I decided to start a new thread because I think I have fixed some of my problem, but I have come into a new problem.

Reference thread for more background:
https://www.audiforums.com/forum/aud...-start-189151/

So, I have the fuel pump replaced, got all of the vacuum lines done, went to start the car and nothing but a grinding noise. So I went after the starter, got the car in service position, started taking things out (all the while charging the battery). Things got difficult (as starters in these cars are), and so I decided to see if a fully charged battery fixed the starter issue. And it did. I felt like an idiot (still do), and the car still won't run now.

I have all the major parts put back together, however the car is in service position still. I can smell gas, and the engine seems like it trying to start, but just can't do it. I check for spark from each wire and they all seem fine, however one seemed rather weak. Timing belt looks good. So I have all three important things covered: gas, spark, timing.

I will also mention that the coolant temp sensor is registering on my vagcom, as well as the crankshaft position sensor. No other codes are being thrown. It was suggested to me that maybe I need to replace my coil pack unit (~$150) but I'm trying to make sure I have ruled out everything else before I throw more money and time into this thing.

Any ideas?

 

you'll have to go back to the very basics I guess. Do you have a fuel pressure gauge? As far as the coil back it pretty much either works or it doesn't (although that is simplistic). Look up lawn mower syndrome.

Engine 850: B5254S/2.4/20v: - Lawn mower syndrome on early 850s - Volvo Owners Club Forum

My old 850 had that problem once. It's possible, after repeated attempts to start the car it has flooded so bad, that it has lost its compression. Dump a little oil in each cylinder and see if that helps.

 

That is interesting.... I'll try that when I get home tonight.

I want to make sure that the wires are good too so I'll be testing them by verifying one port off the coil works, and then removing each wire and testing them all off of the one port.

I'm just trying not to spend $150 for the coil pack and then another $130 for wires which were the issue in the first place.

Does the coil pack/ICM fail in these cars a lot?

 

The information from the crank position sensor controls RPM the ECU uses that data to do its ignition timing.

If the sensor got damaged, then it will give bad readings which will cause a no start to happen.

This can also happen if it wasnt set correctly, when installed.

DId you replace the timing belt or anything like that?

Thanks

 

Nope, I didn't replace the timing belt. I did replace one crankshaft position sensor the rear drivers side one (which is how I broke my vacuum lines). When I use VAGCOM I see Engine RPMs go up to 160-200 RPM when cranking, so I assume that those sensors are working.

Also, on the fuel pressure gauge, I don't have one, but I did unscrew the fuel line and there was pressure because some gas squirted out. I can smell it really quickly while cranking too.

 

Im not sure how the sensors are setup on these cars, but I know on mnay cars there is a procedure to installing them. For example moving the engineto TDC then putting it on then. If you dont have it installed properly, the car will crank u will get spark, but it wont start. The fix is as simple as reinstalling the sensor.

Check your service manual for more info on this.

Also why did you only replace just one sensor?

 

These sensors can sit in only one position. The magnet reads the camshaft via an external spinning dish-looking thing with a notch in it, so unless you put in on exactly 180 degrees, it won't fit. In this case, both of mine cannot be installed wrong because the connectors don't reach if it is the wrong way.

I only replaced one mainly due to cost (~$90 each) and it really only uses one anyway. The other is ancillary. Honestly, both of mine looked to be in good shape anyway, so I didn't pursue that any further.

 

After reading your conversation, one thing came to mind. You said that the crankshaft position sensor you installed reads the camshaft. That is incorrect. The crank sensor reads the position of the crankshaft, not the camshaft. Here are some links

Crankshaft Sensor
Audi B5 A4 Quattro V6 30v > Engine > Electrical > Sensor > ES#1874 Crankshaft Position Sensor - 06A906433C

Camshaft Sensor
Audi B5 A4 Quattro V6 30v > Engine > Electrical > Sensor > ES#277726 Hall Sender - 058905161B

Usually if the camshaft sensor is bad or out of alignment it will throw a check engine light.

So depending on which one of these replaced, could be why you're still having an issue get your car to start.

 

So, I did replace a camshaft sensor. There are two one by the firewall driver's side, and one by the radiator passenger side. I replaced the firewall one.

However, I believe my car was suffering from Lawn Mower Syndrome. Late last night, after trying the hold the accelerator down and cranking a bit, it finally started doing the "fast" crank and then it started up. Because other things were not connected it didn't run well at first, but everything smoothed out after hooking the MAF sensor up and making some vacuum hose adjustments.

Tonight I'm going to put everything else together and see if I can drive it after 3 weeks. Since I'm in the service position with the airbox out, I'm going to replace the serpentine belt, air filter and cabin filter. I'm pretty excited!

I'll update again when I get that all completed.

 

Glad you got it running.