Cas Problems?

[Kwyjibo]

I have an R32 gts-t running a slightly modifed rb20. Had an interesting issue today, was driving along when all of a sudden car will not rev and eventually stalls, couldn't get the car started. Checked for air and fuel, no blockages and fuel is coming back out the return so only possible issue is injectors or spark.

I come back to the car 2 hours later and it starts, I drive it the 2 minutes back and after running it another minute or so it cuts out again. At first I think its heat related(ignitor pack) so I leave it for about 4 hours till everything cools down and start it up, after a few minutes it dies again, but starts running again after a few minutes. I took it for a drive and it feels ok until about 3000rpm where it defintely feels sluggish and struggles to build boost. As I turn into my street it dies again. I checked spark and it has none.

2 Questions:

I checked spark by having the spark plug against the head, does anyone know if this is a good enough ground to check it?

Do people think this is a CAS problem, I've got a feeling it is since it was running as if timing was severely retarded.

Any help would be great!

[SKYPER]

My guess is CAS or TPS.

As far as I know, to test CAS, can mark position of CAS and pull CAS off and I think turn CAS shaft with ignition to 3 (just before turning engine on) and see if injectors click. You'll probaly get a CAS error code on ECU and need to clear CAS error code on ECU by pulling the battery terminals off, pressing brakes to remove any left over charge.

First symptoms of a Faulty CAS = CAS error code on stock ECU and engine is harder to start. I gather when CAS gets worse, stalling, etc. But never had a faulty CAS on engine for that long to find out. If no CAS error code on ECU, oscillioscope is a good tool to use to check CAS.

TPS is another sensor that can cause engine to stall out of the blue. Wiggling TPS plug can somtimes make engine stall or if TPS is misadjusted (not touching idle contact), can cause rpm needle to drop below idle and sometimes not recover when load is applied to engine from aircon, light's, etc + backing off throtttle quickly or going up a hill + backing off throtttle quickly. Or TPS is faulty (low voltages).

Edited March 6, 2010 by SKYPER

[Kwyjibo]

I'm running a Power FC so I don't get error codes:/ TPS voltages are fine ranging from 0.4 to about 4.7v.

I'll test the CAS tomorrow and see how I go. Can anyone confirm about being able to ground the spark plug on the head? I'm not keen on stuffing around with the CAS and igniter only to find it is the injector wiring that is stuffed. For further information I'm running GTR injectors with a resistor pack, I did the wiring myself so it is a possibility that over time my shoddy workmanship has come apart:p

[W0rp3D]

Dont rule out fuel just because its coming out of the return line, the fuel pressure reg is before the return line, if the reg is not holding pressure in the rail then all the fuel will just be going straight back into the tank with very little if any making it through the injectors.

[tridentt150v]

Grounding it on the head is fine, if your not so sure or are having trouble with it, use one of your jumper leads [assuming you have one].

I put one end on an earth point and the other holds the spark plug. That way you can hold the plug up in a better position and don't have to touch it on the motor at all.

[PROXIMITY]

yes ^^^^

I have seen this exact problem with fuel pump, cos its shagged ( if is ) soon as it heats up its too hard for impeller to spin, hence after leaving your car for a while it starts again, and also not wanting to go past 3000rpm.

[Kwyjibo]

I would tend to agree about fuel pump however the pump is only 6 months old. Also I've now found its not only a heat issue. It even happens when cold sometimes.

[jjskyline79]

When it happens next time take the fuse out for the fuel pump turn the ignition a few times then replace the fuse

If it starts first time its flooded and the O2 sensors knackered or an injectors stuck wide open

If its not then I would say AFM on its way out other then that i would need the car and beer to work out what it is lol

[Kwyjibo]

Yep its defintely not AFM as I still get an AFM reading and I've been able to run the car with a dead AFM just by holding revs, at the moment holding open the throttle does absolutely nothing.

Also there is defintely no spark when the car is dead so I am 99% sure the CAS or the igniter is the issue now. I'm thinking CAS since timing is clearly way out when it is running.

Edited March 7, 2010 by Kwyjibo

[PROXIMITY]

When the car is running, have you unplugged the AFM to see if it runs the same or changes ?

You can still get a reading from a faulty AFM.

[MBS206]

Start with the non factory shit... IE YOUR WIRING!

[Kwyjibo]

When the car is running, have you unplugged the AFM to see if it runs the same or changes ?

You can still get a reading from a faulty AFM.

Tested that today and it runs when AFM is unplugged if I give it a bit of throttle, then once the car died again I tried the same thing and it wouldn't fire up at all. AFM also shows a 0.5-1v reading if hold open the throttle and crank when the car is dead.

Start with the non factory shit... IE YOUR WIRING!

I'm trying a different CAS and ignitor tomorrow but if that fails then I'm checking my injector wiring which is the only other wiring I've modified.

Edited March 7, 2010 by Kwyjibo

[Kwyjibo]

In case anyones interested, the problem was with the CAS.

[tridentt150v]

yahoo!!! Its good to find a problem, peace of mind and happy car..........

[Kwyjibo]

Yeah I'm pretty happy, unfortunately I was dumb enough to try the CAS as a solution first. I've got timing set to standard but clearly my tuner didn't because the car is very sluggish now! Even using the temp adjustment on the Power FC doesn't help much.