I have an engine turns/no start issue. I can smell gasoline and I am not seeing my tach needle moving when the engine turns over. I replaced the cam sensor less than a year ago, but I suspect it has already failed.

The problem started one year ago. Bought a Tammken sensor off of the web for fast delivery and it failed within two weeks. Ordered a Bougicord from EEuro and they sent me a Bremsi instead. The Bremsi has lasted 11 months. The previous sensor was Volvo brand and lasted 15 years. Those are over $100 now. Are they all trash now, except for Volvo brand (Bougi)?

Is there any way to bench test these sensors? Could any other issue cause a no start/dead tach needle? Thanks, AG

I haven't had any updates to post since Monday because I was waiting on a part. Tuesday I went to work on the car during a break in the weather and I wasn't smelling gasoline and I wasn't getting intermittent starts like I did on Monday. I decided to focus on the fuel pump relay and it appeared to be dead. I ordered a cheapo from Amazon and it arrived today. The car now starts ands runs as before.

Tomorrow I will reinstall the original Bremi CPS to determine if that is good or not, but upon inspection my fuel pump relay definitely has cracked soldering on the circuit board. It likely has been failing over time and then died suddenly last week.

About the tachometer needle, it still doesn't budge on startup and I know that it did after replacing the CPS last year. In the FAQ, regarding the Hall Sensor on earlier distributors it says: "Quick Hall sensor test: [Note from Dave] the tachometer needle does jump slightly as you crank engine over if the Hall sensor is working, but the needle lays dead if the sensor is not working."

I know my car doesn't have a Hall sensor in the distributor, but the Tach jump on startup is also how you know if the cam sensor is functioning on a 7.3 Powerstroke diesel engine and it has been mentioned somewhere in relation to the B230FT and the crank sensor. It's how I knew to suspect my CPS last year when it died.

If I learn anything else I will update. I can add that the Bougicord CPS has the lowest resistance between pins 1 & 2 of the three I've measured (.171) and if I don't go back to the Bremi I will be installing the Bougicord.

Thanks to all for your help, AG

UPDATE: I received a Tamkken CPS on Saturday and a Bougicord today. I decided to wait and install the Bougicord today and....NO START. I am still getting no movement from my tachometer needle on startup.

UPDATE #2: Ran the OBD diagnostics. Disconnected the coil wire and turned engine in Mode 2. Got the 1-4-1 followed by continuous flashing. This is with the new Tamkken installed. I was able to start the car a couple of times but it is not consistent. Mostly no starts. I already cleaned the connector at the firewall and it looks to be in good order. There is spark to the coil for sure.

I tried both CPS's to be sure the Bougicord wasn't bad. No difference. I just looked over Porkface's process for diagnosing the CPS. I will get some help to turn the car over while I check spark at the coil, but even if the coil or the fuel pump relay is the problem, would it cause the dead tachometer needle on engine turnover?

I had the Fuel Pump Relay out of the car a month ago, but nothing was broken or damaged and it seated properly on reinstall. Still, that is something for me to consider.

But the tach needle ought to move if signal is reaching the control module right?

AG

Hi,

Ok you have me to thinking with you on this.
I haven’t noticed if I see the tachometer move its needle while cranking.
The starter doesn’t turn the engine over all that fast. I suppose maybe one or two hundred revolutions in a minute? On my 91’ 240 the first mark is @ 500 rpm.

Now it does not move until after there is a hitting cylinder and it all speeds up.
I tried it and no movement until after it hits.

I suspect during cranking the voltage in the whole system is down around nine volts. Not that it means anything except the IAC opens faster @ 12 volts. That doesn’t mean anything either.
I’m just putting that out there to think or troubleshoot with on other things for clues.

The ICU is the start man for the beginning of stuff being turned on.
The sequence is very fast with the System relay being the slowest animal in the chain. I
t’s because it’s still mechanical and it is a relatively high current switching device. Fuel pumps being number one.

