[DarkHorse]

As per title - I'm trying to chase down the annoying stutter/shudder that my motor is developing above 3000rpm. Mechanic has suggested that it's almost certainly the MAP sensor playing up.

First things first I guess - am I right in thinking the MAP sensor is this one bolted to the back of the manifold, immediately behind the throttle body?


If so... how the hell do you get at it? I can just get my hands to it but there is no way of getting even the stubbiest of screwdrivers to the bolts.
Am I going to have to take the throttle body and manifold off as well? If so that's a whole extra world of pain trying to get to those bolts.

Any advice much appreciated!

While I'm at it, could someone confirm that I have the following straight:

Top = TPS (how do you trim/adjust this?)
Right = MAF
Bottom = ???

Here is where they all came from (looking at the throttle body from the passenger side)

Left = MAF
Centre = TPS
Right = ???

Finally (for now...) does this look normal? This is the IAT yes? Should it be melted and warped like this?

[DarkHorse]

UPDATE: Have got it out and had a look...

Nothing obviously wrong, but I wouldn't recognise it if there was. Are there multimeter tests I can do on it to check?

Gave it a quick clean and chucked it back in. Started the car and it idles fairly high, up around 12-15,000rpm. CEL is also on - codes are 22 (TPS) and 24 (Speed sensor):
- TPS I've obviously just put it back on wrong - how do you adjust it's position exactly?
- speed sensor is weird since I haven't moved the car since working on it, but that may just be an old one that's still being stored since before I replaced the speedo cable.

[atari4x4]

sure is in a shit of a spot, would a bodylift give you any more room? hopefully you haven't munted the head completely.

i'm thinking the bodylift in mine will allow me to remove the intake manifold & throttle body off in one, where normally you have to remove the throttle body before removing the intake manifold/injectors.

[DarkHorse]

Body lift would help a bit, just for getting your hands under the lip that the bonnet sits against and around behind the manifold.

I don't think it will make any difference to the throttle body and manifold - the problem is access to bolts/studs with sensors, hoses etc in the way. I got as far as having the air intake pipe off and the throttle body undone, but I couldn't slide it off the top studs because of a hard fuel line running to the fuel rail underneath. After dripping a cup or so of petrol all over everything and still not making any progress I gave up on that idea.

Head was well trashed. It's back in the easiest spot and finger-tight for the moment.

[fordem]

I could be wrong, but what I think you have there is the EGR valve - the bit with the two holes that you have labeled as bottom is the idle air control. When I do a parts search for "sensor", there doesn't appear to be a MAP sensor for that vehicle.

[atari4x4]

fark, what's with editing the first posts... makes it hard to follow

that IAT sensor is properly frucked, it's got me fucked how it could even melt like that unless it was left out & the loom unclipped from the air box & it started making love to the RHS exhaust manifold.

[atari4x4]

fordem wrote:

I could be wrong, but what I think you have there is the EGR valve - the bit with the two holes that you have labeled as bottom is the idle air control. When I do a parts search for "sensor", there doesn't appear to be a MAP sensor for that vehicle.

correct on all 3, it's a MAF sensor.

[DarkHorse]

Ah OK, so there's MAF but no MAP. And the last pic is the EGR valve? There ya go...

Everything seems to be OK now except the CEL for the TPS. Any tips for setting/testing that? Would that explain it running pig rich?

Thanks a lot for the help guys, really appreciate it.

[DarkHorse]

UPDATE: Still getting the CEL for the TPS... anyone know how to set it properly without me forking out an unnecessary diagnostic fee from Suzuki to tell me what I already know is wrong?

Drove to Jervis Bay and back plus around a bit, much of it full stick up hills etc. Power seems slightly better, economy is average but OK for me (14.5 and 13.8 l/100km for the two fills) but the stutter/hesitation is still happening. It only happens at upwards of 3000rpm and more than 50% throttle. The weird bit is that it is much more likely to happen with less than half a tank of fuel - usually after filling up I can wring it's neck and it's fine. Get down towards empty and I can hardly put power down without it hicupping.

