedal, the revs used to dive down to almost 0 and come up again. Now, it drops to about 900rpm does a little bounce and then drops to 500.

[mukumu kurubushi]

Took the car out for a drive this evening to see how it starts from cold. Seemed much happier. Think the tps adjustment has made the idle seem a bit more consistent, if a little low.

Though i think that might be down to an exhaust leak. The fumes i smell in the cabin on start up and after boosting i think are exhaust fumes. So think that's gonna be the next place to look.

Also, noticed my front spark plug was covered in carbon deposits, which i think means too much fuel? probably normal for a rotary i guess! :p