# Increasing the rev limiter on a cis-e 16v



## G2GTI (Jun 3, 2002)

Is there any way of increasing the rev limit on the cis-e injection? I read somewhere that cutting the wire that comes out of the ecu at plug #25 will increase the rev limit to around 7300rpm. Is this true? Has anyone ever tried this?
Thanks.
Dave


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## chois (May 12, 2000)

The rev limit is triggered via the fuel pump relay. An earlier fuel pump relay can resolve this. I think that Techtonics sells the correct relay and describes it as a rev limit 'remover'.
There are some CIS-E knock boxes that don't have a rev limit (the knock box is what triggers the fuel pump relay cut from what I can tell), but I don't know what cars those are from.
You can also put the fuel pump on a switch if you wish, but then it will continue to run unless you turn it off - even if you are not able to after a wreck.


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## antichristonwheels (Jun 14, 2001)

*Re: Increasing the rev limiter on a cis-e 16v (RallyGTIG2)*

there is really no need. with 276 cams and puttin 150 to the wheels I still made max power at 6400. This means shift by 7000 for max acceleration...


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## chois (May 12, 2000)

This is true. Without a lot of headwork you are just making more noise.


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## G2GTI (Jun 3, 2002)

*Re: (chois)*

I should have clarified, the motor I am running has Cat 279/268 cams with a pocket ported head. Adjustable cam gear. Decked block making about 11:1 compression. 
I would like to raise the rev limit so that in situations where my choice would be either leave the car in the current gear until the corner, even though I am above the peak of the power band. Or bounce off the rev limiter, I would rather not bounce off the rev limiter.


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## chois (May 12, 2000)

Pull the fuel pump relay. Put some male spade connectors onto the wires going to a switch. Insert the spades into the appropriate terminals for the relay. Test to see if the rev limiter is gone. If gone, go get that old style relay (from the Fox?) from Techtonics.
If the limiter is not gone, report back.
That's how I would handle it.
EDIT - I run a switch on my race car. However I just removed the knock box from the CIS-E system, removing all the no longer needed wiring. I made sure to set aside the wire that carries the 'enable' signal to the fuel pump relay, and plan to find a way to use another ignition related signal to trigger the pump.


_Modified by chois at 8:15 AM 4-3-2008_


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## G2GTI (Jun 3, 2002)

*Re: (chois)*

I removed the knock box and all related wiring on my G-prod Golf (8v). I use aftermarket relays to power the fuel pumps, running a cis-e 16v computer. That setup has the rev limiter kick in at about 7300rpm. I would like to keep the knock box as a safety thing, I have ripped intake boots in the past and without the knock box, it would have burnt up the motor.
Dave


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## chois (May 12, 2000)

Well I have run across knock boxes that did not have the rev limiter, but don't know what they were from. Well one was from an early 8v Golf, but that will have the wrong ignition curve for your 16v.
I run good gas as insurance, because the knock box seems to cause some inconsistency in the timing.


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## G2GTI (Jun 3, 2002)

*Re: (chois)*

Just on a whim I am going to pull the #25 pin out of the ECU harness to see what effect it has. I have a few other tuning things to do first but I should be able to try it this weekend. 
I run an aluminum spacer between my knock sensor and the block. The spacer pretty much took care of my timing inconsistencies due to knock box interference.


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## G2GTI (Jun 3, 2002)

*Re: (chois)*


_Quote, originally posted by *chois* »_
EDIT - I run a switch on my race car. However I just removed the knock box from the CIS-E system, removing all the no longer needed wiring. I made sure to set aside the wire that carries the 'enable' signal to the fuel pump relay, and plan to find a way to use another ignition related signal to trigger the pump.


For the G-prod car I purchased an assembled fuel pump harness from Painless and ran a seperate relay for each pump with the actuator wire coming from the ignition switch. On a road race car I would remove the problemative VW fuel pump relay and go with an aftermarket setup.


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## G2GTI (Jun 3, 2002)

*Re: (RallyGTIG2)*

Well, pulling the #25 pin out of the ECU did not raise my rev limit. It made the car sluggish at part throttle and it would not idle. I will give Techtonics a call about their fuel pump relay.