You are not mentioning any flooding or smelling fuel after several attempts so that has my curiosity up a little.
The tachometer is not a reliable clue.
The sparks you are getting or not getting are apparently not reliable.
So we are back to the ICU’s job.
It sends two signals that the engine is turning over.
One to the spark coil electronic relay and one to the ECU that turns on the System relay that on a 240 is an orange wire tied to the AMM and on to the fuel injectors operated by the ECU by grounding their coils.

So back to the ICU and that electronic relay, that is located on a 240, behind the battery of all places can be cause an intermittent fault. It fires the coil to make sparks by breaking the coils 12 volt from going to ground just like the fuel injector works
The ICU moves the timing around from information from the ECU. So they are talking to each other so together they are partners.

The only outsiders are things on the orange power wires mentioned and the electronic relay out there with working with the ICU all by its lonesome. The ECU gets no feed back and therefore no error codes.

If your spark is intermittent, at best, then I would want to blame that hidden relay. I have only had one go bad but the harness to it can be another option to cheaply investigate.

Get into wherever they hid it on a 900 cars and service that harness connection.
Check out of harness length as they may be a ground. A 240 has a ground wire near there but I don’t remember if it is interconnected. It hooks to a screw on a fender so I’m get after that kind of stuff.
Good but Old American domestic vehicle thinking was to use rusting steel for an electrical circuit to save wire and labor.
My first exposure to green insulated wires started with Hondas first 50 cc scooters.
A joke among bikers, but sad one was, that Harley-Davidson had check with the Smithsonian to make changes on them. Even Washing them made them run better. 😊

This is summer time and that relay has a great big heat sink behind it for a reason.
Every ten years I try to service the heat sink with a special heat conductive paste used on transistors.

Of course that helps the small pins inside the connection.
Some claim just pulling it apart and replacing it cleans the pins if you are dead on the road. But behind the battery leaves it in the “out of site … out of mind” category.

It’s worth a cheap shot but if it is truly a spark issue then that thing is THE middleman.

Kep throwing out what you are doing. It can’t hurt to educate this 240 man.

Phil

Hi Phil,

The 700/900 B230F/FT use the Bosch 16 MAF up to 1993 according to the Pocket data book. Get 2.5 - 4.0 ohms between pins 2 & 3.
There's a trim pot inside some of them, and the one spare AMM I tried to get apart to find the trim pot was corroded and resisted coming apart. Which reminds me to put a few more drops of mystery oil on those screws. A long soak is better than stripping the heads of the screws eh?

I found a reference to the CPS flywheel drive plate that Porkface mentioned.
It's easily damaged and its possible to install it wrong.
Volvo says there's a 1.0 MM +- 0.5MM clearance between the tip of the CPS
and the flywheel set of holes/teeth. The CPS needs to be at right angles, and too big a gap is inviting headaches.
How would you confirm the proper clearance?
What's the part number of the drive plate? I'd like to look up the parts drawing to see what it looks like. Can it be replaced with the engine in place?
If it's so fragile, can it be tweaked to restore the right angle position to the flyweel?

I wonder why AG hasn't posted back, it's easy enough to re-seat the power stage connector a few times and see if things improve.

Keep cool, Bill

Hi Ag,

It turns out there's an early and late CPS.
Early CPS 1389567-7 Between pin 1 & 2 240 Ohms and a max of 400 ohms when engine is hot.
Late CPS 3547847-8 same pins read approx 170 ohms and a maximum of 350 ohms when the engine is hot. (I think you have the late model)
No high resistance shorts from pins 1 & 2 to pin 3 allowed.

Looking at the tach circuitry, It is in common with pin 1 of the power stage and the coil. Maybe the problem is corrosion at the power stage connector or a wonky power stage? Renew the thermal compound while you're at it.

Bill

Hi Bill,

I’m right in there with you only a few minutes behind you.
We must have been having a mind melt or something.

