Please Help!!! Cannot rev beyond a certain RPM..... Rb20det

[FuertesX]

I have a new MAF and did a super clean wiring job but still it seems that the rev limiter cuts on around 3000 rpm. I am stressed!!! What else can be done?!?!?

I remember reading something about this before but I cant seem to find it again.

Thanks

[DeatschWerks]

My RB25 did this on the first startup as well. Check to make sure your shielding for the MAF wire is grounded. Then its time for some work with the multimeter. Make sure you have continuity between the pins on the MAF plug and the corresponding pin numbers on the ECU. Make sure the MAF has power and ground. Check to make sure there is continuity between the shielding on the MAF wire and a chassis ground. If all this comes back fine, let the car idle and make sure that the voltage the MAF is putting out is the same at the MAF and the ECU. This will check to make sure you arent getting interference as well as make sure you dont have a small break or short in the signal wire somewhere between the MAF and the ECU.

[lyon23]

Check the computer for trouble codes... also if its not to much trouble write the computer serial number info... I had a friend who I just finished his rb20det swap and they sent him a rb20de computer..

[BigPar]

My Series II RB25 is also doing the same thing. I'm hoping not a bad MAF.

[FuertesX]

Sorry if I sound like a noob but when you say shielding wire, you mean the frail wires that wrap around the black and white wire? Should they be extended and saudered together also?.... then will they be grounded?



thank you and everyone else for your advice..... I am forever grateful !!!!

[DeatschWerks]

extend the shielding, make sure that part you extend is making a good contact with the shielding before your extension. the shielding, on one end (mine is by the ecu) is grounded.

[FuertesX]

Thanks brother.....

Here is another dumb question.... Do I need to buy special shielding wire to make the extension or will a basic coated wire do?

[Darius]

I made mine out of aluminum foil. Ghetto, but it works and others have done it. Basically wrap the wires that require shielding (two I believe), then solder one end of a wire to the aluminum foil and solder the other end of the wire to a connector. Ground the wire connector and you're good to go. The shielding transmits the electromagnetic "noise" to ground vs. letting it mess up your MAF signal which is sensitive to variation as you have found.

In short, coated wires work but you have to shield them via the above procedure. AND make sure you solder your connections, no twisting and taping.

[FuertesX]

Ok so I wrapped the two wires (black and white) together with a good amount of aluminum foil. Took one end of the frail shielded wire (the stuff that originally wraps those two wires) and did my best to sauder it to the foil.... likewise on the side closest to the connector. At the connector itself there is loose sheilding wire that does not have a home.... i grounded that. Tried it but still she does not want to rev beyond a certain limit.

What am I doing wrong ?

[gawdzilla]

pull the codes off the ecu

[illdrift]

i had the same problem when first starting mine. Eventually blew the fuse to the fuel pump. Turns out i had wired up some aftermarket gauges wrong and when i cut the wires tothe gauges the engine ran fine. So sounds like you've wired up something wrong. Easiest test i found was to check how many amps is being drawn off the battery without the keys in the ignition and all the doors closed. Mines .01-.02 amps, but ive had .07-.45 when ive done something wrong. So id say any reading noticeably larger than .02amps means somethings wired wrong somewhere

[FuertesX]

Now for some reason the light on the ecu comes on and stays on... does not flash a code or anything..... Does not seem right.

ECU # 22 23710 04U02 MEC R132 1619

[FuertesX]

Anyone?

[takaramotors]

did you turn the little screw back and forth untill the light begins to flash

[BigPar]

stuck in "limp" mode? I think thats what is wrong with mine.

[Cornloaf]

did u forget to upgrade ur fuel pump? j/k - but that really did happen to a buddy of mine. similar result.

[FuertesX]

No.. the swap came with the the rb20 fuel pump.

[BigPar]

hey, i figured out my problem. wrong connector was extended and plugged into the maf the whole time. apparently there are 2 connectors that plug into the rb25det series 2 maf. my buddy extended the wrong wires on the wrong connector. I guess check to see if you may have made the same mistake if it applies to rb20's.

[DriftFactory]

If it's cutting at 3K there is a 90% chance it's in limp mode. Check all the wiring connections, I'm going to tell a story on myself here.

After I got the 26 in I could get it to start but it would stall, I immediately thought "vacuum leak" Turns out I was right and I got that fixed. Then it was stuck in limp mode. I started going through the harness with a voltage meter and some things would read fine then when I came back they would be all jacked up. So after several days of doing this and driving myself crazy, I randomly decided to check the ECU harness. I put my hand on it and it moved I tightened the bolt so that the harness way solid and turned the key. Godzilla came to life in beautiful fashion and the rest is history.

[FuertesX]

Problem solved....

Somewhere between the ecu and the connector the signal wire was corrupted. I decided to make a new signal wire and run it directly to the ecu. Now it revs like it suppose too and I no longer get idle fluctuations after it warms up like it did before. She does not crank right away but she never really did before. Kinda putters a little before coming to life. Another battle for another day I suppose.

Big thank you to all those who replyed to this post! True brothers !!!