Engine upgrading

[zdorantes]

Basically I recently bought a 75' 280Z Engine won't start, Everything involving fuel works, Intake is perfect, and Electrical components all work (including starter ignition distributor wires and spark plugs). I haven't checked fuses or relays because I know where they are but don't know how to check them. Also haven't done a compression test but I'll be doing it tomorrow. I'm considering taking my engine in since I've tried nearly everything I can think of to diagnose my engine. While I'm in the process I'm thinking about upgrades I can make to the engine, intake, etc. Anyone have recommendations?

 

3/12/13 5:37pm addition to old post: Something is wrong with the fuel system afterall, I was able to start the car with starter fluid only for it to idle and die. I figure it must be something wrong with either the injectors, the pressure regulator, or cold start valve. Anyone have any ideas of what I should do to check?

[izzo]

compression test will help diagnose it, see if theres compression.  The injectors are squirting in fuel?  Firing order is correct, and you are positive that its sparking at the plugs?

[datzenmike]

Get running first. You need spark and fuel and to some extent compression.

 

Spark: Pull a plug wire off, stick an old plug in the end, lay on a grounded surface and crank the motor. Does it spary?

 

Fuel, Crank over for 30 seconds then go smell the tail pipe. Is there gas?

 

Compression, get a tester and do yourself for $20-$30 .... over half what a garage will charge plus towing and time.

[zdorantes]

compression test will help diagnose it, see if theres compression. The injectors are squirting in fuel? Firing order is correct, and you are positive that its sparking at the plugs?

Yeah the injectors work I tested them, the only way the firing order is wrong is if it somehow the timing belt/clutch slipped because I installed the wiring according to the manual, and 100% sure the spark plugs work because I tested them. But actually I'm doing the compression test today after all.

[zdorantes]

Also what would the compression test diagnose?

[datzenmike]

Possibly leaking/blown head gasket, over tight valves, broken valves, rings or pistons.

 

Set the motor to the TDC mark,  on the #1 cylinder, compression stroke. Take the valve cover off and confirm that both intake and exhaust valves are closed. If not turn ONE revolution and up to TDC. Take the distributor cap off and the rotor will be under the #1 spark plug wire. (or should be) follow the wires around in a counter clockwise direction 1 5 3 6 2 4

[zdorantes]

What is a TDC mark? And how do I set it?

[banzai510(hainz)]

watch this naked while eating Cheetos

this is a 4 cylinder but still applies to fire order when talking the 6 cylinder

http://vimeo.com/19077890

 

olddatsuns.com the tech section read everything.

 

 

upgrades?

How about getting it running first

[datzenmike]

Somewhere on the timing cover is a saw tooth timing marker. On the rear lip of the rearmost pulley will be a small notch. When the pulley notch lines up with the ZERO on the timing marker the motor is at Top Dead Center with the #1 pistop at the very top of it's stroke. Now it's possible that the TDC is also on the exhaust stroke so you have to look at the two valves on #1 to be sure they are on the compression stroke and closed.

 

Timing marker will look something like this. Pulley turns clockwise so the first tooth is 20 degrees advance, then 15, 10, 5 and )(zero) at the top. As long as close this is good enough to check where the rotor is pointing.

[flatcat19]

How did you test the injectors?

If you can test injectors, you can bench test the relays.

 

Make 2 jumper wires. 1 POS, and 1 NEG.

Ground the ground side. Touch POS to POS on relay.

(Thank you dear Lord for inventing the Power Probe!!!)

No click? No good.

 

For the others...

Suck. Squish. Bang. Blow.

What's missing?

[zdorantes]

Possibly leaking/blown head gasket, over tight valves, broken valves, rings or pistons.

 

Set the motor to the TDC mark, on the #1 cylinder, compression stroke. Take the valve cover off and confirm that both intake and exhaust valves are closed. If not turn ONE revolution and up to TDC. Take the distributor cap off and the rotor will be under the #1 spark plug wire. (or should be) follow the wires around in a counter clockwise direction 1 5 3 6 2 4

I finally checked the timing by cranking the engine by hand and lining up the notch with TDC. It's retarded by 15 or so degrees. My next question is what is the spark plug wiring order according to the manual it is 123456 but the manual I had didn't cover L28 engine only L24&26.

