s14 sr20det won't rev past 2800 rpms

[okinawa drift]

ok so i'm sooo close to finishing this swap. i just need a little guidance..

i got an 89 240sx with an s14 sr20det. and i went to start it today for the first time, it took a little bit of cranking.. probably about 5 seconds, i started it, and it ran good, idled good, no smoke, sounded good, and everything, it just wouldn't rev past 2800 rpms... and when i would go to shut it off, and try to start it again, it wouldn't start, at all.. so i take off the maf, and clean it with cleaner, and put it back on, it started up, still didn't rev past 2800. so i shut it off, and it didn't start again... its almost as if i have to wait a period of time before i can start it again...


what does this sound like to you guys? my friend was telling me my ignitor could be bad...

[zachattack_5491]

Any ECU codes? Could be the ignitor chip, coils, maf, or ecu (among other less likely things). Use the fsm to test the ignitor chip, coils, and maf.

[95sky40]

Honestly It pretty much sounds like your ECU is going in "limp-mode" to me. Especially with the MAF thing not happening. Check and see if it is throwing a code for the MAF. A lot of times with the MAF off the ecu will read no voltage from it but still won't allow it to crank and if it does get some sort of read it won't let the car do much because of too much or too little air etc... It's like a fail safe. It doesnt know whats going on. So check and see if it is throwing a MAF code on ECU and then if so check the wire inside the MAF then check connection and then check the wires with multimeter....
Hope this helps.

[okinawa drift]

hmm, my ECU doesn't have a light on the back of it, its a BLACK WC ecu, i guess it didn't come with a diagnostic light from the factory...

damn!

[zachattack_5491]

That's probably not a good sign. There should be a seal on the cover. Has that been broken? Well, that will just make things harder to track down. Test the things I told you about and go from there.

[okinawa drift]

fixed the revving problem!! started the car up today, it reved nicely, and idled really good, a/f was also perfect.


the thing is.. the maf issue didn't fix my starting problem, after i shut off the car, i tried to start it again... and it didn't start.... sound like an ignitor to you guys? i mean, the car was running perfect!

[95sky40]

It is possible of that... What was the rev problem? check to see if you are getting spark. if so then it is not the ignitor... if u arent getting spark put a multimeter to the harness at the ignitor pins while someone turns the the car over. if u get signal then check the ignitor on the coil side. if not then replace ignitor chip but only after u have checked ur cam angle sensor too... it feeds signal in correlation with the ECU and tells ur coil packs when to fire .... u get that? hope so....

[zachattack_5491]

Without the CAS the car won't start at all, and most certainly won't rev up.

What does it do when it won't start? It just keeps turning over and doesn't fire? That sounds like a problem with spark for sure. If you have any doubts on your fuel system you should make sure your injectors are firing when it's turning over.

[okinawa drift]

well no, my car starts everytime, its just usually when i start it, it sounds like it misfires or runs on 3 cylinders for like 3 seconds, and its really lean on the a/f, but then it will fix itself.. or if i rev it, that also fixes it instantly and it will idle pretty decent, 14.7 on the a/f. what you guys think it could be? cuz i mean the car runs awsome other than this start up issue!