Car has a flat spot/juddering & problems with The AA

Tican

Tican

Tican

Soldato
Joined
14 Apr 2003
Posts
5,716
Location
Leicester
Hi there,

I have top level AA cover, which covers £500 worth of parts for a £35 excess. The AA came out the other day to look at the car, as it struggles to start when warm, and it judders and has a flat spot on acceleration when warm. Also when warm the car revs up to 1.6k RPM.

The AA patrol whittled it down to the Temperature sensor (not the thermostat?) which has dodgy wiring, and the Auxiliary Air Sensor (his words), as when this is unplugged the car runs fine once warm. We took the car to the lovely Halfords Autocentre (which is where this cover is accepted locally). I got a call back saying that they can't do the repairs on the car due to them not being able to get a diagnostic machine hooked up (the Engine Management light is not lit up on the dash). So have refused to do the repair, but suggested that I should spend £50 on a new distributor cap and arm (as the arm inside is missing apparently; wouldn't the car not start at all?) and he said that this won't fix my issues.

I cannot find the parts to purchase, I am yet to ring The AA, but I will be on the phone to them first thing in the morning.

Do I have a case in pushing for the repair of the sensors, as this is what the AA Patrol found? I couldn't find the "Auxiliary Air Sensor" on eBay. Could it be an idle control valve which I am looking for?

The car is a 1995 Nissan 100NX. I don't want to get rid for this problem, as it's only just passed the MOT a couple of weeks ago!

"Auxiliary Air Sensor"
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Temp control
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TL;DR: Car is revving high and has a flat spot/juddering when warm. Halfords Autocentre refuse to fix as they can't get it on a diagnostic machine. Refusing the repair and trying to charge me for something which won't fix the issue. Can I/should I push for the repair with The AA.

Thanks in advance
 
Actually the dizzy / leads would have been one of the first places I looked, then for vac leaks. Regardless it sounds like you need to get the car away from Halfords. With this kind of car any back street place should be able to diagnose though

What made mr AA think it was the temp sensor(s)? As they only have a limited amount of time / equipment / space at the roadside the diagnosis can sometimes be way off. I'm not advocating just replacing random parts but if you think the temp sensor is at fault how much is the part itself? It might not even cost your excess

The Air sensor being unplugged and car running fine could be a red herring as it will default to a safe, rich fuelling mode. A vac leak of sort could still be the issue so you'll want to investigate all intake pipes after it for splits. Nevertheless it's worth investigating the cost of the sensor.
 
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rodenal said:
Actually the dizzy / leads would have been one of the first places I looked, then for vac leaks. Regardless it sounds like you need to get the car away from Halfords. With this kind of car any back street place should be able to diagnose though

What made mr AA think it was the temp sensor(s)? As they only have a limited amount of time / equipment / space at the roadside the diagnosis can sometimes be way off. I'm not advocating just replacing random parts but if you think the temp sensor is at fault how much is the part itself? It might not even cost your excess

The Air sensor being unplugged and car running fine could be a red herring as it will default to a safe, rich fuelling mode. A vac leak of sort could still be the issue. Nevertheless it's worth investigating the cost of the sensor
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The dizzy itself is in good condition as are the leads and plugs, however he (Mr. Halfords) said that it was missing the arm inside, I was under the impression that the car shouldn't run if it was missing that?

He was just unplugging stuff with the car running, until the revs dropped down and it ran fine. The issue with the temp sensor isn't to do with the running, but more to do with the fan not kicking in properly. He was doing this on my driveway.

How would I go about finding a vac leak?

The temp sensor is around £10, a dizzy and arm around £15 and the Air Sensor, no idea as I couldn't find one, unless it's an Idle Control Valve (looks similar) then anything from £25 to £109!
 
The problem here is the people you've taken the car to (They are the 'recommended' supplier but you can use any you wish, even main dealers) and not the AA themselves.

Trouble is of course that now the car has been looked at by a garage you are no longer covered under Breakdown Repair Cover for this fault unless you can get the original jokers to play ball.
 
The AA patrol told me to take it there, and he was with me when I took it. They offered no other options.

Halfords Autocentre told me that it has to go to a main dealer, or someone who can read the codes.
 
You need to sort out where it's going really as per the discussion with Fox as above but tbh reading the codes on a car of this age is usually all but a waste of time. Some basic mechanical skills will sort out the issue.

I assumed your air sensor was probably just a part of the map/maf sensor the car had but tbh from that (limited) picture it doesn't appear to be. I don't see that an icv would cause you much in the way of running issues other than at idle/ low revs but if that's what the sensor is attached too you could take it out and make sure it moves freely/clean it up.

The easiest way to check for vac leaks is to visually inspect the boots (off the car). You could try spraying some carb cleaner around any suspect areas with the car running to see if the idle changes too but tbh i've rarely had success with this. Ideally you need either a home made or garage smoke test. Again most places will be able to do this no problem - if they can't they shouldn't be in business.

That includes halfords btw, the "can't read codes" excuse is a sad one, but you'll just need to deal with that through your cover t&c's
 
[TW]Fox;24470503 said:
It is in the terms of your cover - you can select where it goes. They will pay up to £80+vat an hour.
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Ah damn it, I guess it is too late now to have it sorted. Will phone The AA in the morning to see. I will use the reason of "Off the back of the suggestion of Halfords".
rodenal said:
You need to sort out where it's going really as per the discussion with Fox as above but tbh reading the codes on a car of this age is usually all but a waste of time. Some basic mechanical skills will sort out the issue.

