Car only goes up to 3k rpm??

[Drifter]

*AFM VOLTAGE*

Does anyone know what voltages the AFM wires should be (on stock S14a AFM)??

I measured them today and:

BLACK & WHITE = 14.4V
WHITE = 1.4V


Incidentally I've swapped the AFM now for another stock one (thanks Mattie!) but it's not got it out of limp mode However, the WHITE wire for the AFM has suddently completely broken itself off at the harness plug end so more soldering to do and try again grrr!!!!!!

From the service manual

White wire should see 0.8-1.5v at idle and 1.4-2.0v at 3000rpm

[clive]

It's definitely in limp mode as the ECU check light is on

(although it did do this before I got the H-Dev chip fitted).

I don't even remember whether it goes past 3k revs when in neutral lol Definitely did it in all gears I tested

2. Does it have to be an ECU very specific to the S14a? Also are s:

A) wft man. What sort of 'mapper' is playing around with someone else 'chips'

B) " It's definitely in limp mode as the ECU check light is on

(although it did do this before I got the H-Dev chip fitted). "

So you had a problem with the car before fitting the chip! Why fit a chip to a faulty car?



Yes I can see your fed up with the car, but one needs to build some good foundations before building Rome dude...

- Clive -

[JC SX]

http://www.h-dev.co.uk/article.php?article=26

When I had my stage 1a chip fitted by h-dev he definitely changed the timing.
Worth asking him what it should be set as

[JC SX]

http://www.h-dev.co.uk/article.php?article=25

Read last line on that article

http://www.h-dev.co.uk/article.php?article=17

If you have a Nissan car, retard your ignition timing - with my Nissan ECU upgrades 14-15 deg BTDC is usually OK. However, your engine may be different and you may be able to get away with more or have to use less ignition advance. If you have to retard it to 13 deg or less then you may want to try stopping detonation using a different method.

[James_S15]

From the service manual

White wire should see 0.8-1.5v at idle and 1.4-2.0v at 3000rpm

It's definitely reading this so I'm comfortable the AFM wiring is ok now (although I need to get a replacement harness and sort this out properly as soon as it's out of limp mode).

Thanks dude

[James_S15]

A) wft man. What sort of 'mapper' is playing around with someone else 'chips'

B) " It's definitely in limp mode as the ECU check light is on

(although it did do this before I got the H-Dev chip fitted). "

So you had a problem with the car before fitting the chip! Why fit a chip to a faulty car?



Yes I can see your fed up with the car, but one needs to build some good foundations before building Rome dude...

- Clive -

A) Because they officially sell and install Jez's stuff... what's the problem with this when they already done about 40 to 50 units without any issues?? It's not rocket science if you know how to solder, de-solder and do mapping as a your professional job?!

B) The ECU light was only intermittent before I had this done and I presume because I stripped out the car that it was something I removed that cause the ECU light to come on. I drove fine for 40 mins on Castle Combe (albeit was smokey) so I went for upgrade chip thinking it would solve my A/F or fuelling related issues since I upped the boost on stock ECU...


I'm reverting the ECU back to stock today anyway so we'll see if this gets it out of limp mode.

[Jez]

Sounds like the ECU was in limp mode to start with, due to the dogy soldering. Then the chip was fitted and it was still in limp mode. Ignition timing shouldn't need to be changed, it needs to be at the standard 15 deg BTDC unless you're getting knock. If you're getting knock you must find out why and fix it.

[James_S15]

Sounds like the ECU was in limp mode to start with, due to the dogy soldering. Then the chip was fitted and it was still in limp mode. Ignition timing shouldn't need to be changed, it needs to be at the standard 15 deg BTDC unless you're getting knock. If you're getting knock you must find out why and fix it.

These are my exact thoughts now Jez - I didn't realise the ECU was in such a bad state till Gav told me about it So previous owner had fecked around and removed previous daughter board and seems to have butchered it!!

