SR Falls on its Face...HELP

[nismosil40zx]

Ok I just installed my SR20DET redtop and it idles great but when I give it gas it seems like it hits a fuel cut out or something of that nature and falls on its face and wont go. I also hear alot of wastegate noise coming from the air filter. Also when im trying to drive it at 10 mph it seems to be gaining boost psi. very fast and doesnt go anywhere. My vacuum doesnt seem to be all that great either. This engine has also been rebuilt bottom end wise.

Mods Walbro 255, RFL BOV (cold pipe side),Greddy front mount, turbox's boost controller,300zx fuel filter, Wiring harness was sent out and profesionaly done. Hope this Helps...Love to hear some good ideas THANKS

[aNskY]

does it rev? if not check your mafs

if so could be an injector. you running super rich?

[nismosil40zx]

It revs. Sometimes when I rev it its seems to hit the rev limiter or a fuel cut and there is no way Iam rev up to 7000rpm, The MAF is good and so is the TPS, The injectors are stock. I also hear alot of wastegate or turbo noise through my intake is that normal?

[aNskY]

when does it hit the cut? around 4500rpm?

if so it's definately your mafs. if you already checked it per fsm standards.... double check your wiring

[Gramentz]

Check your vacuum lines, you said your vacuum didn't seem all that great.

[nismosil40zx]

I checked vacuum lines I pretty sure it is goin to be a wiring issue. From the looks of my harness. It startes up like a champ but from there on is is shit. thanks for those ideas

[steve shadows]

when does it hit the cut? around 4500rpm?

if so it's definately your mafs. if you already checked it per fsm standards.... double check your wiring


I hope you mean around 2,500 rpms.

there is no FSM for sr maf on a usdm chasis harness converted to sr20det engine harness lol.

Check the maf wiring, fi that is perfect, check the harness if the harness is in "EXCELLENT" condition and you didnt have your swap done by some CRX shop with down syndrome, then check the intake pipe to the turbo for the little metal spring. The metal spring in the intake tube is notorious for being "left out" in swap kits and honda shops that have jumped on the band wagon forget they are doing "TURBO ENGINE" drop with the sr. The vacum and increased cfm pull through the turbo inlet will actually cause the rubber intake hose to collapse on itself under load and cause stuttering or "falling on face" while driving.:fart:

[nismosil40zx]

Im confused about this spring thats in my intake tube unless you are talking about the spring and wastegate setup or what. Or maybe i might just be drawling a blank on what you are talking about. But from what you are saying sounds just like my car.

[BIGREDCORP]

hey man, I reccomend you remove the boost controller. I had the same problem because my car was boosting over 17 punds on the turbo xs. when I removed it, the car ran fine. I had a stock ecu that cuts off at 14. If you have the stock ecu...then try taking off the boost controller.

[steve shadows]

Im confused about this spring thats in my intake tube unless you are talking about the spring and wastegate setup or what. Or maybe i might just be drawling a blank on what you are talking about. But from what you are saying sounds just like my car.


The Spring Im talking about is inside the inlet pipe to the compressor housing on the turbo. The big black rubber hose (2.75 inch diameteriirc) with the ribs in it going up to your stock sr air box/ air filter element location. Inside of the hose should be a big brass spring that traces along and seats inside the ribs. If this giant spring is missing the rubber hose can implode on itself under load and cause the powerdrop slash rev stop. There should be no spring on your internal gate. The internal gate has a diaphram that is not visible, unless your running external but im not referring to that at all.

check it

[carkid0007]

Maybe check your spark plugs

[tiresmokes13]

Check your MAFS wires..Im pretty sure you wired them up wrong. Make sure you unplug your battery when your checking or say goodbye to your ecu if you touch any wires to each other.

Good luck.

[cotbu]

I just fixed this type of issue recently, It was the TPS.
Visual tools:SW A/R gauge, SAFC, watch the safc, to see when the problem occurs.
Our problem was not boost specific
1. easy throttle pressure gradually increasing result 45~k rpm 4th, 51.~% thr
2. 3rd gear mash 78%thr - 39~k rpm then lean
TPS SAFC voltage 0.45~
Reset TPS voltage 0.40~ ECU calibrated it to 0.429 then again to 0.450 steady
1.easy throttle pressure gradually increasing result 57~k rpm 4th, 65% thr
2. 3rd gear mash 100%thr - shift at 56k rpm 4th 55krpm did not rec 5th
called project repaired
sound on high boost full throttle: brap brap brap

[nismosil40zx]

i HAVE ngk IRIDUMS brand new and I dont have a rubber hose for my intake I have a greddy front wont with piping and piping for my intake all out of aluminum.

Thanks for your advice

[nismosil40zx]

Thanks for the Advice, I will let you guys no what the problem was when I fix it

[srs14]

plugs...i have iridiums too but they were gapped to big. fixed it immediately

[dropped]

i have this same problem with mine. ive checked tps afm and coils. alltho i was told that at some point the wires to the afm were bear and did touch. so ill find out this weekend when i try a new ecu and ill let you no if it fixes my problem. feel free to add me to msn if you have it. [email protected]

[cotbu]

This is an update to my reply:
Ok, he said after a couple of days the problem returned. I checked everything previously checked, then test drove it. Felt like the turbo was fighting itself, so I shot 10psi through tail pipe slowly and he heard air escaping for the dump (turbo side). The nuts turned a 1/2 inch on three and 1/4 on two. Test drive completed this with way better response from turbo. He called job complete this time. All for the price of a six pack of cobra

Hope this can help someone!
http://www.cultdeadcow.com/splash/cow4.jpg

[nismosil40zx]

I finally fixed the problem the MAF to the ECU got un pinned. and a ground to the alternator came off. Pretty much thats all that was wrong. easy!! Thanks for your ideas.