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940 no start, £2000 dealer diagnostic, still no start …

bobxyz said:
From earlier thread:
https://www.turbobricks.com/index.php?threads/progress-keep-going-…-no-start-car-has-fuel-and-spark-and-timing-is-correct-wtf.375943/
Jamesmoore said: "I tried starting fluid with the injectors unplugged, and got both a backfire out the exhaust and out of the intake …"


I thought more about this no-start and, grasping at straws, have a few more ideas:

1) Maybe the spark isn't occurring at the correct time?
This could be a bad rotor to camshaft alignment, or a bad cam gear to camshaft alignment. If the cam gear alignment pin had sheared off, it must have spun exactly 180 degrees since the compression test is good. If the spark isn't timed correctly, it would explain the not running on starting fluid.

You could check this with a timing light on #1 plug wire - verify that it flashes ~10deg BTDC on the crank pulley and, through the oil filler cap, that the #1 lobes are both up. You could also crank it around to #1 TDC and verify that the tip of the rotor is roughly aligned with the #1 plug wire post in the dizzy cap.


2) Maybe the spark is too weak?
You could test this with an adjustable "spark gap tester", or follow cleanflametrap's example shown in the last couple pictures here:

If you have a labscope, you could measure the coil tabs and confirm that, while charging, the coil the + tab stays at ~12volts and the - tab drops to ~1volt.


3) Maybe the injector voltage is weak?
Are you running low-Z injectors with the resistor pack, or high-Z injectors with the resistor pack bypassed?

You might be able to test this by running the 4 injectors into small jars and verifying that they're equal and have a reasonable volume of fuel.

If you have a labscope, you'd look at the voltages on both injector pins when energized, and the +12v on the resistor pack (if still present). If the fueling was poor, it should still run on starting fluid, which doesn't match your testing.
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nordmaschine said:
I can't imagine spending 20 hours on what they wrote down. I don't know, if I were them I'd either charge you nothing out of shame or keep living comfortably off of my incompetence. Don't know, "chance is what makes the thief" kind of situation.


Anyway. "Timing verified through starter hole" means nothing. "Missing holes on the flywheel are somewhere vaguely around the starter hole, while mark on harmonic balancer, that is attached to belt gear by a piece of rubber which is know to slip and wander off are somewhere there." Doesn't mention what does dial indicator say about actual piston TDC. For £2000, id definitely check...

Also, having fuel pressure, noid lamp (what current?) blinking and "changing injectors" doesn't equal fuel in proper quantity exiting the injectors. Measuring cups say that.


When you're sure that timing is correct, by way of comparing mark on balancer with actual indicated TDC and no1 valves closed, you can check spark with a strobe light. You're a mechanic, you need a strobe light in your life. And they can be had for around £20, orders of magnitude less than £2000...


Also, any LH2.4 ECU, turbo or non turbo, from 89-94 200/700/900 cars without immo is going to work in a pinch.


Report back when able.
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Ok so an update.

The car actually got sent to the nearest Volvo DEALER. My local specialist have contacts there and got it arranged. It’s all free of charge.

The DEALER has spent a few days trying to sort this to no avail. The car will not run.

The dealer confirmed the timing, both cam to crank. And dizzy shaft ect is all perfect.

They also confirmed fuel delivery. They used their injector tester to confirm my injectors are all correct out of the car. Then ran them into measuring cups whilst fitted to the rail and got the same results.

They suspected it to be an immobiliser issue and have messed around with bypassing it to no avail.

My car has Bosch 470cc ASTRA VXR injectors fitted with the appropriate resistor pack bypass.

as far as I’m aware the dealer has took it back to a bare bones situation ruling everything out (evidently not) and it still won’t run.
They are unwilling to put any more time into it as a favour for the specialist garage which is understandable.

