I have code 21 - ignition signal circuit, causing my car not to start. This problem is obviously electrical, wiring diagram below: As per the factory service manual, i have investigated all options for fixing this fault, but still have no spark on all 6 cylinders. This was deduced by pulling out the coils, earthing them out and cranking the engine. The specifics are as follows: --> NEW PTU installed. --> NEW injector connectors installed -->New spark plugs -->NEW coil pack connectors. --> IGN relay operational, coil clicks closed when 12v applied, and continuity between other 2 poles. -->IGN circuit fusible link is ok. Every other fuse is ok. --> All connectors which havent been replaced have been checked, tensioned and sprayed with deoxit contact cleaner (this stuff is magic for cleaning contacts) -->Coil packs both show battery voltage when ignition key is on. (confirms ign relay is working) They are also earthed. -->Injectors operational. Each clicks when CAS is rotated, cylinder has fuel. -->Fuel pump working, pressure felt on fuel lines when engine is cranking. -->PTU has continuity between each pin and corresponding pin on the ECU harness. Wiring faults ruled out. -->Continuity between PTU connector and each coil pack. -->fusible link shows continuity to positive battery terminal. -->Earth points to rear of plenum are ok. no corrosion (i presume these are the engine earths?) -->Body earth point on passenger side chassis rail is fine. similarly, no corrosion. FSM suggests a Logic Probe to test for changes in current at the coil pack connectors. I have one of these, but dont know how to use it SO WHY THE BLOODY HELL WONT THE DAMN CAR START?!?! All you super sleuths out there help me out, because i'm stumped
Pull a plug and coilpack along with the CAS. Earth the bottom of the plug and twist the CAS and lookee for the spark. We had a similar problem with Marc's, ended up being a back to front fuel pressure regulator. What have you touched since it stopped working?
could be a dead CAS... have u checked that.. oh and just 2 make sure. check your fusible link just incase.... good luck
I'm no expert.. ...but in addition to what you have done, I would like to actually see the spark at the plug - i.e. pull the coilpack and plug, connect them together, press the threads of the plug to a suitable earth and crank the engine. Have you considered your new PTU may be a dud? Put the old one back for a test. As for fuel, I would like to see the actual fuel pressure reading rather than the sound of the pump priming up. Connect up a fuel pressure gauge and confirm it is all happening. You have probably checked this, but the ECU could fail to co-operate if all pins are not fully seated. Have you inspected the ECU pins and sockets to ensure nothing is bent or missing? When I were young (and cars had no sensors or ECUs), a crusty old mechanic told me that there are generally only three reasons why an engine won't go - spark, fuel and timing. It's probably still true today. The next thing to try is to exchange your units with known good ones - ECU, CAS, PTU, AFM, fusible link, etc, etc. I am not far from you and I have a few bits if that helps.
Hmmmm... CAS. I had it off when i tested the fuel injectors, but never thought of doing that for spark. I did a plenum pull ages ago, car ran fine for a good 2 months before it started idling rough, and wouldnt fire up. I suspected PTU from the start, but appears not to be the case. FPR is installed as normal. might replace vac hoses and zip tie them on just to be sure. Looking at the passenger side chassis rail, there are 2 separate earth points- one down below the relay box, the other is right down low near the hard pipe/carbon cannister vac tubes. Does anyone know what this earth point is for? FSM manual is unclear about this.
the ECU should be fine, i have a spare, but unsure if it is as easy as a straight swap. the spare s from a 1990? NA automatic; mine is a 93 NA auto. The one currently in the car has no bent pins, and is seated correctly. I have a spare CAS, but dont know the condition of the unit. The old S1 ptu tested as broken, spare of mine also tested as broken. I bought a new S2 ptu. I am unsure how to test a S2 PTU - Does anybody know? A crusty old mechanic told me once that it is air, fuel and spark. Maybe i should find a new mechanic
Gotta love the old crusty mechs. Had a couple teach me a lot, same as RACQ/NRMA/RACV guys, so much to be learnt off them. :biggrin: The VG will start without AFM, IACV and the inlet piping. Aire never seems to be a problem with Zeds. Try disconecting the CTS and see if that helps, mine idles beautifuly without it Have you got a fuel pressure gauge? Did you solder the new PTU plugs on or just use the adaptor harness?
I was getting code 13- coolant temp sensor, whcih i traced out wiuth the continuity between the harness and the ECU. so wiring for CTS is ok. Error cleared after i cleaned and retensioned the connector. With the new PTU im running the adapter harness. I assume this is doing its job. I dont have a Fuel pressure gauge, but should maybe invest in one just to be sure. What is the fuel pressure supposed to be when cranking / engine running?
Test the CAS Whip the CAS off, plug the harness back in (if removed) turn ignition on and slowly turn the spindle at the back of the CAS. If you hear some clicks, CAS is good, no clicks then CAS is bad. When you had code 13, has the car started since you cleared the fault ? if not theres every chance it is flooded. Remove fuel pump fuse ( small black fuse box infront of brake/clutch servo in engine bay drivers side) and try to start the car about 5 times, it should pretty much fire up now if engine was flooded. hth smithy
i thought it was supposed to be 36psi at idle vacuum, 43.5psi when there is no vacuum and then it rises 1:1 with boost. well, thats what my gauge shows (except i don't make boost... )
Being flooded might explain it. CAS is operational. Injectors ticked when spindle was turned with ign on. When i pulled the old plugs out they were wet with fuel and dirty black. Would removing all plugs and letting the engine cylinders breathe for a day or so help? I will swap out a spare CAS to be sure when i get a chance. Keep the help coming people
In that case take em out, clean up and refit after a wee while. If flooding was the culprit, she'll fire up. When flooded they can be a right arse to start but certainly removing the pump fuse for about 5 starts should prove if flooding was at fault as the car will either start or be 99.9% there. smithy
Re: Code 21 I would clear the error code & rerun the fault code reading. Did you notice the step prior to testing with the Logic Probe? It is START THE ENGINE, perhaps you have rectified the cause of the Code 21 & it's something unrelated to the engine management system.
Latest results: replaced ECU with a similar part, also out of a NA auto I also found a bad connection in the S2 PTU adapter harness The harness is now hard-wired in, all wires cut one by one and soldered in place, heat-shrinked. No mixed up wires. By earthing out the spark plug, and spinning the CAS, spark is seen on the cylinders, which WAS NOT PRESENT BEFORE. so now i have spark. but she will not idle. ECU is still showing CODE 21- but engine will fire up momentarily and then stall. Watch a youtube clip of my problem >>HERE<<
Hi mate, When you had the CAS off, did you do the slow spin the spindle at the back and listen for the injectors clicking ?? Did you whip the front 4 pluds out and see tehy are all wet and dry em off ? smithy
Progress!!- now I bet your spark plugs are fouled from fuel not being ignited. Very common resultant cause of initial ignition-related problems... Pull a few plugs from each side and check them out...
