9A 16v engine problem

[bmwcompact 10]

I bought my car 5 months ago (94 16v with 9A engine). On 3 or 4 occasions it has started but would only tick over and not rev up. After a few minutes it would decide to go and thereafter there were no problems-otherwise it has always started first time and ticked over and run well.

 

Today it took a turn for the worse. It starts but runs very rough and stalls-it will not tick over and it will not rev. I did get it to go this morning, and again this afternoon eventually after many failed attempts. Once it decides to go theres no problem-it doesnt stall at junctions etc. But the general behavior is now not to tick over or rev then suddenly to behave well.

 

Ive had a look in the distributor/leads. Ive removed and checked the inlet tract/ vac pipes for leaks, checked the output of the throttle potentiometer but found nothing.

 

The ISV has never buzzed during my ownership but checks out at 8.5 ohms and there is power to it. When the ISV is disconnected the car wont start so it has always been doing something. If I disconnect the cold start injector the car wont start. If I get the car started then disconnect the cold start injector it runs OK.

 

Ive read lots here about similar problems, and the list of possibles is so long. Its the old story- is it ignition or fuel- all I can say is that an extremely rare intermittent problem has decided to become worse.

 

Im dont fancy replacing every part in sight until I get lucky-can we come up with a sensible regime of testing to identify the problem.

[davidwort 0]

get it checked on vag com or similar, you need to make sure the lambda and temp sensors are all right before moving on, of course checking all the vac lines and rubber inlet boots can be done straight away

[bmwcompact 10]

I dont have vagcom but I have a U281 tester-it came up with 00587 mixture control adjustment but thats a result of not running correctly today rather than identifying what caused the problem-it came up with nothing after the previous little hiccups. (It identified the correct problem when the speedo was disconnected and when the polo was missing from the ignition lead).

 

By temp sensors do you mean the thermotimeswitch and other sensor below the distributor? Oil temp sensor and rad sensor as shown by MFA are normal 108, 90 respectively. (EDIT the 2l 16v 9A doesnt have a thermotime switch-it has a temp sensor vw 026 906 161 bosch 0 280 130 040 for the ECU input)

 

How do I check the lamda-the wires appear to be secure and I broke and remade the connection at the plug below the brake m/c.

 

Cant account for the sudden onset of problems today. Ive spent the last few days replacing my rear beam bushes/ brake reg and rear brake pipes and not been near the engine bay!!!

Edited July 26, 2012 by bmwcompact

[davidwort 0]

It would be good to get an MOT gas analyser on there and check if the lambda is within range, feedback can wobble all over the place, does it have the original, a genuine or quality replacement or a pattern lambda on it? These engines really seem to be problematic if the lamda goes out of range, and some cheaper pattern replacements are as bad as useless, I've seen several 9A's now that will barely idle because of dodgy lambda sensors, trouble is people fit a new pattern lambda, assume as it's new it will be OK and then start tweaking other things to compensate for running problems.

Check the ECU connection for water/corrosion, replace the cheap service stuff like plugs rotor arm and cap, check the plug lead ends and see if the leads are within resistance range.

Has the tamper proof cap on the metering head been removed? little orange bung in the top of the air box where the allen key adjustment for idle CO on the 1.8 16v engines is. this is factory set on the 9A and shouldn't be touched.

[COPPERWASHER 10]

I'm not familiar with these engines, but from what you've said, if its got it i would check TPS (throttle position sensor) air mass meter if it has one and the coolant temp sensor for the ecu! Give these a go and see how you get on!

[ice_killer 10]

A O2 Sensor (also know as lambda), is not of use when starting a car.

 

00587

 

 

Possible defect

feul injector (or multiple defect)

cold start injector defect N17

Idle speed controle faulty

 

Possible solutions

check feul injectors

check cold start injector

check Idle speed controle faulty

 

check for air leaks (EVAP system !!!)

check ignition basic timing (9 degrees before TDC)

check power and earth of the engine controle module

[phantom corrado 10]

my fuel meter played up giving the same problems.

