1990 90 2.3E (NG) running problem?

[dgacampbell]

I have no cat on the car and the exhaust is a new (fitted early summer last year) stainless steel virtually straight through system, if it were not for the bends to suit the shape of the floor of the car you could see right through to the exhaust manifold.
I do have the o2 sensor in a bypass pipe where the cat should live.

Thanks though.

[dgacampbell]

Ok guys,

The 90 runs, providing the differential pressure regulator is unplugged!

where do I go from here?

TIA

Dan.

[missfire]

Personnaly I'd learn how to blink out any codes, if you haven't already. I normally do that first before doing anything else. Problems with lambda probe etc. would show up as a code.

http://www.sjmautotechnik.com/troubl...g/100ecuf.html

I use a 1.2w lamp instead of an LED, and a paper clip. It's pretty easy once you've done it once, if you know what I mean. It's very easy to learn.

[msh]

Well, he can try, but from my personal experience, it's rather worthless exercise. These two control units have self diagnostic capabilities in rather embryonic stage, almost unable to detect anything. I had wired up check engine light since A80 times, which had 3A engine, which had KE-Motronic, with way more advanced self diagnostic capabilities - meanwhile in my A90q I got check engine lit up just once [apart from startup] - once I got "knock sensor" fault, because 98 RON petrol and engine with rattling main bearings together confused ignition control unit. Otherwise, nothing, even while adjusting something - that engine management rather easily goes into limp home mode while doing that, just unplug some connector and put it back, or something like that, you can tell by idle speed and behaviour, but no check engine light, I call that "silent limp home mode". Ah, tried to do that once to C3 NF, which had huge running problems, of course, nothing, only I was glad it was able to put out code to confirm that I had disconnected MAF potentiometer, I've read that it might not do that as well

Originally Posted by dgacampbell

Ok guys,

The 90 runs, providing the differential pressure regulator is unplugged!

where do I go from here?

TIA

Dan.

Let's begin with temperature sensor [not MFTS]. Measure each of two pins against ground and compare with this table, both values should be almost identical



Also inspect connector itself - broken wires, corroded contacts.

[missfire]

Well blinking codes out solved just about every problem I had with the MC2, but I've never worked on an NG, so you'll know better, as usual. (at least if someone gives sub-optimal advice it will trigger a response from you)

[dgacampbell]

Ok guys,

Thanks again for the replies.

Unfortunatly due to my own ignorance I cannot even try the blinking out codes thingymabob.

when fitting the alarm many many moons ago, I had to remove the lower dash panel that had said connectors in, in order to remove the panel I had to unclip conectors and they are now lost amongst a load of other connections that are connected to nothing in the mass of wiring under the dash.

My bad!

Ok Msh,

excuse my ignorance here............

I'm going to assume I need to check these values at various stages of the car heating up from cold.

I did change that sensor last night (swapped it with the old one that was in it when I got the car, thought it was worth a try as it was just lying on a shelf in my garage.) It made no difference, Although there is always the chance they both could be bad.

I shall get back to you's as soon as I have gathered the relevant data.

Many thanks

Dan.

[msh]

Originally Posted by dgacampbell

I'm going to assume I need to check these values at various stages of the car heating up from cold.

Not really. You just have to measure at any temperature and look if the both values are relevant and more or less identical to each other and not, for example, one side is showing 85 degrees, and another 75 degrees.

[dgacampbell]

Ok guys,

Checked the resistance of the 2 terminals on the temp sensor against ground, it just so happens the car was up to temperature ie fan coming on.

One was reading ~196ohms and the other ~206ohms.

Cleaned throttle body etc with some carb cleaner, was next to spotlessly clean anyway.

Unplugged the cold start valve and the car is again going like a scalded cat.

So am I wrong in guessing i need a new cold start valve??

[msh]

Explain that a bit throughly - with cold start valve disconnected there are no problems at all? If yes, what happens if you connect it while engine is running after some time?

Also - I'm curious - where both control units - ignition and injection - are located in RHD B3?

[msh]

Originally Posted by dgacampbell

Ok guys,

Checked the resistance of the 2 terminals on the temp sensor against ground, it just so happens the car was up to temperature ie fan coming on.

One was reading ~196ohms and the other ~206ohms.

Ok, so that sender is fine.