It has new caps, new rotor, new wires now. It was working before but it stalled about six times a week before it refused to start after I put TWO different, brand new, caps and rotor. I've put it on top dead center and it all lines up. Put it back together after checking the timer. It's got gas and spark. Someone said there where two identical black relay's that are supposed to be near the expansion tank but I checked the whole motor and couldn't find them. I really need help here.

 

timing on a LH2.4 car (including your 94 940t) comes from a crank position sensor thats below the distributor and reads notches on the flywheel, not from the distributor itself, so the distributor just has to be in the general vicinity of correct.

how do you know you have 'gas and spark', and what exactly did you do to confirm this?

try cranking it a few times, then pull a spark plug or two and see if they are wet or dry.

 

I pulled the plug out and you can smell the gas on the plug. On the cap and rotor, it's in the back motor and attached to the shaft. Can't be pulled out. The spark plug was wet. Anything else?

 

pop the oil fill cap, shine a flashlight in there and have a friend crank it over, make sure the camshaft is turning inside when its cranking (if its not, your timing belt broke... on these cars, thats actually an easy thing to fix).

assuming the cam is turning, ummmm, if you have fuel, I'd suspect the spark. do you have or can you borrow a old fashion timing light? clip it on the #1 spark plug wire, and the battery + and -, and crank the engine over, you should get flash----flash----flash out of the timing light (when its trigger is pulled, of course).

another possibility is that the engine is getting TOO much gas. this can happen if the fuel pressure regulator diaphragm has failed... pull the vacuum line off the back of the fuel pressure regulator, it shouldn't have be wet in there.

 

The crank is working, the timing light is flashing, and the fuel pressure diaphragm is dry. Now what?

 

any diagnostic OBD codes on the LH2.4 diag block? you dont need any tester or nada, just follow the procedures here... Engine and OBD Diagnostic Codes there's codes on pin 2 (fuel injection) and 6 (ignition).

 

Hello Pierce:

So, I read this posting lately and I noticed that its activity just fizzled out.

I have a 1993 940t with no spark out of the coil wire. I've done & the car has the following:

1. New battery; good battery contacts, & wires
2. A new alternator because recently the last one was giving a 12.67 reading with loads, and a month a ago the vehicle would stall-out some times, so I replaced it recently.
3. Good timing belt & engine crank
4. New & adjusted drive belts
5. Fuel flow to combustion system
6. New coil (although I still think that the old coil functions fine, because of quick old-coil integrity tests of resistance)
7. Current flow of 8 volts to positive (+15) [I don't know why it is not 11-12 volts] blue lead on coil, but when I connect a multimeter to, both, positive & negative (-1) white & red lead on coil there is no voltage reading coming from the primary winding on the new coil (positive & negative terminals)--which has me stumped.
8. I checked the wires continuity for each wire to the coil & they are both good.
9. The spark plug wires resistance readings are within the recommended limits.
10. I've checked the fuse panel & all are good and none are blown.
11. I've also done an OBD check and all circuits on the A panel come back with a 1-1-1 code (which means fine!); however, on the B OBD housing panel: I get a 1-2-2 Fault Code Retrieval from position 2 (B-2), and NOTHING at all from position 6 (B-6). It's as if there is no circuit continuity, but the LED light does turn on when I push the button to activate that post position for Fault Code Retrieval (I do not know what this means...)

I looked up a wiring schematic for the Volvo and noticed that the coil post leads go to a "Power Amplifier." I don't know what this part does for the coil, or if it malfunctions, then does it not allow for current flow to complete the circuit and fire the secondary coil winding? Is there a method to test the Power Amplifier?

All the domino effect of problems started after I replaced the spark plugs, distributor, and rotor recently (which were wasted from the previous owner / poor engine maintenance). I bought the car for my son and continued to recommend that he do a thorough tune-up just after buying it, but he knows nothing about cars and didn't do the tune-up until I did it, a month ago.

Also, I forgot to mention that I replaced the alternator and did the tune-up and all was fine and the car was running well; but it suddenly died a week after I replaced everything I mentioned before--it just died... That's when I checked the spark from the coil wire, and there was none. So I suspected the coil, but that isn't the cause of no spark fire because I put in a new coil and there is still no spark.

I did some research, and read through a Volvo tech site that a poorly maintained charging and ignition systems will generally having a compounding effect on there integral parts (i.e. alternator, coil, plug / engine performance, distributor cap & rotor....)

Any acute and informative suggestions would be appreciated & help to remedy my bewilderment...

