I acquired an R3 instrument cluster for a project car but never fitted it. I now only have an R3, no Series 1.

Having done it, I know that the R3 instrument cluster is a straight physical swap into a Series 1 car. From reading around, I believe that the R3's temperature-dependent rev limits won't work and that the fuel gauge is inaccurate, presumably because the resistance ranges of the R3's 2 fuel senders are different to those in S1 cars.

Does anyone have any hard information on:
@ how the fuel level reads on an R3 cluster in an S1 (compared with reality or the S1 cluster)?
@ the resistance ranges of the 4 level sensors (2 S1 & 2 R3)?
@ is there a simple fix such as resistors in the level sensor leads?

Thanks in advance for any help.

 

I read in a S2 fuel pump in S1 thread that you can install the S2 sensors in the S1 tank (in that case it was to avoid having a problem connecting the S1 sensors to the S2 fuel pump assembly). There was a concern that the fuel level measurement would be off as a result of the fuel tanks being different sizes.

I'm pretty certain that the temp-dependent rev limit is a PCM function so it's no surprise that it doesn't follow the cluster.

 

Thanks.

Fitting R3 level sensors should give more accurate readings. However, given the difficulty of finding R3 fuel level sensors here and removing the locking rings, I think the person thinking of using the cluster won’t take that route.

 

I looked at the Service Manual for S2(R3) and it says that at the top, the resistance is 9.0~11.0 ohms, and at the bottom, the resistance is 322.8~329.2 ohms.

I think the S2 tank is about 1.3 gallon bigger than S1.

And I think S1 only has 2 stages for rev limit. S2 6-speed has the 1st stage(5k RPM) below 104F, and 2nd stage(7k RPM) between 104F and 165F, and full redline above that.

 

I put a S2 cluster in my S1 and for me the Tach was off and few lights where on too. I forget that they where.

Also it seemed a tad glitchy too.

 

Thanks.

I’ll see what resistance values I can find for an S1.

I never had any problems with an R3 cluster I ran in a 231 for a few miles, other than the stated fuel and rev limit issues and that the cluster had TPMS but the car didn’t. The tacho read spot on with the values I got via the OBDII port. The tacho won’t read correct in a 192 though.

 

This subject has been done before, a S1 owner put and S2 IC in his S1 about 5 years ago.

Issues were wrong fuel gauge reading as S2 has a slightly larger tank.
The LED in Tacho (red 3 bars) does not work or correctly.
There was one other, cant recall.
I remember he kept running out of fuel because the reading was wrong, then I told him about IC and Fuel Tank float gauges are different for S2/S1, light bulb went off and he replaced back to S1 IC.

From what I have heard installing S2 Float Sensors in Tank wont work as they are too long to fit in smaller S1 tank.
BTW: 3 Bar Led (adjustment) I think is done by ECU which is different.( Temp controlled as we know)

 

Thanks. That’s more confirmation of the basic points.

Do you have any data to manage or get round the fuel gauge readings, such as that in my original post?

Oh, and thanks for not mentioning the cricket.

 

Sorry the technical stuff, might be in a manual, but I doubt it, float sensors are a disposable part.
I cant recall ever seeing such data for many years in manuals anymore.

Ashes to Ashes.