1994 400HC Fuel map confusion.
Discussion
I have had occasional idle issues and so finally fired up the Rovergauge I bought last year. My car is a 1994 400HC, so has lambdas/ CATs , but when I look at the Rovergauge it shows I have Fuel Map 2, and Tune 2967.
Rovergauge also has the lambda trim type greyed out which suggests to me it can't communicate with them?
Google and the usual RV8 sites suggest that R2967 is indeed a 400cat ecu tune, but Map 2 seems to turn up as a non cat map, supported by what I see wrt the lambdas being greyed out.
At warm idle I have idle bypass reading of 9%, is this too low?
MAF reading direct 31%
Throttle corrected 0%
Hopefully someone can make sense of this and offer me some guidance on whether I have an issue here or not.
Cheers
Iain.
Rovergauge also has the lambda trim type greyed out which suggests to me it can't communicate with them?
Google and the usual RV8 sites suggest that R2967 is indeed a 400cat ecu tune, but Map 2 seems to turn up as a non cat map, supported by what I see wrt the lambdas being greyed out.
At warm idle I have idle bypass reading of 9%, is this too low?
MAF reading direct 31%
Throttle corrected 0%
Hopefully someone can make sense of this and offer me some guidance on whether I have an issue here or not.
Cheers
Iain.
Quick google suggest £30 for a new one....
Making one...is it as simple as cutting off my existing one and soldering and insulating a new one to the existing connector. I assume Marlins for the resistor is okay, and am I asking for something specific, I read that the existing are 1/2 watt, but mention on a 1 watt being compatible and easier to use.
Thanks for the help Steve.
Making one...is it as simple as cutting off my existing one and soldering and insulating a new one to the existing connector. I assume Marlins for the resistor is okay, and am I asking for something specific, I read that the existing are 1/2 watt, but mention on a 1 watt being compatible and easier to use.
Thanks for the help Steve.
http://www.maplin.co.uk/p/metal-film-06w-39k-ohm-r...
Mark/Blitz, cheers for response, does the one above look suitable?
From the first post do you agree my car appears to have the wrong map in place, and should I be concerned/have the opportunity to improve significantly the engine efficiency with something new from the work done by others to apply more modern maps.
Grateful for the help, great to have a forum to canvass opinion and help from.
Iain
Mark/Blitz, cheers for response, does the one above look suitable?
From the first post do you agree my car appears to have the wrong map in place, and should I be concerned/have the opportunity to improve significantly the engine efficiency with something new from the work done by others to apply more modern maps.
Grateful for the help, great to have a forum to canvass opinion and help from.
Iain
Okay, picked up a 3900ohm resistor from Maplins, soldered into the plug and as the gurus suggested, I now have an ecu running map 5, lambda so can watch trimming at idle. Not had time to do much more but will use it for work tomorrow.
Might be wishful thinking, but car seemed to be less rich when idling in garage , last night I had burning eyes from the fumes....
One question for blitz or Steve, there is a bit of an offset between the 2 lambdas,I'll monitor to see if they continue in that state once it's done a few miles.
I'll try the heat shield as well, and the inlet hose looks rough, anyone come up with a budget alternate to the usual suspect for replacement.
Might be wishful thinking, but car seemed to be less rich when idling in garage , last night I had burning eyes from the fumes....
One question for blitz or Steve, there is a bit of an offset between the 2 lambdas,I'll monitor to see if they continue in that state once it's done a few miles.
I'll try the heat shield as well, and the inlet hose looks rough, anyone come up with a budget alternate to the usual suspect for replacement.
Update - I fitted the resistor , map now shows as Map 5 , and car run okay for the 60 miles I did with the laptop on the passenger seat, bit of low speed shunting, and occasional high idle at rest for a period of a few seconds.
I suspect that I may need to check / set base idle and CO/AFM from basic start up again, as the car has has lambdas and an AFM in the period immediately before I got the car, so it may never have been correct since whatever caused the car to be fitted with a 480 ohm resistor, which on inspection looks like another home made affair ....
However, yesterday (Rovergauge left at home) the car got into a real kangaroo mode, cut out and wouldn't restart , wouldn't clear until I did a ECU reset so didn't catch the codes or Rovergauge data...
What does the ECU reset instantly that would have caused such poor running and failure to start...if I know that it may narrow down my fault area somewhat.
I intend to go back to the start , and check for air leaks, test again the Stepper motor ( wiring faults to these???) as my original symptom was poor idle and shunting that I did not experience previously.
I believe it's my own fault since I advertised it for sale, I may rename it Herbie! 5000miles lst yr and never missed a beat despite the wrong map....hope I have done the right thing getting it back to the right one...sometimes ignorance is bliss!
Iain.
I suspect that I may need to check / set base idle and CO/AFM from basic start up again, as the car has has lambdas and an AFM in the period immediately before I got the car, so it may never have been correct since whatever caused the car to be fitted with a 480 ohm resistor, which on inspection looks like another home made affair ....
However, yesterday (Rovergauge left at home) the car got into a real kangaroo mode, cut out and wouldn't restart , wouldn't clear until I did a ECU reset so didn't catch the codes or Rovergauge data...
What does the ECU reset instantly that would have caused such poor running and failure to start...if I know that it may narrow down my fault area somewhat.
