340 1.4 ignition problem

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fire_fox
Posts: 6
Joined: 13 Jan 2011 05:42 pm
Location: Croatia

340 1.4 ignition problem

Post by fire_fox » 24 Jan 2011 11:13 pm

Hi there,

I have an ignition problem with my Volvo 340 1.4 '86, Renix ignition system.

When the motor is cold, it starts normally and it works normally for some time. Then it starts to "kick" every few minutes while driving.
After some time, it stops and i can't start it again.

Last time after it stopped, I checked for sparks between a HT lead wire from the distributor cap and the block. There were no sparks (when the motor is cold there is a spark - tested).

I tried to check if there is a contacts problems so i did this:
- cleaned all the contacts on the fuse box, checked all fuses with ohmeter
- cleaned the contacts inside the distributor cap
- cleaned the rotor
- cleaned all the contacts of the HT leads
- checked HT leads with ohmeter (if i remember correctly, they were about 2 kilo ohms or something similar)
- cleaned the HT contact on the ignition coil
- replaced the spark plugs
- sprayed all the contacts with WD40 (including the Renix control unit multi-pin connectors)

Still no luck.
Today i went a little further and did some checks (from the Haynes service manual) on the Renix control unit.

I disconnected the wider plug A (3 wires), tested with a voltmeter between terminal 3 and earth. My friend started to crank the engine and the voltmeter said about 8.5V or something similar. Haynes manual says it should be a minimum of 9.5V.

When the ignition switch is switched on, it reads 11 and something volts.
Next I disconnected the plug B (central plug) and tested the resistance between terminals 4 and 5. It was 190 ohm. Haynes says is should be 220 +-60 ohm.

There are some further checks to take (from Haynes manual) but I didn't make them yet.
Tomorrow I will remove the ignition coil from the control unit to check terminals 9 and 10 (maybe they are dirty or something).

What do you think? What could be the problem?

Regards,
Igor

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volvodspec
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Re: 340 1.4 ignition problem

Post by volvodspec » 24 Jan 2011 11:28 pm

i'd reconsider pointing the cause out to the ignition unit and check some other basic things first.

i've very rarely had to check all the thing's you've allready done to a car with renix ignition as most of the times it's the simple (service) things that fail;
still, test results look o.k.,

i've found that quickest way to test the spark of the renix itself is to remove the kinglead, crank the engine and get the kinglead near the engine block to let it spark to a ground (only a few times, not too long!).
if there's no or no good spark, main suspect is TDC sensor, though that's when the multimeter starts to come in handy..

i'd personally replace dizzy, rotor, all the leads and the plugs. most of the time this will cure all the problems, contacts (especcially in the dizzy) can be visiually ok and clean, but there's 2 transitions in most dizzy's where the corrosion really affects the strength of the spark or even cuts it out completely. same story for the leads the more they're internally fractured, the weaker the spark gets.

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Chris_C
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Re: 340 1.4 ignition problem

Post by Chris_C » 25 Jan 2011 02:17 pm

I'd agree with Anjo here, though as well as the TDC sensor I also don't trust the renix to coil push terminals, they corrode. A good clean with some contact cleaner is all thats needed, not emery paper as you'll take the plating off.
'89(G) 340 GLE B172k
'03 S60 D5 SE, '91 (J) MX5, 1954 Cyclemaster
Ex:
'89(F) 340 GL F7R (ex B172k) - Fake -> SBKV 300 Runner Up 08, 12; '91(H) 340 GL B14.4E - Kar; '88(F) 360 GLT B200E - Jet -> BKV 300 Runner Up 09; '89(G) 360 GLT B200E - Beast

CBA
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Joined: 24 Mar 2010 02:14 am

Re: 340 1.4 ignition problem

Post by CBA » 26 Jan 2011 06:18 am

Crankshaft sensor.
not mentioned -
this is how they fail from reading ancient texts on such sensors..

check if the coil is ridiculously hot next time it konks out, theres no guide for intermittent shorts other than it will cook.. maybe.

CBA
Posts: 1071
Joined: 24 Mar 2010 02:14 am

Re: 340 1.4 ignition problem

Post by CBA » 26 Jan 2011 06:21 am

thats two things to check, pulse from sensor when cold and when freshly conked out.

and coil temp at failure.

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Chris_C
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Re: 340 1.4 ignition problem

Post by Chris_C » 26 Jan 2011 11:24 am

If it is the TDC/crank sensor, all 300's fitted with them are the same even though they have a differing part number, the wire length is the difference.
'89(G) 340 GLE B172k
'03 S60 D5 SE, '91 (J) MX5, 1954 Cyclemaster
Ex:
'89(F) 340 GL F7R (ex B172k) - Fake -> SBKV 300 Runner Up 08, 12; '91(H) 340 GL B14.4E - Kar; '88(F) 360 GLT B200E - Jet -> BKV 300 Runner Up 09; '89(G) 360 GLT B200E - Beast

fire_fox
Posts: 6
Joined: 13 Jan 2011 05:42 pm
Location: Croatia

Re: 340 1.4 ignition problem

Post by fire_fox » 26 Jan 2011 12:05 pm

Thanks for you suggestions.
As volvodspec said, I'll try to check for the spark from ignition coil (before the dizzy) the next time I go for a ride (to eliminate the dizzy).
I'll also check the temperature of the coil and the signal from the sensor when the motor will not start again.

