cranks but wont start

[utecrm]

Just glanced at my orig post - forgot to say its a 850 turbo, had the turbo replaced about 5 yrs ago

[utecrm]

Ordered a Cam Position Sensor (Bosch) put it in - Bingo. Hope this helps anyone out there with a similar problem.
Car's running great.

[T3T4]

Ok. I have this issue on two volvos currently. 2003 xc 90 and a 2004 XC70. Anyone thinking injectors, gas, battery, starter, spark, or connections is wasting their time just like I did.
THIS IS A THEFT DETERRENT PROBLEM. New fuel with pressure to the fuel rail does little good - the injectors are not opening. How do I know? I can release pressure air rail, bathing my fingers in raw evaporating gasoline. Then turn key, HEAR the fuel pump, and check pressure again.
Although it is dangerous (and rough on the downstream turbo) I attached a bomb, I meana bottle of gasoline to the intake and guess what? It fires up and drives nice as can be. You are probably patting yourself on the back, sure that the fuel WAS an issue but you (as was I) would be wrong. You see, volvos open fuel injectors not with a positive, but by completing the negative circuit. That's correct, the injectors have 12 volts and full power to them...they are NOT opening. The damned "theft" circuit is messed up and no amount of key jigging, door locking, or battery on/off has helped. We owned the xc90 for 20 years now almost. I refuse to go to a dealer because they are NOT troubleshooting experts, they simply swap parts (as a trained monkey could do) and hand the bill to the customer.
I am certified SAE and can read electric schematics as well as hydraulic.
Does ANYONE have in depth schematic of the anti theft box??? If so it is about to become a target for various types of ammunition at the cliff....it is all good to troubleshoot the system in a systematic way, but I have done it and I used to have brown hair. Now it is Grey, what us left of it...
It is so frustrating that I will say if it was an NA motor, u would slap a carburetor on it( like I did a chevy) and deal with the dash lights.
I need schematics or more patience, but it is definitely a FUEL INJECTOR KILL situation. Period. I wish I was wrong...

[abscate]

You can’t troubleshoot CanBus cars with electrical diagrams. Get VIDA up and running and see if the key and immobilizer are talking to each other.

Most everything in modern auto electronics are 12V supply, grounded through ECU

Coils, injectors , solenoids, purge valve, turbo valve,……

[wizechatmgr]

Ok. I have this issue on two volvos currently. 2003 xc 90 and a 2004 XC70. Anyone thinking injectors, gas, battery, starter, spark, or connections is wasting their time just like I did.
THIS IS A THEFT DETERRENT PROBLEM. New fuel with pressure to the fuel rail does little good - the injectors are not opening. How do I know? I can release pressure air rail, bathing my fingers in raw evaporating gasoline. Then turn key, HEAR the fuel pump, and check pressure again.
Although it is dangerous (and rough on the downstream turbo) I attached a bomb, I meana bottle of gasoline to the intake and guess what? It fires up and drives nice as can be. You are probably patting yourself on the back, sure that the fuel WAS an issue but you (as was I) would be wrong. You see, volvos open fuel injectors not with a positive, but by completing the negative circuit. That's correct, the injectors have 12 volts and full power to them...they are NOT opening. The damned "theft" circuit is messed up and no amount of key jigging, door locking, or battery on/off has helped. We owned the xc90 for 20 years now almost. I refuse to go to a dealer because they are NOT troubleshooting experts, they simply swap parts (as a trained monkey could do) and hand the bill to the customer.
I am certified SAE and can read electric schematics as well as hydraulic.
Does ANYONE have in depth schematic of the anti theft box??? If so it is about to become a target for various types of ammunition at the cliff....it is all good to troubleshoot the system in a systematic way, but I have done it and I used to have brown hair. Now it is Grey, what us left of it...
It is so frustrating that I will say if it was an NA motor, u would slap a carburetor on it( like I did a chevy) and deal with the dash lights.
I need schematics or more patience, but it is definitely a FUEL INJECTOR KILL situation. Period. I wish I was wrong...

I'd start by verifying with VIDA that the antenna ring sensor is sensing a key. If it is, it could be a bad immobilizer, but the problem is replacing the immobilizer requires the dealer to program the new one. The immobilizer talks with the ECM & PCM over the CANBUS. They are keyed/serialized and none of these modules can just be swapped. If the other modules aren't given the go-ahead so to speak, the most you'll get is a crank but no start situation. This is intentional and by design. Hard to steal yet resell a vehicle that won't run, and you can't sell the parts either because they won't work without going through a lot of pain with a dealer.

[T3T4]

If it can be built, it can be bypassed. But yes. It is a theft deterent issue.

[wizechatmgr]

If it can be built, it can be bypassed. But yes. It is a theft deterent issue.

If you wish to go that route, you're going to need a logic analyzer and enough input to brute force and figure out the rolling algorithm by spying on the canbus. Keep in mind if you're successful, you're likely to run into DMCA violations at the federal level. Somehow car manufacturers have been granted in court the idea that even attempting to bypass antitheft devices is somehow an exploit of their code, similar to copy protection designed for DVDs/Bluray. I find the argument to be BS, but again, this is currently the way it has been. My guess is the car sends a random value to the key, the key responds with the correct calculation for the return value, then the module verifies it is correct. Then it sends another master key down the canbus to the ecm, pcm, etc. This would be the way I would do it so that you couldn't just record a value once and have it be correct and just replay attack it.

If it were me, I'd locate a new antenna ring as they are most likely to be the culprit. Does this problem occur with one key or all of the keys in each vehicle? The car will sometimes store a code if it is having intermittent or no antenna response from the key. I am unsure if that code is ODBII compliant however, hence the need for VIDA. VIDA will also tell you which key is inserted.

The old '98 V70's you could fix by just wiring across two relays and still have the box sit flat. Not so easy on the newer cars.