I assumed your air sensor was probably just a part of the map/maf sensor the car had but tbh from that (limited) picture it doesn't appear to be. I don't see that an icv would cause you much in the way of running issues other than at idle/ low revs but if that's what the sensor is attached too you could take it out and make sure it moves freely/clean it up.

The easiest way to check for vac leaks is to visually inspect the boots (off the car). You could try spraying some carb cleaner around any suspect areas with the car running to see if the idle changes too but tbh i've rarely had success with this. Ideally you need either a home made or garage smoke test. Again most places will be able to do this no problem - if they can't they shouldn't be in business.

That includes halfords btw, the "can't read codes" excuse is a sad one, but you'll just need to deal with that through your cover t&c's
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The sensor is under the air box, not where a MAF would usually be. This car doesn't seem to have a MAF, as I have always known these to be in the intake hose before the filter?

I have no way of checking that then, as I don't have any kind of area I can do a smoke test. I only have a driveway, no garage. I can do most things on a car (I could change all the sensors myself, but don't want to waste money on it).
 
Closest thing I can find is an Air temperature sensor which should be in the bottom of your airbox, I take it this sensor is actually located in the box and not underneath it?

Again it's clutching at straws without any sort of actual diagnosis but it could be a start. Looks a very cheap part too.

Btw you can visually check hoses without a smoke machine etc what I meant was that's the way that will be quickest and most accurate but you'll be able to inspect the vac hoses yourself, just strip the intake side of any that are there and check them out from the inside.

IF your part is an air temp sensor then it will be either the sensor or an issue somewhere between it and the throttle body etc
 
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rodenal said:
Closest thing I can find is an Air temperature sensor which should be in the bottom of your airbox, I take it this sensor is actually located in the box and not underneath it?

Again it's clutching at straws without any sort of actual diagnosis but it could be a start. Looks a very cheap part too
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Nope, looks totally different to the sensor which is currently unplugged. I am just heading off to work now. I will get a picture in the morning of the location of the part!
 
It's been a while since i had my Almera, which had the same GA16DE engine in it. I remember it having a MAF but it was the older vane type, rather than the hot wire sensor type and from the sounds of things, I would also consider checking the Lambda sensor; Vac leaks, MAF and Lambda would be the most likely culprits of the symptoms you're getting.

I would have thought that connecting a diagnostics computer to the car would allow the technician to read the sensor readings from the MAF, Lambda etc etc and a trained technician should know the ranges and responses of each of them. So I don't think the previous comment of connecting a diagnostics computer is useless is correct; you just might not get error codes like you would do on more modern cars. If you're handy with a multimeter, you might be able to check the sensor values yourself.
 
Jonny ///M said:
http://nissan4u.com/parts/100nx/el_b13/1994_1/type_21/fuel_and_engine_control/throttle_chamber/

I can't see a mention of MAF anywhere on that site and only Idle control and fast idle control.

I somehow managed to leave my airbox unclipped, pre maf ofcourse, and it caused my SR20 to stutter and felt like a misfire. Clipped it back up and I've never had that happen again for some reason.
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That's where the sensor is. It's the "Iacv-aac valve" which is disconnected, I am sure of it!

e: Went on eBay - £49.99. It is the one which is disconnected, so I guess I should phone The AA tomorrow to get it in to a dealer or at least someone who can test it.
 
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daveip said:
I would have thought that connecting a diagnostics computer to the car would allow the technician to read the sensor readings from the MAF, Lambda etc etc and a trained technician should know the ranges and responses of each of them. So I don't think the previous comment of connecting a diagnostics computer is useless is correct; you just might not get error codes like you would do on more modern cars. If you're handy with a multimeter, you might be able to check the sensor values yourself.
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The thing is, with the older jap motors you don't tend to be able to access very much in the way of data at all. You will get some very basic fault codes and may well be able to get into some modules to measure air flow registered at the maf (or equivalent) etc but it's not going to tell you anything that you don't already know in this case (i.e something is disturbing the mix). If it is just the case that that sensor is simply duff it could be checked with a multimeter, vac leaks would still require a manual process.

Good that it's been narrowed down though, at least you now have an idea of what might be wrong and indicative part cost (though I'd check elsewhere including the dealer)
 
Doesn't that just adjust the idle though? I disconnected that on my car to set the idle with the screw.

You could check forums and maybe pick up a throttle body from someone breaking a car but you would be best sticking to the AA setup.
 
The AA are dodgy in my opinion.

When I bought my Mondeo in April, the day after the car started juddering and EML came on etc. AA came out and diagnosed the coil pack as the issue (common fault on mk3s) but hadn't even checked the spark plugs or leads. He fitted a 'new' coil pack (I say new as it looked well worn/used) and I paid the ridiculous £88 for a coil pack. AA left and I took the car out for a spin but was still being retarded. I rang the garage I bought the car off and said I'd bring it back the next day.

They worked on the car for 2 days, changing sparks, leads, sensors etc but they still had this stutter/judder issue on idle and when on full load. So they changed the 'new' coil pack the AA had fitted to a £30 EuroCarParts model and the car worked perfectly. So the AA had supplied and fitted a faulty/worn/used coil pack for almost 3 times the price of a brand new original part.

I spoke to the complaints department and eventually they agreed for a refund after a few documents were sent to and forth. I only have AA cover as it's part of my Halifax Reward account. I'd never pay for their services another way.

(sorry for long post)
 
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