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## E U RO C R A P 87 (Oct 3, 2007)

*Re: (RallyGTIG2)*

i had the same problem and i solved using a cis from a rabbit and the computer fron a cis e advance some wiring need to be don i can email you a pics an diagram .
now i step down o it an i let it go at 7900 just to kcnow how high can it go 
note:: i had 283/279 cams , and ported!
o and i dont use it on street to noisi


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## ABA Scirocco (May 30, 2001)

*Re: (RallyGTIG2)*


_Quote, originally posted by *RallyGTIG2* »_Well, pulling the #25 pin out of the ECU did not raise my rev limit. It made the car sluggish at part throttle and it would not idle. I will give Techtonics a call about their fuel pump relay.


The fuel pump relay mod is a CIS-lambda thing I don't think it will work with CIS-e. The CIS-lambda relay receives a tach signal from the coil and it contains a little bit of intelligent circuitry which implements a rev limit and a zero-rpm fuel cut-out. 
CIS-e on the other hand, has a simple dumb relay, it's either on or off. The relay is controlled by the knock box, the relay is energized by grounding out the coil through pin 10 on the knock box thus turning on the fuel pump. The knock box cuts the ground to pin 10 when you hit the rev limit or the engine rpm drops to zero, cutting off the fuel. You could defeat this rev limiter by providing the relay an alternate path to ground through something like an oil pressure switch.
I'll finish by saying that I don't have any experience eliminating the rev limiter from a CIS-e 16v engine all of my knowledge concerning this comes from working with 8v knock boxes and from studying the wiring diagrams. My CIS-lambda with an 8v knock box and the appropriate fuel pump relay had no rev limiter. You may be able to defeat the fuel cut-out rev limit using the methods I've described I'm not sure if there's another limiter as well. Try searching for posts by "WClark" he's done a considerable amount of research regard CIS-e rev limits.



_Modified by ABA Scirocco at 10:36 AM 4-5-2008_


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## G2GTI (Jun 3, 2002)

*Re: (ABA Scirocco)*

I was using an 8v knock box.(doh) That put my rev limit at 6300, I changed to a 16v knock box and it raised the rev limit up to 7300. I am going to play with tuning to see if I need it higher. Thanks for all the info.

_Quote, originally posted by *ABA Scirocco* »_
The fuel pump relay mod is a CIS-lambda thing I don't think it will work with CIS-e. The CIS-lambda relay receives a tach signal from the coil and it contains a little bit of intelligent circuitry which implements a rev limit and a zero-rpm fuel cut-out. 
CIS-e on the other hand, has a simple dumb relay, it's either on or off. The relay is controlled by the knock box, the relay is energized by grounding out the coil through pin 10 on the knock box thus turning on the fuel pump. The knock box cuts the ground to pin 10 when you hit the rev limit or the engine rpm drops to zero, cutting off the fuel. You could defeat this rev limiter by providing the relay an alternate path to ground through something like an oil pressure switch.
I'll finish by saying that I don't have any experience eliminating the rev limiter from a CIS-e 16v engine all of my knowledge concerning this comes from working with 8v knock boxes and from studying the wiring diagrams. My CIS-lambda with an 8v knock box and the appropriate fuel pump relay had no rev limiter. You may be able to defeat the fuel cut-out rev limit using the methods I've described I'm not sure if there's another limiter as well. Try searching for posts by "WClark" he's done a considerable amount of research regard CIS-e rev limits.
_Modified by ABA Scirocco at 10:36 AM 4-5-2008_


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## chois (May 12, 2000)

You should see some better performance with the 16v ignition advance curve.
On my 8v, when I defeated the knock box to fuel pump relay rev limiter it would rev past 7 (although not making power there). This was before I had removed the knock box, so it was still there and talking to the fuel box (albiet with a jumpered hall signal going direct to the ign module for fixed timing).
I don't know that the fuel box can 'see' rpm without a knock box. It definitely has no rev limit in that configuration. Chuck's rabbit will rev to 9k without issue running a CIS-E box and no knock box.


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