I'll get it back to stock with jumper change (believe it's jumper R020 -> R021 to revert the changes). If this still doesn't do it then I'll get a replacement ECU and try this.

As everyone says it's back to basics and get it working STOCK before I do anything with the chip and board etc.


Thanks everyone - appreciate the advice

[Jez]

You need to do the jumper and remove the board. You can't just move the jumper on its own.

[James_S15]

Nice one - I'll make sure I do both and see what happens. Although having just opened up the ECU, the area around the jumper I need to switch looks like it's seen better days! I'm thinking I'll have to resort to getting a replacement 82F04 ECU


Question - if I were to replace the ECU and start from scratch (get her running perfect before I attempt to fit the board and move jumper) do I have to get the replacement ECU 'syncronised' so it actually works when I turn the key?

Is this done using Datascan?

[James_S15]

Question - if I were to replace the ECU and start from scratch (get her running perfect before I attempt to fit the board and move jumper) do I have to get the replacement ECU 'syncronised' so it actually works when I turn the key?

Is this done using Datascan?

No need to answer - just found the answer on some searches!


Jez - I'll be giving you a call tomorrow as I'll need to get the software and cable to do this

[Jez]

I'm not in tomorrow but Kyle will be able to help

[James_S15]

I'm not in tomorrow but Kyle will be able to help

Cheers Jez - will speak to Kyle


The plot thickens lol...

1. Switched jumper back to stock on ECU.
2. Removed the daughter board (i.e the two ribbons).

*No more ECU check light - it's gone!
*Drives fine and boost as expected.


I'm thinking I maybe had intermittent ECU light before the board/chip was fitted because of my dodgy AFM. At least by replacing the AFM this weekend that's one possible point of failure covered so shouldn't have to worry about that one again.

Thinking about the next step, I'm still convinced my ECU is not looking in the best state so if I can source a replacement ECU which HAS NOT been tampered with then I'll go from here.


Thanks for all the help and replies... starting to feel less stressed and hopefully car will perform ok at Donny following weekend

[Ghazoobe]

Bumping this thread instead of starting my own as I'm having the same sort of problem. Having read this I will try checking the AFM tomorrow but....

I had a standard ECU in there and it was doing it at usually about 3.5k rpm, now put in an ecu with a stage 1a hdev chip and it does it at 3k rpm more often than any other rev range. Although its been happening anywhere from 3k to 4.5k, I haven't been over 4.5k though to find out if it happens any further.
If I let off the accelerator as soon as it happens then it backs off and then seems fine, however if I don't let off instantly then the ECU (engine) check light starts flashing and it goes into some kind of limp mode.

[200sxAndy]

Sorry to bump an old thread, but what was the outcome of this in the end? I seem to have exactly the same issue (H-DEV Stage1A chip in = CEL and limp mode, remove chip CEL = off and normal operation). Was it the MAF/AFM or dodgey soldering? Cheers

[200sxAndy]

Sorry to bump an old thread, but what was the outcome of this in the end? I seem to have exactly the same issue (H-DEV Stage1A chip in = CEL and limp mode, remove chip CEL = off and normal operation). Was it the MAF/AFM or dodgey soldering? Cheers

It turns out that I was a numpty. One of the connectors on the ribbon cable for the Chip wasn't quite aligned. I re-crimped it and it works perfectly!

[Ghazoobe]

Sorry to bump an old thread, but what was the outcome of this in the end? I seem to have exactly the same issue (H-DEV Stage1A chip in = CEL and limp mode, remove chip CEL = off and normal operation). Was it the MAF/AFM or dodgey soldering? Cheers

Mine issue turned out to be sparkplugs, even though they were fairly new at least one of them must have been dodgy as I sold the car to someone (with a spare set of plugs and a with a few hundred quid off the asking price due to it not running right) and he wasn't having any luck figuring it out either and one day changed the plugs and after that it worked fine!