78 280z starting/running issues

[93nismo]

i dont know how much help im gunna find on here but its worth a try. maybe somebody's had the same problem im having. this post i pulled off another forum. word for word, hope the pics work.

alright. i finally got my hands on a clean s30. now, being that it is a "project" car... id like to get it running well and get the body straight again before summer so i can finally drive one that's mine. the first problem im having with it is the starting/running problem. what im trying to figure out before i attack this is everything that could contribute to the problem. the motor turns over fine, it eventually starts. but it runs really rough. its running rich and it dies shortly after starting(from my experience, the dude i got it from said it would run for 30 min sometimes and for 30 seconds other times). so far from the reserching ive done ive gathered that i need to look at:

-afm. clean, realign everything, and put it back together.
-temp sensor
-cold start valve

i found a write up on the afm. ill be doing that tomorrow night probably. and going from there. the firing order is the way it should be, i just wanted to rule that out before i started getting elbow deep in it just to find out a plug wire was int he wrong spot. other then that im not really sure what else too look for. i can get a battery in it and take a video of it starting/running if that would help. i can also take pictures of whatever if that helps too. im pretty much tryin to put a list of stuff to check/clean/possibly replace if needed before i just into it.



edit:

i took the afm off and cracked it open to see whats up. it looks to me like someones already been in it and has either replaced or cleaned everything. the carbon track seems to be fine and looks to have minimal wear on it. and as you can see in the pictures everything looks shiny and new. ill clean the rest of it up and close it and cross it off the list unless something looks funny to someone. i did notice that there are pieces in mine that are not in the write up i found on cleaning them. however, the write up was done on an 81 non turbo afm. this one is from a 78 afm. so im sure there's some differences. either way. everything looks pretty cherry on it. i did notice that the plug from the harness to the afm looks broken it seems to fit tight but i wont rule that out and id like to find one that isent broken.

[rcdad123]

check everything and replace anything that needs replacing. check the rubber pipe that runs from the afm to the throttle body. make sure it does not have any rips. make sure the spark plugs are the correct ones and are clean and not fouled from running rich. when it does run, check for vacuum leaks. get some carb cleaner and spray around the intake ports and injectors. be careful, you can start a fire doing this due to the exhaust manifold under the intake manifold. also check around the throttle body and all of the vacuum lines. make sure the vacuum lines are routed according to the emissions label under the hood. also check the egr valve. make sure it is not staying open. good luck.

[Christine]

I recenty went through this with my 280z, I'm not at a pc right now but I'll contribute soon enough....

[93nismo]

Originally Posted by rcdad123

check everything and replace anything that needs replacing. check the rubber pipe that runs from the afm to the throttle body. make sure it does not have any rips. make sure the spark plugs are the correct ones and are clean and not fouled from running rich. when it does run, check for vacuum leaks. get some carb cleaner and spray around the intake ports and injectors. be careful, you can start a fire doing this due to the exhaust manifold under the intake manifold. also check around the throttle body and all of the vacuum lines. make sure the vacuum lines are routed according to the emissions label under the hood. also check the egr valve. make sure it is not staying open. good luck.

ill check all that stuff saturday. there's no emissions label under the hood as far as a know. whoever tried to paint it before either took it off or painted over it. ive got the '78 fsm though. thanks for the reply. ill report back when i do all that stuffs.

Originally Posted by Christine

I recenty went through this with my 280z, I'm not at a pc right now but I'll contribute soon enough....

kick ass. lookin forward to it

[93nismo]

did some poking around this morning in the sun so i could actually see some stuff. there's a c clamp holding the distributor on. so im kinda thinking most of the problem is timing now. however i still think there may be a vacuum leak somewhere. im gunna eat some food and go play with the timing a bit and see if that helps at all. and try and find that vacuum leak. if i can figure all that stuff out the motors comin out this weekend so i can fix the few rust spots and paint the bay before moving on to the rest of the body. any input on running issues and all that is still greatly appreciated! thanks rcdad for the list of stuff to check! all the plugs are fouled and covered in gas. i found a vacuum routing diagram dealeo so ill be checking all of that today as well. ill report back later.