[datzenmike]

I finally checked the timing by cranking the engine by hand and lining up the notch with TDC. It's retarded by 15 or so degrees. My next question is what is the spark plug wiring order according to the manual it is 123456 but the manual I had didn't cover L28 engine only L24&26.

 

Timing cannot be checked by this method.

 

The firing order is already answered at bottom of post... Find the proper TDC there are two of them. You want the compression stroke. It's all below. Once you have TDC, the rotor must be under the #1 plug wire. The rest follow in a counter clockwise direction.

Set the motor to the TDC mark, on the #1 cylinder, compression stroke. Take the valve cover off and confirm that both intake and exhaust valves are closed. If not, turn ONE revolution and up to TDC. Take the distributor cap off and the rotor will be under the #1 spark plug wire. (or should be) follow the wires around in a counter clockwise direction 1 5 3 6 2 4

[racerx]

timing has to be checked with timing light.  If you are going to get one, get the dial type. or digital one.

[zdorantes]

Compression, get a tester and do yourself for $20-$30 .... over half what a garage will charge plus towing and time.

Before I take the valve cover off to check timing I decided to do the compression test and the results looks bad.

Dry test results

1st valve: 60

2nd valve: 85

3rd valve: 90

4th valve: 90

5th valve: 90

6th valve: 85

 

I'm about to do wet tests

[zdorantes]

You need spark and fuel and to some extent compression.

So this whole timing I had the wiring set in wrong order but I will still be checking the timing because putting the order right still didn't fix it's no start condition.

[racerx]

you did not do a comp. test before you bought the car?

[zdorantes]

you did not do a comp. test before you bought the car?

It's my first car so aslong as it ran I bought it, but somehow I broke something so now i'm trying to figure out what. It's no longer starting.

[racerx]

when you said 1st valve, you mean 1st cylinder?  Also what kind of comp. tester did you use.  Is it the screw in type or hold it with your hand and pray you got a good seal?  If the readings are solid, yeh I say that's low - very low. Should be about 160 or so, even 140 okay...next get a book.

[racerx]

maybe this will help:

 

[zdorantes]

It's the screw in type and when I did the wet test compression went to zero on two of the cylinders... I don't even bother doing the rest. But can bad compression lead to a no start condition?

[racerx]

_{have you tried spraying starting fluid in the intake? just be careful...starting fluid is very volatile...}

 

_{If it does start and does not continue then fuel delivery is the issue, specially after a couple of times.  Forgot to ask how many miles on the car?  Also has the car been sitting for awhile? does the gas smell funny like turpentine...good luck.}

[zdorantes]

Yeah I tried starter fluid with no luck. I just found out the ignition is under spec by half so I'm about to replace it.

 

The car has 250k miles. Before .e the car was sitting for two years. The gas smells like gas unless I just can't tell the difference and thanks.

[racerx]

Car been sitting for 2 years, yikes... when you took off the valve cover was there a lot of sludge?  Have you change the oil?  If so how does it look like? How many times did you try starting fluid, a couple or so is good. If it does not continue to run on its own, then maybe your fuel deilvery is bad.  Or it could be many things.  Forgot to ask if you can crank by hand...disconnet battery first...then get a open end wrench and try turning the crank (clockwise). Take out spraks plugs..it should turn freely, with occasional tighness because pistons are going up and down but should turn.

 

A car sitting for 2 years and not driving all kinds of crap can happen...what do mean ignition is under spec.?  Be mindful about replacing too many things at once.  One thing at a time..what if engine is bad and you've replace a lot of stuff..At this point, don't even think about upgrades..priority is to see if engine/fuel delivery  is okay, if good compression/fuel okay then do upgrades. Good luck.

[TENDRIL]

yes, no compression will effect it starting, as fuel will pass right by the piston, if your pulling numbers between 60-90 you have comp. and should be able to get it to idle at the very least  , a couple things are or can be wrong,

 

 

1.piston rings/walls are worn

 

2.head gasket 

 

3.timing chain off a tooth from worn on slack tensioner  

[racerx]

It sounds like the car ran, for how long, how far , did it have power, was it smoking white smoke, have you checked your dipstick to see wat color oil is