I mentioned the orange wire on 240s being used as the circle circuit for all items turned on by the system relay. Just failed to complete that though process story.
I have seen to many commercials or read short stories in my lifetime. 🤭

Do you know what color is used or pins inside a 900’s AMM?
Are the AMMs different or do they used the BOSCH 016?


On the 240s you can get a peek on whether or not that circuit is getting turned on.

No light … it no runs!
Just some foreign accent to give it flamboyance. 🤭
A Portuguese fellow, that my neighbor worked with while maintaining a fleet of trucks, said if he heard him say, “it’s like my Maria … she gotta go!”
He just stripped the threads on something! 😬

That wire if located on the AMM would be a “tell” to know that the ICU has shot its signals that way.
Art Benstein hooks a tiny light bulb onto orange color AMM PIN under the rubber boot and on to ground.
He cranks the engine to see if the light comes on and stays while cranking.

A quick and dirty test to see if the system is Dead On Arrival of you wanting to go somewhere. 😏

Have a nice week.

Phil

Thanks Dave, BB and PF. It's my Ford diesel that has the cam sensor, I apologize for the mixup. If a moderator can edit the title I would appreciate it, I can no longer edit the post.

I have not checked for fault codes this time but did last year when this started. Everything was okay then, fault-free. I was having no starts, and it did stall at idle once at a traffic light. A new sensor fixed the problem temporarily.

The cheap sensor I installed worked for two weeks, and I was getting tach needle movement with starter turnover until it died. The Bremi replacement worked fine until recently but I started having difficulty on startup and noticed the tach needle was again dead while turning over the engine.

I just tried disconnecting the battery to see if it would correct the problem but it still won't start. I will check for codes again and see what I find. I have a cheap Asian sensor coming tomorrow and a Bougicord arriving mid-week.

I thought I was the last old Volvo on the road, but I'm glad you guys are still here. Thanks for the great information. AG

940s do not have cam sensors. the crank sensor sits in the bellhousing and reads the teeth on the flywheel.

easy crank sensor test-

if the injectors don't pulse and no spark from the coil-crank sensor

if the injectors DON'T pulse and there's spark from the coil-probably fuel pump/system relay-needs further diagnosis.

if the injectors DO pulse and there's no spark from the coil-coil, ignition amp, cap, rotor, etc-needs further diagnosis.

Hi Porkface,

Not a Cam sensor, I meant crank sensor.
I understand the Crank position and engine RPM signals from the CPS.
You can test it to see if it works, but the CPS harness needs better RF shielding especially with old ECU's. The RF can be generated locally by the HV ignition and alternator, or it can come from anywhere.
I think you're a career auto tech, I wonder how many CPS you've junked due to
lousy harness shielding and/or a corrosion problem with the connector.
You probably found after market CPS way less reliable for a reason.
Probably Bougicord uses better shielded wire than other CPS?
Is it braided copper as used in mike cables and RF transmission line or
is it cheesy aluminum foil like the stuff I found in two samples.

Look up EMI shielding and see the wide variety of options available.
There's aluminum tape that you can wrap the CPS harness, but that wont
work over the connectors.

I found a 240 ABS service bulletin that managed some ABS problem by re routing
the ABS harness near the fender, certainly dealing with EMI. Adding snap ferrites might have fixed that. Ferrites come in a variety of mixes that
are designed for certain frequencies. But you can use any cheap ferrite to see if you're on the right track or not. I ordered a pair of 5MM snap ferrites from
China for about $1.50 economy, slow boat shipping. Find a pack of 10 5MM snap ferrites for maybe $10 shipped from USA at Ebay

I'm looking forward to AG's results with his issue.

Whats your email?