(Background: fuel tank has been replaced and issue remained. Fuel filter was new when the tank was swapped, is now less than 3000km old. Undoing the filler cap actually seems to make the symptoms worse.)

I think I'm going to bite the bullet and take it to Suzuki to plug in.

[droverdave]

What happends if you unplug the TPS and try driving? It's a long shot, but my old 4age used to run just fine without the TPS (would throw the code, and slightly less throttle response i think, but perfectly driveable).

As for the TPS adjustment, can you see on it where the screw holes used to be? or can you see any evidence of it being moved? adjusting a TPS involves spinnig it around the throttle shaft (it has elongated mounting holes). its in your photo, you can see the elongated holes.

The TPS will have a "throttle shut" switch, you just need to make sure that this switch is only activated when the throttle is shut. I have always adjusted TPS with the engine running, you twist it around untill you hear the engine click into ilde mode. Hard to descibe but the engine note changes.

[DarkHorse]

Yeah - did about 500km over the weekend and it drove fine, just the annoying orange light on the dash. Would like to get it right though, just so it's one less variable in the trouble-shooting.

I can't see any scratching or indentation where the original position was. Initially I tried adjusting by positioning it so that it was just before the sensor started dragging the throttle around, so it was at it's idle speed but only just - the idea being that as soon as the throttle moved the sensor would be in contact. Maybe it needed a touch more room?

The error was Code 22 which is TP circuit low input... would suggest to me that it is not getting activated when it expects to be...?

[DarkHorse]

Damo posted this a while back:

Quote:

I'm sure my TPS is a 4-wire job. Just looking at that doco again and I have made a mistake. Those voltage readings are for the "TPS idle switch", so that may be the 4th wire.

The TPS signal itself should read 0.5 - 1.2V fully closed and 3.4 - 4.7V fully open.

http://www.auszookers.com/forum/viewtopic.php?f=5&t=2804&hilit=TPS

[Vits93]

I don't think your IAT sensor is melted it looks like black sealant.

[DarkHorse]

It's rock hard, so I'm guessing it's plastic not sealant... but why would it be sealant anyway? Can't be good for a sensor of any sort to be caked in crap like that...?

UPDATE: Attacked the TPS with the multimeter - plugged up, motor running and neg probe on the neg battery terminal I got 5ish volts on what I assume was the power wire (closest to the firewall) and I get 5ish volts. The middle wire, which I'm guessing is the signal I get bubkis, and on the front wire I get nothing.

BUT... unplug the connector and I get 5V on the power wire and 4.7V on the middle wire. The second I plug it back in that voltage disappears.

Does that explain anything to anyone?

[fordem]

It suggests that the TPS circuit is fine and the sensor itself may be dead - what a TP circuit low input means is that the signal voltage is lower than expected, this can be caused by no 5V feed to the TPS, a short to ground on the TPS signal wire or a defective TPS - you have confirmed the 5V power, and your measurement of a voltage (any voltage other than zero) on the signal wire with the TPS disconnected indicates that it is not shorted to ground and is connected to the ECU.

Unplug the TPS, set the multimeter for resistance and connect it to the TPS - center and either outer pin - you should see a resistance value that varies gradually as the throttle is open/closed - if you see that, switch to the outer pin and repeat - you should see the same thing - if not the TPS is defective.

[Rhinoman]

DarkHorse wrote:

It's rock hard, so I'm guessing it's plastic not sealant... but why would it be sealant anyway?

You have a snorkel fitted? maybe someone used sealant to try to seal up the airbox.

[atari4x4]

my IAT sensor

[DarkHorse]

You beat me to it fordem

Resistance across all three terminal of the sensor is a consistent 5ohms, regardless of throttle position.

So dead sensor? Off to SuziFour in the morning for a TPS, IAT and a fan hub. About $170 for the lot which I don't think is too bad.