Yesterday i removed the Renix unit, removed the coil and cleaned 2 contacts between them.
I also removed the TDC sensor and cleaned it.

Haynes manual says that the resistance between the TDC sensor wires should be around 220 +-60 ohm. Mine is around 200. I also tried to measure the resistance and at the same time move the sensor close to a metal. When it's closer to metal, the resistance changes (which is logical to me).

I also took the opportunity and measured the ignition coil windings resistance (tests by Haynes manual). It all looks ok on the primary and secondary windings.
Assembled everything and did a quick ride and still no difference.

One thing is bothering me. I believe i read on this forum that if the voltage on the Renix unit drops bellow 9,5V, the unit will shut itself. Is this true?
If it's true than this could be the problem because i measured this on mine and it was bellow 9V (while cranking the engine) between terminals 3 and ground (while the engine was cold). I didn't measured it yet after it stopped working.

It also bothers me because Haynes manual says it should be a minimum of 9,5V.

Ride_on
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Joined: 26 May 2009 05:34 pm
Location: Belfast, N. Ireland

Re: 340 1.4 ignition problem

Post by Ride_on » 28 Jan 2011 12:56 am

I also had a bad TDC sensor plug-renix problem once cause by corrosion, it usually only if the seal fails. Once it corroded it knackered the plating is gone, I soldered the wires into the renix. Usually just the car wouldn't start atall.

You could be onto something with the low voltage, could have a bad joint somewhere that is heat sensitive (mechanical electrical defects usually are).
1980 345 DL_______1987 360 GLE (project car restored to GLT spec and B230FT'd)
1984 360 GLT______1987 360 GLT
1983 360 GLS______1989 360 GLE
1985 340 GL_______1986 340 1.4
1985 360 GLS______1995 940 SE 2.3 Turbo Estate (daily)
1987 340 GL 1.7

CBA
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Joined: 24 Mar 2010 02:14 am

Re: 340 1.4 ignition problem

Post by CBA » 28 Jan 2011 03:48 am

there should be battery voltage at the blue wire to the renix. if this is 9.5 then check the battery is giving at least 12-13v
test the blue wires voltage back to the ignition switch relay at every join and connector till you find a healthy voltage, replace/repair any bad wire between these points with same or thicker gauge.
the feed for the renix originates at ignition switch relay. Make sure the voltage at the in and out sides of the relay are the same. Could be a bad connector in the fuse box. Either that or deteriorated wire. Either the blue one to the renix or the yellow one from the relay. Forgive the non existent grammar. On a phone. Limited patience.

fire_fox
Posts: 6
Joined: 13 Jan 2011 05:42 pm
Location: Croatia

Re: 340 1.4 ignition problem

Post by fire_fox » 02 Feb 2011 02:20 pm

I checked voltage on the unit while car is running. It's 13.5V.
After the car stopped, I checked the voltage. It was 11.5V which is battery voltage - losses on the way to it. That's still plenty enough.

Then i checked the TDC sensor resistance. It was abnormally high (around 1.8 kilo ohm) and as it cools down, it drops to 250. Then the car can start normally.
It's looks like it definitely the sensor that is causing the car to stop running.

I'll change it and then try again.

CBA
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Joined: 24 Mar 2010 02:14 am

Re: 340 1.4 ignition problem

Post by CBA » 02 Feb 2011 04:54 pm

gloat!!
told ya so. :wink:

CBA
Posts: 1071
Joined: 24 Mar 2010 02:14 am

Re: 340 1.4 ignition problem

Post by CBA » 02 Feb 2011 09:22 pm

Gloat. in a non malicious way.. just enthusiastic boasting- just I twigged it instantly given the symptoms and that the dizzy is good.

fire_fox
Posts: 6
Joined: 13 Jan 2011 05:42 pm
Location: Croatia

Re: 340 1.4 ignition problem

Post by fire_fox » 02 Feb 2011 11:10 pm

The problem is inside the sensor itself. When stretched by force or heat, resistance starts to increase and even go to infinity.
A new one is one the way ;)

Thank you guys for your help.

fire_fox
Posts: 6
Joined: 13 Jan 2011 05:42 pm
Location: Croatia

Re: 340 1.4 ignition problem

Post by fire_fox » 09 Feb 2011 04:44 pm

New (used) sensor installed. I let it run for 10-15 minutes and it didn't stop :)
Right now I'm working on the heater air intake (i have to make a new air filter) so I'll test it as soon as I'm done with that.

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