Keep cool, Bill

if shielding was an issue, it wouldn't take this long to show up. would love to hear from Art on this.

never heard of Bremsi. i hope you mean Bremi, which my crank sensor experience is with v6/8 mercedes, not volvo. mb has 2 part numbers for it-1 for bosch, other for bremi. never an issue. Bremi is a quality brand.

oe sensors have foil wrap, nothing else. i've seen the outer insulation degrade and the sensor still work.

the only 214 code i got was when a sensor was replaced and the bolt fell into the hole. tech got another bolt and sent the car. i get the car, no start, code 214. the reluctor on the flex plate was dinged so bad, the sensor read it but the ecu couldn't use the signal. replaced the flexplate.

resistance is futile. only way to test it is with a scope. i fashioned a harness to plug into both connectors and have pig tails for scope hookup.

haven't needed an lh 2.4 crank sensor for years, and never used anything but oe.

give me a no start and i see off brand stuff, it gets replaced. fixed alot of cars by using the real thing. bosch cap and rotor and fuel pumps to replace airtex fuel pumps come to mind. use them instead of whatever comes from whoever. gee, now it runs. used to see that alot.

Yes PF, it's a Bremi. I never heard of Bremi and did not order it. It's what EEuro sent me instead of the Bougicord I had ordered last year. I was refunded the difference in price and kept the Bremi because I needed the car on the road. I will say that the Bremi looks identical to the Chinese Tammken sensor that I had bought off of Amazon, and I would be surprised if it isn't also made in China. I think the Bremi has failed after 11 months, but I'll soon have the answer.

Hi AG,

Here's a quote from 1989-1993 240 fault tracing manual for LH 2.4 EZ116K TP 32394/1

Checking the RPM sensor connector
- Take apart the RPM sensor connector
- Carefully scrape away dirt and deposits in the connector and clean the terminals
- Grease the connector. Use P/N 1161417

OBD code 2-1-4 check for contact resistance

They specify in another section the same story for the injector EFI connectors
- Disconnect battery minus cable
- Apply rust removal spray 1161034-2 to exposed contacts
- blow with compressed air
-Squeeze grease 1161417-9 into female contacts directly from the tube
- Using a spare male pin check that female contacts give a good contact and remain in place when the male pin is pulled lightly.

Resistive contacts will set a 2-1-4 code

I think that Volvo's "rust remover" is some contact cleaner, Spook?
Dunno what grease that is but Volvo Penta sells it at Ebay... more pricey
than Penetrox-A.

DeOxit has a new anti corrosion grease that they were giving free samples, check their website

Read this about Penetrox-A: http://sw-em.com/anti_corrosive_paste.htm

Good luck, Bill

Hi Porkface,

>if shielding was an issue, it wouldn't take this long to show up.
1. The ECUs get older every year and potentially more vulnerable to RFI/EMI
2. This problem dogged the previous owner for years and Volvo Dealers and Indies struck out trying to fix. Crap out every three months or so, same unfixed problem needing a tow, you'd think it was a Ford: Found On Road Dead

>oe sensors have foil wrap, nothing else. i've seen the outer insulation degrade >and the sensor still work.
My point is that foil is not the best shielding.


> replaced the flexplate.
Is there an easy way to tell that the flexplate needs changing?
Is there some tolerance from the flexplate to the edge of the flywheel
That you could check with a scale?



>resistance is futile. only way to test it is with a scope.
That won't help at the garage when the car is running fine, and if you could test while the car is gagging from EMI, then a spectrum analyzer would tell more than a scope.


> i fashioned a harness to plug into both connectors and have pig tails for
> scope hookup.
I was going to do that but Steve sent me a CPS harness from a 240 that he was junking. Then I found that you can just pry the boot off the Female EFI harness
connector and back probe the CPS pins easily from the drivers side. Putting a dab of dielectric silicone or silicone spray on the harness jacket will help
shove that boot back.


