another car. Checked Wiring to ECU - OK Checked TPS voltage and Wiring to ECU - OK and 0.42V Replaced ECU - Same thing. No change. Code 55. Waiting for two coil packs but replaced with two from another car. No change. No AIV piping. No Cat Temp sensors installed. That is the way I got the car. Series 2 PTU fitted in place of Series 1. Wiring checked. OK. Initially firing order of Coilpack plugs incorrect so fried 1 coil pack badly. Balance test produced no change to engine idle when two coil plugs removed. But when suspect coils replaced balance test was fine. what have I missed? anything is possible as the person who had this car last knew FA about cars. So any suggestions? MichaelZ
Good to know that your MAF is OK on another car, but are you able to check voltage readings for MAF sensor on your car? I know people say its the MAF sensor (or connections to and from) but I think it was a vacuum hose on my car.
Fuel pressure suspect. David, just noticed the Boost gauge (OEM) was not working so I blocked the pipe. No change. Just did a pressure test. 35psi with hose connected. still 35psi disconnected. I am suspecting either the pump, pump controller or the pressure regulator. Also the pressure drops immediately the engine stops but only sometimes. Occasionally the pressure drops 5psi then holds but at other times the pressure drops to 5psi when the engine stops. Has anyone had low fuel pressure? If so what are the symptoms? I find it hard to believe it is fuel pressure as the revving is just too predictable. 1800RPM tops. Other issues to note. If I feather the throttle the revs increase to nearly 2000rpm and when I stop throttling the car almost dies but then idles smoothly after a few seconds. My head and the FSM point to the MAF but then if it is faulty why does the same MAF work on another engine? I am stumped. Any suggestion appreciated. MichaelZ
Not fuel pressure. Just blocked return hose and pushed the pressure up to 40psi. Still upper limit of 1800 RPM. That's a bummer. So that leaves me with a possible CAS malfunction. Again highly unlikely to produce a rev limit but might as well test it. The other supect device is the series 2 PTU. As one of the coils was fried maybe some damage was done to the PTU. I will see if I can test it with another car or get another PTU. The fact that it idles perfectly makes me doubt it is the PTU. I may bite the bullet and against my diagnostic skills I will put a working MAF from my other ZED into this one. MichaelZ
As previously suggested, check the MAF voltages, MAF may be okay but plug and wiring are often the cause
Wiring and connectors already checked. Thanks for the advice Martin but I have thoroughly metered out the connectors all the way up to the ECU and all is rock solid. Jiggled the connectors while testing and running the car. No hesitation or changes when connectors are moved. So I think I can rule out a wiring issue. I will try to place a known working MAF from my other Zed and see what happens. MichaelZ
sounds exactly like mine last week mate. i ended up getting a brand new afm and just kept wiggling shit around until it kicked over and ran. sometimes it would run safety, but then it came good for some weird reason. had the same result from the sparky, all connections getting juice but it still wouldnt act right. he couldnt fix it so i left it a few hours came back with the new afm and then randomly it was good
Stop swearing at her and as SB suggests, give her a tickle in all the right places, buy her a new thing, stop hassling her for a while and she'll come good. (That's the clean version )
That is a great question to ask. If you test with a multi meter set on the beep part it will beep even if a wire is broken/burnt and has a carbon track a lot of times. You really need to be checking voltage at both ends of the wire and always check for a circuit on ohms not the beeping setting. Cheers Dave
Disconnected battery, ecu and PTU firstly Then i got a jumper wire and connected one end to the body of the car and the other to the MAF harness pin to test. I then go the the harness of the ECU and connect one of the meter leads to the body of the car test the ECU harness pin for a short to ground. Only a ground wire or the pin that I grounded at the MAF will be a short circuit to ground. The Resistance should be much less that 1 Ohm and they all were. Also checked and cleaned the MAF ground on the rear of the collector (Plenum) passenger side and the +12V MAF connection. I tested the TPS with an Ohmeter and it measured 9K Ohms as per FSM. Voltages change smoothly on the TPS with 5V across the TPS. Signal voltage at 0.42V. I also adjusted the TPS to both extremes of the adjustment. No effect I also tested continuity of all PTU connections to the Coil Packs and all were less than 1 Ohms. I am now suspecting the Series 2 PTU that was installed. i am thinking that the PTU is not quite working as it should. In the old days of contact points and dwell angles i remember that if the dwell angle was incorrect the car would idle but bogged down under load. I will meter out the PTU when i get the chance and see what results I get. I also moved the CAS to both extremes of its adjustment with no effect to the rev limiting issue, MichaelZ
if the belt is off a tooth on the cam it can rev out ok with no load. But as soon as you try to accelerate in gear you will lose all power and struggle to get near 2k revs. also gives the same symptoms as a coilpack or 2 not working And a few other things you mentioned.
I've seen this issue before with same symptoms and ending up being a boost hose coupling to a front mount intercooler was partially off. Do a boost leak test.
This too... Both times my z ran like a lawnmower the symptoms were exactly the same... first time it was the timing belt. Second time 4 weeks ago it was a 6mm vac line broken clean off on the turbo inlet tube. Occam's Razor the simplest explanation is often the correct one Edit: I lie if it's the timing belt the car can idle fine but dies quick under load then sounds like a lawnmower If its a vac leak the revs dont dive so much under load you just have no power and sound like a lawnmower. Dont want to clog your thread too much with my limited knowledge. But your mention of 'Bogged Down' sounds familiar to my timing belt issue. Thats my 2 cents. good luck!
What voltage is your MAF reading at idle??? should be around 1.22- 1.28v and should increase with Air Flow.
I can see your logic..... ....however, I don't think this is the best way to do it. For starters, you are introducing an additional wire & as such there are two additional connection points which are unnecessary. Twin Terror is correct concerning the audible test as it is unreliable. He is also correct in suggesting measuring the voltages. If you are going to test the resistance of a wire, then the clips should be attached to both ends of the wire. It is also important to zero out your meter for an accurate measurement.
Tried another Maf..... As I suspected it is not the MAF. Rechecked the wiring again . Voltages at the MAF are correct as you all stated. Just checked series 2 PTU and wiring . All ok. I am beginning to suspect the worse now. I suspect the turbos are seized or rag or foreign object is seizing the turbos. I am convinced that it is not electrical. So i will see if I can feel suction at the intercooler pipes. All wiring and readings check out fine and it idles smoothly but hunts from 1200rpm to almost stall then idles smoothly for a few seconds then almost stalls. Also the first thing I did was a boost leak ckeck and no major leaks. Certainly not a big enough leak to cause my problem I would think. About the beep test I also noted the resistance reading as you suggested and all was less that 0.4 ohms and not an issue I would think. MichaelZ
