ca18et bluebird idling and cruising rough. (Read 607 times)

[dennismo]

Car: 910 bluebird
Engine: ca18et
Problem(s): Doesn't start easy. Cranks ok, fires up pretty quick, idles at 1000rpm for a couple of seconds, then dies.
Starting again, same thing happens. Starting again and trying to keep it alive with the throttle and that work with a lot of sputtering, backfiring and shuddering. When I leave the throttle at idle, it idles ok for a couple of seconds, then it want to die out again. When it's idling at 1000 rpm and I want to give it a bit more gas, it backfires and sputters untill I get it up to 2000 rpm and then it's rough, but ok. As soon as it hits 1600 rpm, it goes in 'dying out' mode again. When it's on temperature, it idles between 700 and 1000 rpm with some shuddering. Accelerating and boosting goes without any complains, it pulls very strong. Cruising at low revs causes alot of shaking of the car and in slow traffic I have to use the clutch very often to prevent the car from breaking its driveline. Well, that's what it feels like.

Things I've checked: Timing is at 15 BTDC, spark plugs are new, so are the cables, faulty o2 sensor replaced by another one (it used to runs even worse!), injectors are cleaned.

Things I find a bit strange, but shouldn't cause the problems: It's a twin spark engine with the single spark loom. It barely ran with a single spark distributor and it runs far better with the twin spark dizzy. I only connected the intake Sparks and the outlet sparks are dummies. There's a big voltage leak on the car. After a night, the battery is completely dead. So every time I park the car, I take off the ground cable from the battery.

So what am I missing here?? I have a good pulling and boosting car, that don't want to idle properly and don't want to cruise properly. :no:

[Al Ramone]

is it possible that you need the correct 4 plug distributor? can you borrow one?

[Damien4884]

Has it ran properly and this is a recent problem or has it always been an issue?

[dennismo]

it has always been a issue.


When I got the car back from the guy who did the electric hookup from the ca18et in the 910 it ran, but not even close to ok.
That was with a single spark dizzy.

Then I did a service with new leads, Sparks and dizzy cap. After that it ran like it was on 3 cilinders, wouldn't rev at all. Timing was good.
Put in the twin spark dizzy that came with the engine, hooked up just the 4 intake plugs and it ran so much better!

Then I changed the o2 sensor with another one and it ran again a whole lot better.

Now it's just that last 10% that needs to be sorted out, because it's a pain in the arse to drive in slow traffic and start the car when it's cold.

I am running a ca18det 200sx s13 MAF, but that wouldn't be the issue, would it?

[Al Ramone]

Jun 5, 2013 6:23:44 GMT 1 dennismo said:

I am running a ca18det 200sx s13 MAF, but that wouldn't be the issue, would it?

your engines must be different to what we had because we didn't get o2 sensors till the later CA18DET.

as far as i'm aware, all our CA18ET and early CA18DET were closed loop with no o2 sensor and had a mixture adjust on the MAF. the later CA18DET had an o2 sensor and no mixture adjust on the MAF.


looking at your engine picture.... you have an early, non o2 MAF. you can see it has a little cylinder with a blanking cap, where the adjustment screw is.

the plug on the wiring loom to the MAF is different depending on what MAF you have. has the wiring plug been cut off and changed?

[30psi]

I'd be investigating the cause of the battery discharging. First measure how many amps are being pulled and then disconnect things from the power ciruit and see when it reduces or goes to zero. It's quite possible given the recent engine loom addition that the two are connected and could therefore be having an impact on power to the ECU.

[dennismo]

As far as I know the wiring plug hasn't been cut off and changed.
I can't see how I can ajdust the mixture on the MAF. I see where i could adjust it, but don't see how.





And here's the ECU code...




I'll make the search for the battery discharge a higher priority.

I've played with the TPS adjustment, but that didn't make much diffrence in throttle response.

[dennismo]

Google told me that I have an automatic ECU.... Could that be the reason for the rough running and bad starting?

[Al Ramone]

as far as i know, the only difference with the auto ecu is the idle speed.

the non o2 engine MAF has an alloy blank over the adjustment screw.

the o2 engine should have a 3 wire MAF without that extra bit with the adjustment.

maybe you should disconect the o2 sensor and see how it runs?

the CA18DET's use the same ecu whether they have an o2 sensor or not.


as mr 30psi says. there must be something wrong with the wiring. i'd guess the engine/ecu is getting a constant live rather then a relay controlled live.

[dennismo]

Without the 02 sensor, it runs even worse.
Do you know which color the 3 wires should have if I need a 3 wire MAF?

[Al Ramone]

not sure as i haven't got a wiring diagram for a lambda equipped ca18et.

the wiring diagrams on Wills tech page... www.datman.co.uk/techtips/techtips2.htm shows a non Lambda wiring loom with the 4 wire MAF

[dennismo]

And i have a Lambda loom with 4 wire MAF.. :s

Weird...

[Al Ramone]

Jun 6, 2013 20:51:19 GMT 1 dennismo said:

And i have a Lambda loom with 4 wire MAF.. :s

Weird...

which is why i mentioned it. just looks like the loom may have been modified.


ok... i've compared DET and ET wiring looms online... and it looks to me like the extra wire on the non Lambda MAF is the white one. if your feeling brave, you could temp cut that wire and see if it improves. if it doesn't, just splice it back together. no harm done.

[dennismo]

Thanks for looking it up!
I've got a lot the do and check next time I'm in the barn again!

Cheers!

[Al Ramone]

well there's a chance that that the MAF is wrong so worth a try.

personally i'd want to rewire the lot myself and make sure it was done right.