First up, thanks to everyone who offered suggestions and advice in my thread about my misfiring problem (http://www.300zx.co.uk/forums/showthread.php?t=34627)

 

I was having a look at the coil packs last night and found that the plastic connectors on two of them have snapped. Also, the plastic "heads" are missing on 2 of them. I took them off, checked the connections (which were clean) and pressed them back on.

 

I took the car for a short run (just a couple of miles) and it did feel much better, although still idling rough.

 

Is there any way I can secure the coil packs in place as the plastic catches which have snapped are on the engine side, not on the coil pack itself?

well done mate. Atlast, one of my suggestions has worked. I've only been on here 3 years. :D

If its what I think, try using a smidging of silicone sealant on the inner part of the connector - make sure you dont get it on the connections. Leave to set and your sorted - itll stop them rattling loose but you can still take them off :)

If its what I think, try using a smidging of silicone sealant on the inner part of the connector - make sure you dont get it on the connections. Leave to set and your sorted - itll stop them rattling loose but you can still take them off :)

 

 

Yep good one that,or if this still gives probs then do what i did,super glue the mothers down :D

 

Tony

Silicone sealant - I'll give that a try, thanks! :)

 

Cos - you're owed several beers for that one suggestion in 3 years, mate :duffer:

Update - found that the main problem was that the rearmost coil pack (driver's side) wasn't seating properly. The cause was that for some reason the rubber seal that sits at the bottom of the connector wasn't there - it was in the middle coil pack connector (same side) along with the one that was supposed to be there!

 

I assume this is how it's supposed to be - please put me right if I've just made a massive error.

 

The car seems to be running ok now. :)

 

I reset the ECU and now the idle sits at 700, but every 15 - 20 seconds or so, it drops to about 500 for a few seconds before climbing back to 700. Is this normal while the ECU readjusts?

did you sort your tps?

I cleaned up the contacts on the TPS, although they were fairly clean to begin with. If I unplug it when the car is idling, the revs rise slightly - is this right?

 

The cable going into the front of the TPS looks a bit worse for wear though - not the contacts, the cable itself. I did, however, concentrate most of my efforts on the cable coming out the bottom of the TPS.

 

So far I've cleaned the contacts on the coil packs, TPS, MAF and temp sensors. I know I need to clean the throttle bodies, but I was a bit confused as to whether I should follow the procedure outlined elsewhere (I forget the site) as there are BOVs on the intake pipe, or if there are other considerations due to the BOVs?

you need to ensure that the TPS is set at the correct voltage. It should read 0.44v. I don't have a conzult so to check mine, what I usually do is open out a paperclip and slide it down the middle cable of the TPS connector. Then connect that to the positve end and simply enscrew the tps and adjust if needed. You will be amazed how much diference, 0.05v deference can make.

 

Will you be attending the Notts meet?

I've just taken her out for a run - no sudden power losses although the acceleration didn't feel quite as savage as it did before the problem. Maybe that's just me though.

 

I'd like to get the chance to connect to a ConZult just to see if there are any more problems at all, but I will check out the voltage across the TPS - thanks for the tip :)

 

I wasn't aware there was a Notts meet, but I've been so consumed with trying to resolve this problem, I haven't even looked at the events list...

The cable going into the front of the TPS looks a bit worse for wear though - not the contacts, the cable itself. I did, however, concentrate most of my efforts on the cable coming out the bottom of the TPS.

 

Just so you know, the connector out of the bottom is the hard idle switch, which tells the system if you're really off the throttle pedal altogether (and therefore the idle system should be managing the air intake). It's the other connector which is a way up the cable a bit that carries the progressive signal between 0.4 - 4v, which affects AFR and duty and various exciting things on the auto box and all that guff.

 

I think the problem on mine is the hard idle is lazy or the connector / loom loose somewhere - so sometimes when I'm off throttle the engine doesn't go into idle mode - so there's not enough air getting into the system and it all goes tits up.

 

I also found adjusting the throttle cable for a minimum of play really helped on part throttle, especially round car parks and the like. It's dead easy, take throttle cover off and it's obvious how it works, just like brakes on a bike.

Thanks for the info there :)

 

I'll go back and check that connector further down the cable again.

 

There's definetly at least one cylinder off - when I unplug the coil pack furthest toward the rear of the engine, on the driver's side, it makes no difference to the idle. I'm sure I can hear detonation in the cat, so does this mean there's no problem with the fuel for that cylinder, it mustn't be sparking?

 

Am going to take off the large hoses going into the TBs (with the BOVs on) this evening so I can check out the contacts to the CAS and PTU.

Am going to take off the large hoses going into the TBs (with the BOVs on) this evening so I can check out the contacts to the CAS and PTU.

 

Those hoses are a mofo - use a bowl of hot water to get them back on - or a hairdryer - or I think Andy Duff uses gas mark 2. :rofl:

Got someone with smaller hands to check the CAS and PTU connectors with the BOVs in place - were clean.

 

Fiddled about to swap over the coil packs from the rear and middle cyls on driver's side and the engine sounded much better - can only assume it to be a loose / dodgy connection to the rear coil pack. At the moment, the car is idling perfectly smoothly at 800rpm.

 

I did notice a slight hissing sound, or it could have been a buzzing (my ears are knacked after years in bands) from the front driver side of the engine - couldn't work out if it was a hissing from the air intake hose or a buzzing from the Hicas solenoid...

 

Is there a ConZult in or near the North East I can connect to, to either put my mind at rest or show me there're problems elsewhere?