EECV rev limits

Anything about Ford EEC tuning. TwEECer and Moates questions dominate, but there's some SCT and OBD-II knowledge too.

Moderators: cgrey8, EDS50, Jon 94GT, 2Shaker

Post Reply
cbrown9064
Gear Head
Posts: 49
Joined: Sun Nov 02, 2014 1:04 pm
Location: Mandan, ND

EECV rev limits

Post by cbrown9064 » Sun May 13, 2018 9:58 pm

Have been chasing this weird misfire that happens at about 6800rpm. If you get on it hard in first and it spins quick, it will fall on its face. Turns out it is the rev limiter. WTF... ;)

Dummy me was adjusting the rev limit 0, 1 and 2. I have a manual. Duh... So I found the neutral limit. But what I don't understand is the "on" and "off". The off is set lower than the on. The off seems like a spark limit and the on like a fuel cut off? Does anyone know?

I am using a Coretuning.net database version of CDAN4 on BE. They scalars are simply labeled "Rev limit neutral 0 off" and "Rev limit neutral 0 on".

If I set the off to a low rpm like 3500 and then the on to 4000, the car will start to misfire at 3500 and the buck hard at 4000.

Is that right and what is exactly happening? Spark and then fuel or just fuel? Seems way different than a EECIV.

My strategy does not have other identifiable info on the scalar.
Last edited by cbrown9064 on Mon May 14, 2018 6:28 am, edited 1 time in total.
1996 Cobra, Novi 2k, S-D 60 lb/hr, SCT BA5k, Paxton IC, QH, BE, Innovate AFR,

sailorbob
BIN Hacker
Posts: 1651
Joined: Tue Jul 12, 2005 6:10 am

Re: EECV rev limits

Post by sailorbob » Mon May 14, 2018 1:56 am

The CDAN4 strategy has three ways of limiting the engine speed:

Stage 1 - The rpm at which fuel delivery is enriched and spark advance is retarded.
Stage 2 - The rpm at which fuel delivery is cut to alternate injectors.
Stage 3 - The rpm at which all fuel delivery is cut.

Not all the stages are necessarily used in all calibrations.

There are no 'on' and 'off' scalars for these stages, there are only rev limit values that are acted upon (i.e. the appropriate method of limiting the rpm is taken) when other conditions are met. The 'Rev Limit Hysteresis' (aka PIPLIMHYT) scalar is used to determine when the rev limiting action is to stop.

cbrown9064
Gear Head
Posts: 49
Joined: Sun Nov 02, 2014 1:04 pm
Location: Mandan, ND

Re: EECV rev limits

Post by cbrown9064 » Mon May 14, 2018 6:26 am

Thanks for the info!

So,how would I find out what these scalars are actually doing in my calibration? Box is a LLX3. Am I understanding this right in that while 3 stages of rev limit may be available in CDAN4, not all may be used on my box?

Who would know?
1996 Cobra, Novi 2k, S-D 60 lb/hr, SCT BA5k, Paxton IC, QH, BE, Innovate AFR,

sailorbob
BIN Hacker
Posts: 1651
Joined: Tue Jul 12, 2005 6:10 am

Re: EECV rev limits

Post by sailorbob » Mon May 14, 2018 7:14 am

You can only tell by looking at what the various rev limit scalar values are to determine whether a particular rev limiter is used. An example would be if the 'Rev Limit Low Gear Stage 2' (aka NLMTLO_0) parameter was set to a higher rpm than the 'Rev Limit Low Gear Stage 3' (aka NLMTHI_0) parameter then you would not encounter stage 2 rev limiting when in a low gear.

cbrown9064
Gear Head
Posts: 49
Joined: Sun Nov 02, 2014 1:04 pm
Location: Mandan, ND

Re: EECV rev limits

Post by cbrown9064 » Mon May 14, 2018 9:37 am

Awesome, thanks!

In my CDAN4 strategy, these do not show up with names like that or anything starting with "FN". Will send the guys at Coretuning a message.

CB
1996 Cobra, Novi 2k, S-D 60 lb/hr, SCT BA5k, Paxton IC, QH, BE, Innovate AFR,

motorhead1991
Regular
Posts: 92
Joined: Tue Nov 21, 2017 2:32 am

Re: EECV rev limits

Post by motorhead1991 » Mon May 14, 2018 11:40 pm

Neither does my FLH2, if that helps.
1990 Ford Ranger FLH2 conversion. Ford forged/dished pistons, Total Seal file-fit rings, Clevite rod and main bearings, Clevite cam bearings, IHI turbo, Siemens Deka 60lb/hr injectors, Ford slot MAF in custom 3" housing. Moates Quarterhorse with Binary Editor, using the PAAD6 database.

OpenEEC Telegram Chat:
Telegram

Post Reply

Who is online

Users browsing this forum: No registered users and 22 guests