OBD-I s52, has spark and fuel, but won't start

[e30s50dan]

are ALL your plugs firing, maybe you have a bad coil pack or two..if you are near a Harbor freight,they have a spark plug tool that has a light, so you can see if they are firing....its like$5-$10 bucks.worked for me ..I ended up having two bad coils...just a thought. Good luck

[JGood]

Well has the engine harness been messed with? Are all the connections connected? I know I'm asking obvious questions and you know what you're doing but it can't hurt to double and triple check.

The harness was replaced before it was dropped in this car, the old one was spliced for a late model m20 c101. So he bought this one from Zionsville that came pre-spliced for his m42 connector. Thing is, it's getting spark and fuel, the the c101/x20 has to be right, and even the rest of it should be good.

We triple checked all connectors and tried swapping some around. The ICV and CPS are the only 3-pin connectors that can be swapped, and they are correct since the ICV buzzes with the ignition on. None of the two pin connectors would cause a no-start AFAIK, but they all appear to be hooked up correctly anyway. It sounds like a serious timing issue since it has spark and fuel, and it backfires, but it won't start.

The only 2 clues I have at this point are the 10v at the fuel pump fuse issue, and the apparantly non-functioning cam sensor issue. Still can't find a value for the cam sensor, to test it. Are those Hall sensors different then the VR sensors that the crank uses as far a how they are tested for failure?

[Danny]

Well has the engine harness been messed with? Are all the connections connected? I know I'm asking obvious questions and you know what you're doing but it can't hurt to double and triple check.

[JGood]

Maybe the plugs aren't grounding when placed inside the head? Have you checked compression? I too, am stumped.

The engine ran in the previous e30 it was pulled out of. The only thing that was changed was the engine harness.

If the cam sensor is not reading any resistance values, I don't see how that isn't a problem... I just don't know what values it should be. I don't want to buy a new one until I prove that it's bad, as I don't see how it would go bad since it worked fine in the previous car.

[Danny]

Maybe the plugs aren't grounding when placed inside the head? Have you checked compression? I too, am stumped.

[JGood]

Are the coil packs plugged in in the correct firing order?

Yep.

[Danny]

Are the coil packs plugged in in the correct firing order?

[JGood]

well, if you are indeed getting spark and fuel, the engine would run. those are the two components required along with air to support combustion. did you check your fuel pressure? it should be about 50lbs. there is a schrader valve on the fuel manifold where you can check this. pull the #1 spark plug, ground it against one of the bolts on the valve cover, crank it over to see if you do indeed have spark.. if your cam sensor were bad, you likely would not have spark because the dme would not know when to send the signal to the coils.

That's what we did with the plug, watched/heard it spark while cranking. I didn't put a gauge on the fuel line, but while cranking, I ran a hose from the 'out' side of the rail (after the regulator) to a container, and fuel dumped pretty fast. So if the pressure regulator is allowing fuel past, shouldn't it be at 3.5 bar, and then some? And the fact that the plugs are wet, and it's backfiring, shows that the injectors are at least spraying some fuel.

[flyboyx]

well, if you are indeed getting spark and fuel, the engine would run. those are the two components required along with air to support combustion. did you check your fuel pressure? it should be about 50lbs. there is a schrader valve on the fuel manifold where you can check this. pull the #1 spark plug, ground it against one of the bolts on the valve cover, crank it over to see if you do indeed have spark.. if your cam sensor were bad, you likely would not have spark because the dme would not know when to send the signal to the coils.

[JGood]

Trying to get an s52 running in a 91 318ic. Engine ran in another e30. OBD-I harness was bought pre-wired from Zionsville. It's OBD-I, and has the EWS delete. We are getting spark and fuel (plug sparks while cranking when grounded, and fuel is dumping out of the return side of the rail).

While cranking, it's backfiring a lot, but nowhere near starting. After pulling the plugs, they looked wet.

CPS reads 540ohms.

I don't know how to test the cam sensor, can I measure resistance across the pins? I tried every combination, and couldn't get any reading of resistance. The meter didn't say 0 ohms, it basically said no connection at all... as if none of the pins are even connected through the sensor. I thought that was strange, but don't know how that sensor works.

We also tried a different FPR, and a good 413 ECU from a running m50 e30.

Another thing that was weird to me was the fuel pump fuse was only getting 10v while cranking. Shouldn't it be 12? Other fuses read 12v. I don't think that would effect anything though, as the return side of the rail was dumping fuel, which means the injectors should have had full pressure.