[Christine]

Originally Posted by 93nismo

did some poking around this morning in the sun so i could actually see some stuff. there's a c clamp holding the distributor on. so im kinda thinking most of the problem is timing now. however i still think there may be a vacuum leak somewhere. im gunna eat some food and go play with the timing a bit and see if that helps at all. and try and find that vacuum leak. if i can figure all that stuff out the motors comin out this weekend so i can fix the few rust spots and paint the bay before moving on to the rest of the body. any input on running issues and all that is still greatly appreciated! thanks rcdad for the list of stuff to check! all the plugs are fouled and covered in gas. i found a vacuum routing diagram dealeo so ill be checking all of that today as well. ill report back later.

At least for me, there were several things wrong when I got my car.

• The AFM boot was torn up badly (replaced)
• The spark plug wires were all there, but one of the wire's internal contact point to the plug was missing... (it took a while to find that problem, I had no idea until I tried to do a compression test - I bought new ones and replaced them all)
• I had several vacuum lines that were missing or torn (replaced or plugged ALL of the hoses)
• Timing was off (still haven't adjusted it, but it's ok for now)

After I got that all fixed and put back together, I tried to start the car again and still had a problem. After starting double checking everything, I realized that my AFM had gotten disconnected. The connectors needed to be cleaned and a good tight fit was necessary. Now it runs beautifully!

You might want to check your egr valve ( I replaced mine), your FPR, (I replaced mine also). Also make sure you have the right fuel injectors in there, I had turbo fuel injectors when I got the car... it was running WAY too rich. (Replaced them with the stock ones). Make sure that after you clean up the spark plugs and gap them correctly that you also do the "screwdriver" test to make sure they're all firing.

If I think of anything else, I'll let you know......

Christine
my blog: JDM Gallery

[Christine]

Originally Posted by 93nismo

ill check all that stuff saturday. there's no emissions label under the hood as far as a know. whoever tried to paint it before either took it off or painted over it. ive got the '78 fsm though. thanks for the reply. ill report back when i do all that stuffs.

kick ass. lookin forward to it

If you have egr, your stuff will look like this....

[93nismo]

Originally Posted by Christine

At least for me, there were several things wrong when I got my car.

• The AFM boot was torn up badly (replaced)
• The spark plug wires were all there, but one of the wire's internal contact point to the plug was missing... (it took a while to find that problem, I had no idea until I tried to do a compression test - I bought new ones and replaced them all)
• I had several vacuum lines that were missing or torn (replaced or plugged ALL of the hoses)
• Timing was off (still haven't adjusted it, but it's ok for now)

After I got that all fixed and put back together, I tried to start the car again and still had a problem. After starting double checking everything, I realized that my AFM had gotten disconnected. The connectors needed to be cleaned and a good tight fit was necessary. Now it runs beautifully!

You might want to check your egr valve ( I replaced mine), your FPR, (I replaced mine also). Also make sure you have the right fuel injectors in there, I had turbo fuel injectors when I got the car... it was running WAY too rich. (Replaced them with the stock ones). Make sure that after you clean up the spark plugs and gap them correctly that you also do the "screwdriver" test to make sure they're all firing.

If I think of anything else, I'll let you know......

Christine
my blog: JDM Gallery

Originally Posted by Christine

If you have egr, your stuff will look like this....

thanks for the reply! i dont have an egr on mine, ill put a pic up later. but i did find out alot of my vacuum lines are either routed wrong or not hooked up at all. that's obviously part of the problem. i dont have money for new lines right now so those will have to wait for another week until i get my check. however, going through your blog dealeo i saw you had repaired your dash, that's on the too do list as well so thanks for the pictures of that! lol i think i might snag some plastic repair and some non structural foam from work when i do mine but at least i have a visual of it now. my afm boot is fine, a little dry rotted but no tears at all and the dry rot hasent rotted all the way though so i dont think that's the problem, or at least not a big part of the problem. my plugs are new and the wires are said to be new, they look new and look to be in good condition as far as the contacts and everything goes. ill definitly look into the injectors. i think my cold start valve may be stuck open as well. so ill probably get around to looking at most of these things this weekend along with cleaning all the electrical connections that i intended on cleaning last weekend but dident get around to. again, thanks so much fr the input!