Rb26 Starting Issue

[jonathon]

Hey all,

I've got an intermittent starting issue which is driving me crazy.

I had the car tuned post injector, adjustable cam, and boost upgrade, and since I've had random starting problems.

Initially I thought it was due to the resistor with the injectors now being high impedance (was told they were low when In fact they were high impedance!) - the resistor is now removed, and the car was retuned.

Randomly the car still fails to start after a few days and multiple starts without issue. It cranks over but won't start/run.

I've checked spark - and spark is fine

Fuel is in the rail - so pump is working

Re-soldered the earth to the power transistor as it snapped easily - wondering if it was a bad earth

I think the injectors are working as they sound like they are ticking and I think I can feel them tick, however when unplugging the crank/cam angle sensor and plugging it in sometimes allows the car to start.

Any suggestions? Is the cas stuffed or something else?

Edited July 22, 2014 by jonathon

[scotty nm35]

Sounds like it's running rich and fouling the plugs. What injectors are they?

Could be anything really. You need to work through all the possibilities starting with the easiest. New plugs, check fuel pressure, change CAS with a known good one, etc.

What fuel are you on? Perhaps the cold start enrichment is out in the tune, or the coolant temp sensor is faulty...

[jonathon]

Hi Scotty nm35,

They are 550cc Bosch injectors running 98ron fuel.

I wouldn't think the cold start tune is out as the tuner is well experienced and it happens after driving it (ie 20min drive, park car in driveway for 5mins, then won't start again)

I'll take your advice and check those suggestions - hard part would be finding a cas 2nd hand and knowing its good!

[scotty nm35]

So hot starts are the issue? Have you spoken to the tuner? Even the best tunes can have unforeseen issues, they are tuning a complete map in a few hours, there are bound to be problems.

[scotty nm35]

DP.

[jonathon]

So hot starts are the issue? Have you spoken to the tuner? Even the best tunes can have unforeseen issues, they are tuning a complete map in a few hours, there are bound to be problems.

Not just hot starts - can happen cold too - it's weird as it can be running fine, then stop at the servo, and it won't run...

[XGTRX]

Is the cranking strong or weak when it struggles to start?

[jonathon]

It's cranking strong, I discovered the cas being damaged by the cam bolts and have replaced the cas.

Unfortunately the half moon locator on the cam is broken so I have been trying to start it by rotating the cas tooth by tooth until it runs with no luck.

I did get it to run however the timing was way out so I tried to adjust the cas by a tooth either way, but now I can't get it started at all again!

Any suggestions?

[scotty nm35]

You probably fouled the plugs. Try cleaning them with brake cleaner or carb cleaner, or drop another set in.

Might be time for a new CAS.

[jonathon]

Hmm - I've replaced the plugs and cas and still no luck! Gosh cars can be frustrating!

[blind_elk]

Without the half-moon key on the ex cam, there is only one position where the engine will start and run. Then you need to adjust the timing with a timing light.

[jonathon]

Without the half-moon key on the ex cam, there is only one position where the engine will start and run. Then you need to adjust the timing with a timing light.

I managed to get the car running again, briefly.

I gave up last night as it wasn't starting despite the position of the cas sensor. Even at the correct position lining up the broken key.

This morning I started it straight away without an issue, then checked the timing, and it was idling well. So I thought I'd test it.... Turned the car off, and now it won't start again!!!!!

Rechecked spark to all plugs, all good

Injectors still ticking away

I can smell fuel and can feel fuel pumping in the hose leading to the fuel rail upon cranking

Bloody won't start!

[blind_elk]

If it won't start hot, try giving it some, even lots of, throttle.

Poor hot start suggests a faulty ECU temp sender - try starting with temp sensor disconnected. Or poor setting up of cold start temperature compensation.

Other possible causes:

Fuel pressure - try clamping fuel return, or disconnect vacuum from FPR.

Slow cranking speed - battery, or starter iffy.

[jonathon]

If it won't start hot, try giving it some, even lots of, throttle.

Poor hot start suggests a faulty ECU temp sender - try starting with temp sensor disconnected. Or poor setting up of cold start temperature compensation.

Other possible causes:

Fuel pressure - try clamping fuel return, or disconnect vacuum from FPR.

Slow cranking speed - battery, or starter iffy.

I've tried clamping the fuel return and vacuum with no luck

I think you might be right with the hot start issue as it has started after leaving it for a few hours, but once warm I can't get it going again, even without the temp sensor disconnected.

Ecu diagnostics isn't showing a faulty sensor either.

So I'm guessing an incorrect start set up in the tune?

[jonathon]

Hey all - FYI if anyone is following the post.

The problem was corruption in the data loaded on nistune.

The tuner hadn't seen anything like it - at least it's finally sorted!