Is this right? Water temp related - Again!

[seanl82 23]

Hi Gents, car in question is a 90 Kr I picked up last weekend. :dance: I absolutely adore this car, there are however a few small issues. On cold start, it sometimes takes a little gas, or a couple of cranks before it fires. Once running though everything is ok. Plan is to clean out WUR after doing searches and reading previous posts, but where is it/what does it look like?

 

Second question is that normal running water temps don't rise above about 85. This is pretty constant though so it's swaying me away from the stat. Obviously with the cold weather, does this sound about right? In addition, oil temps are pretty good - between 90 & 100 depending on driving conditions and style. Also my heaters don't get even slightly warm! (not nice in this weather!) top and bottom rad hoses warm, as are the pipes after the bypass valves. Plan is to try and flush through the matrix to clear any possible blockages, just keep getting rained off at the moment! Is this likely to be connected?

 

Third and last question, my fuel economy is seriously low. I've come from a golf3 gti 8v, so I may be a little more "spirited" in my driving atm!, but my economy is well under 20 mpg according to the mfa. Dont get me wrong though, I'm certainly not driving like a mad man! Again could this be related to the above 2, (cold map/constant choke type thing???) or is this more likely to be unrelated?

 

Any help would be very much appreciated. Thanks guys!

[carrots 1]

sounds like the matrix is blocked to me,mines doing about 34mpg 37mpg once warm and driving a steady 60mph

[seanl82 23]

I suspect your right. Why would this cause poor economy though?

[carrots 1]

check the air filters not dirty.try some injector cleaner in it and put some new spark plugs in.

[seanl82 23]

Yeah gonna put some BG44 through it in the week, and gonna give it a good service with oil, filters, plug, leads, dizzy etc etc. Just flushed through the matrix and all seems fine with no apparent blockages. Bypass valves also seem clear. Even if they are stuck open as I can see daylight through them, that would mean the coolant is circulating round the matrix wouldn't it?. Bit stumped now tbh. Anyone got any other theories?? Thanks again guys, appreciate any help.

[Yandards 0]

Oil and water temps sound ok, MPG seriously low but I would double check that using the old fill it up at the pump, note the quantity filled followed by a reset of the trip meter and run it down and then refill again.

 

Used to get around 38 MPG on my daily commute on the valver when it was just a valver, managed over 400 miles from a tank on fill up!

 

As for the heater issue, it could still be the bypass valve worth getting some copper tube and bypassing the bypass valve to check - a blocked matrix will likely need to be replaced as when it does work again it will be a right mess.

[seanl82 23]

Cheers Yan. Will do all above and report back.

[davidwort 0]

Sounds like you need a good going over the engine, its usually the bypass valves and not the matrix that restricts the hot water flow but you can check that out by removing the hoses and just running water from a hosepipe through it.

The small sensors on the rhs of the head can be checked, 3 the same and feed water temp to gauge, ecu and idle control unit, swap round the connectors if you suspect one. There's also a larger thermotimeswitch that controls enrichment on a cold engine. Flow through the main rad should be checked too, you may have a stat that is never shutting fully, how long does it take to get to full oil and water temp?

[seanl82 23]

Yeah I ran a hose through the matrix and it all seemed ok with no evidence of blockages. Gonna get some copper pipe later/tomorrow morning and try that. Water and oil temps rise as they should, up to temp in 5-8 minutes, but water temp seems to stick at 75/80. What does the rad fan take it's temp from as that comes on and switches off ok. Faulty temp sensor makes sense too with the rad fan coming on, but why 3 sensors, and which ones which? (assuming their for specific temps) May as well change the stat when I do the service next week too. Sorry for all the questions, just tryin to get my head round this lump!

[davidwort 0]

No the three small black sensors on the side of the head are all identical, they just feed separate systems, so you can swap round the wires to check them, the rad has a temp switch in the bottom of it, two circuits/temps for the two motor speeds on the fan, there's also a small temp switch on the front left cam cover nut that causes rad fan run-on when the weather is really hot, stops the fuel lines getting too hot when you turn the engine off.

It's worth pulling out the injectors and doing a spray pattern test, even if it drives fine the pattern may be poor at low throttle and that won't help economy.

[seanl82 23]

Fair enough. Thanks David. I did read about injectors a while back. I'm lucky in that I can get access to an almost fully kitted out workshop/garage. Will have it on the ramps when servicing so I can do everything including injector pattern tests etc under cover, which helps this time of year! (too poor for a garage myself!) do a search for the guide I saw on here as I've not done one before. Thanks again mate.

[seanl82 23]

I now have lukewarm heaters. Swapped the bypass out for some copper pipe, and the heaters now start getting warm at around 80/85 degs. Took a while to get there though, so I think it may be a combination of duff stat, and slightly blocked matrix. Will change the stat over next week with a coolant flush anyway, and hopefully that will sort it.