Anyone have any idea why my car would hit the rev limiter at 6375 instead of going up to the 6600 limit I have set in the program? I am using TunerCat and have set the limiter at 6600. I have the program set to return fuel again at 6550 but for some reason the engine will not rev past 6375 on every run I have made.

Initially I was shifting at that RPM and never noticed the problem then once I went a little to far and it felt like the limiter kicked in but I have the rev limit set higher than that. The latest run I decided to test it for sure and it's definitely pulling the fuel at 6375.

In Tunercat there are a couple of switchable tables like "EGR enable RPM's" that limit settings at 6375. I find that quite coincidental that that's the exact RPM I max out at.

Is there something in the program that I am missing to get the engine to rev higher than 6375?

Thanks

Gary

 

Are you getting your RPM reading from a scan tool , or can you see on a "accurate" tach or shift light that it is in fact pulling fuel at 6375 .

This is an area that confused me a little at first . I use LT1 edit and when I log runs , the factory PCM will not display RPM readings in the log higher than 6375 . On the log , it is still showing data all the way up till I shift at 6800 rpm's , but every RPM above 6375 , is displayed as 6375 .

I did verify with a shift light and RPM pills that I am in fact shifting at 6800 and my rev limiter is working the set 7K rpms I have it set at . My factory tach is WAY off up that high , so the shift light is the ONLY thing I have to go by thats accurate .

 

I was using the scan tool (DataMaster) to relay the RPM's which as you stated are at 6375.

So you are saying that the engine is reving to 6600 but the scan tool is only showing 6375 because of the PCM?

If so, it's definitely time for a tach or shiftlight.

Thanks for the explanation.

 

That is the case with me . With the PCM's ability to run to 7-7200 rpms , I have no clue why it wont display rpm values over 6375 The only way to for sure verify it is a shiftlight ~or an accurate tach like an autometer .

Good luck with vert , our combo's look real similar

 

SWEET! Yeah our setup's are pretty close. No X-pipe for me though.

Nice 98 conversion on your vert as well!


Thanks again.

 

The normal value from the PCM for RPM is an 8 bit value (0-255) with each bit representing 25 rpm so 25*255=6375. This is why all you can see on the scanmaster or Datamaster is 6375, unless you use Datamaster and record the automatic transmission data, which has a 16 bit word for RPM and thus will show much higher readings.

 

Thanks for the compliment Gary

At least now I don't have to sound like a dumbass when I explain the computer wont display values over 6375 ....thanks for the insight .

 

Hey Gary.

Having fun?

I have to put the car in the garage for the next 6 months. Getting the motor "refreashed" - too long to explain why - as well as probably going to install a FAST computer.

90 Z28:nice ride. I like duals.

How loud would that be, not exiting at the back.

 

Hey! What up Shaun?

I had lots of fun installing the heads and cam but this tuning is a different story all together.

 

I'm not gonna lie man , its pretty loud . Not unliveable though . I am going to add Car chemisty collector inserts as well to quiet it down just a tad

How will you ever live with tuning on the fly , hehe . My buddy is using F.A.S.T. with his 383/blower 93 Z , it is definately cool stuff . Way easier than the factory computer ever could be .

 

IF you download the current Beta version of DataMaster-EE from the TTS website, there is now a "RPM16" readout that goes up to 10,000 RPM. This is derived from the DRP interval, which is the time interval between distributer pulses.

It does not always agree exactly with the 8-bit RPM value, but it is all we got for >6375 RPM values!

Gary

 

Gary are you talking about version 3.4.8? It says something on the site about having to put a 10k resistor in the cable to place the PCM into 10k mode, does this effect normal communications?

 

I HAVE BEEN BANGING MY HEAD ON THE WALL WITH lt1 eDIT. i ALSO HAD SOME HARDWARD ISSUE AS WELL OF COURSE. INJECTORS NOT BIG ENOUGH (whoops) needed to upgrade fuel pump. But unless you have a passion about tinkering with Edit, it is a tough slog on a blown car.

I'm glad to hear your reassurring comments about FAST. I'm coming around to gettings true duals. I guess there is no way to really take them out the back is there? It looks like an almost impossible job although I know it has been down.

I sit very low though. I have the FLPs and the Spohn TA. In addition I have the Hal adjustable shocks and springs so I COULD raise the front.

GARY: I have not seen Kelly in a while but I know she was at the drag strip recently. She got a cam installed as well as some MAC headers. I think she ran a 13.70 but that was her first run in a long time. Have you done anything on a roll bar. I just got a digital camera so I might send some pic's of my chrome one when I figure out how to use it.

I found a GREEN ride like ours but I forget his name right now.

 

Grover,

The 10K mod is only for the early pre 1990 TPI ECM and will have no effect on anything else. It only allows the early PCM to go into "high-speed" 8192 mode, newer PCMs support this without the resistor.

For EE there is also a beta (now version 3.4.12) at the bottom of the download page, altho the web page may say it is 3.4.8 Give this a try!

Gary