 

yours has the bosch ez116k ignition ... the power module acts as the breaker points did in a old ignition system. when the ignition controller signals it, the power module grounds the pin 1 side of the coil, then when that ground is released, the coil sparks.

the pin 15 side of the coil should be basically battery voltage relative to ground when the ignition is switched on, and if its not, then there's something funky in the power wiring to the coil.

hmmm. on the 1993 turbo, there's a relay between the battery and the ignition coil pin 15 (blue wire), its NOT connected directly to the ignition switch like it is on the non-turbo. ahh, its the Radio Supression Relay, which is under the hood and keeps the ignition and injection power from making noise in the radio. this relay should be somewhere on the front side of the left side strut tower.

its a 4 pin relay. pin 1 goes to ground, pin 2 is blue-yellow from the main fuel injection relay (behind the ashtray inside), this energizes the relay coil. pin 3 is a red wire directly off the battery, and pin 4 goes to the coil pin 15, also to the 'series resistance' that turbos have in line with the injectors (this is tucked against the inside of the left fender, behind the headlight)

 

Pierce, I believe all this has bolstered my suspicions / reasoning. You are magic!!!

Thank you, again!

For all those wondering what wiring schematics I referenced / pages, here you are:

12V Bosch Blue Coil, US Version - Aircooled.Net VW Parts
VOLVO 940 1993 - wiring diagrams
https://volvoforums.com/forum/volvo-...sle-thing-689/
Diagnostic Solutions: Identifying Ignition Switch Failure Symptoms: Import Car

 

Hello Pierce:

So, after an almost complete thorough change-out of my volvo's ignition components, I've recently noticed a rough idle with my 940t after replacing the power amplifier (ignition module); then, the engine would continue its rough idle & stop. It did it shortly after replacing the power amplifier (ignition module) with a new aftermarket product.

I had gotten a comparable power amplifier (ignition module) from the junk yard as a tester piece to verify that it was the actual part that was failing the ignition firing--and it was; however, I left it on the Volvo for about a month & recently ordered the aftermarket power amplifier (ignition module) & installed it yesterday. That is when the rough engine idle began as though it was misfiring, and ultimately stalled a couple of times and died within 3 to 4 times of starting the engine & running.

I know in my previous email I stated that I replaced the ignition coil with a new one, but I never put it on the Volvo because the previous (old) coil was giving better resistance readings than the newly purchased ignition coil. So I never kept the new ignition coil on the vehicle & returned it once the Volvo's ignition system problem was the power amplifier (ignition module).

But now I've tested the ignition coil & noticed that there's NO resistance of its PRIMARY winding / reading. There still is an 8.5 - 9.0 K Ohms resistance on its SECONDARY winding / reading.

Can you please reply to give a viable & verifiable testing method for an ignition coil?

I know I should have keep the newly purchased ignition coil on it since I was changing out almost all of the ignition systems vital components.

Thanks, Pierce!

 

the primary is pretty low impedance, like just a couple ohms. depending on your meter, it might just look like a dead short.

Greenbook TP32043-1 (Multiport Fuel Injection system LH 2.1 and Distributor Ignition System EZK116 for 700/900 1989-)says.. 0.6 - 0.8 ohm. so yeah, less than a single ohm. on a kohm scale, that would just look like a short. thats measured between pins 1 and 15. (and the HV secondary is measured from 1 to the HV output socket)

the HV secondary is speced at 6.9 to 8.5 kOhm.

 

Hello Pierce:

First, Happy Holidays and thank you for your previous emails. They've proved to be informative and helpful.

Just to reiterate, after an almost complete thorough change-out of my volvo's ignition components, I've recently noticed a rough idle with my 940t after replacing the power amplifier (ignition module); then, the engine would continue its rough idle & stop. It did it shortly after replacing the power amplifier (ignition module) with a new aftermarket product.

I did check the resistance specs for the ignition coil, and, yes, all were fine...

I did disconnect the Mass-Air-Flow sensor connection, because I read somewhere that if the MAF is disconnected and the car starts, that the engine is in limp-back-home-mode. I did this, and it did start on my second attempt, and after re-putting on the Power Stage that I retrieved from the junk-yard as a tester & verification that the old unit (ignition module) was the culprit of the ignition problems that I was originally having with not being able to start my Volvo.

My 1993 940 Turbo still has a difficult time starting, or if it does start, it will only stay running in idle for about 5 - 10 minutes. The new Power Stage that I purchased and mounted seems to have affected ECU functions and relay of sensors, fuel ratios, timing and firing functions.

Do you have any further insight / suggestions about why exactly starting--and maintaining an idle--is not reliable, or the ignition firing is unreliable. I do seem to have sensor malfunctions, because my check engine light DOES NOT illuminate after any of the above has occurred in all that I've written or stated.

Please Help & all the best for the coming New Year.

Sal

 

if you installed something and it started running badly, put back the old one

even if the check engine light is not lit, its still possible there are stored codes on the OBD, you should read them and reset any, then if the symptoms persist, read them again and see if they've come back, and if so, act on them according to whatever the code is.