The 28MM EMI shield "Speedpak'ed" taking 10 days from China. It is pressed flat in a roll. In order to fish it over the CPS connector you first slide the braid over a sledgehammer handle to open it up. Then it slides over the male CPS connector OK without a lot of room to spare.
I put a big tie wrap near the and and pressed it down to where it hit the snap ferrite at the bell housing. You can push another 15" back over the male CPS connectorthen pull the end back over the mated connectors and along the firewall. I soldered it to the the engine ground strap that goes to the firewall damper. I'll rig up a better ground later, gotta find some copper braid, maybe use solder wick If I strike out.


I'm having a hassle with Brickboard delaying key strokes?
Constant ad bombs aren't enough.
Must he Google having their fun, Big Brother at work.


Keep cool, Bill

Cant believe with all the lh 2.4s still on the road, 2 people are having trouble with interference. All the other bosch variations in other brands use the same technology.

My point about the oe foil is it may be more robust or more wraps than the aftermarket.

Never having other issues with this a scope is all i need, along wih a cup of cold water to bath it in after it craps out under heat.

Short of pulling the trans, no. Scoped mine, didn't see the correct waveform and pulled trans. About 180 from tdc, there was a large dent in it. POSSIBLY, that could be seen after pulling the screens, don't know.

Never liked backprobing. That's why i have breakout boxes and homemade harnesses.

Cant believe with all the lh 2.4s still on the road, 2 people are having trouble with interference. All the other bosch variations in other brands use the same technology.

My point about the oe foil is it may be more robust or more wraps than the aftermarket.

Never having other issues with this a scope is all i need, along wih a cup of cold water to bath it in after it craps out under heat.

Short of pulling the trans, no. Scoped mine, didn't see the correct waveform and pulled trans. About 180 from tdc, there was a large dent in it. POSSIBLY, that could be seen after pulling the screens, don't know.

Never liked backprobing. That's why i have breakout boxes and homemade harnesses.

If you've got a no-start situation, the ECU can easily tell you if it's the CPS, no need to use a meter or disconnect anything. Refer to OBD DTM 2 on port 2 in the FAQ here. If that test passes then
pull the AMM connector and attempt to start in limp home mode, which would suggest a cooked AMM if it now starts and runs, albeit a little rough and hesitant at higher rpms. From there you would then proceed to try isolating it to the fuel or ignition side.
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

Hello AG,

I'm working on a similar issue with my 1999 945T with a long term bug in my car going back for some years reported by the previous owner.

You can check your CPS with an ohmmeter and see 179 ohms between pins 1 & 2
Then using your VOM's highest resistance scale check for a high resistance short
between ground pin 3 and the two others .

Do as Dave says check for OBD codes, and find out how to use the special modes.
I think they wont report RF corruption directly.

Before your car outright refused to start, did it misbehave by stalling at stop signs or traffic lights? Mine suddenly did this followed shortly by a refusal to start.
I found that I would get a code A6 2-1-4 (faulty or sporadic RPM signal)

Then I could disconnect the battery to clear ECU memory, and the car would start and run normally. See if your car responds this way.

I think that the geriatric ECU's are more sensitive to RF corruption EMI/RFI via
the CPS because of weak aging filter caps. This is certainly part of the problem.

My CPS is a cheap Chinese after market unit, and I suspect the difference between it and the OEM CPS is partly on the quality of the connector which is
probably carefully plated in the OEM and plain steel in the cheap one.
Also the harness shield is of major importance. I found the shielded wire to
be a disappointment since it consists of only a piece of aluminized tape surrounding the signal wires. If the CPS harness sheath has started to crumble
then the shielding is toast and you can expect problems. Corrosion at the
connectors is also a huge issue over time and worse if it's a cheap connector to start with. Spook is right to service the connectors. He likes DeOxit
and I like Penetrox-A, I suggest that you service your CPS connectors especially the female EFI pins in the harness connector. Use a toothbrush and
90% isopropyl alcohol and blow out with air. Then carefully inspect each female pin for damage. Volvo says to test each female pin with a gauge made of a male
EFI pin to insert and see if the female pin grabs and is not loose.
I'll order one myself when I place my next order to www.davebarton.com this week.

