Please help-mission impossible 1986 porsche 944 na wont start

[fitzpac3]

Sorry for the length, but I need to give you Porche 944 experts the full story. I am experiencing a mystery when it comes to getting my 86 944 started. I have followed every tip from Clarks to working with Edredas on Youtube and the car just won't start. It fires but won't start. Background-decided to have the cylinder head rebuilt in the spring by Lindsey racing. I mailed it off and decided to go through the rest of the motor doing the following: - Replaced all vacuum lines - New FPR and Damper on rail - Original fuel injectors rebuilt and flow tested - MAF meter rebuilt and tested - DME rebuilt and certified - New timing and balance shaft belts/timing is set perfect ALL marks line up - New rotor, cap, wires and plugs - New gaskets all around including cam tower, head gasket - New speed and reference sensors/tested their operation using multimeter - Throttle body rebuilt and new o ring - New DME temperature sensor and new DME relay in fuse box And many more little new smaller parts. The fuel pump and filter are about 4 years old. I had the car running but developed a severe oil leak. Discovered I had the wrong size seal on front of the cam tower. Still leaking and appears to be from the old style OPRV and old oil cooler housing which Porsche tech bulletin said needs to be replaced with a 1987 version. I plan to do it as soon as the car actually runs. When it did run after all the above work, it did not accelerate very well. So here we are today. car turnovers, tries to fire but won't start. I have checked the following: - Fuel pressure by jumping DME-PSI spot on from fuel pump to end of rail. - Used a spark tester on each plug and wire....and the coil. Getting spark all the way around The speed and reference sensors must be working correctly if we are getting spark and fuel. I also get tach bounce. When I turn the engine over, I do smell gas from the engine. HERE IS THE MILLION DOLLAR QUESTION: From the list above of items and maintenance performed on the car, what would cause it not to start? Thanks Casey

[9FF]

First there’s no need to bump two old posts and start your own thread for exactly the same issue.

Back to basics. So you are getting fuel, spark and air and everything is arriving in the correct order because you’ve checked your sensors are timing right, your plugs are firing and leads are correctly routed and your afm and throttle are leak free and operating as they should. Theoretically the only thing that will stop it from starting is a lack of compression. Have you performed a compression/leakdown test?

[curtisr]

I'm probably the least likely to be of help; however, here goes.

Did the car start/run before sending the head off?

Did you change the sensors at the flywheel as a matter of course or was this done in hopes of solving the problem? If it's the former, your experience might be similar to mine. I replaced the two sensors in hopes of solving a particular issue (bogging down under load when warm) only to have the car not start. I put the old ones back in and it started correctly. The new ones were FAE and somewhat shorter than the OEMs.

Hope this is some help.

[Stephen03]

Firing order

[mytrplseven]

Did you get the speed and ref sensors switched?

[DannoXYZ]

Make sure distributor rotor is firmly attached with TWO bolts. One holds rotor to intermediate nose-piece. Then 2nd bolt holds that to cam. Either bolt missing would cause rotor to be aimed away from terminal and spark won't grt across.

[fitzpac3]

Thank Mike. Sorry for the multiple posts. I'm a rooking to these forums. The compression issue is a good question. While I had the head off, I cleaned the tops of the pistons very carefully using solvent and non scratch. I did do a compression test and did not get good numbers. I believe they were 95 to 125 PSI cylinder. I did do the leak down (oil in the plug hole). It did go up to about 150 PSI.

[fitzpac3]

Curtis-Thanks

Yes the car ran before I had the head rebuilt. Thought it was time since I has to replace some gaskets. It actually ran after I put the rebuilt one back on, just not as well. Bogged down.

[fitzpac3]

Stephen-I believe the firing order is correct. I have checked to make sure the plug wires are in the right order. Just hope the DME (gone through and certified good) and the sensors are working in concert.

[fitzpac3]

mytrplseven-Good point! I assume you are talking the plug from the sensors to harness. I can switch them and see what it does.

[fitzpac3]

Danno-I will double check that. Thanks!

[DannoXYZ]

Originally Posted by fitzpac3

It fires but won't start.

What do you mean by "fires"?

Do you mean engine spins but won't start and run?
Or do you mean you get actual combustion, but it runs only for fraction of second and it dies?

[fitzpac3]

Danno-It turns over but will not start. It tries but just will not start. After cranking for a bit, I do smell gas. I already checked fuel pressure by using a jumper where the DME plugs into. Got great pressure to the rail. I also checked the rotor and it and the sleeve were tight....no loose bolt or set allen bolt. I am going to run compression again today like Mike recommended above. I may be too low.

[fitzpac3]

Does anyone know what the acceptable PSI readings should be for the compression on a 1986 Porsche 944 NA. Plan to run the test Sunday. Thanks!

[DannoXYZ]

I get about 160psi out of my '86 944na. Squirt some oil and it goes to 170. Higher-compression European verrsion in 180-190 range.

Also can't use '87+ OPRV, won't fit. There's an '86-specific 1-piece OPRV meant for retrofitting '86 models only.

[fitzpac3]

Thanks on the ORPV-I actually meant the cooler case was a 1987-

BREAK/BREAK-Did a little compression reading on cylinder 1 and 2 before retiring for the afternoon. Off course I removed the fuel pump fuse. Here's what I got after trying to twice:

Cyl-1 40 PSI
Cyl 2- 90 PSI

This may be a problem

[jjeffries]

Continuing with basics others have recommended, and in light of compression issues: I wonder if the cam timing is off? John

[fitzpac3]

John-I believe I have the timing correct. The mark on the cam gear when lined up with the mark on the back of the cam housing is perfectly aligned to the flywheel marks. I actually painted everything with white polish when I had it apart so I can see it clear. Both balance shafts are also in line. I will redue the compression correctly today. I just learned I need all plugs out. Thanks

[fitzpac3]

Just ran the dry test on each cylinder. I ensured the compression tester was tight and had all plugs out. Not sure what the below means, but I'm sure one of you 944 experts will know right away. I did NOT run a wet test based on these numbers

Cyl 1-32 PSI
Cyl 2-120 PSI
Cyl 3-95 PSI
Cyl 4-10 PSI

Yes readings of 32 and 10 have to mean something. Thanks

[kdjones2000]

Sounds like you bent some valves during installation....