Hi all. I`m having issues with cold starts/idle/running in that it will start and idle on high but as soon as it drops it chugs, hunts drops and dies.

I`ve swapped maf (cheers joely p) and eliminated that, replaced the water temp sensor last year but still have to check. No vac leaks as far as i can tell.

So i`m now onto the idle valves. I`ve removed both, cleaned and ohm tested but my query is this. All i can find re the ohms is 10 ohms for the main idle, the idle/aircon compensator i`m not worried about as i have no air con. The bi metal idle valve (air regulator) 75ohm.

I`m getting readings of 9.4 ohm and 75.8 ohm respectively . Can anybody tell me whether these readings are in spec i.e is it like the injectors 10-14 ohm or should they be bang on.

Cheers in anticipation of enlightenment

Hi Paul, from the info i have on sensor voltages:

 

o FICD = Resistance = ~22 Ohm Ω & 12V to check operation.

You can also apply a direct 12V and earth to the unit, disconnect

and reconnect the earth and listen for a solid 'thunk'.

o AAC = Resistance = ~10 Ohm Ω & 12V to check operation.

You can also apply a direct 12V and earth to the unit, disconnect

and reconnect the earth and listen for a solid 'thunk'. Also via

datascan: look for 15-40% @ idle & 75-85% while cruising

 

Air Regulator~70-80 Ohm Ω (if not=replace)

Edited October 20, 201312 yr by groover

cheers mate..so looks like my valve is a little off although it does pass the clunk test and hold idle once the cars hot..so ill check the ecu temp sender see if its failing

I had an injector that you could hear clicking away it was reading 17ohms, which was outside spec, so although it worked, it was overfuelling.

Have you got scantech or datascan? If not i have a copy i could mail you.

 

This may help with the other sensors,

 

 

 

Sensor voltages.pdf

Cheers for that,yep injectors is next on the list. Ive got my laptop working now so i can go plug in.

UPDATE

So i`ve checked all injectors, some varying results e.g some 11.5 11.4 others at 12 ohm so although differing still in spec. The balance bar was leaking , now fixed.

I`ve cleaned the idle valves and refitted them. The main idle (adjustable one) is .6 of an ohm out of spec. I changed the water temp sensor for a new one. Changed fuel filter. Checked tps and the idle raised as it should

So the good news is a slight miss i had at idle has gone..its just that i still cant get it to idle or run properly when cold. Today with the maf in it was dying then jumping up a thousand revs for a bit then dying. I did unplug the maf and it idled way better but still conked out after a couple of minutes so i`m still suspicious of that.

Once its hot it seems fine.

So does removing the maf remove the vac part of the cold idle i.e the ecu just runs off a preset and do the injectors behave differently when warm also how much of a difference does .6 of an ohm out of spec have on the idle valve.

If its not raining i`ll change the sparks tomorrow. Any help greatly appreciated as i`m doing this myself as we have no zed garages here.

Edited October 30, 201312 yr by santa

Not sure that the ecu runs on a preset figure when the maf is disconnected, although the reading from the idle air valve would be irrelevent as there is no measured air coming in that the ecu can read. It sounds like your maf is goosed like mine lol

 

Also disconnect the battery for an hour or so to reset the ecu, it may sill be running on old settings if not cleared.

yeah does seem that way..i did borrow one before i cleaned everything and the car behaved the same way though?..from what i`ve found if you disconnect the maf the ecu adds fuel , i`m wondering if i have some sort of injector fault too even though the ohms are in spec..just weird that it behaves when warm, but then the element/wire in the maf would be warm too by then.

I`ve had the battery out of the car for a week,that should have done it lol.

Thinking about the maf this did start after lots of rain and a new apexi filter although it wasnt driven in the rain..maybe it all got wet from water ingress through the nose panel as it was wet on the t piece when i took it off. I have now fashioned a guard out of a plant pot.

And my idle valve is slightly out of spec by .6 ohm do you think it would be affected much by that?

Edited October 30, 201312 yr by santa

Just so you know , i`ve managed to find new oem mass sensors for roughly £205 delivered exc.import duty from oz if you`re interested

Just so you know , i`ve managed to find new oem mass sensors for roughly £205 delivered exc.import duty from oz if you`re interested

 

How much :lol::lol:, well im taking a punt on new one for £70 from a company on ebay, only because they have a 12 month warranty, so if it doesnt work i can send it back :thumbup:

http://www.ebay.co.uk/itm/HIGH-QUALITY-NISSAN-SR20DET-CA18DET-KA24DET-80mm-AIR-FLOW-METER-UPGRADE-ON-SALE-/161049514772?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Model%3A300+ZX&hash=item257f4c9314

 

Or from Aus you have these http://www.ebay.co.uk/itm/300zx-Z32-80mm-AFM-MAF-Air-Flow-Meter-22680-30P00-with-plug-/290954628726?pt=AU_Car_Parts_Accessories&hash=item43be3f4e76

yeah does seem that way..i did borrow one before i cleaned everything and the car behaved the same way though?..from what i`ve found if you disconnect the maf the ecu adds fuel , i`m wondering if i have some sort of injector fault too even though the ohms are in spec..just weird that it behaves when warm, but then the element/wire in the maf would be warm too by then.

I`ve had the battery out of the car for a week,that should have done it lol.

Thinking about the maf this did start after lots of rain and a new apexi filter although it wasnt driven in the rain..maybe it all got wet from water ingress through the nose panel as it was wet on the t piece when i took it off. I have now fashioned a guard out of a plant pot.

And my idle valve is slightly out of spec by .6 ohm do you think it would be affected much by that?

 

 

I ohmed all my inejctors, , replaced injector on cyl 3, but injector 5 was my issue even though it is within spec. I decided to get a needle file and redo the terminals on the injector and the plug and its now running fine, may be worth checking again, even though no corrosion may be visible the terminals still get tarnished, which seemed to prevent a strong signal.

How much :lol::lol:, well im taking a punt on new one for £70 from a company on ebay, only because they have a 12 month warranty, so if it doesnt work i can send it back :thumbup:

http://www.ebay.co.uk/itm/HIGH-QUALITY-NISSAN-SR20DET-CA18DET-KA24DET-80mm-AIR-FLOW-METER-UPGRADE-ON-SALE-/161049514772?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Model%3A300+ZX&hash=item257f4c9314

 

Or from Aus you have these http://www.ebay.co.uk/itm/300zx-Z32-80mm-AFM-MAF-Air-Flow-Meter-22680-30P00-with-plug-/290954628726?pt=AU_Car_Parts_Accessories&hash=item43be3f4e76

 

i saw that one too but cant find any reviews., all i find is people saying ebay ones are crap so i`ll hold off until i see what you think. Oem Mafs are so expensive new!

They claim to be not the usual ebay cheapies, so time will tell, i will order one next week and see how i goes.

 

According to Mike (MJP) maf no longer available and the patent ones he looked into were too unreliable, so there is going to come a point in years to come that either they will be like gold dust and worth a fortune or there will eventually be a reliable patent.

oem are still available in the states..just pricey