I now have a car I need to tow back from a specialist as they aren’t going to be able to fix it at this point. To dump on my driveway for the foreseeable future until I can find someone who can fix it
I know all the above doesn’t really give anyone anything meaningful to try and help off sorry

I’m now considering my options. I’m Volvo through and through. I’ve daily driven them since I was 17 so a good few years now. My redblock cars have always been plagued with problems, mostly due to massive neglect as such is the case with all of them in the uk.
My white block cars have never caused any issues however they are very hard to get hold of now, parts and the cars in general are very expensive. I’m finding it hard to justify daily driving my nice clean 850 through our relatively harsh winters. And don’t want to pile milage onto what is a fairly rare car in our country

I’ve been offered a few cars that have peaked my interest, a bmw e34 TDS. And a Lexus ls400. Both will be much more viable to drive through the winter than the 850. But I don’t want to stray from the Volvo game. But don’t know if I can keep spending money on the 940 when I haven’t had a glimpse out of it.
 
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As one last attempt, I'd rotate the spark plug wires on the dizzy by one position, try starting, rotate by another tower, try starting, rotate by another tower, and try starting. Hopefully one position will at least give a hint of life. The description of the rotor position for #1 TDC compression from your other thread (https://www.turbobricks.com/index.p...ter-changing-distributor-seals-97’-940.375771) sure sounds like the rotor was off by 180deg.

740 distributor cap from stepbystepvolvo.com - Tune Up.jpg
 
Immobiliser ecu should still start the car, but only runs for 0,5-1 second without the correct key. If you want I can test it tomorrow for you on a 940 with 984 ecu.
Have you put some oil in the cylinders? Whiteblock cars suffer from the lawnmower syndrome, I have never experienced it with the red blocks.
If it is a manual you could even try towing the car with the ignition on and in gear
 
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Little numb on end of camshaft where cam gear bolts on and holds cam gear in position broke off and cam is not in correct spot cause numb is broke and cam gear has moved from spot where it needs to be for motor to run... You gotta take off cam gear to see it's broken. Otherwise you'll never see it, never know it's broke. Unless you take off valve cover and put motor top dead center and verify both front cam lobes number one are both up one off to one side the other off to the other side. Other way to verify compression is correct is take out spark plug number one and turn over motor and put thumb on plug hole and feel for compression when turning over motor with starter at top dead center on crank with timing light firing on plug one wire... Other then that all 984 ECU's are immobiliser so swapping to other 984 isn't a fix. I put 967 chip in 984 that works in a working 984 ecu to run car. Or 954 chip will also work in 984 they are all 2.4.4 ECU's. 954 and 967 are non immobiliser so fixes that problem. I also put 984 chip in 967 ecu and then it works. We don't get those 984's in USA but I bought one from UK once for fun.. It didn't work with as is but did swapping chips with other similar 2.4.4 ecu's that are not immobiliser. Looking at the list of ECU's above there are more ECU's that would work over there or in Europe but in USA we never got immobiliser ones or any others then 954 or 967 in the 2.4.4 vain unless 937 is also 2.4.4. I've never had a 937 ECU myself. The bin I am still trying to get from someone is the 983 bin. Not sure why nobody has that bin, but like I said 984 bin runs in 967 ecu.
 
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Appelsap said:
Immobiliser ecu should still start the car, but only runs for 0,5-1 second without the correct key. If you want I can test it tomorrow for you on a 940 with 984 ecu.
Have you put some oil in the cylinders? Whiteblock cars suffer from the lawnmower syndrome, I have never experienced it with the red blocks.
If it is a manual you could even try towing the car with the ignition on and in gear
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Tested the immobiliser today. It does not start without the programmed key, just cranks. It has spark. I had no time to test for injector pulses.

The immobiliser light on the dash is off with ignition on and with the correct key detected.
The light blinks every second or so with no key inserted and the light keeps blinking every second with ignition on but without the correct key.
 
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Leak-down even a compression test?

“injectors are all correct out of the car“

your injector ground is the most important
double check where they terminate after the intake to the firewall, or add a 2nd or 3rd & etc…

you soggy folk in the UK, I feel for ya. from the wolds only inland temperate rainforest-redo your grounds
 
My friend had a cam that broke the locating pin so he put a bolt approx same dia in the hole. As sbabbs says, if that is off the car no runnsies. He tried Everything, and then I noted that spark was not at the right time for the cam lobes. It turned out his bolt had broken and you can't see it until.... etc.
 
The chips delete the imobiliser, if it were not deleted then the injectors would not be firing.

One of two things have most likely happened.

Crank pulley has sheared location tab off
Cam pulley has sheared the roll pin
 
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