[bmwcompact 10]

Thanks for the feedback-Ill keep you posted. Currently waiting for a few bits to arrive ( GSF Beru cap and rotor). Will eliminate HT ignition ct problems first. My Lambda is an aftermarket bodge so has been on my list of parts to replace anyway, so will replace now with a proper Bosch unit. I've replaced the temp sender since the car has always appeared to warm up slowly despite a new thermostat-but am unclear whether this is just for the gauge or also sends a signal to the ECU.

My own thoughts are around the cold start injector/thermo time switch/ISV. (EDIT as above this engine has no thermotime switch) I have to say I am much happier with mechanical issues.

 

The key point is that this fault occurred 2 or 3 times over a 5 month period and now seems to have suddenly worsened.

Edited July 26, 2012 by bmwcompact

[seanl82 23]

I was gonna say possibly Dizzy cap, as the rev on start up sometimes "sparks" it into life on an individual cylinder. You then mentioned cutting out and stalling etc so I'd say probably not on that, although rotor arm would possibly cause it.

[bmwcompact 10]

Here is the latest update on my problem! I changed the distributor for a used unit ( in case the hall sender was the problem) and added a new cap and rotor. I changed the temp sensor which on a 9A with KE injection only goes to the gauge I believe. I think the ECU only gets info from the thermo time switch which I havent changed. I should add Ive cleaned the throttle body and checked engine bay earths. The result was the car started and ran but hunted around 1000rpm. I went for a spin and noted the temp gauge now shows the engine warms in a short time and operates a little hotter than previously indicated, now 95 ( proving the original was faulty as it used to take half an hour before the gauge showed 90)

 

Today I fitted a genuine Bosch Lambda sensor ( I had to remove the cat to extract the old one). The car still hunted around 1000rpm on first start. Went for a spin and saw that my indicated fuel consumption has improved-quickly got to 30 rather than slowly climbing to 26/28. Noted that with a warm engine tickover is now steady but at 1500. (The factory plugs are still in place so it should be less than 1000)

 

Checked engine fault codes and got 00522 (G62 temp sensor), 00533 (idle air control regulation) and 01257 (Idle air control valve N71). I then removed and cleaned the ISV for the second time, verified it responds when voltage applied, and inspected for leaks for the umpteenth time. On refitting the ISV no improvement. I dont understand why none of these codes came up previously.

 

So is the problem the thermotime switch, the ISV or the ecu which controls the ISV based on the info from the thermo time switch or none of these? (EDIT the car has a temp sensor vw 026 906 161 for the ECU and no thermo time switch). Ive reread lots of similar posts on the forum and these symptoms have many causes (including issues with fuel supply/metering head)

 

Finally lets not forget the original problem only a few days ago: an intermittent issue of starting but failing to rev up which degenerated into not even ticking over, but again once overcome, car drove OK.

 

Comments appreciated.

Edited July 26, 2012 by bmwcompact

[davidwort 0]

I think you can test the thermo timeswitch with a multimeter on warming and cooling, I think I have the range graph somewhere

 

edit: here you go, this is for the K-jet 1.8 though, need to check if the thermotimeswitch is identical

[ATTACH=CONFIG]68357[/ATTACH]

 

...yep, it's the same on the 9A as the 1.8 KR :) - just checked the part no.s

Edited July 20, 2012 by davidwort

[bmwcompact 10]

My recent idling problems were caused by a very wet air filter! Its rained none stop here this summer and at times the wind has been so strong the rains been horizontal. It took a few days to find but in the meantime a new temp sensor and Bosch Lambda sensor have done wonders for my fuel consumption. The car now idles fine though I suspect I may still have my long time intermittent running issue. I cleared the fault codes and they have not reappeared.

 

EDIT: I was thrown off scent somewhat by mistakenly believing this car had a thermo time switch. This came about by ref to Haynes Golf 2 and Passat manuals, previous VW cars Ive owned and Vagcat which is clearly wrong. My car 1994 with 2l 16v 9A engine has 2 temp sensors, one is for the temp gauge and the other vw 026 906 161, (Bosch 0 280 130 040), is the one which signals the ECU. This is the important one because it is used by the ECU for control on startup and whilst the car is running and will affect the fueling of the engine appropriately.

Edited July 26, 2012 by bmwcompact