Intermittant running issues

[FFMan]

L reg Griff 500 with Mark Adams rolling road tuned, larger injectors etc - has been running perfectly for a few years. When we mapped it, it had new coil, leads plug, dizzy cap etc, and that was <4000 miles ago.

Out the other night and we hit a bump (i think) and got a misfire, sounded like one bank had dropped out but actually suspect it won't run on four so maybe not that much but a misfire and didn't want to rev and a strange smell, not fuel small but not there normally. Turned it off, checked leads and everything, nothing found, and it fired up ok.

2 miles further on, engine completely died, coasted to a stop - did another road-side check, nothing found, and it restarted and drove the next 20 miles without issue and sounding ok, no stalling.

it has also been intermittent stalling when coming to a junction. Road speed sensor is working, i think stepper might need cleaning but i don't think that can explain the cutouts ?

Got rovergauge on it today, no faults stored and it starts and idles ok. Grabbed a log of it at idle and a few rev ups. Only thing i notices is long term trim shows -100% on both banks, not sure if this is usual, and when running left bank consistently shows more short term trim.

1. datetime,roadSpeed,engineSpeed,waterTemp,fuelTemp,throttlePos,mafPercentage,idleBypassPos,mainVoltage,currentFuelMapIndex,currentFuelMapRow,currentFuelMapCol,targetIdle,lambdaTrimOdd,lambdaTrimEven,pulseWidthMs

2022-05-08_11:43:16.166,0,1987,72,15,0.162268,0.0871024,0.405556,13.56,5,1.25,8.6875,898,-13,-140,2.136
2022-05-08_11:43:16.773,0,1938,72,15,0.162268,0.0883169,0.405556,13.56,5,1.3125,8.625,898,-73,-88,2.229
2022-05-08_11:43:17.430,0,1932,72,15,0.162268,0.0879699,0.405556,13.63,5,1.3125,8.5,898,-21,-165,2.366
2022-05-08_11:43:18.071,0,1972,72,15,0.162268,0.0869867,0.405556,13.49,5,1.25,8.625,898,-81,-81,2.275
2022-05-08_11:43:18.745,0,1960,72,15,0.16129,0.0871024,0.405556,13.42,5,1.25,8.625,898,-6,-165,2.199
2022-05-08_11:43:19.332,0,1965,72,15,0.16129,0.0883169,0.405556,13.42,5,1.25,8.625,898,-92,-79,2.15
2022-05-08_11:43:20.035,0,1983,72,15,0.16129,0.0869867,0.405556,13.42,5,1.25,8.6875,898,-6,-172,2.182
2022-05-08_11:43:20.643,0,1974,72,15,0.162268,0.0871024,0.405556,13.49,5,1.25,8.6875,898,-34,-79,2.321
2022-05-08_11:43:21.301,0,1951,72,15,0.162268,0.0873337,0.405556,13.49,5,1.3125,8.625,898,-65,-109,2.194
2022-05-08_11:43:21.943,0,1969,72,15,0.162268,0.0873337,0.405556,13.49,5,1.1875,8.625,898,-25,-74,2.292
2022-05-08_11:43:22.626,0,1928,72,15,0.0801564,0.0669751,0.45,13.49,5,0.875,8.25,898,-32,-135,2.12
2022-05-08_11:43:23.209,0,1518,72,15,0.0801564,0.0668595,0.427778,13.42,5,1.3125,7.25,898,-69,-141,2.256
2022-05-08_11:43:23.912,0,1301,73,15,0.0801564,0.0641411,0.427778,13.42,5,1.5,6.625,898,-97,-169,2.33
2022-05-08_11:43:24.520,0,1062,73,15,0.0801564,0.0633314,0.427778,13.49,5,1.9375,5.8125,898,-87,-196,2.421
2022-05-08_11:43:25.174,0,1007,73,15,0.0801564,0.0613071,0.422222,13.49,5,2.0625,5.5625,898,-69,-148,2.67
2022-05-08_11:43:25.818,0,1072,73,15,0.0801564,0.0621168,0.416667,13.49,5,1.875,5.8125,898,-50,-129,2.487

i'm going to check out the ecu mount and wiring next as issue might be related to the bump but i can't be sure.

