I replaced the head gasket on my 1993 Volvo 850 and got everything back together, and it is not starting.

The timing took several tries - each time it seemed to be a tooth off, but now it seems to be right on - the mark on the oil pump, the intake and exhaust pulley marks pointing to the notches in the timing belt cowl at the top of the engine.

I have replaced a few things - I double checked the spark plug wiring, and made sure that all of the plugs (new) - are firing. There is fuel pressure. I'm going to double-check the position of the distributor rotor.

One thing though. In socket 7 there is a fault of 1-2-2 which is 'temperature interval signal too long'. The only thing I can think of is maybe it is referring to a bad signal from the thermostat temp sensor? If that is the case, would that prevent it from starting?

This car wants, terribly, to leave my garage where I have held it captive for far too long.

 

yea a bad temperature sensor will cause it not to start. does it crank when you try to start it?

 

Yes, it definitely cranks no problem. I hear maybe one piston fire every couple of seconds. Is there a good way to test this?

I do have a spare temperature sensor in my parts car. I suppose I could swap it out, but I was hoping to avoid draining the coolant again.

Also, I remember in the past cranking this beast for over a minute before it started (after a fix). I'm worried about killing my battery though.

 

I went back and checked the fuel pressure again by depressing the valve on the fuel rail. Nothing comes out this time. I turn on the ignition, wait for the fuel pump to build pressure but apparently no or not much fuel is getting through the fuel rail.

Hmm.

 

check for compression, just to make sure the pistons are still in good working order. because you need compression to start it. plus check for fuel pressure and post it up. the pressure should be around 39-40psi on a cold engine. is there a way you can post a video of it? l suspect the crank position sensor if the fuel pressure comes out good. may be you installed it backwards.

 

swap the coolant temperature sensor and see if that helps. a bad one will send wrong information to the ECU on when to dispense fuel.

 

The fuel lines were reversed. Oops.

So now it definitely has pressure. But didn't start anyway. Now I hear bump bump bump crank bump bump bump while I'm cranking it. I tried holding the pedal down all the way and cranking for a minute. It didn't improve.

Thinking that maybe the fuel was going bad after sitting for a while, I went and got five gallons of new gas and dumped it in the fuel tank. Then I pumped out about a liter by just turning the ignition on a few times. Then reconnected.

Unfortunately a lot of gas got away from me in this time so I am waiting for everything to air out a little before I try again.

 

Woops. Didn't see those last two replies. It seems like there is compression, because it is a lot harder to turn by hand with the plugs in, but don't have any equipment to check. I did have the cylinder head pressure checked before I put it back on and it came out good. It was also resurfaced.

As for the fuel pressure, I would bet that it is good. The car was running fine before I took it apart, just had muddy oil and seemed to be swapping fluids. I parked it the second day of seeing the murky oil, then started the operation.

I'll try the temp sensor swap if the new gas doesn't work out. It sounds hokey, but I have had a bad gas situation before so now I am always looking for it. Hard to test for.

 

As for the crank sensor, I only removed the camshaft position sensor, and it is pretty much impossible to install backwards. I was fairly careful handling it, so I'd be surprised if it were broken, but a lot of what has gone wrong has surprised me.

 

Have you tried the temp sensor yet? you don't have to drain your coolant to do it. a little will come out but not a lot its right on top. 2 min job. turn your key on but dont crank, what does the temp gauge say?

 

also, are you getting spark? have a friend help you check. just pull one out, and put the plug into the distributor wire, and ground it by holding the bottom of the plug to the cam cover. If your getting spark check if your injectors are firing. pull the fuel rail off again and spin it around. put the injectors in and plug them all in. try and point them away from the car but anything will do. make sure they are firing by turning the car over. if you have both spark and fuel, I can almost guarantee you It's the temp sensor. A bad temp sensor will generally tell your ECU that your car is already warmed up. which will not give you enough fuel to start the car, weather your giving it gas or not. If your feeling especially lazy, pull off the maf and spray some starting fluid into the intake tube. if you can get it to start you have a fuel issue.

 

I haven't changed the sensor yet because I got frustrated and took a break.

However, that is a good point checking the gauge. When I turn the key, the needle goes from buried in the bottom of the gauge to the 0 point, which would indicate to me that at least the MCU thinks the temperature is cool (if not 0.00) Maybe that's a default value irrelevant of the sensor?

 

If you have fuel or spark the camshaft sensor is working. I strongly suggest that you go get a compression gauge and check compression. It will be a cold test but you should get no less than 110 across the board.

If you are trying to start it and your plugs get wet, you have fuel.

 

not cranking. meaning you probably not getting spark. it looks like electrical problem. are u certain that you installed the distributor cap and rotor together with the wires back the way it came out? does your dash lights look dim when you try to turn on the ignition? check for spark and we go from there.

 

I checked the distributor again. It is definitely put together right and the plug wires are going to the right places. Still haven't changed the water temperature sensor yet. I had other things I could check first. I almost tried unplugging one from a friend's 850 to see if it would start without it, but was afraid I would freak her out doing it.

I did find that a fuel line was damaged and one of the injectors may have been loose, causing the fuel rail to not fully pressurize. Fixing this made a noticeable improvement in the rail pressure.

It still didn't start - I didn't try to long because my battery is running out. I have a question though. At this point, having tried to start it a bunch, should I always be cranking with the pedal to the floor, to try to overcome the flooding problem?

 

If you don't have a battery charger it's time to pull the battery and take it to an auto parts store and get a free charge.

You should pull the plugs and make sure they are not flooded with fuel while the battery is charging.

Do you know if you have spark yet ??

You said you fixed a fuel injector and the fuel line and the pressure is better, what is the pressure ??

As for the temperature gauge it usually reads from hot at 1 o clock to cold at 5 o clock. What is it you are calling "0" ??

 

I'll probably manage to borrow a battery charger. Yes it does have spark. I think that should eliminate the camshaft position sensor anyway. Yes?

And right, 0. I meant the bottom line. It very methodically bumps up to the bottom line (5 o'clock as you say) when the ignition is switched on.

I don't have a gauge to read fuel pressure right now, but I should say that there was nothing wrong with the fuel pump before this whole operation and it appears that I have the leaks fixed. The gas shoots a healthy distance from the rail when I depress the valve.

I'll take the spark plugs out and let it dry out.

 

Hey guys. Thanks a lot for your help. I got the car started. The only thing is that I don't know why.

My guess is that I kept depressing the pedal to the floor. I had thought that helped to prevent flooding, but then I read somewhere that when you do that the fuel injectors don't fire. What do you think?

My dry compression test yielded about 100 psi per cylinder. That seemed low to me. But the cylinders seemed to hold pressure.

Thanks again. It's awesome to have this resource!

 

All fuel injected cars (that I know of) are programmed so that at cranking speed if you have the throttle pushed all the way down it cuts way back on fuel.

It is designed to allow you to try and clear out the cylinders in case the engine is flooded.

Normal starting you should keep your foot away from the pedal and just let the computer do it's thing. If you find you need to give it a little gas to get it to start you are overriding the computer and that indicates there is a problem somewhere in the system as you're injecting more fuel that the computer thinks you need. Could be a bad temperature switch, fuel restriction .....

 

One more thing. To check the temperature sensor, I just unplugged it. Apparently when there is no signal the ECU interprets it as hot because the fan came on and stayed on until I disconnected the battery. When I plugged it back in it was fine. But the gauge behaved the same both ways. Went to 0 point and held there.