Why all Griffith malfunctions have always a touch of extra..

[panic]

...drama?

My case right now:

Griffith 500 in good order, engine rebuilt, a few solid mods (triple plenum, larger AM, Marks's chip, sport decatted exhaust, new plugs, new battery)...it starts and keeps the idle with grace, smooth like silk....problems start when warming up, the engine does not rev happily, you can feel at the exhaust notes of boom bam releasing the right pedal and a strong smell of unburnt fuel.

The cherry on the mountain of s....the engine might suddenly stop altogether at once and without any prior sign...all these peculiarities happen when the engine warms up, still it keeps the rumble at idle, but when you want to put down the right pedal all sorts of malfunctions start to wake up and the engine gets crazy, the engine does not pull.

I need help here, really.

Thanks in advance.

[FFMan]

I would recommend a short diagnostic rolling road session with an ignition analyser - you'll get to the bottom of the issue pretty quickly.

[V8 GRF]

That sounds electrical to me. Poor connection breaking down somewhere when everything gets hot.

I'd check for a poor earth and then the various ignition components, spark plugs, leads, distributor cap, rotor arm, amplifier, coil, battery cable etc.

ETA I'd try a rest of teh ECU as well by unplugging and leaving off for 30 seconds or so. You may need to re-educate the stepper motor to hold the idle when you first restart the car though.

Edited by V8 GRF on Thursday 2nd October 09:39

[FlipFlopGriff]

You might need to set the car up again and remap after all those changes.
FFG

[panic]

What if it was the cable into the AM, I'll clean it with forced air and will post the results.

Thanks for all the contributions and inputs.

[PeteGriff]

Was the AFM CO trim voltage reset after the chip addition? If you are still using the standard fitment AFM there is an adjuster at the side of the housing (may be capped off with a small plug) Any change in chip which changes fuelling will need a trim on the AFM to ensure proper air/fuel ratios! Ask Blitzracing or SteveSprint on this forum. Regards, Pete

[blitzracing]

Hes running a larger AFM with a Mark Adams chip- so the CO is not adjusted on the AFM any more. The wiring loom is modified to use the CO trim wire to carry 5 volts from the ECU to the AFM, and a variable resistor is then wired into the loom- its pretty messy, unless its been updated since the last one I saw. Hopefully if hes running lambda's he wont need to tweek the CO trim anyway. There are far to many un knows here to even start guessing! The very least you need is a fault code reader as if the AFM output is missing if will flag up an error code. Better than just a fault code reader is an ECUmate for basic sensor code data, or if you want to really see what's going with the fuelling and ECU then RoverGauge software on a laptop and a cable that shows everything that's going on in the ECU at the same time. I have to ask the question- has this ever run OK, or is it a new set up?

[panic]

My Griffith is decatted since day one...

Today I've cleaned the plug into the AM and have unplugged the EU box for a couple of minutes, the engine seems run smoother.

Anyway the mess that there is in the EU box + battery area is incredible, I'm really thinking of swapping in a nice quadruple carb and dump the whole tons of loosing cables away and get a cleaner set up.

I might get some money from my triple ACT carbon plenum plus ancillaries to pay me a new carb.

[stevesprint]

PeteGriff said:

If you are still using the standard fitment AFM there is an adjuster at the side of the housing (may be capped off with a small plug) Any change in chip which changes fuelling will need a trim on the AFM to ensure proper air/fuel ratios

Peter,
That's correct for us precat owners, but sadly for Griff 500 owners the CO trim voltage is literally controlled by the lambda probes to lock the AFR to 14.7. I say sadly because precat owners have more flexibility, for example we can run a richer mixture at slow speed to stop shunting and a smoother idle. So when you buy a Griff it just simply has to be a precat!!!

blitzracing said:

The wiring loom is modified to use the CO trim wire to carry 5 volts from the ECU to the AFM, and a variable resistor is then wired into the loom- its pretty messy,

Maybe I should add to the 14CUX wish list the option to set the CO trim in TunerPro to save the messing wiring with larger AFMs.

[Hoover.]

stevesprint said:

. I say sadly because precat owners have more flexibility, for example we can run a richer mixture at slow speed to stop shunting and a smoother idle. So when you buy a Griff it just simply has to be a precat!!!

Noted

having driven many variants of the Griff I really wouldn't swap my pre-cat .... there is just a little something mechanically missing from the supposedly more powered 500s (ie power delivery, sprightliness, and last of all noise )

[Pasco]

Hoover. said:

Noted

having driven many variants of the Griff I really wouldn't swap my pre-cat .... there is just a little something mechanically missing from the supposedly more powered 500s (ie power delivery, sprightliness, and last of all noise )

Supposedly ? I guess your referring to standard spec 500 mate ?

[tvrcos]

Hi, had the same problems with my modified griff 500 (triple Plenum, cam, bigger am, Tornado Chip, etc.). The car showed the same malfunctions. Every part was checked, in the end problems could be completely solved by mapping the ECU. The Tornado Chip did not work with the bigger am and the triple plenum to get the correct mixture for load and revs, the mixture was too fat in the middle range, too lean on higher revs, the car was a pain to drive in town. After the mapping it drives like a well sorted griffith 4.3.