rallydad

OK, so As far as I know the cold start injector runs for about 4 seconds on startup. I disconnected it and no difference to the (non) rev pattern so that one is eliminated. Interestingly when using medical burn spray( makes things cold quickly) on the ignitor once it is hot sees a brief rise in revs. This begs the question is the ignitor knackered? I was under the impression that these electronic components tend to just fail and stop working. Can anyone enlighten me? Too damn cold and dark in the carport to do any more it will have to wait for the weekend.

Thanks guys, I agree that heat could be playing a factor here, however, if it is just heat this can be detected as a faulty component by the ECU bringing the ignition timing back to TDC at 5,000 rpm? We don't have any wreckers here with 4age bits and a new ignitor is dear as poison. Unfortunately I can't simply swap bits. I'll fit some heat protection and give the engine light a go before I start spending more cash and let you know how I go.

Hello all, First time post, long time reader. I have AE71 with JDM 4AGE bigport conversion. Car is running and driving fine except for a problem with the revs. I have checked fuel pressure it is a steady 40psi through surge tank setup with over 3 litres/minute flow through upgraded 8mm feed and 6mm return. Wiring has been completed using posts on this site and apart from a couple of little hiccups initially it fired up pretty much straight away. Thankyou to those who provided the knowledge! It has new coil, plugs, leads, dizzy cap and rotor.All of which were cross referenced at time of purchase to make sure they were the right ones. All earths have been cleaned and I have added a direct earth into the ignitor body. It also has the oxy sensor installed with shielded wire to the ECU to eliminate static interference. The problem is I can get a full 7,700 rpm out of the engine while it is warming up (not under load) but once heat starts to build in the engine and ignition system the revs drop back to around 5,000 max. The ignitor becomes very hot to touch (not mounted near heat source) and the dizzy also gets super hot as the #1 header pipe runs directly underneath. I intend to fit some heat shield/wrap to the headers asap but i suspect this is not the cause of the problem. I have calibrated the TPS (thanks again to rollaclub members) using the specs on this site. Ignition and cam timing is spot on. Wiring is a tidy splice of 4AGE engine loom into AE71 body loom. No pinched wires. New alternator putting out around 13.5 volts. I have built cars before but this is my first EFI conversion and I am stumped. I THINK i've narrowed it down to either the ignitor or the dizzy but unsure if these components slowly fail or just stop working suddenly if they are stuffed. The spark seems weak when tested at spark plug lead. Ignition timing tested with light at point of revs breaking down sees it come back to around TDC (this is limp mode?) There is a small oil weep into the dizzy from the shaft seal. I have considered fitting engine check light to ECU however with only 10 or 11 fault codes available i'm not sure whether my problem can be diagnosed by the ECU. Any suggestions from those who may have had this problem would be much appreciated! Many thanks.