4AGZE troubleshooting

[TERRA Operative]

Be sure to use good quality capacitors. Rubycon and Nichicon are available from RS Components.
(You can go to their trade counter and pick them up, but you have to buy in multiples of 5).
I can send you the required capacitors at cost price plus postage if you give me a list of what you need and the part number from your ECU.

If not, at the very least be sure to use low ESR capacitors. Jaycar sell them but they aren't quite as good quality as the ones from RS Components.

[cjeff]

Hi Terra,

Thanks for the advice on the capacitors. My mate replaced all the leaked ones over the weekend. He also found one of the tracks on the board completely burnt out, so he soldered in a bypass around it.

So for the good news - my car now starts! There seems to be some slight residual issue, but I'm sure the the not starting at all was completely due to the ECU. It's running the best it's ever been since I dropped it off to the workshop.

[cjeff]

OK, could someone confirm whether having the ECU unplugged for 3 days would clear the Check Engine Light (CEL) codes? The car is now idling quite fine but the CEL is still on.

In summary, this what happened this arvo. Took my freshly re-soldered ECU back to car and plugged it in. Turned on ignition and all dash lights were there this time. Fired it and it started instantly. However it stalled about 10-15 secs later. Tried this about 5-6 times all to the same effect, including trying to rev the engine - revving resulted in instaneous stall. After that, fired it one more time, but this time, after it started, turned the key back to 'start' position one more time and revved it simultaneously. This time it instantly revved. Let the key go, and just revved it with the accelerator. After a minute or 2 of revving it, I dared to stop revving and the car idled perfectly. CEL light remained on.

Once the engine was warm. Switched it off, switched it back on again, started and revved fine. However, all isn't quite right yet. The Fuel Relay is constantly clicking, so something is telling it to constantly switch on off. When revving it to, there is just a small hesitation and a slight miss here or there, but pretty good. I tried bridging the diagnostics again in the diagnostics port, but still got nothing. I tried bridging quickly at the back of the ECU, but got nothing as well - that said, I'm not very confident that that piece of wire I was using was connecting very well, so my mech is going to try again tomorrow.

My mech is also just going to make sure the power and earth to the fuel pump is working properly tomorrow (ie he may re-wire the fuel pump).

So if anyone has any suggestions as to the Fuel Relay clicking, or clearing the ECU codes, or the car needing an extra turn of the start key, I'm all ears...

Cheers for all your help - Craig

[TERRA Operative]

Check the codes and tell us what they are.

http://forum.4age.org/index.php?/top...gnostic-codes/

[punkture]

CJEFF, to be honest, seems very iffy. When mine was doing this, i found the signal to the injectors was very very low and caused alot of issues (confirmed by autoelec specialising on transplants.) I would test the starter signal fromt he key to the relay etc, thatd suss your key turn issues, as for running, are the plugs fouling?

[old_mr2]

Hey mate, use a paperclip to bridge to terminals. It should take you 3 seconds to do this... Report back with codes. Remember, if there is more than 1 code, there will be a 5 second pause between each code given and they will be in numerical order

eg 41, 43, 46, 49.....

[cjeff]

Hey mate, use a paperclip to bridge to terminals. It should take you 3 seconds to do this... Report back with codes. Remember, if there is more than 1 code, there will be a 5 second pause between each code given and they will be in numerical order

eg 41, 43, 46, 49.....

It seems as though the diagnostics port isn't wired properly as I tried that and it wouldn't flash.

I jammed the same wire into the back of the ECU pins T1 and E1 and got nothing, but because I couldn't reach the ignition key and the ECU at the same time, I couldn't guarantee that the wire on the back of the ECU was making a proper connection to the 2 pins. No one was able to help me at the same time. So going back today to check it out.

[old_mr2]

a paperclip is nice and stiff so it wont fall out mate...

PS simply resetting the ECU should clear any stale codes, doesnt take 3 days IME...

[punkture]

It seems as though the diagnostics port isn't wired properly as I tried that and it wouldn't flash.

I jammed the same wire into the back of the ECU pins T1 and E1 and got nothing, but because I couldn't reach the ignition key and the ECU at the same time, I couldn't guarantee that the wire on the back of the ECU was making a proper connection to the 2 pins. No one was able to help me at the same time. So going back today to check it out.

??? just jam the wire in there then turn the ig on? worst case scenario, probe the two wires..

[cjeff]

ok, time for an update. managed to get a lend of an ECU for a few mins today.

Change of ECU hasn't solved anything. Car runs, but engine check is still on. It seemed to be revving a bit better with the ECU, but not sure. So basically, light throttle loads and it revs okay, harder throttle like 30% or more and it stutters and leans out. I noticed that in just neutral, revving it harder causes the supercharged to come in - should that happen even in neutral?

Checked the new ECU for the codes and it flashed the all clear - even though it was showing "engine Check" whilst running. Does it need 2 trip logic test thing done, or is it just something else?

Starter motor has crapped itself from all the extra key turning we've been doing
so to get it started this time, we just pushed it. Interestingly, the car got to it's normal, being able to rev it fine situation directly after push starting without needing to "turn the key" to "start".

So in summary...

Anyone know why engine check light would light up, yet flash all clear signal? Is it anything to do with 2 trip detection logic?

Is the Supercharger coming in revving it in neutral normal?

Any other suggestions?

Cheers - Craig

[JP]

ECU might not store codes if the constant power isnt wired correctly, it might also run like a dog if the STA starter on trigger to the ECU is wired to ignition 12V....

The supercharger switching on when revving hard in neutral is normal.

[cjeff]

Hi JP, thanks for the heads up on the constant power issue. I've got a wiring diagram, which pin on the ECU has constant power? Is it BATT?

Cool on the Supercharger

Not sure why it would run like a dog if STA is wired to ignition? And if that's the case, why would it have been running fine for 2 days and then just start playing up? Not saying you're wrong, I just want to understand how it could cause the issue?

Cheers - Craig

[JP]

If STA receives a constant 12V while the engine's running, the ECU believe's it's always cranking and will run like crap with the CEL on. I've seen a couple of poorly wired conversions do that now.

BATT is the constant 12V feed, the +B's are ignition switched 12V.

[old_mr2]

perhaps there is a loose wire that is grounding to chassis on occasion? Go over your wiring and look for shorts etc

[cjeff]

Alrighty, latest update...

Car got a new starter motor a couple of weeks ago as the bearing that failed bore out some of the casing so it wasn't able to be rebuilt, so $$$ gone there.

Finally found the MAP sensor and tried unplugging it - made no difference at all.

Have finally conceded and dropped it off to QuickFit Motorsport in Hornsby at lunchtime. They seem to think that it won't be too hard to find, but after 10 weeks off the road I'm a little skeptical...

Craig