CA18DET Help Please!!!!!!!!

[korsou]

Hello Gents,

Hope everybody is doing great, I have been away for a while due to medical reasons. Had 3 herniated disks in my back that required surgery, luckily am I back on track and jumping around !!!!!!!! Well, enough about me and I ask you for your help.

I have a 1991 CA18DET equipped S13. The engine is forged with 9.0 : 1 Compression ratio, ported head, stock valves, cams etc. Ported factory intake, front mount intercooler, topmount turbo manifoild, GT3071 turbo, 3" catback, stock fuel rail, stock injectors and now stock ECU. Walbro fuel pump with adjustable regulator set at 1,8Bar of fuel. Innovative Wideband O2, factory MAF.

I cannot manage to get the engine to run smoothly. Idle is erratic and when revving the engine is does not go up smoothly. You see the rpm needle stumbling along . The timing is set at +/- 15º (at around 1500 rpm) . I looked at the plugs and they seem to be burning correctly but I have loads of black smoke (rich) in the exhaust, the Wideband reads 14,5 - 15,2 at idle.

I have installed all the original parts mentioned above to eliminate issues which I cannot figure out. I have no codes on the ECU.

Please gents, any help will be highly apopreciated.

Have a great one,

Korsou

[boost_boy]

Sure you don't have some type of boost leak? What does the codes read on your ECU? And lastly, camshaft timing. Is it corect?

[korsou]

Hello Boost_boy,

Thanks a lot for your response. I have no codes on the ECU, no boost leak, I have checked several times and am 99,9% certain there aren´t any.

I have also checked the camshaft timing several times, all 3 marks of the (crank & cams) are spot on. Was thinking last night the only possible issue is the following:

The exhaust cam has the little key that sits into the CAS. This little key is broken on my cam, what I did is manage to install the CAS as close as possible to the original position. As a matter a fact the CAS sits a little to the left (judging the adjustment is in the exact center) and the timing is adjusted to +/- 15º on the crankshaft pulley.

Thanks and hope I can get some help, this is driving me nuts.

Saludos,

Korsou

[r34 gtr]

You are going to need to replace your exhaust cam. That key turns the CAS and tells the engine when to fire, and if it is in any way broken you will get a whole host of problems. Stock camshafts are pretty cheap and should be easy to find. I would replace it before trying anything else.

[korsou]

Hello r34 gtr,

Yes I have found one but have not yet replaced it. I honestly do no think this is the cause of the problems though. I am able to adjust the timing with no issues up and down and all falls within specs. None the less I will swap cams and inform back. Any other comments are very welcome.

Thanks,

Korsou

[float_6969]

Sounds ignition related to me. Failing Ignition amplifier or a failing coil.

[korsou]

Hello Float_6969,

I have swapped coils and cable and same issue. I will try to swap the amplifier and report back.

Does the amplifier need to be completely vertical? I have mine mounted at an angle.

Thanks for the help,

Korsou

[float_6969]

Vertical shouldn't matter.

[korsou]

Hello Again Gents,

Sorry for the long delay in getting back, been hectic.

Ok, here is the update. I installed a new cam with the CAS key and same results as explained before. I switched CAS, checked the Igniter, switched coils and all is the same.

The issue again, I cannot manage to set the correct facotry 15+/-2 degrees. If I set it at that and rev the engine it stumbles to 7000rpm and when coming down simply dies. Back backfire and also via the intake. If I set the timing closer to 20 degrees it gets better and if I go to 24 or so it revs much much better and almost smoth rpm rising. All of this under no load and at operating temps. With this last setting it stumbles a bit around 2500rpm and smooth but in my eyes slower than what it should all the way up.

Can you guys let me know if you have any ideas? I have raised the fuel pressure to around 36 psi at idle and it goes to around 45psi when revving up.

Thanks for the help guys,

Korsou

[float_6969]

Have you checked the cam timing?

[themadscientist]

Coolant temp sensor plugged in? The engine might be stuck in a warmup timing setting thinking it's still cold.

Idle control solenoid cycling properly? If it's jammed or not active that could cause a problem.

It's going to be something dumb that will make you say "are you ****in kidding me?" when you find it.

[korsou]

Hello Gents,

Yes CAM timing is spot on verified around a million times .

I have checked coolant temp sensor, replaced CAS, idle control sol seems to be working correctly as well. Will check codes again in a few. Now the f*** is doing as if I have a vacuum leak and idle goes up and down. Cannor find any vacuum leaksat all.

I don't mind going "you a freaking kidding me" on the car as long as it is soon cause I am going bananas !!!!

Thanks for the continued help.

Korsou

[korsou]

Hello again,

Checked everything again and all OK. I replaced the ECU for another known goodbone and car runs much better. I am guessing there is an issue with my stage 1 chip so that will stay out for sure. Even so I cannot manage to set the timing anywere close to 15. It is more like 24 if that. Took the car aound the block and it drives OK, sluggish to a certain extend. Should pull much harder with it has.

Any help hints or ideas are very welcome.

Thanks again,

Korsou

[Nunook]

Now I never came across this on nissan, but sometimes on older hondas the crank pulley is sort of separated. I would check to make sure 0deg on the crank is tdc on the piston if you havent already.

Also I always did my timing at idle, is there a reason you are doing it at 1500rpm?
If your in south florida I might be able to take a look at it. Maybe record a video so we can see exactly what you mean.

[themadscientist]

Crank pulley separation has been seen before on the CA.

[korsou]

Hello Nunook & themadscientist,

I have checked and rechecked the pulley and am sure it is not separated. Regretfully I do not live in the USA any more. I used to and specifically in South Florida .

In any case, I am 100% the static-timing is spot on, all marks line up perfectly. Second mark on the crank pulley and both marks on the cam pulleys.

I am away from the car now but I will make a video and post it for sure.

I am going bananas due to this.

Thanks again,

Korsou

[boost_boy]

What is your vacuum reading at idle? Sounds like you have a leak somewhere on your set-up. What's the staus of your oxygen sensor? Does it function? I guarantee most of the guys on here drive their cars with dead oxygen sensors and don't realize how much trouble this can cause. Answer those questions and I'm sure we can get this resolved for you. One last question, why such a big turbo with the stock fuel system?

[korsou]

Hello boost_boy,

Thanks for your answer. Vacuum is fine, it reads over 20 Inches of vacuum. I have a wide-band installed with which I read the mixture, which by the way is erratic but that does not worry me for now. I do not have a factory O2 sensor plugged into the exhaust or ECU. Can thi sbe causing this? If so please do explain to me why.

The reason for the big turbo is that I am in the middle of breaking-in the engine. Want to have some miles running correctly before I start squeezing the engine. I am planning on running 680cc injectors with this turbo. I do have a walbro pump installed on the car. MY goal is +/-350hp whp.

I really appreciate all the help gents.

Korsou

[Spawn_CA18]

please deinstall your ECT sensor and check is the symptoms are same or not . If it is same please can you check your ground that came inside coil harness is properly connected to the bottom metal seat of coils .

also please check your compression.