Any help much appreciated.

[FFMan]

One thing i did notice while checking the wiring was that the relays on the fuse panel were all pretty cold, except the big yellow one bottom left corner mark 2KE500.

This was lightly warm, which given the ignition was off seems odd doesn't it ?

what does this relay control and should i replace it ?

Edit: I think this relay is courtesy light timer, so i guess it's ok it's warm as door was open

Edited by FFMan on Sunday 8th May 14:44

[Belle427]

Do you have any of the old parts to re install?
Some of the stuff available these days is complete junk and that includes Bosch coils.
I’m wondering if one of your new ignition parts is failing.

[FFMan]

i've got a spare coil, but the stuff came from the rolling road guy who Mark knew and I reckon it's a genuine coil etc, but i know they are prone to failure when mounted on their side.

I'm going to do a run in it Wednesday, think i'll take a spare coil and fit it at the road side if it plays up.

[Belle427]

Check the connections to the coil and module are all good and tight too.

[RobXjcoupe]

Check the earth lead and it’s integrity.

[blaze_away]

I can help by analysing RoverGauge data to identify possible problems.

To do the analysis I will need 10 minutes of idling data with engine at full operating temperature.

Set RG to
MAF - Direct
Throttle - Absolute
Trim - Short

If you'd like me to take a look just drop me a message via PH

[FFMan]

thanks - i'll take the laptop with me wednesday and get the nipper to record

thanks

[FFMan]

thanks fhe replies - i've check all the ignitions leads, ht leads, battery connections and all the ecu wiring looks sound.

i don't think mine has the much maligned 100amp fuse down low.

where are the main earths to be found ?

[blaze_away]

I can help by analysing RoverGauge data to identify possible problems.

To do the analysis I will need 10 minutes of idling data with engine at full operating temperature.

Set RG to
MAF - Direct
Throttle - Absolute
Trim - Short

If you'd like me to take a look just drop me a message via PH

[Teamred]

Try replacing the amplifier module on the side of the distributor. These can give intermittent trouble prior to complete failure and won't show up on the Roverguage.

[FFMan]

So a little update - cos the b*gger died tonight.

Since last post, i checked all the wiring connections, and did the wiggle test while it was running. Pulled out the ecu wiring, nothing found.

Took it on a 40 mile round trip last week - good as gold.

Took it out Wednesday evening 40 miles, good as gold.

Tonight on the way home it died and we were coasting down the road on dead overrun. I dipped the clutch, killed the ignition and tried to restart it but it wouldn't. Dropped it into gear and bumped it, thought it wasn't going to catch, then whoosh, picks up and goes and is fine.

Now, i had since the last post temporarily fitted a digital rpm gauge from the 80s. It was meant for 4 cylinders but when the engine died, it was still registering rpm, which means the coil was still firing as it hooks into the 'points' side of the coil, and the ignition circuit was still powered (so not completely dead electrics)

I haven't changed the ign amp yet as when i came to do it, i recalled it wasn't very old, or maybe age isnt a thing - can they go bad any time ?

Any ideas ?

[RobXjcoupe]

The ignition amplifier was playing up on my car when I first bought it. Start up fine but when up to temp and just taking it easy with light throttle, you could hear it missing every so often. Previous owner had said give it a blip to clean the plugs and it would be ok. Long story short, replaced the ignition amplifier and it ran perfectly. Only time it ever died was a faulty air flow meter. It would start but wouldn’t run. Took a while to figure that one but found it, replaced it and all was good again. I was told tvr removed the limp mode from the ecu so if a fault occurs the system won’t let the engine run. No idea if that’s true?