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The mkiv Supra Owners Club

S14a 200SX Tech Help Please


tDR

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Posting this on behalf of a M8 who just got a '99 S14a 200SX on Sunday. He has some worries about it and sent the following to DP Motorsport:

 

Sent this to DP motors. My dad reckons the engine sounds shit tbh its not ace imo either

 

Hi,

 

I picked up a 99' s14a from Widnes car centre on Sunday just gone. I am looking to have a number of issues diagnosed / resolved.

 

1) The DET block seems to be lumpy on idle. It will tick over but every few seconds there will be a stutter which will cause the gear stick to tremor. The RPM needles does not fluctuate but the stutter does not seem normal. Is this just me being oversensitive ? In addition when pulling through the rev range I am finding intermittent hesitancy around 5-6k rpm.

 

2) There is an audible tappety sound like a sewing machine eminating from the the rear of the intake manifold collector according to the workshop manual diagrams.

 

The noise is there at start up and shutdown etc. It increases in conjuction with the rpm of the engine.

 

I have been advised that this noise is a feautre of the injectors on the DET engine ?

 

What I would like to do is gather your throughts on these problems then book myself in for a visit to.

 

a) Shed some light on the above.

b) Consult with you about the best course of action regarding modification work to increase engine output on this vehicle. I believe you work frequently on the DET engine being GTi-R specialists and have come recommended by the SX owners club as a point of contact.

 

I look forward to hearing from you.

 

Many Thanks,

 

David Lenagh.

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He asked me what I thought, to which I replied:

 

"lumpy idle to me would indicate it's not firing on all cylinders all the time ie. it's missing - usually caused by dodgy / old HT (ignition) leads or a dodgy spark plug

the shudder you are experiencing would relate - the engine hunts as it loses a cylinder and then gets it back

also, a ticking noise like a sewing machine can be tracking between the HT leads (again due to degradation) or a missing spark plug"

 

But I'm only a Mechanics son trying to relate the knowledge I've picked up over the years working with my Dad. Perhaps someone more technically adept and familiar with the SR20DET engine could comment? Chris Wilson?

 

Also, I told him that DP Motorsports had a bit of a bad rep on this BBS. Is this accurate or am I thinking of some place else?

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Lumpy idle - probably the previous owner manually tinkered with the timing to get more power out of a certain rpm range. Check the timing on the cams/cranks and reset to stock if its not already.

 

Hesitancy - fooked spark plugs - could be the cause of the lumpyness. If running higher than stock purchase colder than stock plugs otherwise get a set of NGK's and gap them to stock and test - if still lumpy knock 5thou off each one at a time and re-test. You need to find out the max and min anyone gaps their plugs to. Don't just guess!!!

 

Rattle? Could be the timing again? Which is affecting something meallic to vibrate it? Loose heat sheild? Or indeed it could be the injectors, I don't know enough about the SR20Det engine to really comment.

 

Have you re-set the ECU? Can you re-set the ECU?

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I am hoping its not been ragged or tinkered with. It was owned buy a 72 year old retired woman police officer and every aspect of the car other than these silly problems is mint. I can't believe how well its been kept. She has only 10% wear on her pads after three years and 14k miles ! She had to get rid of it because she had an operation on her legs which meant she can't get in and out of it anymore.

 

The last service it had where the platinum NGK's where changed was on 25/09/01 ? Sounds like your pointing in that and the timings direction as a starting point ?

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One of my mates has just bought an S14a and that feels like its holding back about 5000rpm, there's a sort of flat spot, doesn't feel right to me at all, I've checked boost levels and thats all ok so its not leaking boost,changed plugs,fuel filter,air fuel ratio, all ok. Might be just the way they are may be, don't know. One thing I did notice was the cat reeked really badly when driving behind his car so may be the cat is fooked. Was going to remove it but he has now decided to sell it and get a Skyline instead, good move.

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Originally posted by Paul Whiffin

One of my mates has just bought an S14a and that feels like its holding back about 5000rpm, there's a sort of flat spot, doesn't feel right to me at all, I've checked boost levels and thats all ok so its not leaking boost,changed plugs,fuel filter,air fuel ratio, all ok. Might be just the way they are may be, don't know. One thing I did notice was the cat reeked really badly when driving behind his car so may be the cat is fooked. Was going to remove it but he has now decided to sell it and get a Skyline instead, good move.

 

O2 sensor??

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