In addition to disappointing automotive quality of the harness shield, the connectors are also NOT shielded, again automotive quality connectors.

After servicing the CPS and AMM connectors and lubing with Penetrox-A I placed
snap ferrites (RF chokes) on the CPS harness , one at the bell housing and one near the harness connector. I did this because 1. Volvo does not ground the RF shield at the bell housing and 2. the connectors are un-shielded.

My issue quieted down dramatically after adding the ferrites but recently I checked the OBD had thrown another disturbing A6 2-1-4 , this time with no
engine malfunctions. So I ordered 1 meter of 28MM ID tinned braided copper EMI/RFI shield that I hope will pull over the CPS connectors. This is scheduled for delivery today, It will hopefully pull over the connectors to improve the
EMI shielding. I plan to ground it at the firewall and leave it ungrounded at the bell housing for now. This is a work in progress.

Provide an email address in case Brickboard decides to gag again.

Good luck, Bill

Dear AVL940T,

Hope you're well. The tachometers in 940s seem rarely to fail. When cars are 30+ years old, a circuit may be disrupted by a coating of corrosion only a few molecules thick, and so invisible to the unaided eye.

Starting with the instrument cluster, I presume the other instruments - fuel gauge, speedometer, and coolant temperature - work correctly. If so, it is not likely that the tachometer has failed. It is likely that the cluster's ground (behind the plastic panel on the door-side of the driver's footwell) is in good order.

Even so, I'd first remove the instrument cluster, and use an aerosol oxidation remove on the wiring harness connectors and - using a cotton-tipped swab - on the cluster's male wiring contacts. Deoxit has served me well.

Presuming that this makes no difference, I'd apply Deoxit to the wiring harness connecter for the crank position sensor (CPS).

If this does not restore tachometer reading, I'd get a Bougicord CPS and replace the new, in-service unit, which may be defective.

I'd be surprised if one or more of these measures does not restore smooth operation. When the CPS signal is lost, the engine computer does not allow the fuel pump to work after its initial "spin-up". This is a safety measure: should an accident cut a fuel line, that will stop the engine. When the engine stops, the loss of the CPS signal stops the fuel pump, preventing the delivery of fuel to an engine compartment, and so preventing a fire.

Hope this helps.

Yours faithfully,

Spook

Thank you Spook. The importance of the signal to fuel pump operation makes sense now. I assumed that the smell of gas meant that it was spark I was lacking, but it was only "spin-up" fuel I was smelling. I've ordered a Bougicord but will see about cleaning contacts before it arrives. AG

Hi,

A lot of what his is saying makes sense. That was a nice write up.

In order to do it in a scientific way you should only do one thing differently at a time.
This way you can find out which one or what was causing the problem.

You have already been ripping out the sensors.
Get on board with his items first as they are good enough to keep causing repetitive problems.


These things he is talking about are what I call “green gremlins.”
Almost the same as those “fiendish” Irish Leprechauns that laugh with their shenanigans. Both boasting by wearing their Green with White smiles.

Do what ever you can before swapping parts as that alone will help resolve the issue better!

Find something suspicious, test it again by trying to start it with the same old part. Ten to fifteen years should be a normal life span.
Processes of elimination makes for entertainment and for gaining logic skills.
You are exhibiting them all regardless being on the forums.
Take your pick but “knowing” provides self esteem, as in, well done.

IMHO


Phil

Thanks Phil. Yes, it's possible the sensors are not the problem. I took my multimeter to my old Volvo crankshaft sensor and tried to measure resistance between terminals. The only resistance was between the 1 & 2 prongs, (.179). 1-3 and 2-3 were open. I will compare this with the Bremsi when I take remove it and also with the new Bougicord when it arrives. I have some Deoxit on hand for cleaning potentiometers and will be using that on the instrument cluster connections. AG