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ossy

Help, underpowered and sluggish

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Hi,

I'm still trying to get fix the problems and regain the lost power on my NA 2.5 R33 which is stupidly slow as if in limp mode or something... Yes its a non turbo, it's slow, its already been said but this is even worse lol.

 

Anyway it was parked up for a few years. It drives smooth and goes through the rev range fine but the revs just seem slow to climb sometimes and is massivly underpowered. Engine sounds smooth and healthy as well. I previously gave it a full service and replaced its broken cone filter with the stock airbox and funnel. It helped for abit but lost loads of power again.

I've now fitted a new larger battery and new AFM aswell which has improved it massively but it's still not there and good as it should be. It has better uphill pull throughout and the power in 1st and 2nd gear feel decent-ish again when foot down but starts to go sluggish again after that... Its feels like driving a Honda VTEC at times lol. I put foot down, theres a slow laggy build up and then the sound changes and it takes off. 

It's also weird, it randomly gets its power back at times and then loses it again. I don't understand what's wrong with it. Any other ideas what it could be?

 

Some other issues aswell. It has a cold start issue and requires a few attempts and some revs to get it started. Also, the revs start to bounce up and down when I start driving when it's cold and come to a stop at red lights. Have to give it a quick rev otherwise it'll get worse and cut out. I suspect the AAC valve for the cold start up problem which I haven't gotten round to yet but can this cause the revs to bounce up and down aswell?

Then there's the HICAS light which comes on everytime after 15minutes or so of driving and stays on until I switch car off. Steering seems fine so not sure if its causing any problems or not.

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Take it to a mechanic.  Put a scan tool on it.  Find out if there are any sensor problems on the engine.  Also interrogate the HICAS CU and find out what it is upset about.

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Aftermarket steering wheel can cause HICAS light to turn on

Car running shit, could be timing or injectors or a host of other stuff, take it to mechanics or diagnose every angle yourself. You changed AFM which is good, what about spark plugs? Coils?

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1 hour ago, niZmO_Man said:

what about spark plugs? Coils?

Its always good to help, but don't encourage the poor bloke to diagnose by parts changing/guessing.

Put a scan tool on it.  Find out if there are any sensor problems on the engine. GTS Boy gave you the correct answer.

When diagnostic ports were first appearing in cars, Big Bob (our workshop foreman) would march any apprentice down the workshop by his left ear to the Diagnostics Trolley if he found he had not run Diagnostics before hoisting the vehicle. Early Diagnostics units cost the same as a small car, BIg Bob took the price personally.

(Apologies to any new age men out there, this was called learning by example in the old days.)

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I've already taken it several times and had it looked over by some mechanics but unfortunately they don't know. They're kinda useless around here if I'm honest and keep saying crap like the car is too loud so they can't tell what's wrong which is just stupid. They also ended up cutting one of the fuel lines in engine bay and had fuel spraying everywhere which I had to replace at home when I noticed fuel gauge dropping quickly after a short drive so you can see how useless they are... And the Jap/Skyline specialist places are all veerry far from me.

There's no engine management light showing but I've now brought a Consult scan tool anyway so I'll give that a shot and report back. Just waiting till it arrives now... Also am I right reading that the scan tool won't read HICAS faults? If so, how do I go about doing that?

 

And about the HICAS, it has a spec 2 steering wheel but body is spec 1. It's a 1995, so assuming spec 1.5 as some would call it? Also I did service it before trying new battery and AFM. That was changing oil, sparkplugs (was told I need BCPR6ES), filters, fluids and fitted stock airbox which helped only for a day before it lost power again the next morning. Engine sounds super smooth and healthy, no misfires so dont think it's sparkplugs or coilpacks.

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43 minutes ago, ossy said:

Engine sounds super smooth and healthy, no misfires so dont think it's sparkplugs or coilpacks.

Then when you get your cable and software, concentrate on intake air (it was a new filter right) and fuel system. You said it was parked up for a couple of years. Any cracking in intake plastics, change fuel filter (if the tank dried out probably getting clogged already). Did you use any remaining old fuel? Did you check fuel pump relay, is your fuel pump dying? YES you are correct your tool probably won't read HICAS faults

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Cheapy eBay scan tool will only read ECU.  Proper mechanics' scan tool will interrogate every CU in the car.

Steering sensor is #1 likely option for HICAS fault, but there are plenty of other options and every time we point someone to the usual answer we later find out that something hideously stupid had been done to the car and no-one could have ever guessed what the real fault would turn out to be.

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Hi,

So I used ECU Talk and managed to get some readings but not sure what they mean. Can anyone help me out?

Also I noticed that the timing is all over the place which doesn't seem normal to me. What can be the cause of that? On cold start, it's around 20 and drops to 15 as it warms up. Then whilst driving it's bouncing up and down randomly reaching 49 at one point and even -8.

 

I've recorded a 3 minutes long showing this and other readings on a short steady drive which I'll post here below and also have the full ECU Talk log file if needed for more info which shows the readings at cold start, warming up and driving.

https://www.youtube.com/watch?v=bt92Wes7hmY

 

Thanks.

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That is a shit video.

Read ecu codes and report back.

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There's no ECU faults, that's why I took and posted the video so you guys can see the readings... Better than posting a 20minute long data log file lol.

 

I don't understand what most of the readings mean or what values they should be reading, especially the timing as it's all over the place.

Edited by ossy

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