Is it possible to put the air intake from the '83 in the '79, and take the cold air intake out of the equation? I drive an 80zx n/a and have an '82 n/a parts car..all that stuff except for the ignition control module and AFM boot are interchangeable. My 80' has 207k miles on it, has 175+/- compression and runs like a Swiss clock. Mileage is not necessarily an indicator of being worn out.

 

 

 

 

Did I hear a compression check anywhere? when you are having problems you need to diagnosis and work the issue, not throw parts at it and hope for the best, or take random suggestions made based on limited info. I sometimes will throw out a suggestion but its often wrong due to my having to take a SWAG at the issue due to limited info.

Therefore I would recommend:

Compression check, fuel pressure, timing just for starters.

Tune up consisting of fluids, filters (air oil gas). Oh and a check of valve lash, adj if needed, very easy to do on a Z.

Next up would be some new plugs, drive the car several miles then pull them and read for clues on mixture and oil blow by.

listen for a misfire if noted do a balance test to find the offending cylinder, work the problem from there, has to be compression/fuel/spark. Resolve and test again.

There is a process to diagnosis, the FSM covers most of the problems you are likely to encounter. Common problems are poor fuel delivery due to plugged lines, and poor electrical connections on the FI. Sensors on critical for correct fuel/air mix, a reading of the plugs is a good start for this.

forgot to mention, on the bypass as others have noted, if you have a problem with it, you need to correct. Test it to see if it is functioning as designed (added air flow during warm up) using the FSM as a guide. If its malfunctioning replace it. One other item would of course check the vacuum hoses since you mentioned a whistle noise. Vacuum leaks are bad. Make sure the distributer is advancing as designed (there I go with a SWAG).

 

 

 

Edited August 20, 20177 yr by Dave WM
could not help myself

He's selling the 79.  He was just looking for a simple answer to a complicated question.

 

11 minutes ago, Zed Head said:

He's selling the 79.  He was just looking for a simple answer to a complicated question.

 

Roger, wish I had paid more attention, would not have bothered I had realized he was not interested if fixing it. of course the easy answer is there is no easy answer

on second thought, if you are going to have old cars that don't have all the ODB stuff, then the simple answer would be a lot of things could cause the problem and you have to diagnosis it to determine them using proper test procedures and keeping track of results.

Edited August 20, 20177 yr by Dave WM

 

5 minutes ago, Dave WM said:

on second thought, if you are going to have old cars that don't have all the ODB stuff,

Are you a Wu Tang fan?  Where does ODB come in?  Old Dirty Bastard.

8 minutes ago, Zed Head said:

 

Are you a Wu Tang fan?  Where does ODB come in?  Old Dirty Bastard.

yikes! had to look that one up.

OBD

Edited August 20, 20177 yr by Dave WM

I just want someone who has had this issue, and it could be air fuel ratio, but a smog machine is needed for that I think

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Also timing is perfect

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9 hours ago, thetech101 said:

I just want someone who has had this issue, and it could be air fuel ratio, but a smog machine is needed for that I think

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or you could read the plugs, should give a decent idea of A/F mix. all a moot point it would seem. Your looking for an explanation without enough data to draw a conclusion from.

I could but, but I'm looking for someone who has had this, not guesses. It would be nice to figure this out due to there not bring a forum any where without this issue and I'm sure there will be someone else with issue. In addition I just want to sell that car. it would be cool if someone happened to have seen this idle and the issues it developed before.

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With the issue*

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