I intend to go back to the start , and check for air leaks, test again the Stepper motor ( wiring faults to these???) as my original symptom was poor idle and shunting that I did not experience previously.
I believe it's my own fault since I advertised it for sale, I may rename it Herbie! 5000miles lst yr and never missed a beat despite the wrong map....hope I have done the right thing getting it back to the right one...sometimes ignorance is bliss!
Iain.
I'm away for weekend, so will get back to it on Tuesday.
When I first set it to the white map , the long term trim seemed to set up to odd bank at -45 and even to -25 after idling for 10 mins or so at full temp, fans cutting in and out.
For info, no plug extenders, just a set of leads straight onto plugs (!) Not given any bother, and no arcing witnessed under bonnet in darkness (not scientific I grant you ) . I will revisit these also, and look at whether extenders might be a wise purchase.
As always ta for advice....time is my enemy at the moment, but I don't know if there is anyone local to central Scotland who would actually do the basics and not simply throw parts and (my) money at the problem...
Cheers, Iain.
When I first set it to the white map , the long term trim seemed to set up to odd bank at -45 and even to -25 after idling for 10 mins or so at full temp, fans cutting in and out.
For info, no plug extenders, just a set of leads straight onto plugs (!) Not given any bother, and no arcing witnessed under bonnet in darkness (not scientific I grant you ) . I will revisit these also, and look at whether extenders might be a wise purchase.
As always ta for advice....time is my enemy at the moment, but I don't know if there is anyone local to central Scotland who would actually do the basics and not simply throw parts and (my) money at the problem...
Cheers, Iain.
Mmmm,
Got some of that ....my car has a master battery isolator, which doubled as ECU reset in this instance, so I guess that clears the RAM also.
If the ECU is suspect, what is the best source of a reliable replacement, and is there differences between the TVR ECU's and the Land Rover parent unit which you read the part number from on the labels..
Does anyone do bench testing of the units that I could send mine to for checking?
As an aside, is it usual to have "400 HC" written in magic marker on the ECU , or is that an indicator that my car may already have had an ECU change and someone writes this onto a used ebay special and marks price up accordingly...
Got some of that ....my car has a master battery isolator, which doubled as ECU reset in this instance, so I guess that clears the RAM also.
If the ECU is suspect, what is the best source of a reliable replacement, and is there differences between the TVR ECU's and the Land Rover parent unit which you read the part number from on the labels..
Does anyone do bench testing of the units that I could send mine to for checking?
As an aside, is it usual to have "400 HC" written in magic marker on the ECU , or is that an indicator that my car may already have had an ECU change and someone writes this onto a used ebay special and marks price up accordingly...
Steve,
The resistor was not like your photo, it was in a bit of black heat shrink and wires cut back a bit shorter . So probably been changed by someone.
Interestingly I was cycling past be of the old TVR dealers in Scotland , popped in to see if anyone still worked there with RV8 memories, and the owner and mechanic ( young lady unusually) were both adamant that the Chim RV8's should always have 460 ohm resistors and by fitting the 3900ohm one I had somehow caused all my own issues......despite some negative comments about owners messing about with their own cars , they did seem knowledgable , albeit some opposing views to everything I can read online. ( another sin, Internet research, it would seem) .
So , anyone else's Chimaera with cats been supplied from the factory not running a Cat fuel map?
A little knowledge is dangerous, hence why I'm trying to learn a little more....lol.
Cheers, Iain.
The resistor was not like your photo, it was in a bit of black heat shrink and wires cut back a bit shorter . So probably been changed by someone.
Interestingly I was cycling past be of the old TVR dealers in Scotland , popped in to see if anyone still worked there with RV8 memories, and the owner and mechanic ( young lady unusually) were both adamant that the Chim RV8's should always have 460 ohm resistors and by fitting the 3900ohm one I had somehow caused all my own issues......despite some negative comments about owners messing about with their own cars , they did seem knowledgable , albeit some opposing views to everything I can read online. ( another sin, Internet research, it would seem) .
So , anyone else's Chimaera with cats been supplied from the factory not running a Cat fuel map?
A little knowledge is dangerous, hence why I'm trying to learn a little more....lol.
Cheers, Iain.
I'm on hold as during the latest search through the components possibly contributing to occasional poor running and idling, I've found a couple of plug leads with signs od arcing and degradation.
New set of Bosch leads ordered, and a new Bosch coil while I was at it.
I'll get the stepper motor out to check operation as the recent test resulted in high idle from start ,not correcting down even after 20 seconds or so running. Ignition off is resulting in the stepper making a noise as if its returning, but something is amiss.
I will add some thermal socks I think to protect the leads a little from the direct radiated heat from the manifolds. I expect a bit of response to this , seen lots and lots of commentary elsewhere....
Iain
New set of Bosch leads ordered, and a new Bosch coil while I was at it.
I'll get the stepper motor out to check operation as the recent test resulted in high idle from start ,not correcting down even after 20 seconds or so running. Ignition off is resulting in the stepper making a noise as if its returning, but something is amiss.
I will add some thermal socks I think to protect the leads a little from the direct radiated heat from the manifolds. I expect a bit of response to this , seen lots and lots of commentary elsewhere....
Iain
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